PROC. BIOL. SOC. WASH. 93(3), 1980, pp. 593-596 A NEW STROBILOPS (MOLLUSCA: PULMONATA: STROBILOPSIDAE) FROM BAJA CALIFORNIA SUR, MEXICO Walter B. Miller and Carl C. Christensen Abstract. — Strobilops californica, a new species of pulmonate land snail inhabiting the Sierra de la Victoria of Baja California Sur, Mexico, is de-scribed. In December 1973, while searching in the high mountains of the Cape Region of Baja California, Mexico, for live specimens of Rabdotus beldingi (Cooper, 1892), we discovered a single dead shell of an unfamiliar species of small snail. We were successful in collecting living R. beldingi and other terrestrial mollusks but were unable to find additional specimens of the unknown small species. Subsequent examination by Alan Solem, Field Mu-seum of Natural History, revealed that this unique shell is that of a species of Strobilops, a genus only sparsely distributed in western North America and not previously known to inhabit Baja California. Comparison with other west Mexican Strobilops demonstrated the Baja California form to be an undescribed species. We collected this snail in the higher elevations of the Sierra de la Victoria, a region only rarely visited by malacologists; it is therefore unlikely that additional material of this new species will soon become available for study. While we are reluctant to describe a new species on the basis of a single specimen, we believe that the relative inaccessibility of the habitat of this species and the desirability of documenting its occurrence in Baja California justify such action at this time. Strobilops californica, new species Fig. 1 Description. — Shell large for genus, solid, trochiform, sharply carinate, much wider than high, finely and closely ribbed above periphery, with about 140 riblets on body whorl and 120 on penultimate whorl, convex and finely ribstriate below. It is widely umbilicate, the umbilicus contained about 3 times in diameter. Parietal callus thick, prominent where the strong parietal lamella joins it. No infraparietal or interparietal lamellae visible from the aperture, and none can be seen by transmitted light. Nearly a half whorl behind the aperture, a series of 4 basal folds can be detected by transmitted light. The innermost 3 are relatively short, subequal, parallel and equally
BioStor
