|2011 GSA Annual Meeting in Minneapolis (9–12 October 2011)|
|Paper No. 152-13|
|Presentation Time: 11:15 AM-11:30 AM|
WHO'S MAKING ALL THOSE SCARS? FREQUENCY AND IDENTITY OF CRAB PREDATION ON FOSSIL AND LIVING TURRITELLINE GASTROPODS FROM FLORIDA AND PANAMA
PIERREHUMBERT, Nadia D., Dept. of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY 14850, firstname.lastname@example.org and ALLMON, Warren D., Paleontological Research Institution, 1259 Trumansburg Road, Ithaca, NY 14850|
Turritelline gastropods (Caenogastropoda, Turritellidae) show frequent breakage and repair at their apertural lip throughout their long and abundant history (Early Cretaceous-Recent). Almost every shell shows at least one such scar, with more than 5 on larger shells not unusual. Most of these scars are assumed to have been caused by unsuccessful predation by decapod crustaceans, and a number of previous studies have used scar frequency to infer ancient predation activity on these snails. Yet there is no published account of a crab actually attacking a turritelline, nor is anything known about which decapod taxa are involved. One obstacle to such study is that very few data are available on the shape of breakage scars made by different living decapod species.
Our working hypothesis is that different species of crabs will make distinguishable breakage scars when attacking the same gastropod species, and that if this is true in the Recent, we may be able to recognize and quantify predation by different crab taxa in the fossil record. To test this hypothesis, we first carried out a pilot study of fossil turritellines from the Pliocene of Florida, and found that at least four categories of breakage scars can be distinguished based on shape, with at least two of these categories assignable to decapods based on comparison with modern data from the literature. We have now documented, apparently for the first time, attacks by crabs (Panopeus sp. and Xanthodius sternberghii) on living turritellines (Turritella banksi from the Pacific coast of Panama) in lab aquaria. Preliminary results of these observations indicate that Panopeus sp. produces scalloped, distinctly toothed breaks similar to some of those attributed to decapods in the Florida fossils, while X. sternberghii creates smooth, straight-edged breaks that were heretofore unexplained in the fossil material. Concurrent surveys of dead T. banksi shells and fossil turritellines from the nearby Upper Miocene Gatun Formation are consistent with the earlier Florida data in showing distinguishable shape categories of breakage scars, including the scallopped breaks witnessed on the captive snails. Consistent with the presence of numerous unsuccessful scars on most shells, very few of the attacks we have observed (<10%) have been fatal.
2011 GSA Annual Meeting in Minneapolis (9–12 October 2011)
General Information for this Meeting
|Session No. 152|
Lessons from the Living: Paleontological Investigations Using Modern Analogs I
Minneapolis Convention Center: Room 205AB
8:00 AM-12:00 PM, Tuesday, 11 October 2011
Geological Society of America Abstracts with Programs, Vol. 43, No. 5, p. 381
© Copyright 2011 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.