Once again I’m going to recycle an old book review, sorry about that. Have had no internet access at home for the last few days, so things have been difficult here, to say the least (like so many people, I now rely on constant daily internet access for work). Anyway, find below my review of Tidwell & Carpenter’s Thunder-Lizards book. The review was published in 2006 so is now rather dated. I haven’t changed the text, but please note the following; a full technical paper addressing the neck posture stuff discussed below has since been published (Taylor et al. 2009); titanosaurs no longer lack thumb claws entirely, thanks to the Australian lithostrotian Diamantinasaurus, and in fact Diamantinasaurus and Wintonotitan mean that what’s stated below about Australian sauropods is now woefully inaccurate (Hocknull et al. 2009); and the discussion of melanorosaurids given below was written before Yates (2007) published an important analysis where ‘melanorosaurids’ became scattered far and wide across the sauropodomorph tree. The brief comments on the content and phylogenetic definition of Sauropoda are now redundant given the new definition currently in press. Oh, and I do now understand the Stonehenge reference.
Also worth noting while I’m here is that – as you’ll know if you keep tabs on SV-POW! (as I’m sure you do) – the last few weeks have been particularly exciting in the world of sauropod news. We’ve seen the publication of the very neat new taxa Qiaowanlong kangxii and Spinophorosaurus nigerensis, and Mike Taylor has had his Journal of Vertebrate Paleontology paper on the distinction of Giraffatitan from Brachiosaurus published [Taylor's new reconstruction of Brachiosaurus shown below. Unlike him, I don't think that Giraffatitan is such a horrible name]. Anyway, here we go…
I suppose most people have lost track of how many books Indiana University Press has published on fossil vertebrates as part of its ‘Life of the Past’ series. I have: for reviews of previous volumes, see Palass Newsletter 49: 95-98, 49: 101-103, 50: 91-93, 52: 85-87, 53: 110-112, 56: 128-131, 59: 118-120, 59: 131-132, 60: 79-82 and 60: 90-92 (and that’s not all of them). Continuing their theme of multi-authored volumes dedicated to specific dinosaurian groups, Thunder-Lizards covers (or does it? Read on) the sauropodomorphs: the long-necked sauropods and their relatives. The quality of included papers varies, with some being excellent, well written and highly useful, and others being, well, not so excellent.
The book is divided into four sections. ‘Sauropods old and new’ provides new data on several taxa; ‘Sauropods young to old’ includes contributions on ontogenetic variation; ‘Body parts: morphology and biomechanics’ covers assorted aspects of sauropod anatomy; and ‘The global record of sauropods’ is made up of reviews on geographical assemblages. But while the included contributions are grouped into these sections, in terms of what is and what is not included, there is a random feel, and neither taxonomic nor stratigraphic coverage is equal. It is telling that, while the word ‘sauropodomorph’ features in the title, the word ‘sauropod’ is used in the titles of all of the book’s sections. Of the 21 included papers, only one – Galton et al.’s on Melanorosaurus – focuses on a taxon that has traditionally been regarded as a non-sauropod and, if some current phylogenies are to be accepted (Yates & Kitching 2003), Melanorosaurus is a basal sauropod anyway. So non-sauropod sauropodomorphs – ‘prosauropods’ in traditional parlance – aren’t really featured in the volume at all: it may as well have been titled ‘The Sauropod Dinosaurs’. Why weren’t ‘prosauropods’ represented in this volume? It most likely comes down to the fact that they’ve conventionally been regarded as the most boring (and hence least studied) of dinosaurs. Happily the disdain that ‘prosauropods’ have long received will soon be rectified, in part, by an academic volume presently in preparation, and due to appear in 2007.
The ‘Sauropods old and new’ section starts with Galton et al. on Melanorosaurus. This paper provides new information on melanorosaurids and, by comparing melanorosaurid characters with synapomorphies taken from various different studies, discusses how these animals might fit within Sauropodomorpha. Unfortunately the article becomes an inconclusive progress report, rather than the definitive redescription it could have been. While these authors use the term ‘prosauropod’ in places, it is sometimes unclear exactly what they mean by this, given that there is more than one interpretation of this term. At its most inclusive, Prosauropoda might be almost as traditionally conceived, but if other phylogenies are favoured, and if Plateosaurus is used as the anchor for Prosauropoda (Sereno 1998), then Prosauropoda is synonymous with Plateosauria [adjacent pic: rarely seen Greg Paul restoration of Riojasaurus, © Greg Paul].
Contributions from John S. McIntosh are always welcome, and the excellent description he provides here of Barosaurus is useful. Thoughts on Tendaguru material are included as is a mention of his once-held idea that Supersaurus was not a distinct genus, but a large Barosaurus [the AMNH Barosaurus mount as we know and love it shown below, photo by Matt Wedel].
Rather more problematic, however, is Carpenter and Tidwell’s paper on Astrodon from the Aptian-Albian of Maryland. One of their primary arguments is that the name Astrodon johnsoni has priority over Pleurocoelus nanus, and that the latter should be regarded as a synonym. However, they are happy to admit that Astrodon is based on non-diagnostic teeth and I can’t determine how it’s known that the substantial amount of referred material really does belong to the same taxon as the non-diagnostic teeth, as Carpenter and Tidwell assert it does. I am not encouraged by the fact that they switch between the spellings ‘johnsoni‘ and ‘johnstoni‘ throughout the text, that all the characters regarded as diagnostic come from ‘very young’ individuals, nor by the absence of units from the scales that accompany their skeletal reconstruction. Furthermore, while Carpenter and Tidwell regard the vertebral proportions, and extent of pneumatic excavations, of Astrodon as diagnostic for the taxon, a paper elsewhere in the same volume shows that ‘pleurocoel size … appears to decrease in proportion to the total centrum length when compared with that in juvenile animals’ and that ‘neck length increases proportionally to total body length throughout ontogeny’ (Ikejiri et al., p. 173). The section ends with Le Loeuff’s article on Ampelosaurus, an Upper Cretaceous French titanosaur. Given that this taxon is now represented by over 500 bones, including an articulated skeleton that preserves a ‘well-preserved disarticulated skull’ (Le Loeuff, p. 136), the data provided here is, again, a provisional progress report. However, more information is provided on the taxon than has been published before [picture of Camarasaurus below by Vladimir Krb. I quite like some of his stuff. Does anyone know if he's still working? And how the hell do you pronounce his family name?].
‘Sauropods young to old’ includes Foster’s description of new juvenile Apatosaurus and Camarasaurus specimens, Ikejiri et al. on ontogenetic variation in Camarasaurus, Tidwell et al. on ontogenetic features observed in a Camarasaurus pelvis, and Tidwell and Wilhite on forelimb ontogeny in Venenosaurus. Ikejiri et al.’s paper is particularly good in documenting the substantial amount of variation now known for most parts of the Camarasaurus skeleton. Mostly this is ontogenetic and involves the development of rugosities and extra processes, but there are also indications of sexual dimorphism, and superimposed on all of this is individual variation. The new data provided by Tidwell et al. on Camarasaurus shows that characters conventionally regarded as synapomorphic for some sauropod clades (e.g., six sacral vertebrae and widely flaring ilia) occur elsewhere in the group as individual variations. Sigh: another ‘cautionary note for those working with less well represented taxa’ (Tidwell et al., p. 185). Mostly, the take-home message from the section is a coherent and well-supported one: that sauropod growth is mostly isometric (though with some allometry occurring in the neck). This contrasts with the data from other dinosaur groups, and it’s a good question as to why sauropods were so different.
Included within the morphology and biomechanics section are papers on Camarasaurus neuroanatomy, two on neck posture and function, one on hyposphene-hypantrum articulations, four on the morphology and evolution of the appendicular skeleton, and a review article on stress fractures. The strongest papers in this section are Matthew Bonnan’s excellent, detailed review of foot anatomy and D. Ray Wilhite’s on appendicular bone variation seen in Morrison Formation taxa. Bonnan shows that, far from being the ‘rubber stopper on the end of a crutch’ imagined by some authors, the sauropod foot was morphologically novel and uniquely flexible. Sebastian Apesteguía’s two papers – one on the morphology and evolution of the metacarpus and the other on the hyposphene-hypantrum complex – are also good reviews packed with new information. As if sauropods weren’t strange enough with their columnar metacarpal arcades and reduced (or even absent) manual phalanges, Apesteguía discusses the presence of bowed ‘banana-shaped’ first metacarpals in some titanosaur taxa as well as evidence for a novel soft-tissue covering to the distal ends of the metacarpals. I am left wondering why a small photo of Stonehenge is included in one of Apesteguía’s figures, however.
It would be an odd sauropodomorph volume indeed that did not focus at least in part on long necks. However, surprisingly little work has been done on this area, and basic questions of neck posture and orientation, and zygapophyseal movement, remain unanswered, despite the reasonable amount of work published on neck motion and orientation in extant tetrapods. Kent Stevens and J. Michael Parrish have published a couple of articles on sauropod neck posture, and, using software dubbed DinoMorph, have applied computer modelling to digitally reconstructed skeletons (Stevens 2002, Stevens & Parrish 1999) [CG diplodocid with inferred limits of neck posture shown here; from Stevens (2002)]. While there seems to be near-universal agreement that diplodocoids had a horizontal neutral neck posture [UPDATE: err, whoops], Stevens and Parrish hold the more controversial point of view that all sauropods were like this, even Camarasaurus and Brachiosaurus. Already their interpretations have been challenged by those arguing that they have not accounted for flexibility within the dorsal vertebrae, that their reconstructed neck postures are no less speculative than the artistic reconstructions they are so critical of, and that their reconstructed necks contain misalignments and disarticulations. Rather than defending or refining the method, this paper is mostly a review of what previous authors have said about the feeding styles and neck mobility inferred for sauropods, and there is little new data or interpretation. Their reconstructed neck postures do not result from virtual modelling, but from ‘using illustrations of the original material’ (p. 217): in other words, drawings from monographs. Overall is it not a convincing approach to the problem. A second contribution on neck posture comes from David Berman and Bruce Rothschild, who used CT x-rays to establish the internal morphology of cervical vertebrae, and from this work out neck posture. Unfortunately the figures they provide are all but useless and may as well be anything.
The last section of the book (‘The global record of sauropods’) reviews sauropods from southern Europe, Patagonia and Australia, with a contribution on trace fossils from India. Fabio Dalla Vecchia’s article reviews and describes sauropod bones and tracks from the Tethyan carbonate platforms of Italy, Slovenia and Croatia, and also includes interpretation of Cretaceous vertebrate palaeobiogeography across the area. While the material is not fantastic, the figures he provides (particularly of vertebrae) are highly detailed. That’s tremendously useful when you have to spend time trying to interpret sauropod vertebrae, and Dalla Vecchia’s figures contrast markedly with rather less satisfactory figures of sauropod vertebrae recently published in another major work on sauropods (Upchurch et al. 2004). Patagonian sauropods are reviewed by Salgado and Coria, and new data on Australian forms is provided by Molnar and Salisbury. It used to be thought that Australia had a particularly poor sauropod record, comprising Rhoetosaurus and Austrosaurus and not much else. In fact the record is far richer than this – ok, it’s not on par with that of North or South America, or Asia, or Europe… or, err, Africa – but it does in fact include multiple specimens, and by specimens I don’t just mean isolated vertebrae. Furthermore, the old view that Australia lacked titanosaurs during the Cretaceous, and was instead home to late-surviving relict taxa, no longer seems supported.
While previous IUP volumes have been flawless in terms of editing, Thunder-Lizards isn’t up to usual standards. We have specific names spelt incorrectly here and there, or accidentally given capital first letters. A massive shadow, looking suspiciously like that cast by a human holding a camera, looms large in one of several less-than-brilliant field photos. Mostly the figures have reproduced well however, and Todd Marshall’s cover art is brilliant [adjacent image - from one of my talks - shows the late Jim Jensen with (on the left) the holotype Supersaurus scapulocoracoid BYU 5500, and (on the right) the "Ultrasauros" scapulocoracoid BYU 9462].
Overall, IUP have provided us with a volume similar in calibre to the other dinosaur volumes published in the Life of the Past series: sometimes lacking in academic rigour, and indeed flawed in places, but excellent and rewarding in others. The sheer volume of information included means that the articles of highest quality are almost swamped by the others, and for this reason it could be argued that they won’t be as widely read as, or get the accolade and citation, they deserve. So there is novelty, value and excellence in Thunder-Lizards: for this reason this book should be owned by everyone with a serious interest in sauropods. And I do mean sauropods, and not sauropodomorphs.
Virginia Tidwell & Kenneth Carpenter (2005). Thunder-Lizards: the Sauropodomorph Dinosaurs. Indiana University Press, Bloomington and Indianapolis, 495pp. ISBN 0-253-34542-1, $59.95 (hardback).
This book review originally appeared in the Palaeontological Association Newsletter 61: available (for free download) here. It is reproduced with permission.
For previous Tet Zoo articles on sauropodomorphs see…
- Sauropod dinosaurs held their necks in high, raised postures
- Patagonian Mesozoic Reptiles, a book review
- Junk in the trunk: why sauropod dinosaurs did not possess trunks
- Bones of the Krayt dragon
- The hands of sauropods: horseshoes, spiky columns, stumps and banana shapes
- The horror that is LOLSAUROPODS
- The world’s most amazing sauropod
- Gigantoraptor, Eocursor and… baby Toni
Refs – –
Hocknull, S. A., White, M. A., Tischler, T. R., Cook, A. G., Calleja, N. D., Sloan, T. & Elliott, D. A. 2009. New Mid-Cretaceous (latest Albian) dinosaurs from Winton, Queensland, Australia. PLoS ONE 4(7): e6190. doi:10.1371/journal.pone.0006190
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.
Stevens, K. A. 2002. DinoMorph: parametric modeling of skeletal structures. Senckenbergiana lethaea 82, 23-34.
– . & Parrish, J. M. 1999. Neck posture and feeding habits of two Jurassic sauropod dinosaurs. Science 284, 798-800.
Upchurch, P., Barrett, P. M. & Dodson, P. 2004. Sauropoda. In Weishampel, D. B., Dodson, P. & Osmólska, H. (eds) The Dinosauria, Second Edition. University of California Press (Berkeley), pp. 259-322.
Yates, A. M. 2007. Solving a dinosaurian puzzle: the identity of Aliwalia rex Galton. Historical Biology 19, 93-123.
– . & Kitching, J. W. 2003. The earliest known sauropod dinosaur and the first steps towards sauropod locomotion. Proceedings of the Royal Society of London B 270, 1753-1758.