Dinosaurs of Italy!

I'm really suffering from lack of time, so here's another book review (first published in 2005, so with a few updates added here and there)...

Lacking the Mesozoic dinosaur record of Britain, France, Germany, Portugal or Spain, our Italian colleagues have long had to make do with Triassic marine reptiles, Cretaceous squamates, and assorted Neogene mammals... not that there's anything wrong with that of course. Three interesting new dinosaur taxa, and a host of footprint discoveries, have changed all that however, and today Italy clearly has something quite important to say about the evolution and diversity of European dinosaurs. Discussed in depth in Dal Sasso's Dinosaurs of Italy, these Italian dinosaurs are an interesting bunch, comprising the little baby coelurosaur Scipionyx, an early basal tetanuran theropod (informally dubbed the 'saltriosaur') and a new and unusual hadrosaur.

But as is so often the case, the title belies the inclusion in the volume of a far greater diversity of Mesozoic reptiles, with two chapters devoted to protorosaurs, pterosaurs, pachypleurosaurs, rauisuchians, ichthyosaurs and others. The book also includes a chapter on the evidence for the KT event preserved at Gola del Bottaccione, near Gubbio.

When first published (in 2001, as Dinosauri Italiani), Dinosaurs of Italy was the unquestioned premiere source for the new animals and discoveries it discusses. Popular articles (Dalla Vecchia 2001), a technical review (Dal Sasso 2003) and conference abstracts published since then have pre-empted much of this material for English-speaking palaeontologists, but given that most of these publications are obscure or poorly known, the contents will still be new to most readers, whether they be specialists or not.

If this book has a star it is without question the holotype of Scipionyx samniticus, the 23-cm-long theropod hatchling described by Dal Sasso and Marco Signore in 1998. It is entirely understandable that, to Dal Sasso and his colleagues, Scipionyx must have seemed like the discovery of a lifetime, so it is fitting that 45 pages of this 213-page book are devoted to it. Accordingly there is more detail on the specimen's discovery and history than anywhere else and there are some fantastic photos. Scipionyx was first nicknamed 'doggy' by Giovanni Todesco (its discoverer), was later dubbed 'Ciro' by the editor-in-chief of Oggi magazine, and was even later nicknamed 'Scipio' by science journalists. Technical names considered for Scipionyx prior to the official description included Italoraptor, Italosaurus and Microraptor (which isn't much of a coincidence, given that the name hardly has the world's most complex derivation).

Already Scipionyx has been much used and abused in the technical literature. As Dal Sasso describes, it provides further evidence that baby non-avian theropods were precocial. However, despite its undoubted hatchling status it has been allocated a position within coelurosaur phylogeny by some workers (albeit with caveats). Doing so is problematical given that we don't know how much ontogenetic transformation this species underwent and, as some have noted, its plesiomorphic morphology might be more to with do ontogeny than anything else. On the subject of ontogeny I found myself wondering whether the proportionally massive maxillary fangs of Scipionyx were retained into adulthood, or whether they were a special feature of juveniles. This isn't a random speculation as juveniles of a few theropod taxa (including Ceratosaurus and some tyrannosaurids) show that maxillary teeth got proportionally smaller with age*, and what no-one seems to have noted so far (to my knowledge) is that the longest maxillary teeth in Scipionyx were longer than the dentary was deep, a detail which has not been accurately depicted in life restorations of Scipionyx. This is also the case in Ceratosaurus juveniles: these baby theropods seem to have been 'sabre-toothed'.

* Since I wrote this, Phil Currie has argued that the proportionally large teeth of juvenile tyrannosaurids are... are.. I can't remember, I must dig out the paper.

This kind of stuff is obscure and hardly ever discussed: far better known is that the specimen preserves some soft-tissue anatomy [Scipionyx guts, as seen under UV, shown here]. A suboval abdominal mass appears to be the liver, but less convincing is the alleged partitioning of the abdominal cavity into distinct pleuroperidarcial and peritoneal cavities by a supposed diaphragm. What I find curious is that Dal Sasso was second author on the paper which asserted the presence of a diaphragm, and of a hepatic-piston mechanism, in Scipionyx (Ruben et al. 1999): an attribute 'inconsistent with Scipionyx having had an avian-style, lung air sac system' (Ruben et al. 1999, p. 515) and even, allegedly, with the derivation of birds from other theropods. This time round Dal Sasso seems far more happy with the substantial body of data indicating that theropods, and other saurischians, were pneumatic in the avian sense (see, e.g., Wedel 2003a, b, O'Connor et al. 2005), as he should given his familiarity with theropod anatomy. The model proposed by Ruben et al. (1999) has been widely rejected by other archosaur anatomists, so this isn't surprising. I must note that the Brazilian theropod preserved with an abdominal vacuity adjacent to its pelvis, used by Dal Sasso as a trump card in demonstrating the presence of abdominal air sacs, was described in 2004 as the new taxon Mirischia asymmetrica.

Perhaps not as newsworthy as Scipionyx is the large tetanuran discovered at Saltrio in 1996, and also discussed at length by Dal Sasso [adjacent photo of the known elements from here]. The Sinemurian age of the specimen makes it significant, as it is among the oldest of tetanurans. Dal Sasso notes that a possible contender for this title might be Eshanosaurus, an alleged basal member of the therizinosauroid lineage from the Chinese Lower Lufeng Series. If this identification for Eshanosaurus is correct, ghost lineages for virtually all tetanuran clades must extend right down to the base of the Jurassic, and hence the presence of big basal tetanurans (like the saltriosaur) at this time isn't such a big deal. However, a Lower Cretaceous theropod that is quite unambiguously a basal member of the therizinosauroid lineage (Falcarius utahensis, published in 2005) casts considerable doubt on the proposed therizinosauroid-lineage affinities, and thus theropod affinities, of Eshanosaurus: as several have supposed, it probably is a sauropodomorph after all*. A big, basal tetanuran at the base of the Jurassic therefore still is a big deal, and we await the full technical description with interest.

* As regular readers will know, this has since been contested and a new paper has just appeared arguing that Eshanosaurus is a coelurosaur after all (Barrett 2009).

As Dal Sasso points out several times, the discovery of the saltriosaur, combined with other evidence for large dinosaurs in Mesozoic Italy, necessitates a partial rethink of Italian Mesozoic palaeogeography. Areas thought to have been submerged must instead have been at least intermittently emergent and, as indicated by the presence of large predators like the saltriosaur, must in cases have been relatively large in extent. This is reinforced by the new hadrosaur from the Triestine Karst, which isn't just a one-off but among several specimens known from the region. Again, this animal (dubbed 'Antonio' and representing a new taxon) hasn't yet been technically described. Clearly it's morphologically novel, possessing particularly elongate lower limbs and a tridactyl hand. Incidentally, a name used on the internet for this taxon is preoccupied, so isn't going to be the final choice. I won't tell you what that name is, but it's something to do with three digits, and involves 'saurus'.

As noted earlier, it's not all dinosaurs dinosaurs dinosaurs. We also get the full story behind the unusual slim-snouted Triassic ichthyosaur Besanosaurus that Dal Sasso and Giovanni Pinna named in 1996, x-rays of which revealed the presence of embryos [holotype shown in the slide above, from Dal Sasso & Pinna (1996)]. While Dal Sasso notes the phylogenetic position favoured for this taxon by Ryosuke Motani (viz, that it's a shastasaurid), not noted is the alternative position recovered by Maisch and Matzke (2000) where no shastasaur clade was discovered at all - there are two sides in the ichthyosaur wars, after all. Furthermore, while Dal Sasso follows Motani in regarding Cymbospondylus as rather more basal than shastasaurs and even mixosaurs, there is also Sander's (2000) analysis where Cymbospondylus is still a shastasaur, and is in fact sister-taxon to Besanosaurus. A controversy that Dal Sasso doesn't touch on is whether Besanosaurus is the same thing as Mikadocephalus, named in 1997 for a skull from Monte San Giorgio. There is more to this than nomenclatural trivia in that specimens from Spitsbergen have been referred to Mikadocephalus, so if this taxon and Besanosaurus really are the same thing then there is evidence for this animal well beyond Italy.

Still on marine reptiles, the brief coverage of pachypleurosaurs, placodonts, nothosaurs, thalattosaurs and the enigmatic Eusaurosphargis was welcome but, in my opinion, all too brief, especially given the lengthy coverage given to the more familiar animals. In fact there is easily enough literature on these less-famous groups to fill a book the same size as Dinosaurs of Italy, if only a popular volume devoted to thalattosaurs and placodonts would sell as well as one with the word 'dinosaur' on the cover [adjacent picture, showing thalattosaurs and an early ichthyosaur, by the excellent Ken Kirkland].

Finally, I have a few minor gripes. A brief discussion of Dale Russell's 'dinosauroid' is far too sympathetic (in my opinion) and reads as if the idea of the possible evolution of post-Cretaceous humanoid theropods is widely accepted as valid, whereas it really isn't. One could argue that it is misleading to present to lay audiences the idea that palaeontologists really think that tetrapod evolution is predetermined in this way, or that the evolution of humanity or something like it is inevitable. I suppose whole books have been written about this subject however (Gould 1989, Conway Morris 1998). Eudimorphodon does not mean 'double-shaped true teeth' as Dal Sasso states, but rather 'true two types of teeth' (the taxon was so named because Dimorphodon, named a great deal earlier, is markedly less heterodont), and I was a bit confused about his reference to serrated teeth in ziphiid (beaked) whales when writing about the distribution of tooth serrations within tetrapods. No ziphiid has serrated teeth, though of course there are several fossil whale groups that did. The name Lagosuchus is used a few times in the book: well, this name is presently regarded as a nomen dubium, and the valid taxon once referred to it (and oft used as the archetypal proto-dinosaur) is Marasuchus. Some of the illustrations look a bit familiar, strongly resembling earlier works by David Peters and Greg Paul. Finally, remarkably, there is no index.

Overall, Dinosaurs of Italy is pleasant and enjoyable, the translation and editing are excellent and, to nerdy completists like me, the book is essential for all the unique details it provides on the taxa it discusses. I recommend it to those truly interested in Mesozoic reptiles.

Christiano Dal Sasso (2004). Indiana University Press, Bloomington and Indianapolis.
ISBN 0-253-34514-6 (hardback). 213 pp. £24.95.

This book review originally appeared in the Palaeontological Association Newsletter 60: available (for free download) here. It is reproduced with permission.

For previous Tet Zoo book reviews see...

• Patagonian Mesozoic Reptiles, a book review
• 100 years of Tyrannosaurus rex
• Long and Schouten's Feathered Dinosaurs, a review
• Why the Lion Grew Its Mane, a book review
• Oh no, a book review... Dinosaurs The Encyclopedia: Supplement 5

Refs - -

Barrett, P. M. 2009. The affinities of the enigmatic dinosaur Eshanosaurus deguchiianus from the Early Jurassic of Yunnan Province, People's Republic of China. Palaeontology doi: 10.1111/j.1475-4983.2009.00887.x.

Conway Morris, S. 1998. The Crucible of Creation: the Burgess Shale and the Rise of Animals. Oxford University Press, Oxford.

Dalla Vecchia, F. M. 2001. A new theropod dinosaur from the Lower Jurassic of Italy. Dino Press 3, 81-87.

Dal Sasso, C. 2003. Dinosaurs of Italy. C. R. Palevol 2, 45-66.

- . & Pinna, G. 1996. Besanosaurus leptorhynchus n. gen. n. sp., a new shastasaurid ichthyosaur from the Middle Triassic of Besano (Lombardy, n. Italy). Paleontologia Lombarda 4, 1-23.

Gould, S. J. 1989. Wonderful Life. Hutchinson Radius, London.

Maisch, W. M. & Matzke, A.T. 2000. The Ichthyosauria. Stuttgarter Beiträge zur Naturkunde Serie B (Geologie und Paläontologie) 298, 1-159.

O'Connor PM, & Claessens LP (2005). Basic avian pulmonary design and flow-through ventilation in non-avian theropod dinosaurs. Nature, 436 (7048), 253-6 PMID: 16015329

Ruben, J., Dal Sasso, C., Geist, N. R., Hillenius, W. J., Jones, T. D. & Signore, M. 1999. Pulmonary function and metabolic physiology of theropod dinosaurs. Science 283, 514-516.

Sander, P.M. 2000. Ichthyosauria: their diversity, distribution, and phylogeny. Paläontologische Zeitschrift 74, 1-35.

Wedel, M. J. 2003. The evolution of vertebral pneumaticity in sauropod dinosaurs. Journal of Vertebrate Paleontology 23, 344-357.

- . 2003. Vertebral pneumaticity, air sacs, and the physiology of sauropod dinosaurs. Paleobiology 29, 243-255.