Reproduction, duration of embryogenesis, egg capsules and protoconchs of gastropods of the family Baicaliidae (Caenogastropoda) endemic to Lake Baikal

Citation
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
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
MALACOLOGIA
ISSN journal
0076-2997 → ACNP
Volume
43
Issue
1-2
Year of publication
2001
Pages
59 - 85
Database
ISI
SICI code
0076-2997(2001)43:1-2<59:RDOEEC>2.0.ZU;2-2
Abstract
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.