Oxycephalus latirostris Claus, 1879

Gasca, Rebeca & Hendrickx, Michel E., 2022, Pelagic amphipods (Crustacea: Amphipoda: Hyperiidea) in western Mexico. 7 Superfamily Platysceloidea. Family Oxycephalidae, Zootaxa 5105 (2), pp. 219-236 : 224-225

Oxycephalus latirostris Claus, 1879

Oxycephalus latirostris Claus, 1879a: 193 (47); Brusca, 1981: 12 (list); 33 (key), 45, fig. 20i‒j; Vinogradov et al., 1996: 501 (key), 506, fig. 220; Zeidler, 1999: 394 (key), 403‒411, figs. 1B, 7‒11; 2016: 73, 76 (key); Gasca, 2009: 89 (tab. 1); Lavaniegos & Hereu, 2009: 152 (appendix); Gasca et al., 2012: 126 (tab. 1).

Oxycephalus pectinatus Bovallius, 1887:36 .

Oxycephalus notabilis Spandl, 1924: 32–34 .

Oxycephalus longipes Spandl, 1927: 181‒182 , fig. 14.

Oxycephalus mancinii Cecchini, 1929: 483–484 .

Material examined. 1M in one locality ( Fig. 2 ).

TALUD III. St. 19B (25°18’24”N, 109°18’36”W), August 20, 1991, 1M, I-K from surface to 600 m (TD, 1890 m) (ICML-EMU-12961) .

Distribution. A rare species, with a worldwide distribution, preferring tropical waters. Not recorded from the Mediterranean. In the eastern Pacific it has been recorded in the Mexican section of the California Current and off Costa Rica ( Lavaniegos & Hereu 2009, Gasca 2009). Occurring in the SE Gulf of California, Mexico (this study).

Remarks. A single adult male in perfect conditions was collected during this survey. Oxycephalus latirostris is distinguished from the other two species of the genus by the shape of the cutting-edge of the carpus of gnathopods 1 and 2 which possesses a row of conspicuous teeth. This unique specimen features the dorsal notch characteristic of mature specimens, as illustrated by Zeidler (1999).

A relatively uncommon species, mostly found in surface waters. According to Zeidler (1999), Fage (1960) examined the extensive collections of the ‘Dana’ expedition and found that, although specimens were obtained from depths to 2000 m, the species was most abundant at 20 m.

Oxycephalus latirostris was not collected by Siegel-Causey (1982) in the Gulf of California and not cited by García Madrigal (2007) for the eastern tropical Pacific. Records in the region are by Gasca (2009; Costa Rica), Lavaniegos & Hereu (2009; California Current), and Gasca et al. (2012). This species was extremely rare in our survey: one male only in one locality ( Fig. 3 ). Barkhatov et al. (1999) included O. latirostris in the group of “pure tropical species, never penetrating the Subtropical Frontal Zone”.

Figures

FIGURE 2. Localities where Oxycephalus clausi and O. latirostris were collected during this survey.

FIGURE 3. Localities where Rhabdosoma armatum, R. brevicaudatum, and R. minor were collected during this survey.