Robert J. Russell

“ Cueva de San Josecito in the province of Aramberri, near the town on Aramberri, Nuevo León, México, is at an elevation of approximately 7400 feet above sea level on the east-facing slope of the Sierra Madre Occidental in a limestone scarp. The dominant vegetation about the cave is the decidedly boreal forest association of pine and live oak. ”

“ As he points out, that species requires hydric communities of cool climates, and in the Wisconsin Glacial age such climates probably prevailed in the high mountainous region where San Josecito is located. Since the time when a more mesic boreal environment occurred at San Josecito, climatic shifts have favored more xeric conditions as are found in the vicinity of the cave today. The more arid environments would support the occurrence of Cratogeomys and Thomomys; however the ecological affinities of the fragment here referred to Cratogeomys sp. are unknown. ”

“ The breadth of the rostrum measures 10.4, which is comparable to that in the subnubilus group of small subspecies, and less than that [Pg 544] (11.4 in the smaller adult females to 13.7 in the larger adult males) in the subsimus group of large subspecies. The breadth of rostrum in the fossil is 40.3 per cent of the length of the rostrum. In living Cratogeomys castanops (both the large and small subspecies groups, and including both females and males) the breadth of rostrum amounts to between 44.0 and 51.4 per cent of its length. ”