Tilefish (Teleostei, Malacanthidae) remains from the Miocene Calvert Formation, Maryland and Virginia: taxonomical and paleoecological remarks

Abstract

ABSTRACTThe spectacularly fossiliferous Calvert Formation is largely exposed in Maryland and Virginia and comprises the best available record of middle Miocene life in the northeastern United States. Lopholatilus ereborensis, sp. nov., a new tilefish from the middle Miocene (Langhian) of the Calvert Formation, is described herein based on 15 well-preserved three-dimensional partially complete articulated skeletons. These fossils consist primarily of cranial remains and represent the earliest known occurrence of the genus Lopholatilus in the record. Lopholatilus ereborensis is characterized by moderately deep head and short snout, occipital region of the neurocranium obliquely sloping, epioccipital spine extending posteriorly beyond the supraoccipital crest, remarkably shortened ascending process of the premaxilla, villiform teeth on dentary restricted to the symphyseal region, horizontal arm of the preopercle short, and angle formed by vertical and horizontal arms of the preopercle measuring about 120°. Taphonomic and paleoecological considerations suggest that Lopholatilus ereborensis inhabited long funnel-shaped vertical burrows self-excavated within the stable and cohesive bottoms of the outer continental shelf of the Salisbury Embayment, and possibly of other parts of the western North Atlantic outer shelf and upper slope that were characterized by relatively warm oxygenated waters. In that context, the three-dimensional preservation of the articulated skeletons of Lopholatilus ereborensis might represent the product of an abrupt burial resulting from the collapse of the upper part of the burrows. Cylindrical-shaped trace fossils (domichnia) penetrating the fine-grained sands of the middle part of the Calvert Formation are proposed to have been produced by Lopholatilus ereborensis.