The Bernissart Crocodiles |
Gionopholis and Bernissartia
Alongside the iguanodons found in Bernissart there were also four crocodile skeletons belonging to two different species, both of which are small when compared to recent species. The largest, the Goniopholis "simus" is about 2 m long, and the other, which is more typical of Bernissart, the Bernissartia fagesii, is only 0.66 m long. Both have a fairly broad and only moderately long snout. The dorsal shield of Goniopholis "simus" consists of two rows of plates, whereas the Bernissartia fagesii has several rows.
Skeleton of
Bernissartia fagesii, 66 cm
long.
Site and Age
The crocodile skeletons were found in clay layers dating from the Early Cretaceous period (Berriasian-Aptian; 135 to 110 million years old). These layers settled in a naturally circular area of collapse ("cran") through the underlying, Westphalian coal layers (Late Carboniferous).
Skeleton of
Goniopholis "simus" as found in the
Iguanodon site in Bernissart. The total length is
approximately 2 m. Drawing by G. Lavalette
(1883).
Importance of the Collection
Compared with many other crocodile finds from the Cretaceous period, these skeletons are very complete. Goniopholis is one of the most common and characteristic crocodile group in the Northern Hemisphere during the Late Jurassic and Early Cretaceous periods (152 million to 100 million years ago). In Europe the group is most frequently found in the South of England and North West Germany. There are five species of which the best known is Goniopholis "simus". Until recently the Goniopholis specimens of Bernissart were assigned to this species, but recent research (1999) has revealed that they belong to a new, as yet undescribed species. Bernissartia fagesii is a much rarer species, and, outside of Bernissart, where it was first discovered, it is only found in England, Spain, Germany and perhaps Portugal and Texas. Its correct position in the crocodilian phylogeny has been the subject of much debate. Some think it a typical Mesosuchia, and older group from the Jurassic and Cretaceous periods, and others say that is shows the first characteristics of the younger Eusuchia, the modern crocodiles that evolved later, particularly in the Tertiary period (less than 65 million years ago).
Biblography
Buffetaut, E., 1975, Sur l'anatomie et la position systématique de Bernissartia fagesii Dollo, L., 1883, crocodilien du Wealdien de Bernissart, Belgique., Bulletin de l'Institut royal des Sciences naturelles de Belgique, Sciences de la Terre, 51, 2: 1-20.
Buffetaut, E. & Ford, R.L.E., 1979, The crocodilian Bernissartia in the Wealden of the Isle of Wight., Palaeontology, 22, 4: 905-912.
Buscalioni, A. & Sanz, J.-L., 1990, The small crocodile Bernisartia fagesii from the Lower Cretaceous of Galve (Teruel, Spain)., Bulletin de l'Institut royal des Sciences naturelles de Belgique, Sciences de la Terre, 60: 129-150.
Norell, M.A. & Clark, J.M., 1990, A reanalysis of Bernissartia fagesii, with comments on its phylogenetic position and its bearing on the origin and diagnosis of the Eusuchia., Bulletin de l'Institut royal des Sciences naturelles de Belgique, Sciences de la Terre, 60: 115-128.
Salisbury, S.W., Willis, P.M.A., Peitz, S. & Sander, P.M., 1999, The crocodilian Goniopholis simus from the Lower Cretaceous of north-western Germany., Palaeontology, 60, 1: 121-148.