Friday, August 11, 2017

Highly Sensitive Monster Faces: Sensitivity in Humans & Animals

Neovenator sasterii rostral facial nerves. credit Darren Naish


Sensitivity… not usually a word associated with flesh rendering beasts of yore. However the evidence is in and it seems unequivocal. The most celebrated of ancient predators, the theropods, were equipped with high facial sensitivity. Sensitivity, not just of the face but as a package of characters very emblematic of wide variety of animals including ourselves, is a word and concept we need to explore and unpack both culturally and biologically in order to better understand creatures that are actually both cultural and scientific creations. And in doing so I think we will learn more about these animals... and ourselves.



The Cultural Baggage of "Sensitivity" in Humans and Animals: Towards a Unifying Concept

Emotional sensitivity is generally ascribed a feminine quality in western cultures. We don't often ascribe connotations of sensitivity to those human conquests most adventurous, daring, "hyper masculine", and audacious in scope. Sensitivity is usually associated with the weak, indulgent, melancholic souls, too indecisive and wavering to get in the fight or even pick a side… That we have these cultural inscriptions, at least in western culture (especially in America), which are in turn enscripted into gender normative roles is an important concept. The feminine becomes the loci of sensitivity and, presumably, all those features incumbent upon such a character, namely whatever masculinity is not supposed to be; easily overwhelmed; dismayed; and petulant. The masculine defined more by a lack of sensitivity than anything else - stoic, distant, strong and silent - unsuited to express any emotion save anger.

It is interesting and perhaps perspective changing when we look at the two main definitions of  "sensitive":

1. Quick to detect or respond to slight changes, signals, or influences.

2. (of a person or person's behavior) easily hurt or damaged especially: easily hurt emotionally: delicately aware of the attitude and feelings of others.

If we had to make a choice I think most would drift towards definition #1 when thinking of an animal's sensitivity,  focusing more on external stimuli especially as picked up by the "classic" recognized senses. When discussing human sensitivity I think it fair to say that most would drift towards definition #2, where the classic senses are eschewed and the impetus is placed more on emotional cues - both external and internal - as a dominating influence to a sometimes overwhelming degree. Note that in definition #2 the words hurt, damaged, and delicately are used. It is clearly not a good aspect in a person to be emotionally sensitive based on this definition. Sensitivity is conveyed as a weakness, not a strength. Of course, for me personally as a HSP (highly sensitive person), I would highly challenge this notion. However, at least in western societies the conceit remains - being overly emotionally expressive, empathic or "feeling" others emotions is seen as a weakness or shortcoming.

Interesting that there is a bit of a dichotomy in thinking of what it means to be a sensitive animal versus a sensitive human, especially given that we are all technically animals. But this dichotomy is not at all incongruous with our tendency to place humans outside of nature and removed from the behavioral patterns and tendencies of other fellow animals. Does our focus on emotional sensitivity in humans speak more towards a tendency to not only distance ourselves from "the animals" but also disavow our other senses? Does out tendency to highlight the classic senses of animals but diminish their emotional sensitivity likewise further distance us from animals and justify our treatment of them? Could these two separate definitions be combined more succinctly into one unifying concept of sensitivity in sentient beings of any species? I think so and I think such a definition is far more useful and practical despite whatever discomforts and cultural conceits such a definition arouses.  For me there is much more utility in a definition that encompasses sensitivity in animals and humans as an ability to read incoming stimuli from the outer environment that includes not only sight, smell, hearing, taste, and touch but a certain emotional capacity to display and interpret the "vibe" of other sentient animals, even other species.

Despite what I think constitutes a more holistic and encompassing definition of sensitivity we are still left with the (western) culturally enmeshed judgement that heightened "emotional" sensitivity is bad and linked to the feminine BUT heightened sensitivity in other arenas (smell, sight, hearing, touch, taste) is generally valued and revered in people. In fact other being sensitive in other senses is given a lauded and super power status.

Let me pull a Quentin Tarantino tactic (Kill Bill II David Carradine speech towards the finale) and use the comic book super hero analogy to drive home my point further. We've all seen comic book super heroes endowed with super senses; the superman ideal able to see through buildings, hear at infinitesimally low levels etc. etc. Funny that we appreciate and envy such super senses in our super heroes but have you ever heard of a superhero blessed with hypersensitivity on an emotional wavelength? Nope, I'm quite sure that you haven't. In fact just the thought probably arouses a slight chuckle in you. There is no highly empathetic, intensely emotional marvel super hero. Stan Lee did not think of that one. Still emotional sensitivity is seen as a negative i.e."Stop being so sensitive,", "You need a thicker skin,".

Yet if we imagine that reading, reacting, and displaying intense and nuanced emotional information is just another sense - like hearing, smelling, taste, touch, or vision - that is imbued into humans to varying degrees (or more animals than we might be comfortable to admit) then it stands to reason that such an ability has adaptive benefit to the individual and to the species. In humans this is self-evident despite our cultural and gendered normatives grafted upon highly emotional sensitive people. In animals, such as the large macro predatory theropods, being highly sensitive to the emotional cues of other members of your species would have been extremely strategic and adaptive because they could literally bite your face off. Try telling a pair of Tarbosaurus bataar engaged in courtship ritual "not to be too sensitive" and both partners would likely reply with (if they could) "fuck you man, I got to read every nuance of this other monster's emotion because they could bite my freaking face off!!"



"You are too sensitive", "stop being so sensitive"

Admonishing humans for being regarded as too sensitive emotionally is a culturally enmeshed tradition, not necessarily congruent with the adaptive real life brutal Darwinian realities of existence where hyper-sensitive attributes can be life saving. Heightened awareness of emotional cues , readings, and "vibing" things out has obvious and palpable survivorship benefits not just for the individual but for the group. Only in the unnatural setting of culture and society can such benefits be seen as negatives. Such an interpretation is congruent with many strands of feminist theory. In a patriarchal society both men and women are punished. Given that an especially high degrees of emotional sensitivity is equally represented in the sexes, when signals of overtly high levels of emotional sensitivity are displayed shaming and punishments are doled out i.e. "don't be so sensitive", "only women are sensitive" etc etc in a patriarchy. Such punishments are fear responses meted out when something arises that does not fit the mold.  A spider is seen on the wall, smash it. A snake in the garden, kill it. Scapegoat it. Silence it. What is actually a strength and benefit to the individual and species is hammered down and shamed into silence together with a concomitant psychic and emotional paralysis for the person shamed and shunned. Saying someone is "too sensitive" is the equivalent of saying someone can see too well; hear too acutely; or have too refined a palate. It is a damning indictment on the current status of many cultures, but especially western, that the sense of empathy and emotional fluency is the only sense that is routinely disavowed and squashed - especially in men but to some degree in both genders - BUT is exactly the sense that needs to be heightened in order to combat the ills of the modern age.



It is also interesting that many of our most vaulted and celebrated animals - often times seen as symbols of courage, conquest, and power - are actually the most intensely hypersensitive of animals. And therefore, more acutely gendered as feminine. Cats for instance have always been associated - and often times reviled and persecuted - for their association with the feminine. Also highly sensitive. Including all those warlike symbolic gestures towards lions and coat of arms. Sharks, also highly sensitive and much more nuanced in social behavior than we might generally think. Crocodiles are surprisingly delicate lovers and more than equipped with a suite of features most accurately described as highly sensitive. Many theropods sported (or still sport) a panoply of highly sensitive qualities, including extreme facial sensitivity.

Ironically, western cultures in their disavowal of emotional sensitivity in males have negated some of the most powerful animals as sources of identity - as "spirit animals" - per se. Powerful and predatory felids go to the girls. Sharks and crocodiles, sorry guys if you disavow your sensitivity you don't get to keep them, they too go to the girls. And the penultimate insult to the male ego, those awesomebro predators of yore, they hypersensitive theropods - the girls get them too. Guys we are left with freaking water buffalo. Yup and other big stinky herbivores, omnivores and other "prey species". And dogs, woopty-doo, as if anyone had to ever work hard to earn their respect.

Maybe, in a post presumably about the sensitive snouts of theropods, you were not expecting a neo-feminist thesis illuminating the need for contemporary H. sapiens to reclaim not only our emotional sensitivity as a species for both sexes, but our place within a pantheon of emotionally sensitive animals. It should not be too surprising that I blend the cultural withe the scientific, that has been a constant theme of this blog, and one I will continue with even if some find it distracting, biased, or not rigorous enough. Dinosaurs especially, but really all animals to some extent are a blend of the scientific and socio-cultural-mythos.


You may want to skip to 2:50 to see the shark overwhelmed by the sensory input from the world. Sheesh, that shark is just too sensitive for the world!!

Face Nuzzling in Humans, Felids, Crocs, Birds and Monster faced Theropods

H. sapiens fits within a pantheon of sentient beings that has finely attuned neuro-sensory capabilities not limited to classic senses, but emotional ones too. While nerve endings are concentrated in our hands as well as our genitalia - we also share a highly sensitive oral region with the animals in discussion. A finely attuned and sensitive snout that is perhaps quite capable of soothing social relations and establishing long term pair bondings…

http://avangardphoto.com / Mario Caputa CC3.0
That a highly sensitive snout/oral region evolved in our species, presumably for such tactile benefit as regards sexo-social relations, despite the lack of an obvious exaptation for such behavior in our species should give us moment to pause. Humans do not explore the world or handle prey via their mouth, unlike the other animals I will discuss, but via their hands. That we independently evolved face nuzzling behaviors should awaken our curiosity. The self reinforcing and adaptive philosophy behind such behavior is simple: face nuzzling engenders activation of nerve endings, which in turn begets pleasure centers, which then enhances pair bonding and what can be dubbed "emotional attachment" and finally disarms the violent, predatory proclivities of several of the species I will mention. The net result is that those individuals that face nuzzle, reproduce more often and more successfully, and their progeny do the same.




If the extant phylogenetic bracket is your thing we have abundant evidence of both crocs and birds showcasing face nuzzling within the context of mating/pair bonding.





Where to put theropods in this pantheon? Probably starting somewhere between crocodiles and albatross is a good ballpark. Theropods do appear to have long incubation times, their clutches were larger than birds but smaller than crocs, and due to their high metabolisms it would be hard to hunker down and babysit a nest for a month or two in a solitary fashion. The responsibility for nest and clutch guarding likely fell on the shoulders of both parents to some degree.

In terms of parental care of the hatched offspring I like to think of theropods parents as a bit like delinquent parents: "Yeah, you can hang around here for a while, even nibble a bit on my leftovers. But look I'm not gonna baby you, you should go out and get your own food and hang out with your clutch mates for the most part. Did I mention you are freaking annoying sometimes? And if shit hits the fan, if I can't feed myself, yeah I'm gonna eat you? So you better grow up and move out, pronto!!" Again, somewhere between crocodiles and birds is a good place to start from in these regards. With a sprinkle of some cannibalism if the need arises. (See I did not go all hippy-dippy, lubby-dubby on you, just mainly)



REJOICE by Duane Nash

It should not at all be too obvious that I went to UCSC where nekkid hippy chicks frolicking through redwood glades was definitely not a thing… No apologies for the gratuitous female flesh, I'm still a dude after all. Some of my fondest memories as a kid were sneaking through my dad's Heavy Metal comics. Some where along the line bewbs paired up with prehistoric beasties became something not to do despite the fact that everyone loves Mesozoic beasties and bewbs. That such Boris Valejo type art might now be considered a bit backwards, a bit passé, a bit too boys club, this makes me sad.  Women and theropods are a natural pairing!!

Apart from that slight observation of perhaps an over political correctness what I really want to illustrate is that if we take this hypersensitive facial business and face nuzzling behavior to its logical conclusion in theropods there is quite the argument to be made that pair bonding between theropods and big brained, tactile, and empathetic humans is possible. Start with a young theropod and form that physical bond early, especially along the sensitive facial areas, and you have a friend to the end!!




It's actually an idea not outside the bounds of possibility… If humans could endear themselves to theropods at a young age and strategically take advantage of the facial sensitivity of theropods then we could see such a union forming per chance. Such facial sensitivy in theropds, if it was used for face muzzling, would also engender a heightened or hypersensitive emotional ability to read the other theropods intentions. Why? For the simple fact that if you are going to get close enough to face nuzzle you better be damn sure your presumed partner doesn't actually want to bite your face off!! Such an ability and need to "read" or "vibe" out your presumed partner would also engender more committed physical social cues. These could include ritualized head, body, tail movements i.e. "dance" moves. Also certain display structures that could be flushed with blood or inflated to various degrees to express intent. In mammals we have exquisite facial muscles, giving us highly communicative expressions. In many mammals it is the ears, especially in dogs, that can be used to express emotion and intent. Theropods, bereft of such facial muscles and communicative expressions - would invent other alternative modes of communication. The ability to flush with blood areas of the face and forequarters to show intention. Inflatable gular sacs and other fleshy display structures. And of course flesh antlers, the highest potential for and use of likely occurring in tyrannosaurids. Don't be so surprised when you notice that after we see a decline in the size and extravagance of hard tissue crests, lacrimals etc etc which seem to have peaked in the early mid Jurassic we see larger and larger supra temporal fenestra in many predatory theropods, especially tyrannosaurids.

The False Positive of Theropod Facial Biting

I think one of the more fascinating aspects of paleontology - and really paleoculture, because there is a constant dance between the culture and the science - is a certain appreciation of the oscillation of ideas. Unfortunately this oscillation can only really be appreciated with age and experience. For instance in my lifetime I have seen the wobble of Tyrannosaurus locomotion go from vertical tail dragger, to horizontal 45 mph speedster, now going back to a power walker. It still might oscillate some more, but I think the oscillations are getting tighter and tighter and we might be honing in on some truths. Younger enthusiasts might today scoff at the notion of tail dragging tyrannosaurids but need to realize it was some of the top minds of the time positing this stuff. To suggest that todays "top minds" all of a sudden are going to stop making mistakes - not the same ones but different ones - is naive and incongruent with the history of paleontology.

One idea that I think is due for a bit of an oscillation is the notion of face biting theropods. It has taken on kind of a dogmatic lore lately. I think that there is a notion out there, not really challenged, that a typical day in the life of a large carnivorous theropod went like this: "Wake up. Walk up to another theropod. Gnaw on each others faces for a bit. Eat something. Gnaw on another theropods face. Go to bed. Have dreams of gnawing on the faces of theropods. Next day repeat."

The question or challenge I posit is not that theropod face biting was not a thing, it clearly was, it was just not as much a thing as we are making it. Instead of a documentation of a daily ritual of antagonistic clashes, face biting represents the occasional lover's quarrel or a truly aggressive encounter for dominance, territory, mates etc. etc.

Towards a More Nuanced, Complex, and Varied Theropod Social Dynamic

I think that the startling and profound facial sensitivity of predatory theropod dinosaurs really pushes us to consider an increasing likelihood of a profoundly socially complex animal. Not necessarily socially complex in the same way primates are, or mammals in general, but by splitting the difference between modern crocodiles and aves we can hone in on some distinctly possible truths… or at least a modicum of truthiness. Having such social bonds established via feedback loops - i.e. face nuzzling behavior - is rather simple and straightforward. I suspect that facial sensitivity originally was furnished in prey manipulation and later proved a fortuitous exaptation that mollified aggressive tendencies and allowed pro-social behavior. Such pro-social behavior does not necessarily invoke a high canid or primate type of intelligence, altruistic behavior, pack hunting or other overtly advanced symptoms of "highly complex social behavior". It does not negate the possibility either. But I think as a baseline face nuzzling has some patently obvious benefits for peacemaking capabilities both between and among the sexes in predatory theropods. Basically enough tolerance generated for the animals to capitulate to, "OK this feels kinda good and pleasurable when we do this, I won't bite your face off. We can both stick around and take some turns guarding this nest of eggs we created." Seems like a win-win right? Predatory theropods would get some pleasure through face nuzzling, not get their faces ripped off, and win the genetic sweepstakes. Seems like a pretty good feedback loop, no? Those theropods that could nullify their aggressive tendencies through face nuzzling would have the best reproductive success because they would stick around long enough to share clutch watching duties…

 I'm gonna leave this here…


And this is an important point that I want to stress here… egg incubation times for dinosaurs might be pretty darn long. Somewhere between incubation times for reptiles and birds is what we might be looking at for an average. Having an incubation period of several weeks or even months poses some profound difficulties for high metabolic rate large terrestrial predators. First of all it would prove difficult to go the route of mother crocs and simply hunker down on the nest for several months, the caloric and water needs would be too high for predatory theropods. Unlike large sauropods, hadrosaurs, and other herbivorous/omnivorous dinosaurs predatory theropods could not simply form huge colonies that overwhelmed the local ecosystem with eggs and babies - they did not have equal population densities.  Finally predatory animals would have to abandon the nest for some time in order to forage, they don't have the luxury that herbivores or omnivores have in these regards. These simple deductions push us to consider two or more predatory theropods sharing clutch guarding burdens. It does not necessarily even have to be a classic monogamous male-female alliance. It could be a sisterhood that grew up together since clutch mates. It could be an alliance of male brothers that likewise came of age together. Or some combination there - of, there are actually a lot of alliances that could crop up. All of which were fostered and ameliorated via pro-social face nuzzling behavior.

Again let me state crystal clear the link - long incubation times and the realities of predatory ecology - push us into a realm where pro-social bonding behavior and shared clutch guarding duties become a very palpable possibility. I would say the favored image actually.

I realize that there a lot of other suggestions for high theropods facial sensitivity none of which are mutually exclusive to the scenario I have painted here. I though about discussing those ideas here but I think that is enough for now. Gonna have to revisit the other ideas in future posts, I also have heard of some other info coming down the pike…

For this post I also made some quick and dirty Youtube clips to sort of a give another avenue and thought document to these ideas. Gonna see how these work out, hopefully the video can work in conjunction with the writing and the illustrations to better drive home and express these ideas.





Best,

Duane



Refs

Barker, C.T., Naish, D., Newham, E., Katsamensis, O.L., Dyke, G. 2017. Complex neuroanatomy in the rostrum of the Isle of Wight theropod Neovenator salerii. Scientific Reports 7, 3749

Carr, T. D., Varricchio, D. J., Sedlmayr, J. C., Roberts, E. M. & Moore, J. R. 2017. A new tyrannosaur with evidence with evidence for anagenesis and crocodile-like facial sensory system. Scientific Reports 7, 44942.

Ibrahim, N., Sereno, P. C. Dal Sasso, C., Maganuco, S., Fabbri, M., Martill, D. M., Zouhri, S., Myhrvold, N. & Iurino, D. A. 2014. Semiaquatic adaptations in a giant predatory dinosaur. Science 345, 1613-1616.

Naish, Darren. The Sensitive Face of a Big, Predatory Dinosaur. Scientific America. June 16, 2017
https://blogs.scientificamerican.com/tetrapod-zoology/the-sensitive-face-of-a-big-predatory-dinosaur/

Tanke, D. H. & Currie, P. J. 1998. Head-biting behavior in theropod dinosaurs: paleopathological
evidence. Gaia 15, 167-184.








Friday, July 28, 2017

Lord of the Flies: Difficult Truths, Questions, and Burnout Within the Online Paleocommunity

It is with a bit of heavy heart that I write this. That it even has warranted this much thought on my part compels me though. I feel we have reached a sort of tipping point and, for lack of a better term, a crisis as goes this circus we call the online paleocommunity. We have been witnessing a startling attrition in the number and quality of blogs, fruitful interchanges, and general positive social media encounters. We have seen some very talented and valuable individuals decrease their engagement or fall off completely within the community. We need to be asking some very hard and difficult questions at all levels. In order to get at these difficult aspects I myself have to play a bit of the heel, the bad guy so it may seem. I am doing this in order to stem what I perceive as a growing burnout, disillusionment, and fatigue within a social community that is actually somewhat new and unparalleled in intellectual history - the online paleocommunity. I think we should take a moment to realize that it is a special and unique place and one worth fighting for. Where else in the history of science have we seen a meeting of multiple strata of interested parties get together in such intellectual, engaging, and profitable way? But there are problems to face and some rather ugly truths and questions need asking. In speaking so bluntly I ask simply for your open mind, reason, and an effort to grasp at nuance. And know that in casting such a wide net I don't fall outside its bounds.

So with that it mind, and I think that is a fair opening statement, we shall proceed.

Special Unique Times With Special Unique Problems

When I was a young grommet of about 10 years of age leafing through Gregory S. Paul's Predatory Dinosaurs of the World for the umpteenth time I had no inkling that one day children of my age, likewise possessed mentally with all things dinosaur, would have unfettered access to not only some of the best minds in the field of paleontology but due to the growing open-access movement direct access to many of the original scientific texts. So if you are a young dinosaur grommet - and I use that term endearingly because I was once just like you - realize that you are living in a very privileged and special time. So don't take it for granted.

But more importantly don't abuse it.

What do I mean by don't abuse it? First off I think for some of these younger paleo-grommets we should burst their bubble as to what the working schedule of a professional academic is actually like, because I think it might be eye opening. Not working as a professional academic myself, but having been around them in various permutations, I'll give you my ballpark estimate of what their daily schedule is like. I would wager that, conservatively, 50% or more of their day is spent doing boring bureaucratic stuff. Yup, exchanging emails, going to faculty meeting, writing grant requests, paper requests, fee waivers, maintaining funding because original research and testing is quite expensive. So the vast majority of time is not even spent on the work they are most known for. If they are  professional academics they are also, by necessity, probably teachers. Some may actually like teaching and thrive doing it. Some probably just teach as a means to an end, a way to allow time for research. In any case you can bet that teaching, office hours, grading, making tests, preparing lab - all that stuff - is gonna take up the bulk of the rest of the time of a professional academic, probably upwards of 4o% although again I might be lowballing this. That leaves  probably less than 10% of time dedicated to new and original research, blogging, writing papers, hypothesizing i.e. "pushing the field further".

In other words - regardless of the actual time break downs - the real "fun" work of paleontology gets squelched into a relatively tiny compartment compared to the obligations of bureaucracy, teaching, and other more tedious details.

And it is somewhere in that 10% of time professional academic have to follow new leads, research, hypothesize, and think of new ideas that their social media time is met too. What does this mean for you young dinosaur grommets? It means that you should not hit up such and such with extreme and lengthy questions, ask for them to do research for you, and don't expect that they have time to consult on your expose or fact check your document. Google it!! Wikipedia!! You have access to more information at your fingertips than we ever did! I'm not going to name any names and it is not my intention for the parties involved to be harassed or shamed in any ways but I recently saw on social media a well known researcher given a list of over 3000 genera with lengths and weight estimates and asked to correct, augment, and fix said list. Please kids, just don't. It might be naivety but realize that time is no luxury for professional academics and the more burdens and requests you place on such people you can expect more and more social media burnout and people dropping out. This is why we can't have nice things folks!!

Now my experience is a bit different as I am not a career academic, nor do I think it was the right path for me in any case. But the crux of the issue remains the same… time. I don't have to sift through bureaucracy nor do I have the responsibility and energy that is demanded of being a teacher. For me my path involved decoupling paleontology from financial realities. Fortunately my day job involves lots of driving and I get to do my best thinking while driving, which is why I have a backlog of ideas and material I have yet to unpack!! Frustratingly the stresses encountered in the online paleocommunity sometime act as a distraction from getting the work done that I need to get done. But the point remains, whether someone does this stuff as a passionate hobby or are career academics those in the online community need to realize that time is our most limiting asset which we need to spend wisely!!

The Boy's Club of Online Paleo - whether we like it or not

Leading from this it is also time we face the fact that the online paleo-community, especially the dinosaur aspect, is dominated by young males. Now, you can ascribe whatever cultural reasons, biases, biological determinisms or whatevers to why this is. There have been some valiant efforts to make paleontology more amenable to female retention and inclusion. Certainly some females may have their perspective on how things can be improved and I'm not discounting their truth but I'm just noting what I see and what I think we will continue to see - a bit of a boy's club. I doubt we will ever see exact parity in the genders for paleontology both professional or in the online community. For now I'm just going to go with an observation of "it is it what it is" and that boys love dinosaurs. Especially the big and violent ones.

From this observation, that a big chunk of the online pale-community (esp dinosaurs) is dominated by young males, we can start to extrapolate some general observations of the young male psyche because that is where the problem (mainly) lies. I'm sorry to inform you young bloods, and I speak from experience, but I'm gonna make a sweepingly blunt generalization that young males are the least empathetic, most anti-social, most cruel, and generally the most vile and violent sexo-social caste in any human population. I'm sorry guys its true. There is a reason that we send you off to war and you do it so splendidly and without question. There is a reason that Lord of the Flies was about a group of boys stranded on an island, not a group of elderly women. There is a reason that behind the vile comments on social media is almost always a young male. There is a reason for Gamer-gate. There is a reason for the alt-right. That reason is young males and all the conditions, trappings, and baggage incumbent upon you.



The Prevalence of Autism & Mental Illness Signals Within the Community

Again this might not be the most deft treatment of the subject but if we start with the observation that young males dominate the online paleocommunity - and that this probably won't change in the foreseeable future - we can start to arrive at better answers by asking the right questions. Before we do that I feel we must address little discussed truths about the online paleocommunity that encompasses both genders and probably run the gamut from novice to professional.

That difficult truth is that I believe there is a higher than normal incidence of mental conditions and mental illnesses in the online paleocommunity. Austism and the subtype Aspergers syndrome I suspect are especially common within the field from aficionados to even esteemed thinkers. An immersive subject such as paleontology provides a natural intellectual pasture where people lacking in social skills and prone to obsessive interests can flourish. Especially online where social interaction is devoid of the nuance of face to face contact and one can literally spend countless hours going down whatever wormhole one finds themselves in. I myself probably fall somewhere on the spectrum to a very slight degree given my propensity to obsess on subjects and really dive into them to an extreme degree.
Working from the perspective that a big chunk of people online might be on the autistic spectrum, have difficulty with social pragmatics, and find a natural refuge in paleontology might prove useful if you are having trouble distinguishing between classic autistic type thought processes (i.e. lack of social cues & pragmatics but no ill intent to harm) or if someone is just trolling (out to harm).

That people who find themselves somewhere on the autistic spectrum might have a predilection towards paleontology should come as no great surprise. I've often discussed the connection between dinosaurs and autistic children with my mom who is a professional child speech therapist, indeed simply google autism and dinosaurs and you will see that there has been much discussion in these regards.

The necessary corollary is one which I have grappled with discussing because I can't really discuss these issues without decoupling them from my own life, so I won't. In addition to the online paleontological community acting as a bit of a refuge to those on the autistic spectrum I also suspect that it attracts a fair number of people who, for whatever reasons, don't exactly fit into most mainstream elements of modern society. I suspect that in addition to high incidence of autism in the community that there is a high incidence of risk factors and associated characters emblematic of conditions referred to, for lack of a better term, mental illness. I say this because when I go down the checklist I meet most of these requirements and I suspect that there probably are a lot like me. I have been visited upon by depression most of my life and even an isolated manic episode. I've had troubles establishing relationships with people, dealt with loneliness, isolation, self doubt, low self esteem, jealousy, chemical dependency issues, addictions, numbing my emotions, and suicidal thoughts. For all my bluster I consider myself and meet the qualifications of being a highly sensitive person (HSP) who probably feels things deeper and more passionately than most. Highly sensitive males are not supposed to be "out" in American society and most are not.

I make the point of mentioning all of these aspects of my life I have sustained and lived through to show that each one of us is carrying the invisible battle scars and wounds of a life lived and invisible struggles not known to others. That, speaking for myself personally, sometimes the slightest poke or prod can unleash a lot of anger and grief barely simmering under the surface.

So when you see someone go off the rails, as I've done it myself, ask yourself: is this person always like this? Did he/she simply have a bad day? Is there more to the story that I don't know?

Online "Consensus", the Perils of Group think and Ideological Bubbles

One of the pitfalls I think we all should be wary of is the dangers of becoming too insular a community.  Such scenarios can quickly establish a path leading towards intellectual bubbles and group think. We also should be wary of calls towards consensus culled primarily from the online community. Such thinking negates the fact that many thinkers, professional included here, abstain from social media discussions of paleontology. They just don't do it. This can also create a skewed impression of what consensus really is and how nebulous a concept it is and will continue to be. The online community does not always reflect the full gamut of thought and opinion.

This creates a self reinforcing intellectual bubble where group think is primed to take over. Why? Because we are social animals discussing science on a social platform. Social primates are going to drift into group think if not steeled against it. Now I'm not going to say this is an insurmountable problem… yet. But we should be on guard against it.

Another pitfall we should be wary of is a tendency for almost a type of artificial democratic voting of ideas and willful confirmation bias. Sorry but this is destructive to the science when ideas are simply voted upon by a delegation not yet amenable to change or with the maturity to recognize that the once solid footing that their ideas once seemed to rest upon is crumbling beneath their feet. Again this is a byproduct of the youth and inexperience of many younger paleo - enthusiasts. Your brain is literally not yet fully formed. And life has not kicked your ass enough. But give it time, it will.

What to Do?

It may seem that I have painted a particularly bleak picture of the online paleo-community. Beholden by hordes of young males; many perhaps autistic; lacking social cues; rife with mental illness, isolation, anger, and the power of anonymity; intellectual fiefdoms developing; egos, egos, egos; large scale disengagement and attrition by any adults in the room; skewed consensus; Lord of the Flies brought to life.

With all of these negatives at hand how have things hobbled along so well to this point? I can only speak of my own personal recommendations and ideas for a more synergistic and positive online experience. I'm very amenable to hearing others thoughts and ideas and am certainly not above reproach or even innocent of many of the criticisms I myself have put forth.

Sometimes Its Good to Just Watch, Listen, and Learn From the Sidelines

Every once in a while I am pleasantly surprised by coming across a new commentator who admits to having read the my blog for some time but has more or less quietly lurked in the shadows. I really like you guys because you remind me of myself a bit. I didn't really get into commenting myself until after lurking for many years, and even now I generally peruse and monitor discussions rather than always feeling it necessary to throw in my two cents. You know, it is not really necessary to always chime in right?

There is a proverb that goes "Still water run deepest" which you may have heard before. Less well known is that there is an inverse to the proverb:  "Shallow water makes the most noise"

"Where the water ran smooth he found it Deepest: and on the contrary, Shallowest where it made most noise." Theres more danger in a Reserv'd and Silent, than in a Noisy, Babbling enemy

Put It in a Sandwich

The following is a rather simple and easily remembered formula to allow a more positive and fruit full exchange of ideas and criticism. When someone puts out a new idea, thought, or piece of art it is always like a little baby. You are going to be a little attached to it. You want to see it do well. When it is attacked it is normal to get a little defensive. Then arguments occur and all kinds of nastiness. This is how to sidestep such quarrelsome exchanges by simply bracketing your (constructive) criticism by putting a complimentary/positive statement both before and after the criticism. In other words put it in a sandwich.

Example of a positive art critique: " What an interesting design (positive opener). Have you come across the article suggesting such a feature was likely not there? (non-condesdending tone allowing person to answer) Again, thanks for sharing your work you obviously put a lot of effort into it!! Keep it up!! (positive closure)"

Is that so hard? And guess what it might leave both parties feeling better than before the exchange!?! Imagine that, feeling better after an internet exchange!!

How much better does the above feel to read and write as opposed to this: "I doubt it, that's kinda ridiculous. That is not how these things work."

There might be a good reason for the person doubting the accuracy of a picture. But have they given that reason? Nope they have not. Have they assumed that the person who did the picture has not read what they are speaking of? Yes, they made an assumption. Is it condescending? Yup. Have you learned anything or have you become more enlightened in any way? Nope and nope, in fact you probably feel a bit crummy.

Avoid "gotcha" statements, those are the worst. You can inform someone else about some knowledge they may not be privy to without being a holier than thou, know it all.

And finally take a loooooooong look in the mirror if you are the person always leveling criticisms at others without producing anything of your own. Your constant nit-picking and criticisms reflect more on your own dissatisfaction with yourself than a genuine desire to better and help out the other person. Take that cold shower.

If the ratio of criticism to creation is overly high in your online footprint you are part of the problem.

"Those who can, do. Those who can't criticize." Robin Sharma

Learn to Walk Away

Just do it. Walk away. It's not worth it. There is hardly ever a final word in most issues in paleo anyways.

If you are always getting into tifts maybe it is time to take a look in the mirror. Is it really because you are so superior and everyone else is a dumbass? Maybe when you realize that the common denominator in all of these exchanges is yourself then you can see where the problem lies.

Don't Be a Stalker or a Harasser

This has happened to me several times already. If someone bans you in one social media outlet do you take that as an invitation to find them on another and contact them there? If so, that is in my book stalking/harassing behavior and it does not feel good. It feels like what it is, a violation. If you do this you are part of the problem.

Realize that paleontology is more or less intellectual entertainment, a hobby. Even if you have a point if its got to the level of someone blocking you or disengaging from the exchange, just leave 'em alone. Walk away. It's not your job to be the self appointed grand poo-bha of all thing correct and true. No one owes you their time or to give you a forum, these are voluntary exchanges, not mandatory.

Don't Say Something to Someone That You Wouldn't Say Face to Face

Pretty self explanatory right? I'm guilty of not following this one myself sometimes. Maybe we all can get too easily emboldened by a type of anonymity and keyboard warrior bravado that the internet provides.

What you say on the internet, you own. After saying enough crappy things that becomes you. We should realize that even if we are discussing someone who is not currently engaged in the conversation - that doesn't mean that it won't get back to them. So think a bit about what you write.

Don't Pile Up On People

Even when someone behaves egregiously and have already been called out on it, don't feel like you have to dog pile on that person. Are you doing it for beneficial reasons or are you just trying to get your shots in? People are not defined by one post, by one drawing, by one exchange, or by one action. We have good days and bad days. Allow for some nuance in life. 
 Conclusions: A Better Version of Our Online Selves

I sincerely hope that people get the gist of what I'm saying. Granted that a big portion of my readership is actually the "young male demographic" which is the group I am most singling out and criticizing I do this at some risk. But I think a greater good is at stake and that is the strength and vibrancy of the online paleocommunity. I'm not the only person to notice a diminution of upper talent and people generally suffering burnout and attrition. So I felt compelled to call a spade a spade and if that means I got to play the heel, play the disciplinarian, give the masses of paleo-grommets a spanking, so be it.

Just know this: If you are 15 years old, what do you now think now about some of the things that the 10 year old version of yourself said online? You probably think of things a little differently now with more knowledge and life experience, right. Now with this observation in mind is it not too difficult to imagine that what you say now online at age 15 might be a tad different that what you say and think when you are 20, 25, 30? Remember what you say online you own so be careful about this, some things may come back to haunt you.

That also goes to giving a little credence and respect to any adults in the room. Remember in most cases that they have been in your shoes, they have been young paleo-grommets themselves. They have the intellectual context to have seen the oscillations in scientific discourse bounce back and forth before. To put it bluntly they have already forgotten more than you know. I'm not saying the adults are infallible or that you have to worship them or follow blindly. But let's interact in a way that preserves peoples sanity and does not drive them away. Because when all the adults are gone, and many are already leaving, what do we have left? Lord of the Flies is what we have left.













Saturday, July 22, 2017

Pierced From Within: Utahraptor Cometh and the Return of the Killing Claw

Utahraptor by Duane Nash


You know its that time again folks, more dromie madness. Antediluvian salad has a bit of a controversial history with these most pernicious of stem birds. You can be sure that part is not going to change, the controversial bit, that is.

For a brief review:

Making Dromaeosaurids Nasty Again Part I: Wing Pummeling Abuse In which I discuss the current state of affairs with regards to killing claw use and hypothesize that prey restraint by the foot "killing claw" coupled with clawed wing pummeling may have been utilized. As you will see in this post I no longer consider such a method of restraint and killing as preeminent. That is - shades of grey here folks - I don't think that both the raptor prey restraint model and the wing pummeling hypothesis were chief strategies for prey dispatch in most dromies. Could both style of attack been used on occasion by some dromies? Yes, but as I will explain both theses methods become vanishingly tenable tactics especially at larger sizes (hello Utahraptor).

Making Dromaeosaurids Nasty Again Part II: No Shame in the Scavenging Game I start building the case for many dromies as excellent facultative scavengers. Not only is there fairly unequivocal fossil evidence for it, the size range of dromies slots in nicely to an ecological "sweet spot" where terrestrial scavenging is most utilitarian. Also Dakotaraptor as a large, cursorial carcass bully.

Making Dromaeosaurids Nasty Again Part III: Life Appearance - Dapper of Deranged Probably - at least based on the comments - the most controversial of the series. I would say it has held up nicely, especially in light of the compelling evidence that tyrant lizards "de-feathered" significantly. "Wut you mean that dromies did not all look like carbon copies of each other in the 100 million years of evolution they underwent? Get out!" Look folks it's not even that wild of a suggestion, in fact pretty common sense actually. Almost boringly so.

Making Dromaeosaurids Nasty Again Part IV: New Hypotheses on Dromaeosaurid Feeding Technique & Role of Tail in Movement For me this was the most fun and interesting post in the series as it combines unusual oral feeding styles with a novel idea on dromaeosaur locomotive strategy.

I introduced, for lack of a better term, the "woodpecker hypothesis" of dromie carcass feeding technique. In this scenario quick twitch muscles generated in the body vibrate culminating energy at the tooth tip where strange apically hooked serrations on the teeth allow the tooth to literally dig into carcasses. Several examples of worn dromie teeth and inexplicable bone damage on Tenontosaurus can be potentially explained by this hypothetical feeding style.

I then discussed how the pattern of caudal rods in dromie tails could potentially work as an elastic recoil allowing energy efficient, long distance travel, useful for reaching ephemeral food sources and carcasses. I make the comparison to wolverines which, despite their short legs, are remarkable and unstoppable moderate paced long distance cursors. I augmented this suggestion with a review of dromie ichnological traces - the footprint record shows that these animals had not only large foot and toe pads but that they most likely cruised at a fairly high pace.

Here I have to admit to having a bit of mud on face here folks as a frequent theme of my "Making Dromaeosaurids Nasty Again" series was a diminishing of the  role of the killing claw in predatory endeavors, highlighting wing pummeling and biting as more preeminent tactics for dispatch while the feet grappled and held prey. So I'm gonna eat some crow here in coming around full circle in my opinion on that most famed of claws - foot ungual #2, aka the "killing claw" I now believe really was a killing claw just not in the way that we have been interpreting it.

Full disclosure, the genesis of this idea is not mine own although after mulling it over and especially with the Utahraptor reveals I think it should be the leading hypothesis. What I want to document is the transmutations and permutations an evolving hypothesis should go through and in this case I believe did go. New ideas rarely come fully realized and perfected into the world. They need refinement. In the case of this idea which I will dub the "pierced from within" hypothesis the first semblance of it to my knowledge was put forth by Kenneth Carpenter. However the man who improved - but didn't perfect it - is.... wait for it... a certain chap named John Jackson.

Upon writing that name I can almost hear the sound of mouses clicking on the close window for this page. But bear with me. To those uninitiated John Jackson is best known as a chief proponent of the "Birds Came First" BCF idea of theropod/dinosaur evolution. He also has a reputation online for a particularly prickly correspondence to put it mildly. You can do your own internet sleuthing on John Jackson if you are new to this idea or the man - here is a good place to start (read comments). But let me unequivocally state I don't subscribe to the BCF idea of dinosaur/bird evolution (ironically someone brought up a retooled version of this in the comments from my last post). I'll admit it had a certain intuitive appeal to it in the 90's and was fresh and original - but the evidence has not borne it out. John got in contact with me after reading several of my dromaeosaurid posts and we had a brief series of email exchanges (we don't correspond anymore, you can take a wild guess why). I try to keep an open mind on things and gave his self published book - The Secret Dinobird Story (free on kindle) - a read. The book is a bit of a slog to get through, and I told John this. I came away still unconvinced about BCF and this post is not about this topic nor do I want to discuss BCF in the comments. But nestled within John's writings on the philosophy of science, unorthodox family trees, "arboreal stem dinos",  and complete eschewing of cladistics ( I have problems with cladistics too but don't think we should discount them), is hidden what I believe is an important and unrecognized broad stroke analysis of how dromaeosaurids actually used the famed killing claw. I can only assume that people who know of John or have perused his book glossed over his bit on the killing claw. It is in my opinion an unpolished gem and should see the light of day. With whatever light I can give this idea I will shine upon it.

The killing claw is not a tool used as a crampon to hang onto the sides of other dinosaurs, nor is it a tool used to pin and hold subequal sized prey items ala the raptor prey restraint hypothesis. It is a tool used with almost surgical precision to slice into and penetrate a prey item in select spots. Such a claw is not optimized to scythe style cut long gashes in the tough hides of prey but instead cuts a single entry hole into prey. A laterally compressed horny sheath with a cutting edge can, after the initial entry into said prey item, now repeatedly plunge into, explore, and cut into the underlying soft tissues. Such trauma will perforate vessels, arteries, lungs, and viscera. Although from the outside trauma will be evinced by a simple entry hole the interior damage will be substantial and often times fatal. Arms and/or jaws assist in stabilizing struggling prey in such a manner to allow entry of killing claws into prey for fatal dispatch. Such a tool is every bit the theropod equivalent to saber - toothed predators and allowed dromaeosaurids an ability to punch well above their weight class in predatory endeavors.




John called it the toe and tail, grab and stab method. He believed that the caudal tendons of the tail worked somehow to help "kick into" the prey item deeper but the (unpublished) revelation that Utahraptor dispensed with these caudal rods causes me to distance myself from that aspect of the idea. As I have discussed before I think that those caudal rods assisted in long range, mid paced efficient travel and it makes sense that Utahraptor dispensed with them as it likely was the >the most predatory< and least adapted to facultative scavenging among known dromaeosaurids due to its size, extreme robusticity, and heavy investment in weaponry. Furthermore the loss of such rods helped the tail in flexibility as it could both deliver and take a beating.

To better understand and see how we got to where we are today and where I think we will be going a quick review of the pertinent thought on the use of the killing claw in these animals dominated by two papers Manning et. al. (2005) and Fowler et. al. (2011) with necessary criticisms.

Not a Slicing Weapon But a Puncture and Pierce Weapon

The main death knell to the "ride the back of iguanodonts and slash at the sides with toe claws" hypothesis of dromaeosaurid killing technique came in the form of a mechanized Deinonychus leg built and utilized by the team of Manning et. al. back in 2005. They found that not only was the hole created by the claw very superficial but slicing through skin in order to create long gashes would be inefficient due to the skin tending to bunch up prevent said slicing. However, as John points out in his book such an analysis is lacking in terms of puncture depth because the experiment did not take into account the compliant nature of body tissue and that the claw can be pressed into the prey animal deeper via body weight and/or muscular force. Long story short the experimenters did not think with enough murderous intention. They did not think like prison inmates trying to achieve fatal blows with self made prison shanks. When body tissue is not put under pressure all the soft, delicate and gushy stuff is relatively safe due to the layer of integument, muscle, adipose tissue etc etc. But press into this tissue - with a prison shank or a dromie killing claw - and the margin of safety diminishes.  Stick the knife in and twist.

Critical reception to Manning et. al. is not however new and not isolated to John Jackson. Both Dave Hone (archosaur musings) and Mike Taylor (SV-POW) express similar notions in this interesting back and forth from Ask a Biologist. Many of the points they raise, especially with regards to the problems of "puncture and hold" and the likely inference of a sharp cutting edge to the killing claw can be extended out to criticisms of the now dominant RPR model of Fowler et. al. (2011).

Not a Holding Claw But a Cutting Claw

After Manning et. al. prescribed their case against killing claws slicing meter long gashed into the side of prey items the next big chapter in this saga came in a paper by Fowler et. al. (2011) that brought us the now dominant hypothesis of the Raptor Prey Restraint model (RPR) that proposes a certain commonality with modern birds of prey that grab prey with foot talons, flap with wings to maintain dominant position, and eat/dispatch with the head. As I have said in the past there is much to like here and it is not surprising that many have become somewhat smitten with the RPR restraint model. But as the authors themselves concede the grasping ability of dromaeosaurids is not >as mechanically strong< as modern raptorial birds of prey. Add to this; dromaosaurids do not have truly opposable halluxes like raptors - they can't do a good strong vice grip; longer legs decrease mechanical advantage further diminishing the strength of the grip; and dromaeosaurids had big foot and toe pads which would diminish the tightness of the grip. Because of the big foot and toe pads that dromies had getting a firm grasp becomes problematic, sort of like trying to grasp things with your own toes to a lesser extent. Not impossible for us and not impossible for dromies, but issues arise suggesting a less than optimal performance.

But the final nail in the coffin for the dominance of the RPR model lies in the shape of the claw itself. It is not circular in cross section as we see in extant raptorial birds of prey but is laterally compressed like a knife is. It is just begging us to infer a sharpened cutting edges for the keratin sheath.

credit Robert DePalma  killing claw Utahraptor (L) Dakotaraptor (R)

*Update 8/3/17
However even in claws with a more circular cross section it is possible for not one but two cutting edges to develop as shown in this graphic provided to me by John Jackson of a claw from a hawk of the genus Buteo. The black cross section gives an idea of what is possible with a keratin growth over the bony core. Also might be useful to take a gander at your cats claws if you one has so adopted you...

Buteo claw credit John Jackson


The Diminishing Utility of Stability Flapping in Larger Dromaeosaurids

Not to dismiss the RPR restraint model in its totality - I can picture small game and smallish dromies (troodontids especially) - pinning small with their #2 claw and even flapping with their arm wings a bit to maintain top dominance. However in larger and larger dromies this tactic becomes vanishingly feasible and outright ludicrous in Utahraptor sized dromies. It is, in essence the bio-functional equivalent to a fat guy in a little coat, two things combined that don't make sense.



Think about it, Utahraptor was big and robust, like polar bear sized. It was no light weight. The notion that arm wings on such an animal - if they even existed and were not functionally reduced - could generate enough power and lift to achieve any semblance of control and lift necessary for stability flapping should be tossed in the scrap heap of bad ideas. Again, not sail gliding Stegosaurus bad, and it is entirely possible that some small dromies/microraptorines/troodontids engaged in some stability flapping in choice circumstances. But pretty indefensible when we imagine what stability flapping really means - that dominant vertical position is maintained via wing-arm strength flapping strong enough to control not just one body but two struggling bodies - then the utility of stability flapping becomes vanishingly small in dromaeosaurids much larger than - ball parking here - turkey sized? I definitely would say stability flapping is pretty nonsensical in full grown Deinonychus and maybe even Velociraptor...

What Does the Evidence Actually Show?

Which is exactly what the fossil record tells us. Remember we do have a certain Velociraptor locked in mortal combat with a Protoceratops.

CC2.0 credit Yuya Tamai Protoceratops & Velociraptor fighting dinosaurs

We shouldn't feel compelled to explain such a situation as abnormal or a very rare occurrence. It was common enough to enter the fossil record after all.  And it is doing exactly what should be expected in the scenario John Jackson laid out in his book. Velociraptor is not hitching a ride on the side of the Protoceratops, not is it stability flapping or grasping the animal with all of its foot claw in some weird type of proto-raptor foot grasp. The head of the Velociraptor is poised to strike but may not be all that important for the killing. The arms and hand claws are very important in the predatory endeavor as they seek to restrain and stabilize the prey animal for ultimate dispatch by the killing claws. Given their increased range of motion and length compared to other theropods they performed a different role in predatory actions. They grappled with prey and helped to hold and stabilize prey which in turn allowed the killing claw to strike with better precision and accuracy. This is directly analogous to the manner in which large felids will grapple with prey using their forelimbs and secure the prey for dispatch via throat bite or nasal blockage. Finally the killing claws are doing exactly what they should be doing... killing!! They appear to be literally gouging into the neck region!! Poor Protoceratops!!

We actually had an earlier iteration of this idea laid out to us by Kenneth Carpenter in a review paper titled Evidence of Predatory Behavior by Carnivorous Dinosaurs (GAIA, 1998). Carpenter raises concerns with the idea of sickle clawed theropods disemboweling prey items but in his analysis of the fighting dinosaurs he makes specific mention of the likely killing style as evinced by this most remarkable of preserved interactions:


Carpenter also provides several diagrams of sickle claws with specific mention of a likely sharp cutting edge. Unfortunately Carpenter strangely backs off of the cutting edge aspect of the claw likening it to being "less sharp than a dull knife". Perhaps he was being a tad overly conservative, in any case Carpenter reasons that sickle clawed dinosaurs had  such blunt claws because: "although we don't know how sharp the keratin sheath of a dromaeosaurid claw was, it was probably less sharp than a dull knife because there was no way for a dromaeosaur to hone an edge."


Let's reason this out. Dromaeosaurs revamped their entire hindlimb morphology, literally raising digit two off the ground in walking posture. And we are to presume all of these sweeping morphological changes were done merely to create a claw with a sharpness less than a dull knife?!? Come on now.

If we merely make the defensible assumption that the keratin sheath grew constantly then we can safely assume that the animal had to hone it down through use on prey items or why not simply hone its claw like a felid does? What's going to stop it?

So when we add it all together we see this first iteration of the stab and kill from the inside hypothesis from Carpenter. Unfortunately Carpenter downplays several aspects of it such as the likelihood of a sharp cutting edge and for whatever reason the idea doesn't get much traction, even though it better explains the evidence than what Ostrom suggested or even subsequent works by Manning (2005) & Fowler (2009). Then comes along John Jackson, whom I don't recall if he cited or read Carpenter, but suggests an improved, but still problematic hypothesis, of sickle claw killing. Jackson gets it right I think in assuming a sharp cutting edge and that once the claw had penetrated and pressed into tissue it was free to repeatedly stab and traumatize tissue from the inside. Jackson thinks that the caudal tail rods of dromaeosaurids were necessary for this motion but I have my doubts and the revelation that Utahraptor lost its tail caudal rods but otherwise shows hyper carnivorous attributes supports this. Finally it should come as none too great a shock that the burly iguanodonts, nodosaurs, and sauropods that Utahraptor shared its habit with and which formed its prey base all had a singular vulnerability - a vulnerable neck.



So that is where I stand with what I regard is the leading hypothesis on dromaesaur killing claw function. It is interesting I think not so much for what it says about dromaeosaur killing claws but what it says about us. It is a tale on the transmission of ideas and hypotheses - what counts as a good hypothesis and who is allowed to advance such hypotheses. It also shows how good ideas - though not necessarily perfect when advanced - sometimes get pushed aside or disregarded. Lost in the mix so to speak. But then later on they can get rediscovered, dusted off, and shown the light of day.

I do think that this idea - or collection of ideas, the evolution of a hypothesis via disjointed bits and pieces - will ultimately be one that is nursed back to health, retooled and refashioned.

The Raptor Fossils Project (Utahraptor) w/link to gofundmeUtahraptor



Refs

Carpenter, Kenneth Evidence of Predatory Behavior by Carnivorous Theropods. GAIA no 15 (1998) December pp 135-144 online pdf

Fowler DW, Freedman EA, Scannella JB, Kambic RE (2011) The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE 6(12): e28964. doi:10.1371/journal.pone.0028964

Jackson, John. The Secret Dinobird Story December, 2013

Manning, PL, Payne, D, Pennicott, J, Barrett, PM, Ennos, RA (2006) Dinosaur killer claws or climbing crampons. Biology Letters (2006) 2 110-112 pdf


"A Long habit of not thinking a thing wrong, gives it a superficial appearance of being right, and raises at first a formidable outcry in defense of custom". Thomas Paine


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Tuesday, July 4, 2017

Meathook Parade: Permutations, Iterations and Revelations On Predatory Theropod Forelimb Use

The following will be a blending of several under appreciated ideas on theropod forearm use combined with some of my own ideas. It seeks to drive at better answers by asking better questions.



Ahhh those theropod forelimb. They are a bit of an enigma, no? As bipedal primates descended from a brachiating pedigree of ape we have an intuitive awareness of our ability and utility to reach out and grab things.  Predatory theropods, despite being bipedal and equipped with arms and fingers like us, were a bit more constrained in their forelimb movements. The neck and head would be the first to contact with prey, the arms and claws being substantially rearward. Furthermore, the range of forearm extension and wrist movement was severely limited. Essentially the forearm and wrist acted as one single unit with the wrist unable to rotate and the radius and ulna locked together unable to rotate as well. The shoulder was likewise constrained to a relatively smal range of motion. Would it not have benefited predatory theropods to have freed up their forearms, wrists, and shoulders for a wider range of motion to assist in prey capture and manipulation? So that they could "reach out and grab stuff" like we do?

Suchomimus credit Duane Nash


Interestingly, there appears to have been at least one instance of theropods increasing both wrist and shoulder mobility and thus evolving the ability to "reach out and grab stuff" (Zanno et al., 2006). From wikipedia: "Within Therizinosauridae, broad changes to both the structure of the forelimb, pelvic, and pectoral girdles likely corresponded to changes in the lifestyle of the animals. The forelimb has undergone a drastic increase in robustness, the flexibility of the wrist has increased, and the presumed reach of the animal is believed to have lengthened. Moreover, the pectoral girdle has been modified to further augment upright reach, however the grasping ability of the animals is thought to have decreased. As with the modifications to the head, these adaptations are thought to have assisted with an herbivorous lifestyle, as they may have increased the ability to harvest and collect vegetation.[3]The obvious implication is that when the need arose to "reach out and grab things" the commensurate forelimb adaptations did arise - except that they did not arise in a predatory theropod but a likely herbivorous/omnivorous one!! Maybe the predatory theropod forelimb arsenal was not functionally adapted for "reaching and grabbing things" but served a separate purpose? Perhaps we are not satisfied with theropod forelimbs - that they are a bit enigmatic - because we are assuming the wrong job for them?

credit IsisMasshiro


There is currently a strong notion that whatever the forelimbs were doing - they were of secondary importance to what the head was doing in predatory theropods. And that if the hands were involved in prey capture they stabilized and held prey for the benefit of the head to deliver the dispatch. This notion is actually impractical for several reasons. Theropods neck musculature studies on Allosaurus indicate a design optimized to strike ventro-flexively (Snively et al, 2013). In other words they struck down and out away from the body. They were not optimized to strike back towards the body as would be expected if they bit into prey held in place by the arms. Furthermore the sheer implausibility of such a design is patently obvious when one tries to align the kinematics of such an action in the theropods with especially reduced forearms and short powerful necks such as tyrannosaurids and carcharodontosaurids.  Can anyone point me to one convincing depiction of short armed theropods holding prey with their arms as the bead bites into it?  It is also a bit of a myth that grasping hands are even necessary for the killing and dispatching of reluctant prey items by the mouth. Even a cursorary overview of both terrestrial and aquatic predators reveals that this is not the case - that the skull can be both a grasping and killing instrument - no hands need be involved.

Crylophosaurus credit Duane Nash


For this piece I am going to approach these "limitations" in wrist/arm/shoulder mobility from a different perspective. That these limitations were not at all limitations - they were in fact adaptive benefits. And that these benefits were not actually in place to assist in the capture of prey i.e. "the reaching out and grasping of prey", that was the job of the head. The forearms and wrists of predatory theropods were in fact so severely limited because of two, not mutually, exclusive reasons; 1)  many theropods would have dispatched prey with hand claws after the initial grasp by the jaws and 2) all predatory theropods - with notable exception of abelisaurids - would have used their forearms to transport food parcels to localized feeding locations and perhaps mates/offspring.

In other words it proves useful in flipping the equation: " the arms held prey for the head to dispatch" into " the head grabbed prey for the arms to dispatch" in order to understand the forearm use in a great many predatory theropods.

credit Brian Engh.

An important distinction that will color these arguments arose from an observation that Andrea Cau brought up to me in discussions on abelisaurids, theropods, and forearms. That there is a roughly inverse relationship between the power and bite of the head and the bulk and importance of the forearm in predatory endeavors. That is, for the theropods with weaker, slashing, and more modest skulls and teeth,  forearm strength and killing capacity are enhanced: spinosaurids, allosaurids, neovenatosaurids, megaraptors, basal tyrannosauroids, among others . Alternatively, where head power is enhanced arm strength and killing capacity is diminished: carcharodontosaurids, ceratosaurids, tyrannosaurids, abelisaurids. Now certainly this is not a hard and fast distinction, there were shades of grey, but I think it is a useful way to parcel out the discussion. No I am not saying that Suchomimus never killed with its mouth, nor am I saying that T. rex never killed anything in its hand claws. But they did invest in different arsenals and this should matter.
*Note that only in abelisaurids do we see the arms mutated into vestigial structures. This is an important distinction because even in theropods with reduced forearms they were not vestigial but offered an important functional usage in the transport and relocation of food resources. Dromaeosaurid forearm use will be discussed in a future piece.

In order to disabuse ourselves of the  notion of theropod forearms as tools for "reaching out and grabbing" or "holding onto prey for head dispatch" I want to revisit a term often used in the discussion of predatory theropod hand claws: meathooks. The term is a useful one, not only because it alludes to a human contrivance, but expresses quite succinctly the use of these forearms with due credit to notions of form and function having applicability not only in natural systems but culturally mediated systems of butchery. In both situations form follows function.

Megaraptor hand. author raffaeli serge CC2.0

Enough with all these academic pedantry I want to give you, the reader, an immersive feeling on what it was like to be young sauropod skewered alive on the Megaraptor meathook claws.





Ladies and gentlemen it is disturbing because the Mesozoic was disturbing - a real horror show. Now keep in mind the meathook claws of theropods, combined with a rather inflexible, strong, and stoutly built arm, work in conjunction to lock a food item in place. Such food items are pinned by either the opposing arm and claws or are wedged in against the torso. It is the meathook morphology of the claw combined with the limited range of motion of the arm and wrist that actually make escape from such a contraption very remote. In other words, the exact flaws that we have felt for so long are built into the system actually in this view are benefits. The prey can't squirm out of the arms due to the inherent inflexibility of the arms!!

credit Brian Engh used w/permission
Brian Engh (Don't Mess With Dinosaurs) did this evocative mural depicting speculative dinosaurs of the early Jurassic Navajo sand-stone of New Mexico. Brian made the rather atypical depiction of the putative top predatory holding a coelophysid in its claws. Also check out Brian Engh and other paleo goodies on July 13th 2017 at nerd night in L.A. if possible. I will try and make it too!!



There have been some detailed studies on large predatory forelimbs. One of the most interesting and little heralded studies is by Senter & Robins 2005. What I want to draw attention to in this abstract is; the extreme flexibility of the manus - the fingers can hyperextend; the permanently locked and bent elbow, unable to straighten; the notion of struggling prey further impaling itself on digit 1; and the noted difference between coelurosaur finger flexibility (they were doing different stuff) and other theropods .


What this study gets really right I believe is where they say "Acrocanthosaurus could manually grasp prey that was beneath its chest, towards which it may have used its mouth to move prey. Struggling prey would have impaled itself further upon the permanently and strongly flexed first ungual." Perfect, they really nail it here because they are the first - that I know of - to really decouple the forearms from the head as killing instruments in their own right. That is, it is not the claws holding the prey for the head to dispatch it is the head moving prey towards the claws for dispatch!! And this notion of the head deliberately moving prey items towards the killing hand claws does mesh well with the idea of sub equal sized prey items (i.e. loads of baby dinos) forming a heavy part of the diet of these animals. So while I am not the first to make this distinction - that the hands were killing implements independent of the head - I see no reason why this method can not be extended out to a whole range of other meathook handed theropods. Again, I'm not the first to advance this idea but I still maintain it has not garnered widespread exposure and knowledge.

The almost preternatural flexibility of some theropod fingers is something that does not get enough press. Once you look at the range of extension one has to wonder, why? The answer I would suggest is that the fingers took a lot of abuse from prey items squirming while engaged in the meathook bear hug. In order for the fingers to remain hooked in such flexibility would be paramount. No matter how hard and strongly the prey item squirmed the fingers would just flex and move to keep the hapless victim ensnared. Furthermore the basic function of an animal lifted off the ground and struggling against gravity would dictate that the claws dug in deeper to the animals; body cavities penetrated; lungs punctured; ribs cracking; viscera perforated; tendons gouged; and spinal integrity compromised. Abso-fucking-lutley brutal.

It is an ingenious solution: the fingers can bend and extend all over the place to absorb the struggles of the prey item, alternatively the extremely inflexible wrist, forearm, and shoulder maintain a rigid "meathook bear hug". Diabolical.

Probably the best visual I can find for the crazy hyper extendable meathook claws of some theropods is this visual from the recent study on Australovenator forelimb motion.





"I'll Show You the World" Australovenator credit Duane Nash



The megaraptoridae took this forearm dominance to the hilt, they also appear to show a bit more forward mobility in the shoulder joint perhaps even allowing food clenched in the hands to be brought up to the face - an unsettling manner of eating due to the similarity to our own feeding style.


credit Matt A. White, Phil R. Bell, Alex G. Cook, David G. Barnes,
Travis R. Tischler,Brant J. Bassam,David A. Elliott
Also of note is that by allowing the arms to engage in the killing activity the head - and most importantly the eyes - are safeguarded from retaliatory jabs of struggling prey. Many a prey item probably met their end after the initial grasp of the head in the clutches of the meathook bear hug. Trenchant hand claws - especially massive ungual one - dealing the death blow via grievous bodily insults much quickly and safely than injury incurred by the slashing teeth.

Of course I would be remiss to not give a mention to the several studies documenting abundant - and often extreme - forearm pathologies in predatory theropods (Senter & Juengst, 2016) in which a Dilophosaurus got absolutely wrecked, like freaking Monty Python style.

from Senter & Juengst. credit L. Walters (LWPaleoArt)
Senter & Juengst do a nice summary of documented forearm pathologies in theropods in the introduction - therefore saving me a load of work so I will put that here:

Some comments - a lot of mention of T. rex here. That might be a bit surprising considering T. rex should fall more into the "kill with mouth" gestalt. But there might be some reasons. As I will discuss later specific circumstances may have necessitated live prey being put in the arms of T. rex and other mouth dominant killers; the public, and researchers, like to obsess on T. rex so it might just be more looked over; multiple specimens; pathological features may often be omitted or overlooked in descriptions. Overlooked and omitted pathologies is interesting and Senter & Juengst go into some detail in these regards:

I should also give a mention to the work of Rothschild et al, 2001 that did some work on stress fractures and tendon avulsions in theropods as indicative of an active predatory lifestyle. I don't have the original work but it is heavily cited in the wikipedia articles on Ceratosaurus and Allosaurus both of which evince evidence of forearm and manus pathologies. Indeed the well documented trauma that Allosaurus sustained might be indicative of a willingness to sink its meathooks into prey substantially larger than itself!!

Earlier in this discussion I alluded to some of the reasons why a T. rex or other "mouth killing" theropods would have put a live or still struggling prey item in the grasp of its forearms. I also want to suggest some reasons why we should be optimistic about the utilitarian benefits of hauling parcels of food around in the arms (except for abelisaurids of course wink, wink). Let's remain mindful that as reduced as tyrannosaurid arms were, they were not vestigial. They were actually pretty damn powerful, conservative estimates give T. rex about 430 lbs on the bicep curl - a feat no human, not even pro-body builders can ever hope to achieve.

Removal of food from a highly competitive/dangerous arena to a more secure locale. Modern predators do it all the time. Hyenas haul off bits or whole carcasses. Raptors will take their prey off the ground to a safer location to eat. Leopards haul their kills up into trees. Carcasses can attract a lot of undue attention and if you have a way to move your larder to a more secure locale all the better for you.

*Note that, unlike quadrupedal predators that have to carry food in their mouth, theropods carrying food in their hands can still lash out and defend against would be usurpers with their mouth.



Transport of food to a mate and/or offspring. It is weird to think of such prosocial behavior in these animals but not without merit. Especially in light of the recent incubation lengths given for some dinosaurs - if such lengths were emblematic of theropods - then I think the discussion swings more and more into this realm.

Southern Ground Hornbill feeding mate. credit Steve Upton
Maximize exploitation of an abundant ephemeral food source. This is one of the funnest ones for speculative and humorous depictions. A bivouac of baby dinosaurs, a trapped pool of lungfish, a beach full of nesting/hatching sea turtles. Every once in a while predators get a gargantuan smorgasbord of easily acquired and abundant food stuffs and then it is gone. Theropods I would put forth as champions at taking advantage of these windfalls. First swallow as many as you can, then have each arm carry one, and finally cram as many into your maw as possible.

Greedy Daspleto credit Duane Nash


Atlantic Puffin w/sand eels credit Paul Mcllory CC2.0

So to review some of the main points:

- Predatory theropod forearm use has been stymied by our own intuitive understanding of having flexible, grasping forearms. We expect that theropods should have the same use of forearms in "reaching out and grabbing stuff" as we do, so that when we see they are limited in this regard it is thought of as an imperfect, problematic system.

- A study on the forearms of Acrocanthosaurus is one of the first mentions of theropod forearms being decoupled from the head as a killing mechanism in their own right. Forearm killing dominance has also been suggested for megaraptorids but can be extended out towards other theropods to varying degrees.

- There is a general pattern showcasing a trend from more mouth dominant predators to more arm dominant predators. Towards the extreme of forearm dominant predators would be spinosaurids and megaraptorids, towards the mouth dominant extreme would be tyrannosaurids and carcharodontosaurids.

- A meathook type claw morphology combined with a rigid arm anatomy would allow predatory theropods to not only kill but to carry prey/remains manually, useful for several very practical and not mutually exclusive reasons i.e. relocation of carcass, feeding of mates/offspring, hoarding of ephemeral rich food source.

- Forearm pathology in theropods is consistent with a heavy dependence on forearms in acts of predation.





References

Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 331-336.

Senter, Phil; Robins, James H. (2005). "Range of motion in the forelimb of the theropod dinosaur Acrocanthosaurus atokensis, and implications for predatory behaviour". Journal of Zoology266 (3): 307–318.doi:10.1017/S0952836905006989

  1. Snively, E., Cotton, J. R., Ridgely, R. & Witmer, L. M. Multibody dynamics model of head and neck function in Allosaurus (Dinosauria, Theropoda), Palaeontol. Elect. 16(2), 11A 29p (2013).


White MA, Bell PR, Cook AG, Barnes DG, Tischler TR, Bassam BJ, et al. (2015) Forearm Range of Motion in Australovenator wintonensis (Theropoda, Megaraptoridae). PLoS ONE 10(9): e0137709. https://doi.org/10.1371/journal.pone.0137709

Zanno, Lindsay E. (2006-01-01). "The Pectoral Girdle and Forelimb of the Primitive Therizinosauroid Falcarius utahensis (Theropoda, Maniraptora): Analyzing Evolutionary Trends within Therizinosauroidea". Journal of Vertebrate Paleontology26 (3): 636–650. JSTOR 4524610doi:10.1671/0272-4634(2006)26[636:tpgafo]2.0.co;2.









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