'Monster of Aramberri' update

I should have posted this short essay a lot earlier, but have only just got around to it...

The 'Monster of Aramberri’ and other plesiosaurs from Mexico

Plesiosaurs are especially rare in Mexico. The only plesiosaur material was until recently only in the form of a snout and teeth from the Neocomian of Oaxaca (Persson, 1962). These were originally referred to ‘Plesiosaurus’ mexicanus, but the species was later disregarded by Welles (1952) and the material was considered only diagnostic to the family level - Elasmosauridae.

Recently however, more complete skeletal material, previously interpreted as dinosaur remains, has been recognised as plesiosaurian (Frey et al. 2001). One giant vertebral column with associated material housed at the University of Linares is the first Jurassic plesiosaur from Mexico to be scientifically described (Buchy et al. 2003). It belongs to a pliosauroid (typical ‘pliosaurs’ can be identified by their large heads and short necks) and has been nicknamed the ferocious-sounding ‘Monster of Aramberri’, after the village of Aramberri, Neuvo Leon, near where it was found. It was originally discovered in 1985 (Buchy et al. 2003) in the Kimmeridgian (Upper Jurassic) La Caja Formation. This monster is estimated at 15 meters, a size closely approaching if not exceeding the previous record holders, Kronosaurus and Liopleurodon. Unfortunately it cannot be diagnosed past the family level of pliosaurid because much of the skeleton is unknown or lost.

A second pliosaur from younger Tithonian (Latest Jurassic) deposits seems to represent a new species (Frey et al. 2001). The specimen comprises the most anterior part of a skull with four teeth, which are triangular in cross section. Such teeth are typical of Late Jurassic pliosaurs (Tarlo, 1960) as seen in derived species of Pliosaurus and Liopleurodon (‘Stretosaurus’?), but not exclusively (Noe, 2004). However the new species also has a unique surface ornamentation (Frey et al. 2001).

There are many questions still to be answered, but one thing is certain: ‘The Monster of Aramberri’ and its pliosaur contemporaries must have been ferocious predators in Mexico’s ancient marine food web.

Temporary fossil exhibit at Warwickshire Museum, UK.

An Ichthyosaurus skull dominates this new display illustrating the Jurassic Fauna of Warwickshire. Although there are no plesiosaurs in this small exhibit (below) I mention it here for three reasons. Firstly, this is my local museum, where I have conducted a lot of voluntary work. Secondly, part of the material on display forms the basis of a paper that Jon Radley, the curator of geology, and myself are preparing to submit. The paper includes some plesiosaur descriptions. Finally, some of my palaeo-artwork is featured in the exhibit, a restoration of an Ichthyosaurus.

Update on research in Dublin 2

There are two additional plesiosaurs in Dublin which will be useful in my research, one at Beggars Bush Museum Store is catalogued as Eurycleidus arcuatus (below) and the other at UCD, which shows affinities with Thalassiodracon. The latter (not pictured) is an almost complete skeleton currently stored out of sight in a geology store room, I hope to arrange to have this dismounted from the wall it is on, and transferred to a lab for study.

Update on research in Dublin 1

Last month (March 2005) I gave a talk at the Irish Geological Research Meeting, discussing the prospects of my research project on plesiosaurs in Dublin. Here is the abstract:

Important Plesiosaurs in the National Museum of Ireland (Natural History)
By Adam Stuart Smith (adam.smith@ucd.ie)
Department of Zoology, University College Dublin, Belfield, Dublin 4.

Abstract
The type material of the ferocious Jurassic marine predator Rhomaleosaurus has a long and convoluted history, but it is now in storage in the National Museum of Ireland (Natural History). This specimen (R. cramptoni) is of vital importance in resolving the taxonomy and understanding the evolution of plesiosaurs, particularly the typically short-necked ‘pliosaurs’. However, the current state of the material is poor, and parts of the specimen as mounted, are erroneous. Through this project the specimen will be cleaned, prepared and described, and finally applied to phylogenetic analyses to secure a sound systematic basis for the future development of plesiosaur palaeontology. A second and much more gracile specimen attributed to Rhomaleosaurus megacephalus (=Eurycleidus arcuatus?) [pictured below] is also being described and appears to represent a new species.

Plesiosaur discovered in Manitoba, Canada

A short-necked plesiosaur was discovered in 2003. Story covered here:

New plesiosaur from Germany

The August issue of the Journal of Paleontology (volume 78 part 5) contains an article by Robin O'Keefe describing an old plesiosaur mount in the Staatliches Museum fur Naturkunde, Stuttgart, Germany (below). The new name Plesiopterys has been given to this animal, meaning 'near wing'. According to O'Keefe, this plesiosaur is one of the most basal plesiosaurs forming the sister group to plesiosauroidea. The skeleton is remarkable in that the front fins are mounted upside down and on the wrong side of the body.

N.B. I have this article as a PDF which I would be happy to share.

Somerset plesiosaur discovered

A specimen recenty discovered in Somerset, England (reported by the BBC, April 2004), representing a more-or-less complete plesiosaur, 1.5 metres long, has been returned to County Museum (Taunton Castle) for future display. The specimen bears a resemblance to the 'Plesiosaurus' macrocephalus but diagnosis must await a proper study of the specimen. It has also been suggested that this may be a juvenile Rhomaleosaurid pliosaur such as Rhomaleosaurus, but again, such an interpretation is premature and must await an investigation of the specimen.

A new take on the colour of plesiosaurs?

This month (March, 2004), I was pleased to join fellow plesiosaurologists Mark Evans and Richard Forrest at the 'Sea Monsters' open day, held at the New Walk Museum, Leicester. Young visitors to the Museum were invited to contribute to a full size (8 metre long )

restoration of the infamous pliosaur, Liopleurodon. Of course, nobody knows what colour plesiosaurs really were, but the resulting creature (pictured below, with Richard Forrest for scale) supports a huge variety of scales and colours, very interesting! Thanks to everyone who contributed! A.S

Rediscovered Warwick Plesiosaur

Often, the best place to look for new fossils is not in the ground, but in museum stores. This long-necked Liasic plesiosaur (pictured below) (labelled, but possibly not 'Plesiosaurus' (=Eretmosaurus) rugosus), from Honnington, Warwickshire, was recently rediscovered (Jan. 2004), after being boxed up for an unknown number of years in the Warwick Museum geology stores. I am in the process of preparing and reconstructing this interesting animal for possible display in the museum. Unfortunately, as is common amongst plesiosaurs, the specimen lacks a head and many other key areas, which would otherwise be useful for determining the affinities of this animal. A.S.

3-eyed plesiosaur?!

The text reads as follows:

A 3-eyed Monster, 100,000,000 Years Old, Found in WarwickshireThe last few days have witnessed a dramatic geological discovery which is now being fully examined by Scientists from the South Kensington Museum. This is a three-eyed plesiosaurus, one hundred million years old, unearthed by a workman's pick in the Red Triangle Quarries in Warwickshire. The picture we reproduce above shows the skeleton of the plesiosaur fully uncovered; the lower picture shows a similar specimen already in the South Kensington Museum. We are indebted to Dr. F. A. Bather, F. R. S., the learned Keeper of Zoology at the Natural History Museum for the following notes on this great new discovery. The rock in which the specimen was found at Harbury is known as the lower lias, and is the same age and of the same dark-blue clay with bands of limestone as occurs at Lyme Regis. From the latter place many skeletons of plesiosaurs, now shown on the walls of the Fossil Reptile Gallery in the British Museum, were obtained by Thomas Hawkins about seventy years ago. Many of them are almost complete, whereas the specimen found in the Red Triangle Quarry at Harbury has unfortunately lost its ribs and most of the limb bones. What is complete is the series of vertebrae forming the backbone, which attains a length of 16 feet. The plesiosaurs found in the lias have as a rule been left on the large slabs of rock to which they are attached, but the closely allied forms in the much later Oxford clay have been extracted bone by bone and built into perfect skeletons. The name Plesiosaurus means 'near to a lizard'. It has been compared to a snake threaded through the body of a turtle, and that is by no means an inapt description of an animal with a barrel-shaped body and a long neck. The neck, however was stiff and not swan-like as it is sometimes represented. It bore a small head with small conical teeth. The body had a short tail with a small vertical fin; on each side of the body was a pair of large paddles placed in front and behind, with these the animal could row itself along. Plesiosaurus lived in fairly shallow water, and its stomach was protected from the battering of the rocks by a number of additional ribs. These are well shown in the skeletons, because the animal is generally found lying on its back. The middle eye on the top of the head is a structure common to all primitive reptiles, in many of which it seems to have been quite large. Creatures that crawled on their bellies naturally wanted an eye to warn them of enemies approaching from above. Some skeletons of plesiosaurus contain, in the place where the stomach was, a number of stones which were used to help in the grinding of its food."