Prognathodesgeminus, a new species of butterflyfish (Teleostei, Chaetodontidae) from Palau.

Joshua M Copus,John E Randall,Richard L Pyle,Brian D Greene

doi:10.3897/zookeys.835.32562

Abstract

A new species of the butterflyfish genus Prognathodes (Chaetodontidae) is described from two specimens collected at a depth of 116 m off Ngemelis Island, Palau. Prognathodesgeminussp. n. is similar to P.basabei Pyle & Kosaki, 2016 from the Hawaiian archipelago, and P.guezei (Maugé & Bauchot, 1976) from the western Indian Ocean, but differs from these species in the number of soft dorsal-fin rays, size of head, body width, and body depth. There are also subtle differences in life color, and substantial differences in the mtDNA cytochrome oxidase I sequence (d ≈ 0.08). Although genetic comparisons with P.guezei are unavailable, it is expected that the genetic divergence between P.guezei and P.geminus will be even greater than that between P.geminus and P.basabei. It is named for the strikingly similar color pattern it shares with P.basabei.

Highlights

While no tissue samples or DNA sequences have been reported for P. guezei, we expect that given the geographic distributions of P. guezei in the western Indian Ocean, and P. geminus and P. basabei in the Pacific Ocean, a much greater genetic divergence between P. guezei and the other two species likely exists
Mixed-gas closed-circuit rebreather diving technology has revolutionized the exploration of the deeper depths of coral reef environments across the globe (Pyle 1996, 2000)
One of the more interesting aspects of this new species is the contrast between the strikingly similar color pattern it shares with P. basabei, against the substantial genetic differences

Summary

Introduction

Several individuals of a butterflyfish with dark bars resembling both P. guezei from the Western Indian Ocean and a species from the Hawaiian Islands that was later described as P. basabei were recorded on video at depths in excess of 110 m during a series of submersible dives in Palau conducted by Patrick L Colin and Lori Bell Colin in 2001. In April 2007, while conducting a series of deep exploratory dives off Ngemelis Island, Palau (Republic of Belau) in the Caroline Islands, authors Pyle and Greene collected two specimens of this unidentified Prognathodes at a depth of 116 m. Based on an examination of a combination of morphological and genetic characters of the Palauan specimens, in comparison to six specimens of P. basabei and two specimens of P. guezei (the two species that most closely resemble the Palauan specimens), we describe the new species as Prognathodes geminus

Materials and methods

Discussion