Notes on Kenya land and freshwater snails. 9. A rediscovery of Microstele iredalei (Preston)

Preston, 1912, Proc. Zool. Soc. p. 188, pl. 31, fig. 18 ( [Leucochiloides i.); Pilsbry, 1921, Man. Conch. (2), vol. 26, p. 148, pl. 14, fig. 18, pl. 17, fig. 7; Adam, 1954, Vol. Jubil. V. van Straelen, vol. 2, p. 789; Verdcourt, 1958, Basteria, vol. 22, p. 4. In 1958 I described a collection of Pupoides from drift material collected in the Turkana District of Kenya. This material varied over a wide range of size and shape and three varieties were distinguishable. Whether these occurred together or in different areas could not be ascertained from drift material. I was, therefore, very pleased to see in an interesting collection sent to me by Dr. A. RIEDEL of the Polish Academy of Sciences abundant material of what at first sight appeared to be two species of Pupoides. This material had been collected in Kenya by Messrs. BANIEWICZ and KNABE ‘150 km. E. of Nairobi, 700 m. altitude, dry terrain under stones and pieces of stem or bark’. The material had been found alive together with Trochonanina pyramidea von Martens and obviously had been in a state of aestivation since epiphragms were in position. The material was easily sorted into two groups save for a very few intermediate specimens. On removing some epiphragms it was a surprise to find that the small species had a parietal and a columellar lamella in addition to the nodule close to the top of the peristome. Clearly it was Microstele iredalei (Preston) and, apart from the report of ADAM (1954) that a ‘cotype’ said to be of Pupoides chanlerensis (Preston) and received at the Institut Royal des Sciences Naturelles de Belgique from PRESTON himself was in fact Microstele iredalei, no other records could be traced. This statement of ADAM, together with the fact that in the new material the lamellae are often not visible unless the shell is tilted, made me query the identity of some of the drift material previously mentioned. The bulk of this is preserved in Nairobi and not readily available to me.