PRELIMINARY REPORT OF A FOSSIL LIZARD SKULL FROM LA PALMA (CANARY ISLANDS)

CRUZADO CABALLERO, P.; ARNAU BOLET; J. R. COLMENERO; JOSEP FORTUNY; FEDERICO BERNARDINI; CAROLINA CASTILLO RUIZ; RAMÓN CASILLAS

Caparica

Congreso; XVI Annual Meeting of the European Association of Vertebrate; 2018

Canary Islands, a volcanic archipelago formed during Neogene and Quaternary periods located northwest of Africa are a great natural lab to understand evolutionary processes thanks to the diverse presence of endemic taxa. On this aim, the giant lizard genus Gallotia is an emblematic and endemic taxon with extinct and extant record. Regarding giant forms Gallotia four living species (G. bravoana, G. intermedia, G. simonyi and G. stehlini), one fossil (G. goliath) and one possibly extinct (G. auaritae) are known. The fossil record includes disarticulated and articulated specimens mainly preserved in volcanic tubes showing different ontogenetic stages. Here we describe the best-preserved material recovered from La Palma Island representing an almost complete skull and a partial endocast thanks to X-ray micro-computed tomography that allowed to digitally preparing the material embedded in a sedimentary matrix. This specimen shows some characters of the group formed by the species G. auaritae, G. bravoana, G. intermedia and G. simonyi: 1) big skull (between 20-40 mm), 2) maxillary tooth crown size and height constant throughout tooth row, 3) maxillary tooth count more than 25, 4) frontals unfused, and 5) occiput fully covered by the parietal, or nearly so, in dorsal view. Of particular interest, the almost straight lateral margins of the paired frontals are shared only with G. auaritae, suggesting affinities of this specimen with this taxon.