The trilobite family Shumardiidae is characterized by small size, lack of eyes, yoked librigenae, and a small number of thoracic segments. Here we report the successive occurrence of three middle Furongian shumardiid species from the Sesong Formation of Korea: Elaphraella? taebaeksanensis n. sp., Elaphraella microforma, and Elaphraella nodus. They appear to represent the oldest shumardiid morphology known so far. This genus lacks the anterolateral swellings on the glabella and has a conical glabella. Its yoked librigenae also encompass a comparatively wide genal field. Elaphraella? taebaeksanensis has a highly inflexed facial suture which may reflect the presence of small palpebral lobes. Taken together, the plesiomorphic morphology of the Shumardiidae can be summarized as having a conical glabella, small palpebral lobes, highly arched anterior cephalic margin, a wide librigenal field, and no anterolateral swellings on the glabella.
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1 January 2012
Middle Furongian (Late Cambrian) Shumardiids from the Sesong Formation, Taebaek Group, Korea
Tae-Yoon Park,
Duck K Choi
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Journal of Paleontology
Vol. 86 • No. 1
January 2012
Vol. 86 • No. 1
January 2012