RESEARCH ARTICLE

Pteropsaron indicum, a new species of signalfish (Teleostei: Trichonotidae: Hemerocoetinae) with a micro-CT analysis of osteology

Benjamin C. Victor & A. Biju Kumar

Abstract

An unusual yellow-striped deepwater hemerocoetine fish trawled up from 70 m depth in the Lakshadweep Sea (Laccadive Sea) off Kerala, southern India is described here as the new species Pteropsaron indicum, based on two male specimens measuring 82 and 84 mm SL. The new species of signalfish is notable among the grouping of three genera sharing crowded dorsal-fin spines and a maxillary spine (Acanthaphritis, Osopsaron, and Pteropsaron) in having only three dorsal-fin spines, greatly extended dorsal-fin soft rays in addition to the greatly extended dorsal-fin spines, high counts of rays in the dorsal and anal fins (D- III,27 and A- 29), a high number of vertebrae (38), and a relatively large body size. Pteropsaron indicum possesses the distinctive arrangement of the spinous-dorsal-fin-pterygiophore complex found in this subset of trichonotid fishes. In P. indicum, the complex is placed between the fourth and fifth neural spines. The micro-computed tomography technique (micro-CT) is used to illustrate that osteological peculiarity in fine detail.