T. Sitnikova et al., Reproduction, duration of embryogenesis, egg capsules and protoconchs of gastropods of the family Baicaliidae (Caenogastropoda) endemic to Lake Baikal, MALACOLOGIA, 43(1-2), 2001, pp. 59-85
Data on the reproduction and duration of embryogenesis have been obtained f
or the first time for the Lake Baikal endemic gastropods of the family Baic
allidae. Their reproduction occurs throughout the year, but with peaks in s
pring and autumn. Embryogenesis duration supposedly depends on the near-bot
tom water temperature. Hatching appears to be timed to coincide with the pe
riods of increased food supplies. Egg capsule and protoconch morphology has
been examined in several species, and four types of capsules are described
. Shells of the Baicaliidae are orthostrophic, and only in Liobaicalia stie
dae does the protoconch axis differ significantly from the telecconch axis,
which was previously mistaken for heterostrophy. Three groups were disting
uished on the basis of a cluster analysis of size and number of protoconch
whorls. These clusters do not fully coincide with the recent taxonomy of th
e Baicaliidae based on shell morphology and the female reproductive system.
Some species assigned to the same genus or subgenus differ either in proto
conch size or egg capsule morphology.