Rhomaleosaurus cramptoni (Tate and Blake, 1863)

Synonyms: 'R. thorntoni'?

Maybe R. cramptoni is a synonym of R. zetlandicus but it will be treated here as unique, if only because of its historical significance and current status as holotype of the genus Rhomaleosaurus.

Distribution: Hildoceras bifrons zone, Alum Shale, Toarcian, Lower Jurassic, Whitby, Yorkshire, England.

Material: NMING F 8785, a complete skeleton exposed in dorsal view.

Images

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1.Cast of the holotype of Rhomaleosaurus cramptoni. Taken in the Natural History Museum, London. (photograph courtesy of Hector E. Rivera )

2. Cast of the holotype of Rhomaleosaurus cramptoni. Taken in the Bath Royal Literary and Scientific Institute. Curator Matt Williams for scale.

3. Skull of actual holotype of Rhomaleosaurus cramptoni in the National Museum of Ireland (Natural History). Note also the crates in the background - these contain the segments of body and limbs of the rest of the skeleton.

4. Victorian model of Rhomaleosaurus cramptoni in the National Museum of Ireland (Natural History).

Notes

The type specimen of Rhomaleosaurus (R. cramptoni) is held in the National Museum of Ireland (Natural History). This material is currently forming the basis of my Ph.D. project reviewing the systematics and phylogeny of Lower Jurassic pliosaurs. Rhomaleosaurus cramptoni remains to this day the largest complete pliosaur ever discovered, and is currently known from just the single complete specimen. The triangular skull is reinforced to help resist torsion and bears a ferocious set of teeth – a combination perfect for snatching and killing cephalopods, fish, and other marine reptiles.

The complicated history of Rhomaleosaurus cramptoni

In 1848, the fossil skeleton of an unusual giant reptile was unearthed by workers in an Alum quarry at Kettleness on the Yorkshire coast. The magnificent fossil was secured for five years at Mulgrave Castle, the home of the Marquis of Normanby, owner of the quarry. But the specimen was soon to move home…to Ireland. The Marquis presented the fossil in 1853 to his friend Sir Philip Crampton who brought the specimen to Dublin to be displayed as centrepiece at the 1853 British Association annual meeting. A specially constructed building was created by the Zoological Society of Ireland to accommodate the huge specimen, and the fossil found a temporary home. In 1863 the specimen was loaned for display in the Royal Dublin Society museum and was scientifically described and named. The Royal Dublin Society museum was later merged with the National Museum of Ireland who in 1877 paid £200 to acquire the specimen permanently. In 1890, the fossil moved buildings again, into the museum’s ‘fossil hall’. But in 1979 the hall was demolished and the specimen, together with rest of the geological collection, was transferred to storage. The collection was moved yet again in 1992 to the National Museum of Ireland (Natural History) reserve stores at Beggars Bush, where the giant reptile currently resides. After all this tooing and froing the specimen is rather worse for wear.

Casts

A number of casts were made of the fossil throughout its history probably purchased from Henry. A. Ward, a fossil caster who dealt in replica fossils, including Rhomaleosaurus cramptoni, throughout the late1800s. Specimens are on display in Bath, London and New York. The Bath specimen is unique. Look closely (see above), and you will notice that the two forelimbs are identical copies of each other. And to add extra confusion, this duplicated limb is in the wrong place – it is actually a hindlimb – the two hindlimbs in the cast are really forelimbs placed in the wrong sockets. The London specimen is also unique, a new set of limbs have replaced the original ones which were mounted wrongly.

Rhomaleosaurus zetlandicus Phillips, 1854

Distribution Alum Shale, Toarcian, Lower Jurassic, Whitby, Yorkshire, England.

Synonyms 'R. thorntoni'?, and 'R. cramptoni'?.

Images

Skull of holotype of Rhomaleosaurus zetlandicus on display at the York Museum

Notes - The skull formed the Ph.D. thesis of Dr Mike Taylor who subsequently published a description of the cranial anatomy (Taylor, 1992)

Rhomaleosaurus propinquus (Blake, 1876)

Distribution Alum Shale, Toarcian, Lower Jurassic, Whitby, Yorkshire, England.

Material: on display at the Whitby Museum, UK

Section under construction

Images

Holotype of Rhomaleosaurus propinquus mounted on a wall of the Whitby Museum.

Notes

'Rhomaleosaurus' victor (Fraas, 1910) ('Thaumatosaurus' victor)

Material: SMNS 12478, complete articulated skeleton.

Distribution: Posidonien-Schiefer, Toarcian, Lower Jurassic, Holzmaden, Germany.

Images

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1. Perhaps the most beautiful specimen of a plesiosaur ever? 'R' victor skeleton in ventral view and a 2. close-up of the skull (from Fraas, 1910). Recommended! 3. The specimen as currently displayed in the SMNS. 4. A life-restoration of R. victor on diplay in the SMNS with a close up of the head (5).

Notes - The species 'R'. victor is well figured in Fraas (1910) and according to recent studies may deserve generic status of it's own.

Rhomaleosaurus megacephalus Stutchbury, 1846

Material Neotype, LEICT G221.1851, complete skeleton.

Type distribution: Early Hettangian, Lower Jurassic, Barrow-upon-Soar, Leicestershire, England.

Images

Rhomaleosaurus megacephalus (the Barrow Kipper) in the New Walk Museum, Leicester (the skull is a cast.)The specimen was designated as the neotype after destruction of the original type (see below) during the Second World War. (photographs by A. S. Smith)...

The original skull in anterior and in lateral view, with a reconstruction for reference (modified from Cruickshank et al. 1991)

Rhomaleosaurus megacephalus (labeled as 'Plesiosaurus megacephalus'). Photograph of a life-size image in the Bristol City Museum.The specimen was destroyed during the Second World War. (Composite photograph by A. S. Smith)

R. megacephalus skull in right lateral view showing the relative position of the internal and external nares. (modified from Cruickshank et al. 1991)

The Wilmcote plesiosaur in Warwick Museum, UK. Catalogued as Rhomaleosaurus arcuatus, and on display as Eurycleidus arcuatus, a detailed study of this specimen will probably reveal it to be another specimen of Rhomaleosaurus megacephalus (Cruickshank, 1994b). N.B. the image on the right has been digtally altered, the preparators mounted the skeleton wrongly, leaving a considerable gap between the neck and the body. (Photographs by A.S. Smith).

Notes - R. megacephalus is nicknamed the 'Barrow Kipper' (Taylor and Martin, 1990) after the locality where it was discovered. The skull is described extensively by Cruikshank (1994b), and can be seen on display at the New walk museum in Leicester, UK. The plesiosaur olfaction ('smelling') system was first recognised in Rhomaleosaurus megacephalus (Cruickshank et al. 1991) and seems to be an adaptation common in the majority of plesiosaurs (Brown and Cruickshank, 1994). The anteriorly placed internal nostrils on the palate have grooves to channel water, the flow of which would be maintained by hydrodynamic pressure over the posteriorly placed external nares (on the top of the skull) during locomotion. During its passage through the nasal ducts, the water would have been 'tasted' by olfactory epithelia.

'Rhomaleosaurus' longirostris (Blake, 1876)

Section under construction

Images

The university of Manchester specimen of 'R' longirostris (from Broadhurst and Duffy, 1970).

Notes - This species was wrongly placed in the genus Macroplata by (White, 1940). It almost certainly does not belong to Rhomaleosaurus either, and probably deserves a unique generic name.