Gennadas sordidus Kemp, 1910

Hendrickx, Michel E., 2015, Further records of species of Gennadas (Crustacea, Decapoda, Dendrobranchiata, Benthesicymidae) in the Mexican Pacific, Zootaxa 3980 (3), pp. 417-426 : 420-422

Gennadas sordidus Kemp, 1910

Gennadas sordidus .— Burkenroad, 1938: 57, fig. 1. Hanamura, 1983: 57, figs. 4 d–f. Hendrickx & Estrada–Navarrete, 1989: 107 (list); 1996: 34, figs. 9, 19, 22 C. Guzmán & Wicksten, 2000: 929. Wicksten, 2002: 130; 2012: 24, fig. 5C, D. Hendrickx, 2005: 161 (list); 2013: 441. Guzmán, 2008: 29.

Material examined. 183 specimens. TALUD III. St. 13 (23º38'30"N 107º58'48"W), August 18, 1991, 2 M (CL 7.9–8.3 mm) and 5 F (CL 6.4–9.9 mm) (EMU–10877), and 8 juv. (CL 2.9–5.7 mm), 19 F (CL 5.7–10.9 mm) and 14 M (CL 3.9–10.4 mm) (EMU–10878) IK operated between surface and 720 m; St. 19 (25º12'N 109º07'W), August 20, 1991, 7 M (CL 5.18–10.0 mm) and 10 F (CL 5.81–8.40 mm), IK operated between surface and 410 m (total depth: 920 m) (EMU–9961) (id. J. Flores A.).

TALUD IV. St. 15 (23º23'30"N 107º47'48"W), August 24, 2000, 2 F (CL 7.9–10.2 mm), MN operated between surface and 1500 m (total depth: 2350 m) (EMU–10914–A); St. 18 (24º15'12"N 108º17'10"W), August 25, 2000, 2 M (7.4–9.0 mm) and 3 F (6.5–8.0 mm), BS operated at 908–944 m (EMU–5985–A); St. 19 (24º15'18"N 108º24'06"W), 1 juvenile, BS operated at 1196–1200 m (EMU–5985B); St. 22 (2417'20" N 10850 '30"W), August 26, 2000, 1 M (CL 7.3 mm) and 1 F (CL 9.8 mm), MN operated between surface and 1325 m (EMU–10914–B).

TALUD VII. St. 5 (22º00'24"N 106º39'54"W), June 5, 2001, 1 F (CL 6.5 mm), BS operated at 1490–1520 m; St. 19 (24º16'12"N 108º23'42"W), June 7, 2001, 2 M (CL 8.3–9.1 mm) and 3 F (CL 7.35–8.30 mm), BS operated at 1160–1180 m (EMU–6693); St. 20 (24º14'48"N 108º35'12"W), June 7, 2001, 8 M (CL 7.5–10.5 mm) and 6 F (CL 7.7–10.2 mm), BS operated at 1480–1520 m (EMU–5984); St. 27 (25º01'30"N 109º12'W), June 8, 2001, 2 M (CL 9.3–9.8 mm) and 4 F (CL 6.5–9.3 mm), BS operated at 1580–1600 m (EMU–6697); St. 34B (26º05'30"N 110º10'30"W), June 9, 2001, 2 M (CL 8.0– 8.7 mm), BS operated at 1500–1520 m.

TALUD VIII. St. 13 (25º21'N 110º17'W), April 18, 2005, 2 F (CL 9.09–9.91 mm), BS operated at 1625 m (id. J. Flores A.) (EMU–9962); St. 15 (25º23'06"N 110º18'06"W), April 18, 2005, 2 M (CL 6.8–8.0 mm), BS operated at 1030 m; St. 16 (25º24'48"N 110º34'48"W), April 18, 2005, 1 M (CL 9.0 mm) and 1 F (CL 9.0 mm), BS operated at 1030 m; St. 17B (25º24'24"N 110º50'06"W), April 18, 2005, 4 F (CL 6.0–10.0 mm), BS operated at 700–750 m; St. 20 (25º56'56"N 110º43'W), April 19, 2005, 1 M (CL 8.8 mm) and 2 F (6.0– 8.9 mm), BS operated at 1140–1150 m; St. 21 (26º02'18"N 110º37'06"W), April 19, 2005, 2 M (8.2–9.0 mm) and 4 F (CL 5.0– 8.9 mm), BS operated at 1380 m; St. 22 (26º03'42"N 110º23'54"W), April 19, 2005, 1 F (CL 9.1 mm), BS operated at 2200 m.

TALUD IX. St. 2 (24º38'42"N 109º17'36"W), November 11, 2005, 2 F (CL 7.5–8.9 mm), BS operated at 2195–2300 m (EMU–8241); St. 10 (24º56'24"N 110º16'42"W), November 12, 2005, 1 M (CL 9.0 mm) and 2 F (CL 6.5–7.0 mm), BS operated at 969–1225 m; St. 15 (25º21'27"N 110º18'18"W), November 13, 2005, 3 M (CL 8.1– 9.7 mm) and 3 F (CL 8.0– 10.5 mm), BS operated at 1985–2290 m (EMU–8235); St. 16 (24º23'48"N 110º36'42"W), November 13, 2005, 1 M (CL 10.2 mm) and 1 F (CL 10.1 mm), BS operated at 997–1021 m; St. 17 (25º19'54"N 110º47'42"W), November 13, 2 M and 2 F, BS operated at 626–846 m; St. 18 (25º49'38"N 110º34'45"W), November 13, 2005, 2 M (CL 7.0– 9.95 mm), BS, depth unknown but> 500 m (EMU–9963); St. 20–B (25º58'07"N 110º40'04"W), November 14, 2005, 1 M (CL 8.5 mm), BS operated at 1229–1343 m; St. 21–B (26º04'42"N 110º34'48" November 14, 2005, 1 M (CL 6.8 mm), BS operated at 1349–1369 m.

TALUD X. St. 5 (28º14'50"N 112º24'53"W), February 9, 2007, 1 damaged specimen (CL ca 8.5 mm), BS operated at 820–837 m; St. 8 (28º05'56N 112º26'50"W) 1 M (CL ca 9 mm) and 2 F (CL ca. 9 mm), BS operated at 975–1007 m (EMU–8200–B); St. 9 (27º48'30"N 112º17'12"W), February 10, 2007, 4 M (CL ca 8.5 mm), BS operated at 1396–1422 m; St. 13 (27º49'46"N 111º43'18"W), February 11, 2007, 1 M (CL 8.0 mm) and 3 F (CL 5.5–9.0 mm), BS, operated at 668–704 m (EMU–8112); St. 14 (27º44'53"N 111º36'58"w), February 11, 2007, 3 M (CL 8.2–11.1 mm) and 5 F (CL 7.2–9.8 mm), BS operated at 905–943 m (EMU–8091); St. 15 (27º40'24"N 111º39'54"W), February 11, 2007, 4 F (CL 6.5–8.5 mm), BS operated at 1528–1530; St. 17 (27º08'N 111º44'10"W), February 12, 2007, 2 F (CL 8.8–10.4 mm) (EMU–8093–A), and 2 M (CL ca 8 mm) and 2 F (CL ca 7 mm) (EMU–8093–B), BS operated at 1289–1326; St. 18 (27º09'06"N 111º46'54"W), February 12, 2007, 1 M (CL 9.6 mm), BS operated at 1526 m (EMU–8200–A); St. 19 (27º36'08"N 111º36'08"W), February 12, 2007, 2 F (CL 7.0 mm), operated at 1786–1816 m (EMU–8092); St. 22 (27º02'46"N 110º52'57"W), 1 F (CL 7.0 mm), BS, operated at 1575–1586 m; St. 25 (26º39'04"N 111º18'20"W), February 14, 2007, 1 M (CL ca 8 mm) and 3 F (CL ca 8 mm), BS operated at 837–840 m; St. 26 (26º35'16"N 111º05'59"W), February 14, 2007, 3 damaged specimens (CL ca 8 mm), BS operated at 1292–1301 m.

TALUD XII. St. 26 (18º33'27"N 104º28'21"W), April 1, 2008, 1 F (CL 8.2 mm), BS operated at 2125–2165 m.

TALUD XV. St. 2 (23º12'02"N 111º20'50"W), August 4, 2012, 1 M (CL 8.6 mm), BS operated at 1118–1150 m (EMU–10868); St. 3 (23º09'55"N 111º20'W), August 4, 2012, 1 F (CL ca 7 mm), BS operated at 1395–1465 m (EMU–10874–A); St. 5E (23º05'22"N 110º27'54"W), August 5, 2012, 1 F. (CL 10.1 mm), BS operated at 948–954 m (EMU–10874–B); St. 13 (25º02'12"N 112º54'06"W), July 30, 2012, 2 M (CL 7.1–9.4 mm) and 1 F (CL 8.6 mm), BS operated at 1210–1245 m (EMU–10876–A); St. 15 (25º18'50"N 113º12'17"W), August 2, 2012, 2 F (CL ca 7 mm; damaged), BS operated at 1246–1309 m (EMU–10874–C); St. 17 (26º20'14"N 114º13'07"W), July 31, 2012, 1 F (CL ca 9 mm), BS operated at 2111–2136 m (EMU–10876–B).

TALUD XVI–B. St. 1 (28º27'24"N 115º48'55"W), May 23, 2014, 1 M (CL 10.2 mm), BS operated at 2038– 2054 m (EMU–10869).

Distribution. Indo –Pacific. In the eastern Pacific it has been recorded in the San Pedro Basin, California, USA, along the Baja California Peninsula, off the Revillagigedo Islands, and within the Gulf of California north to Tiburón Island; also reported from "Dowd Tablemount", off SW Mexico and off Chile ( Burkenroad 1938; Hanamura 1983; Hendrickx & Estrada-Navarrete 1996; Gúzman & Wicksten 2000; Guzmán 2008; Wicksten 2012).

Distribution in western Mexico. As reported previously, G. s o rd i d u s is widely distributed throughout the southern and central Gulf of California, and along the west coast of the Baja California Peninsula ( Hendrickx & Estrada-Navarrete 1996). Material examined herein includes the first record of this species for SW Mexico (18º33'27"N 109º17'36"W) ( Fig. 2 ).

Remarks. Hendrickx & Estrada-Navarrete (1996) reported new material of this species from 22 localities throughout western Mexico, except along the SW coast and north of Tiburón Island, Gulf of California. All their specimens had been captured with small and medium–sized pelagic gear operating from the surface to a minimum depth of 165 m and a maximum depth of 300 m. Wicksten (2012) provided a depth range of 0–915 m corresponding to the deeper midwater trawl in which G. s o rd i d u s has been caught. There is, however, no precise information related to the depth of residence of G. s o rd i d u s except for the data provided by Hendrickx & Estrada- Navarrete (1996) indicating that it occurs in the epipelagic zone and maybe slightly deeper.

Gennadas sordidus had previously been reported from five Mexican localities by Burkenroad (1938). Material examined herein came from as many as 38 localities, 31 within the Gulf of California, 6 off Baja California, and one off SW Mexico ( Fig. 2 ), and G. sordidus is therefore and by far the most common and abundant species of the genus in western Mexico. In this study, 76 males and 107 females were collected providing an overall sex ratio of 1: 1.4 in favor of females.

Figures

FIGURE 2. Localities where specimens of Gennadas sordidus Kemp, 1910, were collected during this survey.