Late Pleistocene Lizards from Barbuda, British West Indies

Abstract

In 1958, 1962, and 1963 field parties from the University of Florida collected large numbers of Quaternary vertebrate fossils from five caves near the northeast shore of the island of Barbuda, British West Indies. Fossils from the loose floors of Caves I, II and V are at least pre-Columbian in age but possibly not older than post-mid-Wisconsin. Fossils from breccia, and consolidated cave earth on the walls of Caves III and IV are somewhat older but probably not older than Late Pleistocene. Fossils of seven species of lizards are present in the caves. One species, Leiocephalus cuneus described as new, is extinct. A member of the West Indian section of the genus, it reached a maximum snout-vent length of 200 mm, far exceeding the largest extant species. Its occurrence on Barbuda, between L. herminieri on Martinique and the remaining Antillean species on Cuba, the Bahamas, and Hispaniola, indicates Leiocephalus was more extensively distributed in the eastern Caribbean during the late Pleistocene. Fossils of three species of Anolis are present in the caves. The largest reached a maximum snout-vent length of 120 mm and represents a giant ancestral population of Anolis bimaculatus leachii which occurs on Barbuda today. The two smaller forms of Anolis reached maximum snout-vent lengths of 72 and 48 mm. Their allies or descendents cannot be determined, but are probably to be found among the living species of the eastern Caribbean. One of the two smaller species may be ancestral to Anolis forresti which occurs on Barbuda today. Fossils of Thecadactylus rapicaudus and Ameiva griswoldi are identical in structure and size to individuals now living on Barbuda. Two fragments of a large iguanid apparently represent a large iguanine. They cannot be referred to Cyclura or Iguana and most closely resemble the Galapagoan genus Conolophus. The medium sized species of Anolis occurs only in the younger deposits, the large iguanine occurs only in the older deposits. All other species occur in both, and the older fossils are indistinguishable from those of the same species in the younger deposits. The affinities of most of the Barbudan lizards in the Late Pleistocene clearly lie within the islands of the eastern Caribbean. All but one of the species found as fossils occur in this region, or are related to species that occur there today. A cursory examination of lizard fossils from other West Indian islands suggests that the pattern of late Pleistocene gigantism and extinction found on Barbuda may have been of general occurrence in the West Indies.