Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 23 Feb 2009

Revision of Indo-Pacific Species of the Loosejaw Dragonfish Genus Photostomias (Teleostei: Stomiidae: Malacosteinae)

Page Range: 175 – 189
DOI: 10.1643/CI-07-224
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Abstract

Several studies of the ecology of mesopelagic fishes off Hawaii published in the 1970s and 1980s reported the existence of as many as two undescribed species in the Pacific Ocean. Diagnosed primarily on the basis of postorbital and accessory orbital photophore size and size at maturity, three new species are described: P. liemi, new species, and P. tantillux, new species, both endemic to tropical and subtropical Indo-Pacific water masses, and P. lucingens, new species, a species distributed in the subtropical and tropical Pacific and South Atlantic oceans. Photostomias liemi and P. tantillux represent smaller forms, with females maturing at standard lengths less than 70 mm, making these species the smallest sexually mature stomiids. Despite the analysis of some 35 morphometric and meristic characters, females of P. liemi are indistinguishable from females of P. atrox. The current study brings the total number of valid species of Photostomias to six. A key to these six species is provided.

Copyright: 2009 by the American Society of Ichthyologists and Herpetologists
Fig. 1
Fig. 1

Left lateral view of heads of Indo-Pacific species of Photostomias: (A) P. tantillux new species, holotype, SIO 73-171, male, 90.3 mm SL; (B) P. liemi new species, holotype, MCZ 49151, male, 95.2 mm SL; (C) P. lucingens new species, holotype, USNM 219291, male, 78.2 mm SL; (D) P. atrox, neotype, MCZ 151289, male, 92.0 mm SL.

Fig. 2
Fig. 2

Left lateral view of Indo-Pacific species of Photostomias: (A) P. tantillux new species, holotype, SIO 73-171, male, 90.3 mm SL; (B) P. liemi new species, holotype, MCZ 49151, male, 95.2 mm SL; (C) P. lucingens new species, holotype, USNM 219291, male, 78.2 mm SL; (D) P. atrox, neotype, MCZ 151289, male, 92.0 mm SL.

Fig. 3
Fig. 3

Postorbital photophore (PO) size versus upper jaw length (UJL) of Indo-Pacific species of Photostomias.

Fig. 4
Fig. 4

Accessory orbital photophore (AO) size versus upper jaw length (UJL) of male Indo-Pacific species of Photostomias.

Fig. 5
Fig. 5

Ovum size versus standard length (SL) of female Indo-Pacific species of Photostomias. Ovum values of zero reflect specimens with no apparent ovarian development.

Fig. 6
Fig. 6

Distribution of Photostomias tantillux and P. lucingens. Symbols may represent more than one record.

Fig. 7
Fig. 7

Distribution of Photostomias atrox and P. liemi; symbols corresponding to P. atrox/P. liemi represent captures of females that were ambiguously identified as either of these species. Symbols may represent more than one record.

Contributor Notes

Associate Editor: D. Buth.

1 School of Aquatic and Fishery Sciences, College of Ocean and Fishery Sciences, University of Washington, Box 355020, Seattle, Washington 98195; E-mail: ckenaley@u.washington.edu.
Received: 04 Oct 2007
Accepted: 02 Oct 2008
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