Two new species of Plectranthias (Teleostei, Serranidae, Anthiadinae) from mesophotic coral ecosystems in the tropical Central Pacific.

Bart Shepherd,Claudia R Rocha,Hudson T Pinheiro,Tyler A Y Phelps,Luiz A Rocha

doi:10.3897/zookeys.941.50243

Bart Shepherd, Claudia R Rocha + Show 3 more

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https://doi.org/10.3897/zookeys.941.50243

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Abstract

Two new species of Plectranthias perchlets are described, collected from mesophotic coral ecosystems in French Polynesia and the Republic of the Marshall Islands, in the tropical Central Pacific. Plectranthias polygoniussp. nov. was collected at a depth of 105 m in Tahiti, French Polynesia, and 120 m in Maloelap Atoll, Republic of the Marshall Islands. It was also observed in Moorea and Rangiroa (French Polynesia), and at Majuro and Erikub Atolls, Republic of the Marshall Islands. Plectranthias hinanosp. nov. was collected at a depth of 90–98 m in Tahiti, French Polynesia, and observed in Moorea. The barcode fragment of the cytochrome oxidase I gene of Plectranthias polygoniussp. nov. does not closely match any published sequence of Plectranthias, with approximately 15% uncorrected divergence from several species. Plectranthias polygoniussp. nov. can be distinguished from all of its congeners by coloration and morphology. The barcode fragment of the COI gene of Plectranthias hinanosp. nov. is closest to Plectranthias bennetti, with 5.4% uncorrected divergence. Plectranthias hinanosp. nov. is also distinguished from all of its congeners by morphology, and a coloration that includes two indistinct black spots along the base of the dorsal-fin, and transparent yellow dorsal and anal fin membranes. With this publication, the genus Plectranthias now comprises 58 valid species, with representatives from tropical to temperate waters of the Atlantic, Pacific, and Indian oceans. These two new discoveries add to the growing body of research highlighting the rich biodiversity of mesophotic ecosystems.

Highlights

The anthiadine genus Plectranthias Bleeker, 1873, currently comprises 56 valid species from tropical to temperate waters in the Atlantic, Pacific, and Indian oceans (Fricke et al 2019)
We describe two new anthiadine fishes within the genus Plectranthias from French Polynesia and the Republic of the Marshall Islands
Species within the genus Plectranthias appear to be common and conspicuous inhabitants of Mesophotic coral ecosystems (MCEs), and we have regularly observed them in highly complex, rocky habitats with abundant coralline algae, sponges, and black corals (Fig. 3)

Summary

Introduction

The anthiadine genus Plectranthias Bleeker, 1873, currently comprises 56 valid species from tropical to temperate waters in the Atlantic, Pacific, and Indian oceans (Fricke et al 2019) Most of these fishes are found in relatively deep habitats (depths of 90– 420 m) with complex rocky formations (Allen and Walsh 2015; Gill et al 2016). They are small (20 cm max length, but most in the 5–10 cm range), benthic, feed on small mobile invertebrates, and hide in crevices and holes on the reef (Kuiter 2004). These two new perchlets represent the 57th and 58th species of Plectranthias, adding to the spate of recent new species from MCEs

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