Wyominge gracilis ayne: G.novum, Sp.novum. A new trilobite from Carboniferous of Appalachia

Abstract

Trilobites are a highly diverse group of extinct arthropods persisting for 300 MYA in the marine ecosystem of the Earth. Though uncommon elements of Pennsylvanian rocks. A new species and genus rank is proposed. The specimen consists of a well-preserved cast mold of exoskeleton. Horizon Late Carboniferous. Etymology, of name, type locality and named after prominent naturalist, gracilis L. for graceful. Holotype JRF, 13-16. Description Exoskeleton specimen is roughly oval to semi-elliptical in outline. A well preserved pygidium and near complete thorax, cranidium is missing. Thorax 9-10 segments, axial furrow deep and curved. X-ray study helped to appreciate sutures, furrows and angulation. Pleural furrows are distinct and convex anteriorly. Thorax axis with gentle slope to pygidium. Length of thorax (sag) exoskeleton is 65mm,width 32mm. Width of pygidium across the anterior margin 15 mm, length 29 mm. Pygidium, semi-elliptical 9-10 axial rings of terminal pad like structure and the lateral area. Furrows well marked and deep. Small posterior axial ridge. Conclusion: The characteristic of the specimen size and configuration of pygidium differed from typed species and needs to be placed in a separate and specific genus. X-ray study helped in delineating fine structures. It can be a useful research tool for study of unusual specimens. These findings add to Paleoecology and stratigraphic knowledge of marine fauna.