Accepted by E. Hilton: 1 Sept. 2015; published: 28 Sept. 2015 Licensed under a Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2015 Magnolia Press Zootaxa 4021 (3): 475–481 www.mapress.com/zootaxa/ Article 475 http://dx.doi.org/10.11646/zootaxa.4021.3.7 http://zoobank.org/urn:lsid:zoobank.org:pub:22DB5AA9-883A-43B0-A233-2CBBBFE75785 Redescription of the percoid fish Symphysanodon andersoni Kotthaus (Symphysanodontidae) from the northwestern Indian Ocean, based on the holotype and the second known specimen WILLIAM D. ANDERSON, JR. 1 , MIKHAIL V. CHESALIN 2 , LAITH A. JAWAD 3 & SAID R. AL SHAJIBI 2 1 Grice Marine Biological Laboratory, College of Charleston, 205 Fort Johnson, Charleston, South Carolina 29412-9110, USA. E-mail: andersonwd@cofc.edu 2 Fisheries Research Center-Salalah, Ministry of Agriculture and Fisheries Wealth, PO Box 33, Salalah 217, Sultanate of Oman. E-mail: mchesalin@ukr.net 3 Flat Bush, Manukau, Auckland, New Zealand. E-mail:laith_jawad@hotmail.com Abstract Symphysanodon andersoni was described in 1974 from a single specimen collected southwest of Socotra Island, near the entrance to the Gulf of Aden. A more recent report (2003) of its capture in the Gulf of Kutch, Arabian Sea, was based on a misidentification. The second known specimen of the Bucktoothed Slopefish, S. andersoni, (at 204 mm SL the largest known specimen of the genus Symphysanodon) was collected off the south coast of Oman, Arabian Sea, in April 2014. Symphysanodon andersoni is distinguishable from its congeners by number of tubed scales in the lateral line, 60 to 65 versus 42 to 59 in the other species of the genus. In view of the fact that S. andersoni is poorly known, we redescribe it based on the holotype and the new specimen collected off Oman and provide the first color photograph of the species. Key words: Symphysanodon andersoni, Indian Ocean, Arabian Sea, Socotra Island, Oman Introduction The marine fish family Symphysanodontidae contains a single genus, Symphysanodon Bleeker 1878, and 12 described species (Anderson & Bineesh 2011, Anderson & Springer 2005, Khalaf & Krupp 2008, Quéro et al. 2009). In addition, McCosker (1979) and Anderson & Springer (2005) reported a species of Symphysanodon, as yet undescribed, that was obtained from the stomach of a coelacanth (Latimeria chalumnae) caught in the Comoros in the southwestern Indian Ocean. Later Heemstra et al. (2006) mentioned an undescribed species of Symphysanodon from the Comoros that may be conspecific with the species reported from the coelacanth stomach. Also, Campos et al. (2009) reported two larval Symphysanodon, collected off southern Brazil, that may represent another undescribed species. In view of the fact that the genus Symphysanodon is not well known, with most species poorly represented in museum collections, it seems likely that other species await discovery. Symphysanodon (largest known specimen 204 mm SL) occurs in depths of about 80 to 700 m in the Atlantic, Pacific, and Indian oceans. Five species of Symphysanodon have been described from the Indian Ocean (sensu lato), viz., S. andersoni Kotthaus 1974 (southwest of Socotra Island, near the entrance to the Gulf of Aden), S. rhax Anderson & Springer 2005 (off the Maldive Islands), S. disii Khalaf & Krupp 2008 (Gulf of Aqaba), S. pitondelafournaisei Quéro et al. 2009 (off Reunion Island), and S. xanthopterygion Anderson & Bineesh 2011 (Arabian Sea off southern India). Manilo & Bogorodsky (2003) reported Symphysanodon andersoni from the Gulf of Kutch, an inlet in the northeastern quadrant of the Arabian Sea on the west coast of India. The second author (MVC) asked L. G. Manilo, at the National Museum of Natural History in Kiev (Ukraine), to check that record. Manilo found three specimens of Symphysanodon, identified as S. andersoni, in the Kiev collection, and sent MVC data on two of them (the third is in poor condition). Based on the number of lateral-line scales (54, 55) and total number of gillrakers on the first arch (39, 40), those two specimens appear to be identifiable as S. xanthopterygion.