Pelagic amphipods (Crustacea: Amphipoda: Hyperiidea) in western Mexico. 7 Superfamily Platysceloidea. Family Oxycephalidae Author Gasca, Rebeca 0000-0002-9716-1964 El Colegio de la Frontera Sur, Unidad Chetumal, Av. del Centenario km 5.5, Chetumal, Quintana Roo, 77014, Mexico. rebegasca @ gmail. com; https: // orcid. org / 0000 - 0002 - 9716 - 1964 & Currently retired. rebegasca@gmail.com Author Hendrickx, Michel E. Laboratorio de Invertebrados Bentónicos, Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, PO Box 811, Mazatlán, 82000 Sinaloa, Mexico. text Zootaxa 2022 2022-03-03 5105 2 219 236 journal article 20349 10.11646/zootaxa.5105.2.3 d9ad8d5b-dd70-4efe-8a01-76ea5babc6b8 1175-5326 6332529 2B46C765-C80B-437B-B8C2-95335D589E9F Oxycephalus clausi Bovallius, 1887 Oxycephalus clausi Bovallius, 1887: 35‒36 ; Brusca, 1981: 12 (list), 33 (key), 44‒45, fig. 20a, 20e; Siegel Causey, 1982: 330 (key), 331; Vinogradov et al ., 1996: 504 , fig. 219; Zeidler, 1999: 394 (key), 411‒416, figs. 1C, 12‒15; 2016: 73 (passim), 76 (key); García Madrigal, 2007: 157 (list); Guillén Pozo, 2007: 18 (key), 98‒100, fig. 34; Valencia & Giraldo, 2009: 268 (tab. 1); 2012: 1493 (tab. 1); Gasca, 2009: 89 (tab. 1); Lavaniegos & Hereu, 2009: 142 (tab. 1), 146 (tab. 2), 152 (appendix); Gasca et al ., 2012: 126 (tab. 1), 127‒134 (passim), 132 (tab. 3), 133 (tab. 4), 134 (tab. 5), 135 (tab. 6); Lavaniegos, 2014: 5 (tab. 1); Valencia et al ., 2013: 52 (tab. 1); Violante-Huerta et al ., 2021: 81 (tab. 1). Oxycephalus erythraeus Cecchini, 1929: 482‒483 , pl. 2. Material examined . 50M, 102F in 24 localities ( Fig. 2 ). TALUD I. St. 6 ( 23°15’54”N , 107°31’12”W ), December 12, 1989 , 1M, BO, from surface to 1550 m (TD> 2000 m ) (ICML-EMU-12950). TALUD III . St. 3B ( 22°36’36”N , 106°35’54”W ), August 17, 1991 , 1M, 4F, I-K from surface to 275 m (TD, 1585 m ) (ICML-EMU-12951-A); St. 5 ( 23°22’N , 107°10’W ), August 24, 1991 , 1F, I-K, from surface to 365 m (TD, 698 m ) (ICML-EMU-12951-B); St. 6 ( 23º17’54”N , 107º30’18”W ), August 18, 1991 , 1F, AD from surface to 996‒1148 (ICML-EMU-12951-C); St. 10B ( 23°43’24”N , 107°39’06”W ), August 18, 1991 , 3F, I-K from surface to 630 m (TD, ca. 900 m ) (ICML-EMU-12951-D); St. 19 ( 25°12’00”N , 109°07’00”W ), August 20, 1991 , 2M, I-K, surface to 410 m (TD, 920 m ) (ICML-EMU-12952-A); St. 19B ( 25°18’24”N , 109°18’36”W ), August 20, 1991 , 1M, 4F, I-K from surface to 600 m (TD, 1890 m ) (ICML-EMU-12952-B); St. 25A1 ( 25°51’00”N , 109°57’00”W ), August 21, 1991 , 4M, 3F, I-K from surface to ca. 200 m (TD, 1280-1360 m ) (ICML-EMU-12952-C); St. 25A2 ( 25°50’54”N , 109°56’54”W ), August 21, 1991 , 1M, 4F, I-K from surface to 230 m (TD, ca. 1200 m ) (ICML-EMU-12952-D). TALUD IV St. 7 ( 22°00’22”N , 106°49’18”W ), August 23, 2000 , 4M, 11F, MN from surface to 500 m (TD, 1970 m ) (ECOSUR-10559); St. 15 ( 23°23’30”N , 107°47’48”W ), August 24, 2000 , 2M, 2F, MN from surface to 1500 m (TD, 2350 m ) (ICML-EMU-12953-A); St. 22 ( 24°17’20”N , 108°50’30”W ), August 26, 2000 , 5M, 3F, MN from surface to 1325 m (TD, ca. 1800 m ) (ICML-EMU-12953-B); St. 25A2 ( 25°50’54”N , 109°56’54”W ), August 21, 2000 , 3F, I-K from surface to 230 m (TD, ND) (ICML-EMU- 12954-A); St. 36 ( 25°51’59”N , 110°11’00”W ), August 27, 2000 , 1M, 1F, MN from surface to ca. 1300 m (TD, 2100 m ) (ICML-EMU-12954-B) . TALUD V . St. 5 ( 22°00’57”N , 106°40’00”W ), December 13, 2000 , 7M, 9F, MN from surface to ca. 1400 m (TD> 1600 m ) (ICML-EMU-12955-A); St. 29 ( 25°14’36”N , 109°24’15”W ), December 17, 2000 , 2F, MN from surface to 1290 m (TD, 2040 m ) (ICML-EMU-12955-B) . TALUD VI . St. 7 ( 22°21’39”N , 107°01’42”W ), March 14, 2001 , 19M, 40F, MN from surface to 1305 m (TD, 2100 m ) (ICML-EMU-12956); St. 15 ( 23°14’42”N , 107°30’W ), March 14, 2001 , 1M, 1F, MN , surface to 1300 m (TD, 2390 m ) (ICML-EMU- 12957-A); St. 22 ( 24°17’34”N , 108°50’25”W ), March 15, 2001 , 2M, 1F, MN from surface to 1410 m (TD, 1760 m ) (ICML-EMU-12957-B); St. 29 ( 25°16’24”N , 109°24’54”W ), March 16, 2001 , 1F, MN from surface to 1440 m (TD, 2080 m ) (ICML-EMU-12957-C) . TALUD XI . St. 6A ( 16°58’00”N , 100°57’00”W ), June 7, 2007 , 1M, 1F, MN from surface to 1400 m (TD, 1960 m ) (ICML-EMU-12958-A); St. 19B ( 17°56’00”N , 103°10’00”W ), June 9, 2007 , 1M, 3F, MN from surface to 1490 m (TD, 1750 m ) (ICML-EMU-12958-B) . TALUD XII . St. 4 ( 16°59’39”N , 100°58’07”W ), March 28, 2008 , 3F, MN from surface to 1200 m (TD, 1995 m ) (ICML-EMU-12959); St. 15C ( 17°27’51”N , 102°10’43”W ), March 31, 2008 , 1M, 4F, MN from surface to 1530 m (TD, 1880 m ) (ICML-EMU- 12960-A); St. 28B ( 18°56’00”N , 104°59’57”W ), April 2, 2008 , 1M, 1F, MN from surface to 1425 m (TD, 2041 m ) (ICML-EMU-12960-B) . Distribution . Circumtropical and in the Mediterranean Sea. In the eastern Pacific from California to Costa Rica , Panama , Colombia , and Chile ( Vinogradov et al . 1996 , García Madrigal 2007, Valencia & Giraldo 2009 , Valencia et al ., 2013 , Violante-Huerta et al . 2021 , this study). Remarks . Oxycephalus clausi is easily recognized for the presence of a medial tooth on the ventral margin of pleonites 1‒3, and by the shape of the anterodistal corner of the carpus gnathopods 1 and 2 which are produced in a sharp point. Siegel-Causey (1982) reported Oxycephalus clausi as common in the Gulf of California , where it was collected in the northern, central and southern Gulf. Our results indicated a similar pattern ( Fig. 2 ). In the Mexican portion of the California Current, it has been reported as rare by Lavaniegos & Hereu (2009) and by Lavaniegos (2014 ; 7.5% of the samples). It inhabits predominantly in surface waters ( Zeidler 1999 ).