Discovery of a larval shell in Middle Paleozoic subulitoidean gastropods with description of two new species from the Early Devonian of Bohemia

 

Authors: Frýda J

Published in: Bulletin of Geosciences, volume 76, issue 1; pages: 29 - 38;

Keywords: Gastropoda, Caenogastropoda, Subulitoidea, planktotrophy, Early Devonian, Prague Basin,

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Abstract

The discovery of a true larval shell (protoconch II) in Middle Paleozoic subulitoidean gastropods is described. Three gastropod genera, Balbiniconcha Horný, 1992, Holynelites Frýda, 1998, and Prokopiconcha gen. nov., are united in a new subfamily Prokopiconchinae of the Soleniscidae. The Prokopiconchinae also includes two new species, Prokopiconcha bisinuata sp. nov. and Balbiniconcha cerinka sp. nov., from the late Early Devonian of Bohemia. Distribution of larval development among Paleozoic Gastropoda is briefly discussed. During Devonian time there were several gastropod groups developing a true larval shell (Cyrtoneritimorpha, Perunelomorpha, Mimospirina, Caenogastropoda, Heterobranchia and Amphigastropoda). Thus, it is quite evident that the evolution of planktotrophy in the Gastropoda was much more complex than had been suggested by neontologists.