The Relationships of the Lizard Genera Anelytropsis and Dibamus

Abstract

This paper deals with 3 problems: the relationships of Anelytropsis and Dibamus, their relationships to other squamates, and their species taxonomy. The external morphology, osteology, soft anatomy, reproduction, ecology and behavior of both genera are described. The poliarty of character states is determined by comparison with kuehneosaurids, sphenodontids and eosuchians. The similarity between Anelytropis and Dibamus in derived character states is so extensive and detailed that it is obvious they are each other''s closest living relatives and warrant grouping in 1 family, the Dibamidae. Other squamates are surveyed to determine the proportion of dibamid derived character states each possesses. The most similar taxa are amphisbaenians (64%), snakes (58%), anniellids (53%) and feylinine scincids (49%). If dibamids share an exclusive common ancestor with any one group of living squamates, it is likely to be with one of these. Alternatively, 1 unique and 5 unusual primitive character states suggest that dibamids may have arisen early in the radiation of squamates. This latter interpretation, however, is very tentative in the absence of an overall analysis of major squamate lineages. The species taxonomy of dibamids is reviewed and 1 spp. of Anelytropsis [A. papillosus] and 9 of Dibamus [D. alfredi, D. bourreti, D. celebensis, D. leucurus, D. montanus, D. novaguineae, D. seramensis sp. nov., D. smithi sp. nov., and D. taylori sp. nov.] are recognized. There is a brief account of each species and a key to all.