DATOS ACERCA DE LA VARIACION INTRAPOBLACIONAL DE LA MORFOLOGIA DE LOS MOLARES DE ENTIDADES DE LOS GENEROS GALEA Y MICROCAVIA (RODENTIA, CAVIIDAE).

Abstract

The author studies the variability observed in the morphology of the masticatory surfaces of the molar teeth in two different populations of the taxon Galea musteloicles musteloides Meyen, one from Abra Pampa (Jujuy) and the other from Tucuman. The same analysis is made with two populations of Microcavia austmlis australis Geoffroy & D'Orbigny, one from Estancia "El Tranquilo", Santa Cruz (Patagonia), and the other from Pichi Ciego (Men-. doza). About ten specimens from each population were observed for morphological .variations, and measures for statistical analysis were taken in larger samples. Nearly every trait of the molar pattern shows a great amount of variability in each of the studied populations. These variations are more evident in the premolar and in the last molar. Both populations of Gale(}) clearly show a greater indi:vidual variation than the ana- lyzed populations of Microcavia. The Tucuman sample of Garlea musteloides musteloides has a greater individual variation than the Abra Pampa sample of the same subspecies, which is connected with the fact that the fo1mer represents a pool of specimens from two different localities. The observed intrapopulational variation includes morphological differences which in many cases surpass those used by some authors to define new species and also new genera of fossil Caviids. This is an indication of the necessity of a thorough revision, on the basis of a clear understanding of intraespecific and intrasubspecific variability, of the present systematics of fossil representatives of this family.