Geological Magazine

Original Article

A review of Pachyvaranus crassispondylus Arambourg, 1952, a pachyostotic marine squamate from the latest Cretaceous phosphates of Morocco and Syria

ALEXANDRA HOUSSAYEa1 c1, NATHALIE BARDETa1, JEAN-CLAUDE RAGEa1, XABIER PEREDA SUBERBIOLAa2, BAÂDI BOUYAa3, MBAREK AMAGHZAZa3 and MOHAMED AMALIKa4

a1 CNRS UMR 7207, Département Histoire de la Terre, Muséum National d'Histoire Naturelle, CP 38, 8 rue Buffon, 75005 Paris, France

a2 Universidad del País Vasco/EHU, Facultad de Ciencia y Tecnología, Departamento de Estratigrafía y Paleontología, Apartado 644, 48080 Bilbao

a3 Office Chérifien des Phosphates, Centre Minier de Khouribga, Khouribga, Morocco

a4 Office Chérifien des Phosphates, Centre Minier de Ben Guerir, Ben Guerir, Morocco

Abstract

The discovery of new specimens of Pachyvaranus crassispondylus Arambourg, 1952 from the Maastrichtian phosphates of Morocco and Syria enables us to (1) redescribe in detail this poorly known varanoid lizard, (2) provide a more detailed diagnosis and (3) re-evaluate the systematic affinities of this taxon within squamates. The latter is placed in Pachyvaranidae nov., considered a new unranked clade of non-pythonomorph Varanoidea. The intense pachyosteosclerosis observed in the vertebrae and ribs suggests a primarily aquatic mode of life for Pachyvaranus. This is in accordance with the sedimentological context (shallow marine environment). As for its palaeobiogeographical distribution, Pachyvaranus is a component of the marine reptile assemblages from the southern margin of the Mediterranean Tethys, around palaeolatitudes 20° N. The osteoderms previously referred to this taxon by Arambourg are reanalysed and assigned to a teleost fish.

(Received November 02 2009)

(Accepted May 27 2010)

(Online publication July 09 2010)

Keywords:

  • Pachyvaranus;
  • Varanoidea;
  • Pachyvaranidae clade nov.;
  • Maastrichtian;
  • Southern Tethys;
  • pachyosteosclerosis

Correspondence:

c1 Author for correspondence: houssaye@mnhn.fr

Metrics