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Ateleocystites? lansae sp. nov. is characterized by an elongate body with short spines that taper relatively rapidly. It has granular plate ornament adorally in addition to cuesta-like ridges. Ateleocystites? lansae occurs commonly in a 5-cm-thick fine- to medium-grained sandstone bed, which was rapidly emplaced and transported fossils from shallower water, within the Upper Ordovician (Katian), Slade and Redhill Beds along the A477 road and in the new quarry above The Old Mill Cafe, Tenby Road (now C3236), west of Llanddowror, Carmarthenshire. Other specimens are known from Sholeshook, Pembrokeshire. On the convex surface, the Welsh species differs from A. guttenbergensis Kolata and Jollie in having a larger central ‘placocystitid’ plate (C17) in contact with six, not five other plates. In addition, the marginal plates are scarcely visible on the convex surface. Plating on the planar surface agrees well with that of both A. guttenbergensis and the type species, A. huxleyi Billings. The presence of articulated appendages and spines and the lack of sediment fill in the bodies suggest that the new specimens were alive when buried. Ateleocystites? lansae probably lived largely buried in the sediment with the convex surface below and moved with the appendage in front. Copyright © 2015 John Wiley & Sons, Ltd. |
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