Eupronoe minuta Claus, 1879

Gasca, Rebeca & Hendrickx, Michel E., 2021, Pelagic amphipods (Crustacea: Amphipoda: Hyperiidea) in western Mexico. 2 Family Eupronoidae, Zootaxa 4948 (3), pp. 419-430 : 422

Eupronoe minuta Claus, 1879

Eupronoe minuta Claus, 1879: 28 ; Siegel-Causey, 1982: 275; Vinogradov et al., 1996: 448 (key), 449, fig. 195; Gasca, 2009 b: 87 (table 1); Gasca et al., 2010: 933; 2012: 126 ( Table 1 ); Lavaniegos & Hereu, 2009: 139–147 (passim), 142 (table 1), 152 (Appendix 1); Lavaniegos, 2014: 1–8 (passim), 4 (table 1), 10 (table 4); 2017: 13–24 (passim), 18 (table 2).

Material examined. 5M and 21F from 8 stations. ( Fig.3 ). TALUD I. St. 5 (23°16’N, 107°31’W), December 12, 1989 , 1M, BO, surface to ca. 200 m (ICML-EMU-12768-A). TALUD III. St. 3B (22°36’36”N, 106°35’54”W), August 17, 1991 , 1M, 1F, I-K from surface to 275 m ( TD ND) (ICML-EMU-12768-B); St. 10B (23°43’24”N, 107°39’06”W), August 18, 1991 , 2M, 6F, I-K from surface to 630 m ( TD ND) (ECO-CH-Z-10369); St. 19B (25°18’24”N, 109°18’36”W), August 20, 1991 , 6F, I-K from surface to 600 m ( TD 1890 m) (ICML-EMU-12768- C); St. 25A1 (25°51’00”N, 109°57’00”W), August 21, 1991 , 3 F, I-K from surface to 200 m ( TD 2000 m) (ICML- EMU-12768-D) . TALUD IV. St. 7 (22°00’22”N, 106°49’18”W), August 23, 2000 , 1F, MN from surface to 500 m ( TD 1970 m) (ICML-EMU-12769-A) . TALUD VI. St. 7 (22°21’39”N, 107°01’42”W), March 14, 2001 , 2F, MN from surface to 1305 m ( TD 2100 m) (ICML-EMU-12769-B) . TALUD VII. St. 29 (25°18’02”N, 109°24’09”W), June 8, 2001 , 2F, 1M, MN, 1335 m ( TD 2080 m) (ECO-CH-Z-10370) .

Distribution. Cosmopolitan. Epipelagic in tropical and temperate areas ( Vinogradov et al. 1996). In the eastern Pacific it is known from the Gulf of California ( Brusca & Hendrickx 2005; Garcia-Madrigal 2007) and has been reported as ‘very common’ along the west coast of the Baja California Peninsula ( Lavaniegos & Hereu 2009; Lavaniegos 2014, 2017); its known distribution stretches south to off Jalisco and Colima ( Gasca et al. 2012).

Remarks. According to Siegel-Causey (1982) and Brusca & Hendrickx (2008 onwards), E. minuta is widely distributed in the Gulf of California, where it occurs from 29°57’N (off Punta Tepoca) in the northeastern Gulf to 22°21’39”N in the southwestern Gulf (TALUD VI. St. 7 record). Our material, however, did not include specimens from the northern Gulf and all samples were taken south of 25°51’00”N ( Fig. 2 ). This species is the smallest in the genus, with adult reaching 6‒8 mm of total length. The specimens examined herein feature especially long dactyls on pereopods III and IV. Indeed, in some specimens, particularly in some females, dactyls are up to 85% as long as propodus. This is much longer that what has been reported in the original description ( Claus 1879) and in subsequent contributions by Vinogradov et al. (1986) and Zeidler (1998) (i.e., less than 50%). However, among our specimens some fit well with this feature (i.e., dactyls less that 50% of propodus length) and this could therefore represent a variation within E. minuta adult population or an ontogenic variation.

Figures

FIGURES 3–4. 3. Localities where Eupronoe minuta Claus, 1879, was captured during this survey. 4. Localities where Parapronoe parva Claus, 1879, was captured during this survey.

FIGURES 1–2. 1. Localities where Eupronoe armata Claus, 1879, was captured during this survey. 2. Localities where Eupronoe maculata Claus, 1879, was captured during this survey.