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A CAMBRIAN MERASPID CLUSTER: EVIDENCE OF TRILOBITE EGG DEPOSITION IN A NEST SITE

2019; Society for Sedimentary Geology; Volume: 34; Issue: 5 Linguagem: Inglês

10.2110/palo.2018.102

1938-5323

David R. Schwimmer, William M. Montante,

Evolution and Paleontology Studies

Research Article| May 22, 2019 A CAMBRIAN MERASPID CLUSTER: EVIDENCE OF TRILOBITE EGG DEPOSITION IN A NEST SITE DAVID R. SCHWIMMER; DAVID R. SCHWIMMER 1Department of Earth and Space Sciences, Columbus State University, Columbus, Georgia 31907-5645, USA email: schwimmer_david@columbusstate.edu Search for other works by this author on: GSW Google Scholar WILLIAM M. MONTANTE WILLIAM M. MONTANTE 2Tellus Science Museum, 100 Tellus Drive, Cartersville, Georgia, 30120 USA Search for other works by this author on: GSW Google Scholar PALAIOS (2019) 34 (5): 254–260. https://doi.org/10.2110/palo.2018.102 Article history first online: 22 May 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation DAVID R. SCHWIMMER, WILLIAM M. MONTANTE; A CAMBRIAN MERASPID CLUSTER: EVIDENCE OF TRILOBITE EGG DEPOSITION IN A NEST SITE. PALAIOS 2019;; 34 (5): 254–260. doi: https://doi.org/10.2110/palo.2018.102 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyPALAIOS Search Advanced Search ABSTRACT Recent evidence confirms that trilobites were oviparous; however, their subsequent embryonic development has not been determined. A ∼ 6 cm2 claystone specimen from the upper Cambrian (Paibian) Conasauga Formation in western Georgia contains a cluster of >100 meraspid trilobites, many complete with librigenae. The juvenile trilobites, identified as Aphelaspis sp., are mostly 1.5 to 2.0 mm total length and co-occur in multiple axial orientations on a single bedding plane. This observation, together with the attached free cheeks, indicates that the association is not a result of current sorting. The majority of juveniles with determinable thoracic segment counts are of meraspid degree 5, suggesting that they hatched penecontemporaneously following a single egg deposition event. Additionally, they are tightly assembled, with a few strays, suggesting that the larvae either remained on the egg deposition site or selectively reassembled as affiliative, feeding, or protective behavior.Gregarious behavior by trilobites (“trilobite clusters”) has been reported frequently, but previously encompassed only holaspid adults or mixed-age assemblages. This is the first report of juvenile trilobite clustering and one of the few reported clusters involving Cambrian trilobites. Numerous explanations for trilobite clustering behavior have been posited; here it is proposed that larval clustering follows egg deposition at a nest site, and that larval aggregation may be a homing response to their nest. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.