Gennadas capensis Calman, 1925

Alves-Júnior, Flavio De Almeida, Lemos, Rachel De Jesus Feio De, Cardoso, Irene Azevedo, Araújo, Marina De Sá Leitão Câmara De, Bertrand, Arnaud & Souza-Filho, Jesser F., 2018, New records of deep-sea prawn of the genus Gennadas Spence Bate, 1881 (Crustacea: Decapoda: Benthesicymidae) from Southwestern Atlantic, Zootaxa 4450 (3), pp. 376-384 : 377

Gennadas capensis Calman, 1925

( Figure 1 A‒C )

Gennadas capensis Calman, 1925: 5 , pl. I, figs 1, 2.— Burkenroad 1936: 67, figs 51, 53.— Barnard 1950: 630.— Kensley 1971: 277, fig. 3a–e.— Dall 2001: 430, fig. 15.— Hendrickx 2015: 423.

Material examined. ST44A, 2 males (CL, 3.2 mm, 3.5 mm), Fernando de Noronha Archipelago, 3°52'52''S, 32°17'32''W, 1662 m, 28 May 2017, MOUFPE 18673. ST35, 2 females (CL, 3.4 and 3.6 mm) and 1 male (CL, 3.3 mm), Atol das Rocas, 4°19'36''S, 35°29'51''W, 1660 m, 20 April 2017, MOUFPE 18742. ST47, 1 Female (CL, 3.0 mm) and 1 Female (CL, 3.6 mm), Fernando de Noronha Archipelago, 4°25'5''S, 32°57'51''W, 505 m, 30 April 2017, MOUFPE 18741. ST52A, 1 Female (CL, 3.3 mm) and 1 Male (CL, 3.4 mm), Fernando de Noronha Archipelago, 3°31'21''S, 32°31'38''W, 440 m, 26 April 2017, MOUFPE 18680. ST53A, 2 Females (CL, 3.3 mm, 3.5 mm) and 2 Males (CL, 3.5 mm, 3.4 mm), Atol das Rocas, 3°48'59''S, 33°59'16''W, 610 m, 0 2 May 2017, MOUFPE 18718. ST54B, 3 Females (CL, 3.0‒ 3.4 mm) and 2 Males (CL, 3.5 mm, 3.4 mm), Seamounts- Ceará Chain, 3°45'17''S, 34°41'3''W, 830 m, 0 3 May 2017, MOUFPE 18688.

Diagnosis. Carapace thin. Antennal angle acute and infra-antennal angle quadrate. Thelycum with plate of sternite 7 with W-shaped process, sternite 13, with median apex formed by convex process. Coxa of pereopod 5 expanded and bilobed; coxa of fourth pereopod with slender, elongate process; coxa of third pereopod bluntly lobed; coxa of pereopod 2 bearing posteriorly-directed spoon-shaped process. Petasma with external lobe acute, triangular, with smaller acute lobule on median margin; median lobe truncate; internal lobe with 2 bluntly rounded lobules; accessory lobe low, bipartite.

Distribution. Western Atlantic: Gulf of Mexico, Caribbean Sea, Bahamas, Venezuela, Brazil (Seamounts- Ceará Chain, Atol das Rocas and Fernando de Noronha Archipelago) ( Figure 2 ). Eastern Atlantic: West coast of South Africa. Indo-Pacific Oceans: Australia, Nova Caledonia and Wallis and Futuna Islands ( Gore 1985; Dall 2001; Poore 2004; Hendrickx 2015).

Bathymetric Distribution. Maximum of 2000 m depth ( Kensley 1971; Gore 1985; Dall 2001; Poore 2004).

Remarks. According to Kensley (1971), the species closest to G. capensis is G. kempi Stebbing, 1914 , but these two species can be distinguished from each other as follow: thelycum of G. capensis with the 6th sternite lacking shield, or with subcircular shield and the 7th somite forming a W-shaped process, while in G. kempi the 6th sternite has a triangular or subtriangular shield and the 7th sternite features a rectangular process anteriorly directed. The petasma in both species present the external lobe undivided or with small acute process on the median margin, but in G. capensis the accessory lobe is bipartite, while in G. kempi the accessory lobe form a single flap. Gennadas capensis has a cosmopolitan distribution, but it has never been registered in the southwestern Atlantic.

Figures

FIGURE 1. Gennadas capensis Calman, 1925, female (CL, 3.3 mm), carapace (A) (AA= Antenal Angle; IAA= Infra-Antenal Angle), thelycum (B) (Cx = Coxa); male (CL: 3.5 mm), petasma (C) (EL= External Lobe; ML= Median Lobe; AL= Accessory Lobe; IL= Internal Lobe), Abracos 2 #ST 35, 1660 m, MOUFPE 18742.

FIGURE 2. Sampling stations visited during this study where specimens of Gennadas were collected (Abracos 2 and MAR- ECO Projects).