Book review: British Polacanthid Dinosaurs by William T. Blows

Tentative reconstruction of the ankylosaur currently under study at the University of Southampton.

It would not be unreasonable to say that since their discovery in 1832 in a Sussex quarry, ankylosaurs have had a far more modest amount of attention directed at them than some of their more famous relatives. This may seem odd as the first to be discovered, Hylaeosaurus, was one of the three taxa that led Owen to erect the Dinosauria in 1842 and was the subject of one of Waterhouse Hawkins superb reconstructions at Crystal Palace. It seems that despite their spectacular array of spikes, clubs and shields they might forever be in the shadow of taxa considered more exciting by both palaentologists and the public alike, so a book dedicated to British ankylosaurs is a very welcome addition to the palaeontological literature.

William Blows has been working on British ankylosaurs for several decades and discovered and excavated one of the specimens discussed in this book (NHM R9293) and has published many papers on the subject in that time; he is probably the leading worker on British Wealden ankylosaurs. Siri Scientific Press, based in Manchester UK, are a prolific publisher of paleontological and natural history books and specialise in well-illustrated textbooks that often cover niche areas of interest, although they also publish more general volumes. One of their most recent publications was Dean Lomax and Nobumichi Tamura’s ‘Dinosaurs of Great Britain’, an exhaustive and lavishly illustrated review of British dinosaur specimens, some never figured before in the literature. 

British Polacanthid Dinosaurs continues in the same vein, although obviously concentrating on a far smaller number of specimens. The book begins with a review of British ankylosaur research (fronted by the excellent Neave Parker reconstruction) which discusses systematics, polacanthid synapomorphies, stratigraphy and possible relationships with other taxa, principally those from North America. This is followed by a historical account of the discovery of Hylaeosaurus and the subsequent milestones in British ankylosaur research. This includes some gems like the tale of Mr Lee’s lost sacral shield specimens (which I discussed here last year) and contains some wonderful quotes from early dinosaur workers such as Hulke and Nopsca. This chapter is a good overview of the subject and a welcome addition to the literature, putting modern research into British ankylosaurs into context.

The main bulk of the book consists of descriptions of most of the currently known specimens, broken down into sections by skeletal element: skull and jaws, vertebrae and ribs, limbs etc and the descriptions of the specimens are clear and detailed. This part of the book contains many photographs and these images are of excellent quality, captioned with accession numbers and (with the odd exception) are accompanied by scale bars and are the real strength of this book for ankylosaur workers; these images are a valuable resource. Most of the known specimens are covered here, although some are being worked on and are not included (this does include the Soton specimen, although the parts of the specimen held at Dinosaur Isle are figured and described here). The remainder of the book is given over to a brief discussion of other polacanthids, especially the North American taxa and the re-assignment of Polacanthus rudgwickensis to the newly erected taxon Horshamosaurus which Blows now considers a nodosaurid and not a polcanthid.

But there are a couple of issues. Firstly, who is the book aimed at?  At £59 plus postage this is an expensive volume and running at 220 pages not huge (although no-one can doubt the considerable work gone into creating it) and this would suggest it was aimed at academic and avocational palaeontologists rather than amateurs and curious layfolk. On the other hand, the tone of the book is not written in the scientific prose we expect from a paper or technical volume and the referencing is inconsistent. It contains some jargon but is more accessible than much of the scientific literature is, presumably for the benefit of the lay audience, but this gives the impression the book falls between two stools.

Secondly is the existence of the ‘Polacanthid’ clade. The author states his opinion on this subject right from the outset in the title of the book (as well as his distrust of modern phylogentics, stating: “It is possible too much faith is applied to cladograms”), and confirms his position in the text: Polacanthidae is a valid clade and most British ankylosaurs are polacanthids. A lay person coming to the subject via this book would be forgiven for thinking this issue is cut and dried, which it is not. There are conflicting hypothesis about whether Polacanthidae (a clade alongside Ankylosauridae and Nodosauridae) or Polacanthinae (a clade nested within either Ankylosauridae and Nodosauridae) represent a monophylectic clade. The author justifies his conclusion it is by citing support from Kirkland (1998), Carpenter (2001) and Burns and Currie (2014) as well as Martill and Naish (2001). Kirkland’s recovery of a polacanthine clade was based on morphological similarities between several taxa and supported by cladistic analysis, however Carpenter’s assignment of Polacanthus to polacanthidae was based on a priori sorting of the sampled taxa into the three clades which were then analysed. Martill and Naish (2001) adopt Kirkland’s suggestion of a polacanthid clade because of doubts about the evidence for polacathines as basal ankylosaurids rather then direct evidence to the contrary, whilst Barrett and Maidment (2010) adopt Thompson et al’s 2012 conclusion of these taxa as basal nodosaurids, however Arbour’s 2015 analysis of ankylosaurids recovers Gastonia as a basal ankylosaurid. There is much work to be done in untangling the relationships of basal ankylosaurs and at present the exact status of all British ankylosaurs are uncertain.

If you’re interested in ankylosaurs at all then it’s worth buying this book; if you're interested in or work with Early Cretaceous ankylosaurs it's essential. In years to come I can see this book being a very useful resource for workers and other interested parties alike; hopefully in future editions we will see more specimens are they come to light and are made available. It is a good review of the field as it stands from an author with decades of experience of studying British ankylosaurs and the images are superb, the specimen descriptions are detailed and the history of ankylosaur research is a great read.

If only it wasn’t so expensive.

References:

Arbour, V. M., M. E. Burns, and P. J. Currie. 2011. A review of pelvic shield morphology in ankylosaurs (Dinosauria: Ornithischia). Journal of Paleontology 85:298–302.

Victoria M. Arbour & Philip J. Currie (2015): Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs, Journal of Systematic Palaeontology, DOI: 10.1080/14772019.2015.1059985

Barrett, Paul M. and Maidment, Susannah C.R. 2011. Armoured Dinosaurs In: English Wealden fossils. Paleontological Association Field Guide to Fossils. Batten DJ, editor. 26: 391-406.

Blows, William Taylor. 2015. British Polacanthid Dinosaurs. Monograph Series Volume 7. Siri Scientific Press. Manchester, UK.

Michael E. Burns & Philip J. Currie (2014) External and internal structure of ankylosaur (Dinosauria, Ornithischia) osteoderms and their systematic relevance, Journal of Vertebrate Paleontology, 34:4, 835-851, DOI:10.1080/02724634.2014.840309

Carpenter K (2001) Phylogenetic analysis of the Ankylosauria. In: Carpenter K, editor. The Armored Dinosaurs. Bloomington: Indiana University Press. pp 454–483.

Kirkland, J.I. 1998. A Polacanthine ankylosaur (Ornithischia: Dinosauria) fron the Early Cretaceous (Barremian) of eastern Utah. In Lucas, S.G., Kirkland J.I. and Estep, J.W. (eds), Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin 14: 271-281. 

Martill D, Naish D. 2001. Armoured Dinosaurs: Thyreophorans. In: Martill D, Naish D, eds. Dinosaurs of the Isle of Wight. London: Field Guide to Fossils No. 10: Palaeontological Association, 310–323.

Richard S. Thompson, Jolyon C. Parish, Susannah C. R. Maidment & Paul M. Barrett (2012): Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora), Journal of Systematic Palaeontology, 10:2, 301-312