CONRAD: SQUAMATE PHYLOGENY

摘要

Squamata (amphisbaenians, "lizards", mosasaurs, and snakes) is an extremely diverse cladewith a rich fossil record. There is little consensus about the interrelationships of the majorsquamate clades (i.e., Iguania, Gekkota, Scincomorpha, Anguimorpha, Amphisbaenia, andSerpentes), or even the membership of some of these clades. Morphology-based cladisticanalyses typically agree only that the major dichotomy in extant squamates is between Iguaniaand all other taxa. The phylogenetic placement of Amphisbaenia and Serpentes is particularlyproblematic. Incomplete taxon sampling is likely a major contributing factor to the absence of aconsensus about squamate interrelationships. This study examines squamate relationships using222 ingroup taxa scored for 363 morphological characters. Analysis of these data recovered2,213 equally short trees with a length of 3,273 steps and a retention index of 0.7164. The resultsconfirm the monophyly of the clades Scleroglossa (extant squamates exclusive of Iguania),Gekkota, Scincomorpha, Lacertoidea, Scincoidea, Anguimorpha, Carusioidea, Platynota, andVaranoidea. Novel results include the identification of a clade containing Scincidae sensu lato,Dibamidae, Amphisbaenia, and Serpentes; identification of a Mesozoic clade containingBainguis, Eoxanta lacertifrons, Globaura venusta, and Myrmecodaptria; and identification ofDalinghosaurus as a basal shinisaur. A new taxonomic scheme is outlined. The namesIguanomorpha, Scincogekkonomorpha, Evansauria, and Mosasauriformes are applied to thestem-based groups including Iguania, Scleroglossa, Autarchoglossa, and Mosasauria, respec-tively. The importance of strict rigidity within taxonomy is questioned; taxonomy is most usefulas a tool for communication about organisms or groups of organisms.