T58 The Early Paleozoic II: Radiations, Extinctions, and Environment

Sunday, 15 October 2023
1:30 PM - 5:30 PM
304 / 305

A NEW LUOLISHANIID FROM THE EARLY ORDOVICIAN AND THE AUTECOLOGY OF SUSPENSION FEEDING LOBOPODIANS

Paper number: T58-3
Program: Technical Sessions
Time: 1:55 PM – 2:10 PM

Authors

Abstract

Lobopodians are a diverse clade of soft-bodied, vermiform marine invertebrates crucial to understanding panarthropod evolution in deep time. We describe a new luolishaniid lobopodian from the early Ordovician Fezouata Shale biota of Morocco with adaptations for suspension feeding. The Fezouata Shale luolishaniid features at least nine relatively robust and annulated limb pairs. The anterior-most limb pairs are elongated with setiform structures emerging from either side of the limb in a chevron pattern. The remaining posterior limb pairs likely end in a terminal claw. The Fezouata Shale lobopodian extends the evolutionary history of luolishaniids, previously only known from early and mid-Cambrian deposits in North America, South China, and South Australia. We also explore the autecological implications of the suspension feeding morphology of all described luolishaniid taxa. Luolishaniids sifted particles and organisms out of the water column that are on the larger end of the micro-planktonic spectrum (20μm - 200μm) and on the smaller end of the meso-plankton spectrum (200μm - 20 mm). We find a statistically significant, positive relationship between luolishaniid maximum body size and setae mesh size, suggesting that larger luolishaniids specialized on meso-plankton while smaller taxa specialized on micro-plankton.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-391739

© Copyright 2023 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.