Gnathophausia childressi Casanova, 1996

Hendrickx, Michel E., 2019, Species of Gnathophausiidae (Crustacea, Lophogastrida) collected off the west coast of Baja California, Mexico, during the TALUD cruises, Zootaxa 4609 (3), pp. 449-468 : 451-452

Gnathophausia childressi Casanova, 1996

( Figs. 1 , 2A, B )

Gnathophausia childressi Casanova, 1996a: 192 , figs 1–2.― Nouvel et al. 1999: 46, fig. 4.6F.― Meland & Aas 2013: 207, fig. 5, 219 (key).― Wittmann et al. 2014: 349 (list).― Petryashov, 2015: 242 (list).

Material examined. TALUD XVI-B, St. 8 (29º23'48"N, 115º45'16"W), May 31, 2014, 1 male (CL 24 mm), BS operated at 1416–1480 m ( ICML-EMU-12295 ) ; St. 16 (29°51'04"N, 106°09'10"W), May 29, 2014, 1 male (CL 22 mm), BS operated at 1360–1425 m ( ICML-EMU-12293 ) ; St. 22 (30º49'47"N, 116º35'54"W), May 28, 2014, 2 males (CL 27–28 mm) and 1 female (CL 38 mm), BS operated at 1480–1560 m ( ICML-EMU-12294 )

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Distribution. According to the USNM data base, G. childressi is previously known from the type locality (female holotype, USNM-268483, off California, 32.45°N, 118°W), from 32.45°N, 118°W (male allotype, USNM- 268484), and from 31°57'12"N, 117°54'36"W (1 juv.). Paratype female (MNHN My 480) is from 32°27'N, 118°W (L. Corbari, pers. comm., August 2018).

There is a discrepancy between the coordinates provided by Casanova (1996a: table 1) and the data in the Smithsonian Collection (USNM). The type locality (holotype) given by J.P. Casanova appears to be at 32°27'N, 118°W, at 2080 m depth, and the locality where the allotype was collected is reportedly at 32°27'N, 118°02'°W, at 2084 m depth (Casanova 1996a). The paratype material deposited in the Paris Museum (MNHN-My480) corresponds to one female (Casanova 1996a) also collected at 2080 m depth. Data in the MNHN holdings match these provided by Casanova (1996a). The fate of the additional male and female included in Casanova's (1996a) study is unknown. The Mexican material ( Fig. 3 ) is the first reported since the original description and it increases the known distribution of F. chidressi by about 2.5 degrees of latitude to the south.

Remarks. The material examined fits well with the original description of F. childressi . It features the typical rostrum with a series of dorsodistal small denticles, a proportionally long carapace, and the proximal carapace bump at the base of the rostrum ( Fig. 1A ); the upper lateral keel on the carapace is missing ( Fig. 1A ); the abdominal somites are dorsally unarmed ( Fig. 2A, B ). The shape of the antennal scale ( Fig. 1B ) and of the telson ( Fig. 1C, D ), including the deeply channeled dorsal area, also match the original description.

Specimens of different size were collected during the survey. No significant variations were observed among these specimens in what concerns the general shape of the carapace and the proportional length of the rostrum and of the posterodorsal carapace spine ( Figs. 1A , 2A, B ).

Figures

FIGURE 1. Gnathophausia childressi Casanova, 1996. A, carapace, lateral view, female (CL 38 mm) (ICML-EMU-12294); B, same, left antennal scale, ventral view; C, telson, dorsal view, male (CL 28 mm) (ICML-EMU-12294); D, same, tip of telson.

FIGURE 2. A, B, Gnathophausia childressi Casanova, 1996. C, D, Fagegnathophausia gracilis (Willemoes-Suhm, 1875). A, lateral view, male (CL 27 mm) (ICML-EMU-12294); B, lateral view, male (CL 22 mm) (ICML-EMU-12293); C, lateral view, female (CL 28 mm) (ICML-EMU-12320); D, same, dorsal view.

FIGURE 3. Localities where Gnathophausia childressi Casanova, 1996 and Fagegnathophausia gracilis (Willemoes-Suhm, 1875) were collected during this survey.