Neoetropus macrops Hildebrand and Schroeder, 1928: A Reversed Specimen and a Junior Synonym of Citharichthys arctifrons Goode, 1880 (Teleostei; Pleuronectiformes; Paralichthyidae)

Abstract

Neoetropus macrops Hildebrand and Schroeder, 1928, a nominal genus and species of dextral flounder known uniquely from the holotype, has been problematic regarding its identity and taxonomic status since its description. Previous treatments considered this dextral flatfish as a possible member of the dextral flounder family Poecilopsettidae or suggested it as a reversed individual of a sinistral paralichthyid species (either Etropus microstomus or Citharichthys arctifrons). However, its identity and status have never been confidently resolved. Following detailed examination of the holotype of N. macrops and comparison with other taxa, the identity and status of this species is resolved. Except for features determined to be anomalous in this specimen (dextral symmetry and short, ocular-side upper jaw), counts, measurements, and other morphological characters (e.g, arrangement of pelvic fins, position of urogenital papilla, and pattern of caudal skeleton ossification) of N. macrops agree with those of Citharichthys arctifrons Goode, 1880. Thus, N. macrops is identified as a reversed individual of the sinistral C. arctifrons. Accordingly, based on this finding, Neoetropus is relegated to the synonymy of Citharichthys Bleeker, 1862, and N. macrops becomes a junior synonym of C. arctifrons Goode, 1880. The reported capture location for this specimen (off the mouth of the Potomac River in Chesapeake Bay) is suspect because of its extremely unusual occurrence for C. arctifrons and discrepancies in documentation associated with this specimen.