23 D22. Recent Developments in Biogeography and Biostratigraphy (Posters)

Sunday, 15 October 2023
8:00 AM - 5:30 PM
Hall B

REASSESSING AND ADDING TO THE BURGESS SHALE-TYPE FAUNA OF THE KINZERS FORMATION, EARLY CAMBRIAN OF S.E. PENNSYLVANIA

Paper number: 23-7
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

The Kinzers Formation is well known for its fine olenellid trilobites and for special preservation of a Burgess Shale-type fauna at some localities. The disparity of its faunal associations is less well appreciated. Distinct faunas record early Cambrian marine life in varied settings on a muddy continental shelf that was replaced upward in time and to the southwest by deeper-water of a collapsing continental margin. Shale of the basal Emigsville Member is variably calcareous and locally fossiliferous. In its most characteristic assemblage, mainly disarticulated olenellids are accompanied by a varied shelly fauna in sediment evincing considerable bioturbation. Locally, finer grained Lagerstätten yield undisturbed remains of worms, a hemichordate, a gastropod with preserved impressions of its paired sets of unique chaetae, and weakly sclerotized arthropods. One site, the Getz Quarry, was formerly famous for its exceptionally large, often fully articulated trilobites. At other localities, echinoderms are disproportionately common. Recent fossil discoveries bear on significant issues. Long, spineless endites, attached at the exposed (directly visible) ventral margins of podomeres of the frontal feeding appendage of a new anomalocaridid species, link it to taxa that have been assigned to different families of the radiodontid arthropods, signaling inconsistencies in their definitions. An undescribed bivalved stem-arthropod, Odaraia sp., with large eyes and a triple-flanged tail, is intermediate in age between relatives from Chengjiang in China and the Burgess Shale in Canada. It is substantially closer in form to the latter. Trunk somites (chevron-shaped muscle blocks) of a small chordate may be assignable to Emmonsaspis or to Metaspriggina, depending on whether or not these taxa prove to be congeneric. A partial mold of an armored lobopod with spines close in form and spacing to those of Hallucigenia; near relatives of the possible red alga Waputikia ramosa and the demosponge Vauxia gracilenta, both known from the Burgess Shale; and a species of the hemichordate Oecia, recently recognized from the reconstruction by Nanglu et al. (2016) of two pre-existing Burgess Shale taxa; are all now recognized for the first time to occur in the Kinzers Formation.

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

doi: 10.1130/abs/2023AM-391173

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