The Pied-Billed Grebe in Ancient Deposits in Mexico
The pied-billed Grebe in Ancient Deposits in Mexico.-The finding of a human skeleton near Tepexpan in the State of Mexico, northeast of the City of Mexico, has attracted much scientific attention as the oldest discovery of the kind yet made in North America. Dr. Helmut de Terra, working with the investigators who made the discovery, took out also bones of other animals, including those of the imperial mammoth. Among the other remains is one specimen of bird which has been placed in my hands for study.
The bone in question is a complete right tarsometatarsus from an individual fully grown but probably only recently so as porosity of the bony structure at the extremities seems to indicate immaturity. It comes from the Pied-billed Grebe, Podilymbus podiceps (Linnaeus), known in Mexico as zambullidor pica pinto. The bone has the large size characteristic of the male in this species and resembles modern specimens in detail, the only difference being that the lower support of the hypotarsus is slightly more constricted and somewhat more elevated on the shaft than in part of the comparative material in hand. This, however, is regarded as individual variation.
The Tepexpan man, excavated from beneath a layer of caliche, has been accorded late Pleistocene age with an antiquity of 10,000 to 15,ooO years by Dr. de Terra, a belief shared by some of his colleagues among anthropologists. Most geologists, however, attribute the deposit to the early part of the Recent epoch, as in their opinion the Pleistocene terminated at a considerably earlier time.--ALEXANDER WETMORE, Smithsonian Institutiotu, Washington, DC., January 27, 1949.