Long and Schouten's Feathered Dinosaurs, a review

Another book review. I've had a lot of them to do lately.

The idea that feathers decorated and insulated the bodies of the small bird-like predatory dinosaurs of the Jurassic and Cretaceous - the coelurosaurs - is no longer a speculation limited to controversial artwork, but the mainstream view [for background info see Feathers and filaments part I and part II]. Spectacular fossils from the Lower Cretaceous rocks of Liaoning Province in north-east China have shown that feathers, and simpler, filament-like 'proto-feathers', were widespread among coelurosaurs, being present in compsognathids and basal tyrannosaurs as well as in the maniraptorans (the oviraptorosaurs, troodontids, dromaeosaurs and kin). In this new book, author John Long and artist Peter Schouten have worked together to show-case a diversity of coelurosaurs (many of which are only recently discovered) in modern, state-of-the-art life restorations.

The author is an Australian palaeontologist who has published technical articles on dinosaurs, as well as on Mesozoic marine reptiles, pterosaurs and other fossil groups. Schouten is well known for the several volumes he has illustrated for author Tim Flannery: Possums of the World: a Monograph of the Phalangeroidea (Geo Publications, 1994), Tree Kangaroos: A Curious Natural History (Reed Natural History, 1997), A Gap in Nature (William Hieneman, 2001) and Astonishing Animals: Extraordinary Creatures and the Fantastic Worlds They Inhabit (Atlantic Monthly Press, 2004). Like A Gap in Nature and Astonishing Animals, Schouten's artwork is the main focus of Feathered Dinosaurs (rather than Long's text), so it would be wrong for a reviewer to comment on the text and to merely state in passing that there were lots of pretty pictures.

I love Schouten's art and think that his renditions are novel, insightful, exciting and often just beautiful. The giant compsognathid Sinocalliopteryx is depicted attacking a dromaeosaur (an interaction inspired by the fact that the Sinocalliopteryx type specimen has a dromaeosaur leg preserved in its stomach) and Saurornitholestes pulls flesh from the immense carcass of a fallen Quetzalcoatlus, the sheer size of the pterosaur being wonderfully conveyed by the fact that, even on this double-page spread, all we get to see of it is its eye and the back of its head. An adult Epidendrosaurus feeds its young, and the alvarezsaurid Shuvuuia - shown as having a head resembling that of a pangolin - licks termites from an opened gallery in rotten wood. Buitreraptor gapes wide in a silent scream, and both Ornitholestes and Huaxiagnathus (referred to throughout the book as Huaxignathus [sic]) are shown clambering around in trees (homages to Paul's 1988 Predatory Dinosaurs of the World?) [I can't show any of Schouten's pics here for copyright reasons, but the adjacent image is a screen-capture of what you can see at Schouten's website].

Schouten's attention to detail is so good that we see the ticks nestled in the folds of skin around the eye of Alioramus. Scavenging insects are visiting the eyes and decomposing flesh of that dead Quetzalcoatlus, tyrannosaurs have eyelashes and fine hairs in their ear and nasal orifices, and frayed feather-tips betray the fact that maniraptoran hand feathers must have been subject to a reasonable amount of erosion. These animals are vibrantly alive, and they fit into their environments in the way that real animals should.

In an introductory section, Schouten writes that painstaking research and extensive inspiration from living animals have allowed him to devise the colour patterns and integumentary details that he has. While the convention among good palaeo-artists has been simply to do what looks good (to paraphrase Greg Paul), Schouten describes how he tries to imagine the creature's biology when restoring its appearance. What did it eat? How did it evade predators? How did it attract mates? The technique clearly works: his animals are complicated and wonderful, often with dashing colour schemes. In fact my favourite thing about the book is that each painting is accompanied by an 'artist's note' where Schouten explains why he has depicted some of the details he has. There are some really nice little nuggets of information in these bits. Animals inferred to have foraged out in bright sunlight are mostly white; those from shady, wooded habitats are dark but sometimes with bright stripes or prominent pale markings that would have stood out to conspecifics. Sinocalliopteryx - inferred from its stomach contents to have bolted down big chunks of prey animals on occasion - is shown with an expandable throat sac that would have allowed this behaviour. Therizinosaurs are shown with bluish tongues because (inferred here to be browsing herbivores) they would have required a high amount of melanin to help protect the tongue from sun exposure, and calloused facial skin and bristles around the eyes help protect them from vegetation. Schouten even mentions the idea that naked skin patches on the face of an oviraptorosaur would have been accentuated in the eyes of a conspecific, given that non-avian dinosaurs could (like birds) probably see in the ultraviolet part of the spectrum.

It's clear in cases that he had the appropriate literature to hand when bringing the animals to life. Archaeopteryx, for example, is shown with a slightly raised second toe, a detail that has often been considered incorrect since first proposed (by Greg Paul) in the 1980s. The idea that the second toe of Archaeopteryx might have been hyper-extendable is based on the fact that the distal condyles of the basal-most phalanx are dorsally expanded relative to the long axis of the phalanx (Paul 1988, 2002). This is most obvious in the Eichstatt specimen but might also be present in the London and Berlin specimens too. Elzanowski & Paśko (1999) and Elzanowski (2002) argued that this could be ignored, as in fact the entire phalanx of the Eichstatt specimen had been rotated, such that the ventral surface had become the dorsal. I know that this has been accepted by at least some experts (Peter Wellnhofer, for example, promoted Elzanowski & Paśko's suggestion at a 2008 meeting). In fact Elzanowski & Paśko (1999) are unlikely to be right as, if the second phalanx was rotated, the second phalanx and ungual must have been rotated with it... yet they don't appear to be: the ungual is preserved parallel to those of digits III and IV. The 10th or Thermopolis specimen [shown here] settles the matter once and for all: its fully articulated foot clearly exhibits distal condyles that extend dorsally (Mayr et al. 2005, 2007), hence making the toe hyper-extendable as Paul has been saying, and as Schouten shows.

Schouten's theropods are undeniably avian in appearance, and among the most avian of non-avian theropods depicted so far. But I actually think that the birdiness often goes too far, especially when the modern-day inspiration that Schouten drew from is all too obvious. Nemegtomaia looks based on a Helmeted guineafowl, Tsaagan is just a griffon vulture with teeth, Proceratosaurus is modelled after a Helmeted hornbill, and Sapeornis is all too much like a Golden eagle, but with hand claws and a toothy bill. And while it's true that many oviraptorosaurs have superficially parrot-like heads, Schouten's oviraptorosaurs almost literally have parrot heads: it looks as if the head of, say, a Military macaw or whatever has been grafted on to an oviraptorosaurian body.

The bad news is that Schouten's lack of experience with non-avian dinosaurs shows. The most obvious problem with his dinosaurs is that many of them are far too chunky, with stout hindlimbs and bodies way broader than they should be. Two offenders stand out among all others. An Albertosaurus sarcophagus is an immense, wide-bodied hulking creature with column-like hindlimbs (ironically, Long's accompanying text describes it as 'gracile' and 'slender'), while the body of a Dromaeosaurus is shown as being so broad relative to the animal's head that the animal looks like a toothed emu with stripes. The Albertosaurus is particularly offensive because it has two cow-like brow horns that projects upwards and forwards from in front of its eyes. There is, of course, always the possibility that live animals sported soft-tissue structures for which all fossil evidence has been erased, but the bony preorbital horns evident on the Albertosaurus skull are not compatible with what Schouten shows [Albertosaurus skull shown here from Palaeos.com].

A Tyrannosaurus rex - noted by Schouten as being a battle-scarred male - is shown with a series of large keratinous knobs along the top of its head. Again - so far as we can tell from the fossils - this is just downright wrong. T. rex does preserve bony evidence for large keratin hornlets, bosses and ridges, but they don't really correspond with what Schouten has depicted (it had a rounded boss behind the eye, a blunt hornlet in front of and above the eye, and a bumpy ridge along the midline of the snout). The hands of a hadrosaur shown in one painting, and the hand of a sauropod shown in another, are also totally inaccurate when compared to the fossil evidence. Sinosauropteryx looks extraordinarily heavy-bellied and its hands aren't right: the palms face downwards in the old 'bunny rabbit' pose. Caudipteryx is depicted with a full compliment of small, needle-like teeth lining its jaws, and hands with three clawed fingers. In fact, its teeth were limited to the front of the jaws alone and, bizarrely, its third fingers lacked claws and were blunt-tipped (Zhou et al. 2000). Jinfengopteryx (initially described as an archaeopterygid bird but widely thought among theropod workers to actually be a small troodontid) has a thoroughly screwed up right foot: rather than the second toe being shown as shorter than the third, it is longer and hence the longest toe on the foot. That's just wrong, unless this animal is meant to be a mutant.

Pelecanimimus is given a hooked tip of the upper jaw - this is contradictory to what's present in the fossil [shown here] - and its teeth are too long and not as closely packed as they are in the fossil. Juravenator looks just like a baby Komodo dragon [the fossil is shown below]. While originally inferred to be scaly-skinned due to the discovery of scaly, featherless skin on the tail (Göhlich & Chiappe 2006), in the absence of better evidence we should infer an integumentary covering similar to that of other small coelurosaurs for this taxon (fibres are preserved adjacent to Juravenator's tail (Göhlich et al. 2006) but they look like muscle or collagen fibres). Indeed, Schouten notes that the live animal may have had fibrous integumentary structures when alive (like those present on, for example, Sinosauropteryx and Dilong), and again I would remind people that rotting carcasses often lose their fur or feathers during decomposition (the Montauk monster now provides the world's best example of this sort of thing). Juravenator is also interesting because its phylogenetic position has been controversial. Originally described as a compsognathid, it was argued by Butler & Upchurch (2007) to be more basal, and this controversy is reflected in the book. When, in 2005, I looked at Juravenator in detail I actually came away with the impression that it wasn't a coelurosaur at all, but in fact a more basal theropod (essentially a mini-carnosaur). In a strict consensus analysis I ran for my phd however, it was recovered as part of a polytomy near the base of Maniraptoriformes (the ornithomimosaur + maniraptoran clade), as were other 'compsognathids'.

On the subject of phylogeny and taxonomy, a couple of problematic statements appear in the book. The name 'Coeluria' is used (no such group is presently recognised, though the name has been used in the past) and 'Oviraptosauria' appears in a few places (sic: it's actually Oviraptorosauria). Falcarius, Beipiaosaurus and Alxasaurus are classified as part of Therizinosauridae. Though Sereno (1998) used Therizinosauridae for all members of the therizinosaur clade, it better reflects current phylogenetic recommendations (Clark et al. 2004, Kirkland et al. 2005) to regard basal therizinosaurs as outside of Therizinosauridae. Similarly, Pelecanimimus and Shenzhousaurus are not part of Ornithomimidae as said here, even though Ornithomimidae has been used this way in the past (e.g., Sereno 1998) (though, actually, Ornithomimidae is accidentally written 'Ornithomimosauridae' and 'Ornithomimosauroidea' is used for Ornithomimosauria. Not sure where that came from*). Eotyrannus is classified as a member of Tyrannosauridae, and this is also not correct: it's a non-tyrannosaurid tyrannosauroid.

* Though Ornithomimoidea has been used by a few authors.

I was interested to see Yandangornis longicaudus classified as an indeterminate coelurosaur and described as a 'small winged predatory dinosaur, perhaps a troodontid'. Admittedly, little information is available on Yandangornis bar the original paper (Cai & Zhao 1999), and the opinion that it's non-avian has been mooted in the technical literature (Ji & Ji 2007). We lack enough information to be too confident either way, but various of this animal's characters suggest that it is a basal bird after all, probably close to the similarly poorly known jeholornithids. A good modern analysis of all of these unusual animals is needed [image below is Mike Skrepnick's restoration of Falcarius: nothing to do with Long and Schouten's book].

There are a few places where I thought the text failed to deliver. The entry on Chirostenotes, for example, makes no mention of Senter & Parrish's (2005) proposal that the specialised fingers and claws of this dinosaur were indicative of an aye-aye-like probing lifestyle, and there's no mention of the fact that Confuciusornis is now known to have eaten fish. It's also unfortunate that, in one or two places, the impact of Schouten's paintings is ruined by their position relative to the book's spine. But, regardless, if anything, this volume is thought-provoking and attractive, and anyone (of any age) interested in dinosaurs will enjoy looking at it.

Long, J. & Schouten, P. 2008. Feathered Dinosaurs: The Origin of Birds. Oxford University Press (Oxford), pp. 193. ISBN 978-0-19-537266-3.

You can see some of Schouten's images from the book here.

Refs - -

Butler, R. J- . & Upchurch, P. 2007. Highly incomplete taxa and the phylogenetic relationships of the theropod dinosaur Juravenator starki. Journal of Vertebrate Paleontology 27, 253-256.

Cai, Z. & Zhao, L. 1999. A long tailed bird from the Late Cretaceous of Zhejiang. Science in China (Series D) 42, 434-441.

Clark, J. M., Maryańska, T. & Barsbold, R. 2004. Therizinosauroidea. In Weishampel, D. B., Dodson, P. & Osmólska, H. (eds) The Dinosauria, Second Edition. University of California Press (Berkeley), pp. 151-164.

Elzanowski, A. 2002. Archaeopterygidae (Upper Jurassic of Germany). In Chiappe, L. M. & Witmer, L. M. (eds) Mesozoic Birds: Above the Heads of Dinosaurs. University of California Press (Berkeley), pp. 129-159.

- . & Paśko, Ł. 1999. A skeletal reconstruction of Archaeopteryx. Acta Ornithologica 34, 123-129.

Göhlich, U. & Chiappe, L. M. 2006. A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago. Nature 440, 329-332.

- ., Tischlinger, H. & Chiappe, L. M. 2006. Juravenator starki (Reptilia, Theropoda), ein neuer Raubdinosaurier aus dem Oberjura der Südlichen Frankenalb (Süddeutschland): Skelettanatomie und Weichteilbefunde. Archaeopteryx 24, 1-26.

Ji, S.-A. & Ji, Q. 2007. Jinfengopteryx compared to Archaeopteryx, with comments on the mosaic evolution of long-tailed avialan birds. Acta Geologica Sinica 81, 337-343.

Kirkland, J. I., Zanno, L. E., Sampson, S. D., Clark, J. M. & DeBlieux, D. D. 2005. A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah. Nature 435, 84-87.

Mayr, G., Pohl, B., Hartman, S. & Peters, D. S. 2007. The tenth skeletal specimen of Archaeopteryx. Zoological Journal of the Linnean Society 149, 97-116.

- ., Pohl, B. & Peters, D. S. 2005. A well-preserved Archaeopteryx specimen with theropod features. Science 310, 1483-1486.

Paul, G. S. 1988. Predatory Dinosaurs of the World. Simon & Schuster, New York.

- . 2002. Dinosaurs of the Air: the Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore: Johns Hopkins University Press, Baltimore.

Senter, P. & Parrish, J. M. 2005. Functional analysis of the hands of the theropod dinosaur Chirostenotes pergracilis: evidence for an unusual palaeoecological role. PaleoBios 25, 9-19.

Sereno, P. C. 1998. A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 20, 41-83.

Zhou, Z.-H., Wang, X.-L., Zhang, F.-C. & Xu, X. 2000. Important features of Caudipteryx - evidence from two nearly complete new specimens. Vertebrata PalAsiatica 38, 241-254.