Tetrapod Zoology

In 1997, Polish palaeontologist Gerard Gierliński worked together with artist Marta Szubert to create the amazing furry green(ish), life-sized Dilophosaurus model you see here (and below), nicknamed Dyzio. It was displayed at the Polish Geological Institute’s Geological Museum at Warsaw and, while much discussed in the Polish media, is poorly known internationally.

Yes, there are a few inaccuracies (the hands are palms-down, rather than shown with the inwards-facing palms that are more correct), but overall it’s a pretty neat looking model, and it’s also bold and daring. What led Dr Gierliński to create this starling vision? As we’ll see, an interesting and controversial fossil led Gierliński to argue that big early theropods like this really were covered in fur-like feathering…

We now know without doubt that coelurosaurs – the theropod dinosaur group that includes tyrant dinosaurs, ostrich dinosaurs and maniraptorans – were feathered. The more basal coelurosaurs (like tyrants) had simple, quill-like ‘proto-feathers’ on their bodies, while the more bird-like maniraptorans (dromaeosaurs, oviraptors and so on) had complex, vaned feathers on their limbs and tails at least. At the moment, we have very little data on the integument of non-coelurosaurian theropods, so one of the big questions is: how widespread were such structures within Theropoda as a whole? Were baby allosaurs and megalosaurs ‘feathery’, and what about small and juvenile ceratosaurs and coelophysids? The recent discovery of quill-like integumentary structures within ornithischians (like the heterodontosaurid Tianyulong, shown here), combined with their presence in pterosaurs, has made it seem all the more likely that these structures were present throughout Dinosauria (and Ornithodira?), though uncertainty and argument remain [photo below courtesy of Andy Wolniewicz].

It’s relatively little known that a fossil track from the Lower Jurassic Portland Formation of Massachusetts has been interpreted by some as revealing evidence for a feathery pelage in…. shock horror…. a large dilophosaurid. You don’t have to be a dinosaur expert to know what dilophosaurids are: everyone these days is familiar with Dilophosaurus, a large (c. 6 m long), slender theropod famous for its paired, plate-like head crests (it was depicted, for no reason whatsoever, as a hopping, venomous pygmy theropod with a short skull, neck frill and ability to spit thick blinding venom, in the movie Jurassic Park [its 'ancestor' - Crichton's book version - was also in the habit of spitting venom, but at least it looked like the real Dilophosaurus]).

The Portland Formation track (known either as AC 1/7 or as PMNH-EHC 1/7*) is not a new discovery: it’s one of Edward Hitchcock’s finds from the 19th century, and was acquired between 1858 and 1865 when Hitchcock named it Anomoepus major [the fossil is shown below, together with Gierliński's interpretation of it]. Hitchcock considered the trackmaker as a marsupial at times, and as a bird at others (remember that, when he was writing, we were at a very early stage in our knowledge of Mesozoic tetrapod diversity). Most modern workers have regarded Anomoepus tracks as the products of ornithischians. Today it’s obvious that AC 1/7 was produced by a large theropod; it can’t be regarded as an Anomoepus track therefore and was identified by Gierliński (1996) as belonging to Grallator minisculus. Grallator tracks were made by theropods, and some of these trackmakers were large, by which I mean 5 m long and more. At least some of the larger Lower Jurassic Grallator tracks were quite probably produced by Dilophosaurus. Martin & Rainforth (2004) have since argued that AC 1/7 is instead better referred to Fulicopus lyellii (the taxonomy of Grallator, Eubrontes and similar ichnotaxa is very confusing and I think that this name is likely incorrect. I’m going to avoid this whole mess, but feel free to elaborate in the comments if you have time).

* AC = Amherst College. PMNH = Pratt Museum of Natural History at Amherst College.

Feather impressions in a big, early theropod?

AC 1/7 is very interesting: it’s a squatting trace, made when the animal placed its belly, pelvis and metatarsi in contact with the ground. Theropod ‘resting traces’ of this sort have been reported from elsewhere (Lockley et al. (2003) provided a review), the best known and best preserved being the amazing Moenave Formation tracks from Utah, described recently by Andrew R. C. Milner and colleagues (Milner et al. 2009). What makes AC 1/7 unusual is that there are peculiar ‘feathery’ markings located around the sides of the belly and foot impressions.

What could these represent? Gierliński (1996, 1997, 1998) and Kundrát (2004) identified these as feather impressions, and argued that here was evidence for the presence of a feathery pelage in a large, Early Jurassic theropod. Pretty incredible if true: Gierliński wrote of his reluctance to share this hypothesis without becoming thoroughly convinced of its reality (Gierliński 1998, p. 3). By pressing modern feathers into soft substrates, and by looking at resting traces produced by large birds (such as an Andean condor Vultur gryphus at Warsaw Zoo), Gierlinski concluded that the trackmaker was indeed covered with a feathery integument where the structures were ‘more flexible than scales, thinner than flight feathers, and broader than mammalian hairs. Probably they were similar to the furry feathers of flightless birds’ (Gierliński 1996, p. 183). Kundrát (2004) compared the feathery impressions of AC 1/7 with the down of ratite chicks, and also concluded that the AC 1/7 trackmaker was most likely covered by filamentous, ratite-like feathers [image of Dyzio below from here].

Well, so far so good. But you’d be forgiven for being sceptical. Does the impression really demonstrate the existence of a furry/feathery pelt in Dilophosaurus (or, at least, in a Dilophosaurus-like theropod)? Both Gierliński and Kundrát argued that the impressions didn’t match with the drag marks sometimes made in the mud around large animal tracks, and hence insisted that they were produced by structures attached to the animal’s body.

However, other palaeoichnologists (palaeoichnology = the study of ancient tracks), including Paul Olsen, Ray Stanford and Emma Rainforth, have stated that the impressions are far more likely to be sedimentological artefacts. An idea once considered for the traces is that they were caused by vegetation dragging across damp mud. Martin & Rainforth (2004) have since argued that they’re ‘pressure release’ structures caused by the movement of the animal as it shifted its weight when rising up after resting: as it did so, the sediment deformed into a pattern of tiny ridges and grooves, and it’s these that have created the look of feather-like structures.

Is Martin and Rainforth’s argument any more realistic than Gierliński’s, or Kundrát’s? I find their explanation more convincing, and I also can’t help but be swayed by the fact that more workers have favoured the ‘artefact’ explanation than have favoured the ‘feather’ explanation. It’s a shame really, as the idea that Dilophosaurus was decorated by a sort of ratite-like furry feathering is obviously cool. But, as Martin & Rainforth (2004) stated, even if the ‘artefact’ explanation is correct, the possibility of feathers in early, non-coelurosaurian feathers is not precluded. We need more evidence.

My initial plan with this ‘article’ was simply to post the photos of Dyzio and accompany them with a few tens of words (by the way, this article contains more images of Dyzio than any other place on the web, so far as I can tell). Alas. And, incidentally, this was all inspired by something altogether different that I hope to discuss some time over the next few days. Things here are kinda busy though… [photo below courtesy of Andy Wolniewicz; thanks again Andy].

For other articles on feathered non-avian theropods, see…

And here’s some more Dyzio, this time from wikipedia.

Refs – -

Gierliński, G. 1996. Feather-like impressions in a theropod resting trace from the Lower Jurassic of Massachusetts. Museum of Northern Arizona Bulletin 60, 179-184.

- . 1997. What type of feathers could nonavian dinosaurs have, according to an Early Jurassic ichnological evidence from Massachusetts? Przegląd Geologiczny 45, 419-422.

- . 1998. The furry dinosaur. Dinosaur World 4, 3-5 [author's name mis-spelt 'Geirlinski'].

Kundrát, M. 2004. When did theropods become feathered? – evidence for pre-Archaeopteryx feathery appendages. Journal of Experimental Zoology (Mol. Dev. Evol.) 302B, 355-364.

Lockley, M., Matsukawa, M. & Li, J. 2003. Crouching theropods in taxonomic jungles: ichnological and ichnotaxonomic investigations of footprints with metatarsal and ischial impressions. Ichnos 10, 169-177.

Martin, A. J. & Rainforth, E. C. 2004. A theropod resting trace that is also a locomotion trace: case study of Hitchcock’s specimen AC 1/7. Geological Society of America, Abstracts with Programs 36 (2), 96.

Milner, A. R. C., Harris, J. D., Lockley, M. G., Kirkland, J. I. & Matthews, N. A. 2009. Bird-like anatomy, posture, and behavior revealed by an Early Jurassic theropod dinosaur resting trace. PLoS ONE 4(3): e4591. doi:10.1371/journal.pone.0004591

Comments

#1 Chaz
September 7, 2009

It’s strange, but somehow Dyzio ‘looks’ right.
Chaz.
#2 Allen Hazen
September 7, 2009

The reddish sandstone of the Portland Formation is what provides the “Brownstone” characteristic of New York City’s older and lower-rise areas. Anybody have a reference where it would be easy to look up where the “type” Portland Formation is? The formation extends across the state line between Massachusetts and Connecticut; some of the major quarries supplying “brownstone” to New York were in Portland, Connecticut (across the Connecticut River from Middletown): my guess is that this is what the formation is named for.

I never saw fossils in situ in my childhood years in Connecticut, though I remember some oddly shaped bumps in the stones in one wall…
#3 Michael
September 7, 2009

Seems to have started a trend, a few other furry Dilophosaurus models in Poland:

http://commons.wikimedia.org/wiki/File:Dinusie_biegna.JPG

http://commons.wikimedia.org/wiki/File:Baltow,Poland_Dilophosaurus.jpg
#4 Darren Naish
September 7, 2009

Thanks for those Michael, interesting I should also note that Dilophosaurus was shown as being feathery/furry in Felder and Colagrande’s In the Presence of Dinosaurs. This was nothing to do with AC 1/7 (so far as I know): Colagrande depicted all kinds of dinosaurs (including juvenile ornithischians) as ‘furry’.
#5 Andy Wolniewicz
September 7, 2009

great to read an article about palaeontological studies in my mother country!
thanks, keep up the good work!
#6 David Marjanović
September 7, 2009

great to read an article about palaeontological studies in my mother country!

About five sites from Devonian to IIRC Cretaceous are discovered in Poland every year. There just aren’t enough palaeontologists to study them. But the amazing news stories will keep rolling!
#7 johannes
September 7, 2009

Speaking of feathered non-tetanuran theropods, the Bullyland *Liliensternus* has a crest or tuft of protofeathers on the top of its head, but is otherwise scaly. This model is actually a scaled-down replica of the life-sized *Liliensternus* reconstruction from the Staatliche Museum für Naturkunde/Museum am Löwentor in Stuttgart, Germany. The museum boldly calls *Liliensternus* “the king of predators”, but I think some of the contemporary crurotarsans would probably dispute that claim ;-D
#8 Lars Dietz
September 7, 2009

“Speaking of feathered non-tetanuran theropods, the Bullyland *Liliensternus* has a crest or tuft of protofeathers on the top of its head, but is otherwise scaly. ”

I’ve seen many “Syntarsus” resaurations that also have this, probably inspired by the one in Predatory Dinosaurs of The World by Greg Paul (which however also has feathers elsewhere on the body).
#9 AD
September 7, 2009

sort of amazing that we have information on what a particular theropod did for a few moments hundreds of mya in the Jurassic- rested on the mud, then got up, compressing the mud in a particular way (according to one theory) or leaving feather impressions (other theory).

I like the model but in addition to the wrists, it seems to me that the right leg is hyperextended or something..
#10 Andrea Cau
September 7, 2009

Why only small sized species and babies of large sized dinosaurs are usually depicted with “protofeathers”? In my opinion, the “big-dinosaurs-weren’t-fuzzy” seems a useless “dogma”…
Are there some biological arguments against a large-bodied dinosaur (bigger than Dilophosaurus) with fuzz “protofeathers”? Most workers seem to use a mammalian analogy for rejecting the presence of these integument in large-bodied forms, saying, for example, that baby tyrannosaurids would be fuzzy, whereas adults not because they were “like adult elephants”.
Big saurischians were not elefants. Are modern large mammals good tegumentary and thermo-physiological analogues for mesozoic dinosaurs?
Is there an upper mass limit for a thermically efficient fuzzy vertebrate? If elongate neck and tail and the air sacs were parts of the thermoregulatory system, it would be possible that this mass limit, if present, was upper in a long tailed, long necked, air sac-bearing big saurischian than in a (relatively) short tailed, short necked big mammal lacking air sacs.

(I’m sorry if my English in not perfect)
#11 Matt Wedel
September 7, 2009

I’ve seen many “Syntarsus” resaurations that also have this, probably inspired by the one in Predatory Dinosaurs of The World by Greg Paul (which however also has feathers elsewhere on the body).

The feathery Syntarsus goes back to Bakker’s 1975 “Dinosaur Renaissance” article in Scientific American. That might have been the first feathered theropod restoration in modern (i.e., post-Deinonychus) times. Can anyone confirm/deny?
#12 Jerzy
September 7, 2009

Gierlinski paper, if I remember correctly, appeared just before the discovery of several famous feathered theropod fossils. Now, I suppose, it would not generate so much controversy.

I was always convinced that these impressions were made of feathers. Ockham’s razor here, alternatives were just too stringy. I don’t remember ever seeing tracks of modern animals distorted by dragged vegetation, dried algae, ripples on the sand etc to create similar patterns. If anything, hair of mammals just doesn’t show. The critics actualy failed to show them, too.
#13 M. O. Erickson
September 7, 2009

*points to the second paragraph of preceding comment*

I agree. I am firmly convinced that the impressions on PMNH-EHC 1/7 are, indeed, feathers of some sort. I just don’t find the “artifact” explanations in any way convincing.
#14 M. O. Erickson
September 7, 2009

“it was depicted, for no reason whatsoever, as a hopping, venomous pygmy theropod with a short skull, neck frill and ability to spit thick blinding venom, in the movie Jurassic Park”

In defense of the Stan Winston crew, the small size of the animal was because it is intended to be a juvenile (Dennis Nedry actually alluded to this before he was eaten: “Oh, I thought you were one of your big brothers, you’re not so bad”). It’s short snout was apparently also due because of the animal’s juvenile status – although the tyrannosaur-like binocular vision was, of course, wrong. As for why they chose to depict a juvenile, apparently Speilberg wanted it smaller so the audience wouldn’t confuse it with the dromaeosaurs. Perhaps this also explains the addition of the speculative (and completely, totally, stupendously unlikely) flaring frill, which was not present on the dilophosaurs in the book.

About hopping… Didn’t Mike Raath suggest Coelophysis rhodesiensis hopped, based on two side-by-side theropod tracks from the same formation as the bone bed? I don’t have his original description.
#15 Kevin Schreck
September 7, 2009

Damn it, Darren! You still have us wanting more, with each new bit of information!

Oh, and a fuzzy Dilophosaurus?: DO WANT.
#16 Nathan Myers
September 8, 2009

Putting on my ignoramus hat here, what’s so stupendously unlikely about a neck frill? It’s one thing to say there’s no positive evidence for it, entirely another to insist it couldn’t be there in any of a host of similar species over many millions of years.

For unlikely, consider pterosaurs budding off from the neural spines of sauropods.
#17 M. O. Erickson
September 8, 2009

“Putting on my ignoramus hat here, what’s so stupendously unlikely about a neck frill? It’s one thing to say there’s no positive evidence for it, entirely another to insist it couldn’t be there in any of a host of similar species over many millions of years.”

I said “stupendously unlikely” mainly for two reasons:

1) In exant taxa with neck frills (i.e. Clamydosaurus), there are prominant muscle scars on the cervical vertebrae were the “frill-erecting muscles” attach. These appear to be wanting in Dilophosaurus (although I’m not sure anyone has actually purposely looked or them…).

2) Clamydosaurus (the extant animal with a frill that most resembles that of the Jurassic Park dilophosaur) is a smallish-sized prey species, and its frill mostly exists to make the animal look more threatening to would-be attackers. Dilophosaurus, being the top predator of its enviornment, would probably not have had nor needed such a structure.

I do, however, admit to being sypethetic to the idea of a venomous Dilophosaurus. For one thing, although there is no osteological evidence for venom glands in Dilophosaurus, the same is true of varanids, which are venomous (Fry et al. 2006). I also find it a wee bit (emphisis on ‘wee bit’) suggestive that Varanus komodoensis, which has a suprisingly weak bite for a predator, utilizes venom (like all varanids). Dilophosaurus also apparently had a weak bite (Welles 1984), and may have possibly been venomous as well. But note that I’m not endorsing the extremly speculative idea of venomous dilophosaurs, I am merely stating that I beleive it to be a distinct possibility.

Refs.

Fry, B.G.; Vidal, N; Norman J.A.; Vonk F.J.; Scheib, H.; Ramjan S.F.R; Kuruppu S.; Fung, K.; Hedges, B.; Richardson M.K.; Hodgson, W.C.; Ignjatovic, V.; Summerhays, R.; Kochva, E. (February 2006). Early evolution of the venom system in lizards and snakes. Nature 439: 584–588.

Welles, S. P. (1984). Dilophosaurus wetherilli (Dinosauria, Theropoda), osteology and comparisons. Palaeontogr. Abt. A 185: 85–180.
#18 Colin Swift
September 8, 2009

Far be it from me to leap (hop?) to the defence of Messrs. Crichton and Spielberg, but I always understood that the poor little Dilophosaurus in the first Jurassic Park film was intended to be a juvenile, hence its small size and (potentially) the shortish skull. Re the venom, I remember seeing several serious discussions over the decades leading up to the book regarding the allegedly weak jaws of Dilophosaurus, so venom and scavenging were both hypothesized as potential lifestyles that would allow such a ‘weak-jawed’ theropod to feed itself. (Never mind, of course, the complete lack of dental evidence for venom delivery, and the obviously STRONG jaws of modern mammalian ‘scavengers’ such as hyenas…) And I understand that dilophosaurid jaws are no longer considered particularly weakly-muscled anyway; but looked at in context of the times (the book research would have been about 20 years old – an eternity in light of modern paleontology), some of the features of the JP Dilophosaurus are not unreasonable. I’m as puzzled as anyone else by the neck-frill, of course…

I’m NOT defending the Crichton/Spielberg interpretation, just putting it in context….

But, re Dyzio, here, it’s odd, but I am getting more and more acclimatized to seeing feathered theropods – as the first comment said, this ‘looks right’ somehow… or at least, it no longer looks ‘wrong’…
#19 Colin Swift
September 8, 2009

My apologies for repeating the comments made in the post preceding my own. I thought I had read all the way to the end, but missed this one.

However, two serious questions about theropods:

1. at what point in the fossil record do we see theropods adopting the ‘bird-hand’ instead of ‘bunny-hand’ default rotation of the forearm? Presumably their more quadrupedal ancestors would have held the forearm/manus in a ‘bunny’ (TM) orientation; so when, and for what advantage did the rotation first appear?

2. re the ‘hyperextension’ of the ankle alluded to in this model – given that modern ratites (indeed most long-legged extant dinos) seem to default to a fully-extended ankle, is there a skeletal contra-indication in their much heavier predecessors? Intuitively, it would seem that a fully-extended ankle would reduce stress on muscles and connecting tendons.
#20 Leonardo Ambasciano
September 8, 2009

Thank you, Darren, for this brilliant post. On the same topic see:
- an interview with Robert Bakker on “Prehistoric Times”, jan.-feb. 1997, discussing Hitchcock’s fuzzy animals (I remember Bakker quoting ?”ornithischian” proto-feathers around the footprints of the crouching/resting/squatting dinosaur – I’m not sure about it, so please correct me if me I’m wrong);
- a very interesting discussion [ended on 12th jan., 2001] on the “Dinosaur Mailing List”…click here
http://dml.cmnh.org/2001Jan/msg00336.html (a useful comment by D. Marjanović)
[there was a lot to say on Gerard Gierliński "Feather-like Impressions in a Theropod Resting Trace from the Lower Jurassic of Massachusetts", 179 -- 184, in Morales (ed.), "The Continental Jurassic", Museum of Northern Arizona Bulletin 60, 1996].

I’ve written a few lines on this subject on http://geomythology.blogspot.com/2009/05/jurassic-dinosaurian-feathersor-just.html

Leonardo Ambasciano
#21 Thomas R. Holtz, Jr.
September 8, 2009

Colin:

No, there is no reason to think that the JP film Dilophosaurus was intended to be a juvenile. It is simply a bad design. And the “weak-jawed” Dilophosaurus had been debunked by the time of the writing of Predatory DInosaurs of the World (one of the main sourcebooks for Crichton and Speilberg). The problems with the dinosaur as portayed are for plot reasons only, not backed by science even at that time.

And the palms-inward position is basal to Saurischia as a whole (present in herrerasaurids, basal sauropodomorphs, and coelophysoids on up within Theropoda).
#22 David Marjanović
September 8, 2009

Didn’t someone claim in a paper that “plant prints” like the one in question have been found all over the sediment level where the footprints come from?

For unlikely, consider pterosaurs budding off from the neural spines of sauropods.

Erm. Dr Evil? That already exist, too.

One word: Tantulocarida. Little marine crustaceans with a complicated life cycle where the males form, at adult size, out of undifferentiated tissue on the back of the previous generation. No zygote, no embryo, AFAIK no growth. Flummoxing. Flabbergasting. Batshit insane.

Give it up! You’ll never manage to create a fiction that’s stranger than reality. =8-)

at what point in the fossil record do we see theropods adopting the ‘bird-hand’ instead of ‘bunny-hand’ default rotation of the forearm? Presumably their more quadrupedal ancestors would have held the forearm/manus in a ‘bunny’ (TM) orientation

Funnily enough, that’s not the case. Crocodiles are still limited to the bird-hand position – they circumvent it by sprawling.

I don’t know how often and how late the bunny-hand position evolved in ornithischians, but the recent description of the forelimb of Camptosaurus (Carpenter, Bulletin of Carnegie Museum) shows that, despite its adaptations for weight-bearing, it was limited to the bird-hand position and can’t have been more quadrupedal than a kangaroo.

Antetonitrus was capable of free rotation; Plateosaurus was bird-hand only (and bipedal-only).
#23 Strangetruther
September 8, 2009

It’s useful to keep all options open until the answer is known “for sure” (ie, never in palaeo!) while remembering as ever, that our “best” explanation is our best explanation. With regard to feathered theropods, save some of your betting money for a theory which explains the original bipedality of dinosaurs…

As far as I know, there are very few fossilised impressions of any attached feathers left in mud, from any age – presumably dinobirds avoided getting their clothes messy. Limbs bearing big feathers would be kept away from the ground as much as possible (admittedly not always easy for extremists where all their limbs had flight feathers) so bipedalism would be expected if ancestors had large feathers on the forelimbs. Add to this the surprising difficulty of evolving a feather from a feather-duster format complex fibre, which seems easy to do until you try to imagine any detailed scenario, and you are only left with a flat “solid” blade as the original format of a flight feather.

Fibrous feathers would end up as herringbone fibres in large flightless types, and solid plates would become single spines or fibres (or any rows of non-“herringbone-fibre” decorations on the back of your favourite archosaur). This explains well the difference in archosaur pelage/decorations that we see.

While all archosaurs have and probably had scales, we should now look to narrow the gap of uncertainty between types with and without herringbone fibres.
#24 seabold
September 8, 2009

I too always assumed that the Dilophosaur in JP was intended to be a juvenile (although in the book it was an adult), there is also the juvenile T-Rex in the book and a juvenile tricertops although in the later book they pretty much negated that by stating that the animals were all held on a seperate island until mature. Bad continuity.

Crichton does state at several points that they aren’t sure if the animals they created are true to nature because of the manipulation and splicing going on. My guess was that they made the animal smaller to fit the scene where Dennis Nedry is attacked INSIDE the vehicle. A 15 tall dilophosaur wouldn’t fit in the jeep. That being said, the head was poor design and the frill was pure fantasy.
#25 Darren Naish
September 8, 2009

Tom (comment 21) is right: there’s no indication that the JP Dilophosaurus was meant to be a juvenile. It was just a totally bastardised version of the real thing. The proof? Shay & Duncan (1993), in The Making of Jurassic Park, say ‘The dilophosaurus represented the film’s only serious departure from scientific veracity. In actuality, the beast stood about ten feet tall; but for movie purposes, and to avoid confusion with the velociraptors, it was decided to make it about four feet tall instead’ (pp. 35-36).

As I learnt from Tim Haines just the other day, one of the problems that the media encounters when representing theropods for a popular audience is that they’re all so samey. People, apparently, struggle to distinguish, say, a Velociraptor from a juvenile tyrannosaur. This partly explains stuff like the neckfrill on the JP dilophosaur. And Nedry refers to it as different from its ‘bigger brothers’ because he’s relieved to see a small animal rather than a giant one: this is not a comment on the animal’s ontogenetic stage.

Shay, D. & Duncan, J. 1993. The Making of Jurassic Park. Boxtree, London.
#26 M. O. Erickson
September 8, 2009

I am glad the Jurassic Park dilophosaur issue is cleared up, with no thanks to me and all thanks to Tom and Darren.

“Never mind, of course, the complete lack of dental evidence for venom delivery”

As I stated in comment 17, we simpy cannot use a lack of “dental evidence” against the idea of venom, becaue venomous varanids lack any osteological correletes for their venom glands. If Varanus were totally extinct and one were pondering its fossilized skull, one would note the lack of “dental evidence” and conclude it to have lacked any sort of venom, when in fact the opposite is true.
#27 David Marjanović
September 8, 2009

so bipedalism would be expected if ancestors had large feathers on the forelimbs.

Theropods — saurischians in fact — are already bipedal by default. Large feathers evolved later.

Add to this the surprising difficulty of evolving a feather from a feather-duster format complex fibre, which seems easy to do until you try to imagine any detailed scenario, and you are only left with a flat “solid” blade as the original format of a flight feather.

What do you mean, and have you read the papers by Prum and Brush?
#28 Paul S
September 9, 2009

Just wanted to chip in. From the Cinefex #55 article (pp. 81-3), also by Jody Duncan.

‘Although the actual dilophosaur on which the spitter was based was about ten feet tall – and was not, at least to anyone’s knowledge, equipped with toxic venom or a vibrating cowl – Spielberg decided to make his version of it much smaller, in part to distinguish it from the velociraptors which would play a major role in the film.

As with the other dinosaurs, the spitter had its origin on the drawing board of Crash McCreery. “I started with the skeleton of a real dilophosaur and then evolved my drawings from that. The flaring cowl was based on that of an Australian frilled lizard. Spielberg’s people came up with that idea, which I thought was pretty cool.”

Credit (or responsibility) where due, I fear.
#29 Diego
September 9, 2009

Hmm, vegetation dragged over it? Perhaps the Dilophosaur was trying to hide its tracks.

Just kidding.
#30 Jerzy
September 9, 2009

Maybe somebody can explain why theropods had hands aligned in a position unsuitable for using them?

Either we don’t understand their functional anatomy – or reconstructions are wrong!
#31 Dawid Mazurek
September 10, 2009

“Were baby allosaurs and megalosaurs ‘feathery’, and what about small and juvenile ceratosaurs and coelophysids?”

And what about adults? It’s higly unlikely for a dinoaur to lost feathers and gain scales in ontogeny. I had a nice reference to a science blog post on that… but cannot find it right now…
#32 David Marjanović
September 10, 2009

Maybe somebody can explain why theropods had hands aligned in a position unsuitable for using them?

“Unsuitable”??? That position is great for grabbing prey and holding it, as well as for making defensive swipes.
#33 Strangetruther
September 10, 2009

so bipedalism would be expected if ancestors had large feathers on the forelimbs.

Theropods — saurischians in fact — are already bipedal by default. Large feathers evolved later.

I think not. These large feathers were from a time early enough to somewhat precede, cause and explain bipedality. I’m talking ancestral archosaur. You don’t think there’s much evidence for Permian/E Triassic feathers? Think how long it took us to find any evidence of feathered non-”birds” from the Cretaceous.

Add to this the surprising difficulty of evolving a feather from a feather-duster format complex fibre, which seems easy to do until you try to imagine any detailed scenario, and you are only left with a flat “solid” blade as the original format of a flight feather.

What do you mean,

“You must think about this.” (Miyamoto Musashi)

and have you read the papers by Prum and Brush?

I course I have but I wish I hadn’t. They should be read only as a cautionary tale of claiming scientific evidence in vain. Saying that the cellular process of feather formation was evidence for their evolutionary theory because it was compatible with it, without mentioning that alternative versions are equally compatible if not more so, is bad science. The cellular machinery is more complex than needed for down-type feathers, but complex enough to produce blade-shaped feathers. I’m surprised you didn’t notice any of this!
#34 David Marjanović
September 10, 2009

You don’t think there’s much evidence for Permian/E Triassic feathers?

There is no known evidence for Permian or Early Triassic feathers.

I still don’t see why bipedality in archosaurs needs more of an explanation than bipedality in squamates.

What do you mean,

“You must think about this.” (Miyamoto Musashi)

No, we’re in science here. When I don’t understand what you write, and you can’t explain it, that’s bad for you, not for me. If you can’t explain it, chances are good you haven’t understood it yourself. Worse yet: it gives the appearance that you’re making an argument from personal incredulity.

Musashi is a novel, right? I haven’t read it.

The cellular machinery is more complex than needed for down-type feathers, but complex enough to produce blade-shaped feathers. I’m surprised you didn’t notice any of this!

Huh? The cellular machinery of extant birds is complex enough for contour and flight feathers (types IV and V), so…
#35 Strangetruther
September 10, 2009

For unlikely, consider pterosaurs budding off from the neural spines of sauropods.

I wish I could remember more about a TV program I saw about a year ago where a marine biologist was saying there were two species apparently quite closely related – starfish? – one of which developed through a sequence typical of the group and the other of which developed from something that looked like a crustacean – or was it a mollusc? – type larva.
#36 Hai~Ren
September 10, 2009

[quote]I wish I could remember more about a TV program I saw about a year ago where a marine biologist was saying there were two species apparently quite closely related – starfish? – one of which developed through a sequence typical of the group and the other of which developed from something that looked like a crustacean – or was it a mollusc? – type larva.[/quote]

Departing from tetrapods, I believe you’re talking about Luidia sarsi, which has a very interesting larval stage. You can read all about it here.
#37 Strangetruther
September 11, 2009

[quote]I wish I could remember more about a TV program I saw about a year ago where a marine biologist was saying there were two species apparently quite closely related – starfish? – one of which developed through a sequence typical of the group and the other of which developed from something that looked like a crustacean – or was it a mollusc? – type larva.[/quote]

Departing from tetrapods, I believe you’re talking about Luidia sarsi, which has a very interesting larval stage. You can read all about it here.

Ah – thanks Hai.
#38 Christopher Taylor
September 11, 2009

Alternatively, you could be thinking of asterinid starfish, where species that are very similar as adults may have very different development, depending on whether they go through a planktonic larval stage and metamorphosis (the ancestral state), or whether they hatch directly into small pre-developed starfish and don’t metamorphose (the derived state, but seems to have evolved multiple times). As far as I know, the larval stage of the indirect developers isn’t any more mollusc-like than any other sort of echinoderm, but it’s not beyond the possibilities of poor TV phrasing or misrememberance.
#39 Strangetruther
September 11, 2009

Thanks for that too, CT. I suppose I’d better look into these.
#40 grok
September 14, 2009

That’s one honking big rooster you’ve got there. Tastes like chicken too, I’ll bet.
#41 Rob Jase
September 15, 2009

That’s it! I’ve been overdue to visit Dinosaur Park, Rocky Hill, CT, and now I have an even better reason to go. I’ll bring a magnifying glass this time around to check for feather impressions.

But if I don’t find any the fact that most of them are still buried will frustrate the heck out of me.

There is also a small site in Middletown, CT, where these same tracks are exposed, unfortunately I don’t remember how to get there.

And I know of at least two other places in the area where tracks were found but never publically announced so they could be sacrificed to install highways.
#42 Nathan
July 13, 2011

For real, though… why does anybody care whether or not the Dilophosaurs in Jurassic Park spit venom and had a frill? It’s a move that was meant to entertain, not an educational tool. And anybody arguing that the actual dinosaur might have actually spit or actually had a frill is an idiot. It was an idea based on what would be cool to see in a movie, not based on scientific evidence. The odds that they would’ve stumbled upon something that specific by accident would be so incredibly tiny that it would be nothing short of a miracle.
There is also the fact that one of the major plot points of Jurassic Park is that the dinosaur’s are NOT historically accurate because their DNA has been tampered with, the gaps filled in with the DNA of various other animals. This is why they were able to breed despite the fact that they were all created female.
As for whether or not it was a juvenile Dilophosaur or a full grown one, that issue is up for debate. This is something Jurassic Park fans have been arguing about for years. Maybe it was, maybe it wasn’t. There is plenty of Jurassic Park media that suggests Diolophosaurs did grow to 10 – 15 feet tall (such as trading cards and comic books which depict them that way). So let’s not instantly shoot down ideas.