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Australo-Papuan snakes of the genus Dendrelaphis have historically been a taxonomically confusing group, with 28 nomina applied to snakes in this region. Recent taxonomic revision has established the presence of nine valid species in this area, though few specimens were examined from across most of the large island of New Guinea. This lacuna, along with unreliable application of names to Melanesian Dendrelaphis in museum collections, means that the ranges of each species remain to be properly resolved on New Guinea and islands immediately to the east. Herein I examine the taxonomic status of Dendrelaphis specimens from outlying large islands in Milne Bay Province, off the southeastern tip of New Guinea, and I find that each of the three large islands of the Louisiade Archipelago, as well as Woodlark Island, contain their own endemic species. Based on hemipenial morphology, three of these species (D. anthracina sp. nov., D. melanarkys sp. nov., D. roseni sp. nov.) belong to the D. papuensis group and the last (D. atra sp. nov.) to the D. punctulatus group. Identification of the first three species requires reassessment and rediagnosis of D. papuensis. Two of the new species are characterized by ontogenetic melanization of animals, and a third is also uniformly black with a white chin when adult, though juveniles are unavailable to determine whether melanization also occurs ontogenetically in that species. Melanesian species of Dendrelaphis are largely diagnosed by unique color-pattern features, and this work identifies additional diagnostic features of color pattern for these species and confirms the critical importance of hemipenial differences in distinguishing among similar-appearing species in this region.
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Halichoeres sanchezi n. sp., a new wrasse from the Revillagigedo Archipelago of Mexico, tropical eastern Pacific Ocean (Teleostei: Labridae)
A new labrid fish species,Halichoeres sanchezin. sp., is described from eight specimens collected in the Revillagigedo Archipelago in the tropical eastern Pacific Ocean, off the coast of Mexico. The new species belongs to theHalichoeres melanotisspecies complex that is found throughout the region, differing by 2.4% in the mtDNA cytochrome c oxidase I sequence from its nearest relative,H. melanotisfrom Panama, and 2.9% fromHalichoeres salmofasciatusfrom Cocos Island, off Costa Rica. The complex is distinguished from others in the region by having a black spot on the opercular flap and a prominent black area on the caudal fin of males. The juveniles and initial phase of the new species closely resemble those ofH. salmofasciatusandHalichoeres malpelofrom Malpelo Island of Colombia, differing in having an oblong black spot with a yellow dorsal margin on the mid-dorsal fin of initial-phase adults as well as on juveniles. In contrast, the terminal-phase male color pattern is distinct from other relatives, being vermilion to orangish brown with dark scale outlines, a white patch on the upper abdomen, and a prominent black band covering the posterior caudal peduncle and base of the caudal fin. The new species adds to the list of endemic fish species for the isolated archipelago and is an interesting case of island endemism in the region. The discovery was made during the joint 2022 collecting expedition to the archipelago, which featured a pioneering collaborative approach to an inventory of an island ichthyofauna, specifically including expert underwater photographers systematically documenting specimensin situ, before hand-collection, and then photographed fresh, tissue-sampled, and subsequently vouchered in museum collections.
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- Award ID(s):
- 2215184
- PAR ID:
- 10659315
- Publisher / Repository:
- PeerJ
- Date Published:
- Journal Name:
- PeerJ
- Volume:
- 12
- ISSN:
- 2167-8359
- Page Range / eLocation ID:
- e16828
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.7717/peerj.16828
