Studies on Quinqueserialis hassalli and Taxonomic Considerations of the Species of Quinqueserialis (Trematoda: Notocotylidae)

Abstract

A morphological study was made on 176 specimens of Q. hassalli (McIntosh and McIntosh, 1934) Harwood, 1939 taken from meadow mice, Microtus montanus caryi Bailey, M. m. fusus Hall, M. pennsylvanicus modestus (Baird), and the n. pocket gopher, Thomomys talpoides ssp., of New Mexico, Colorado and Wyoming. These specimens showed considerable variation in body shape and size, number of ventral papillae and size, shape and position of internal organs. Three species of Quinqueserialis are considered valid: Q. hassalli, Q. quinqueserialis (Barker and Laughlin, 1911) Harwood, 1939 and Q. floridensis Rausch. 1952. Q. wolgaensis Skvortsov, 1934 is considered a synonym of Q. hassalli. The number of ventral papillae, form and distribution of vitellaria, length of metraterm in relation to length of cirrus sac, and egg size appear to be poor characteristics for differentiation of the 3 spp. The transverse uterine coils of Q. quinqueserialis do not extend laterally past the intestinal ceca as they do in Q. hassalli and Q. floridensis, Q. floridensis has vitellaria almost wholly posterior to the uterine loops while Q. hassalli has vitellaria extending from the testes anteriorly to a point 2/3 or more the distance to the cirrus sac. The similarity of Q. floridensis and Notocotylus noyeri Joyeux. 1922 to Q. hassalli is such that the possibility of their specific identity to Q. hassalli should be considered.