178-7 Proposed Revision and Early Radiation of Svalbardiinid Brachiopods

Session: Paleontology, Diversity, Extinction, Origination

Presenting Author:

Authors:

Abstract:

The Svalbardiinae are a group of chonetoid brachiopods typified by Brachiosvalbardia (Ceccolini & Cianferoni), whose small size and smooth exterior have led to much taxonomic confusion.  In an effort to stabilize the Svalbardiinae, we have redescribed the type species of Brachiosvalbardia.  We propose to broaden Brachiosvalbardia to incorporate species formerly assigned to Komiella and Chonetes.  Developmental series of the interiors of both valves highlight the relative stability of some features of the dorsal interior, which are interpreted to have taxonomic implications.  The dorsal valve interior of Lissochonetes uralensis (Kalashnikov) was reconstructed in three dimensions, illustrating effects of static secondary shell features on water flow.  Features of Tornquistia? transversalis (Carter), are shown to be inconsistent with placement in the Anopliidae, but consistent with placement in the svalbardiinid crown group.  Reinterpretation of brachiopods from the Urals, Australia and Greenland supports the interpretation that the shallow Panthalassic Ocean in the region of present-day Texas was a significant site of early radiation and global dispersal of svalbardiinid brachiopods.  This revision is intended to provide a stable taxonomic basis for future studies of Svalbardiinae, and their ecology.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9234

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