Dental Anomaly in Tapirus Terrestris (L.)

Abstract

A male skull of Tapirus terrestris (L.) originating from Dutch Guiana (Leiden Museum, reg. no. 11632), received from the Rotterdam Zoological Garden through the kind intermediary of Mr. F. J. APPELMAN on July 15, 1952, is remarkable for the abnormal development of its right P1. The full permanent dentition is in place except for the posterior premolars and last molars, which are in alveolo. The teeth are but little worn and, apart from the right P1, they do not show anv unusual characters. The left P1 has the shape normally found in the Brazilian tapir; the crown is triangular with rounded angles, and bears a continuous outer crest (ectoloph) extending from the front angle (parastyle) to the posterior outer cusp (metacone). The position of the central outer cusp (paracone), merged in the crest, is indicated only by a weak vertical ridge on the labial face of the ectoloph, flattening toward the crown base, the paracone style. The posterior inner cusp (hypocone) is a low but distinct, anteroposteriorly elongated elevation of the cingulum. The protocone is just visible as a tiny cusp on the lingual cingulum, internal to the paracone. The labial cingulum is shown as a slight swelling all along the base of the ectoloph. There is a broad posterior root, imperfectly subdivided into a larger labial and a smaller lingual portion, and there is a single anterior root; the roots are but slightly divergent. The anteroposterior diameter of the crown is 17.1 mm, the posterior width, 13.2 mm.