Robertsella meridionalis Tavares and Gouvêa, 2013

Cintra, Flavio de Almeida Alves-Júnior Girlene Fábia Segundo Viana Maria Fernanda Abrantes Torres Kátia Cristina de Araújo Silva Israel Hidenburgo Aniceto, 2021, New distributional records of species of the family Pseudorhombilidae Alcock, 1900 (Crustacea: Decapoda) from Brazilian waters, Nauplius (e 2021016) 29, pp. 1-10 : 6

Robertsella meridionalis Tavares and Gouvêa, 2013

( Figs. 3A–E , 4E, F , 5 )

Robertsella meridionalis Tavares and Gouvêa, 2013: 72 , figs. 1A–D, 2A–D, 3A, C, 4A–B.

Material examined. 1 male (CL = 12.21 mm; CW = 16.86 mm), Bpot (Potiguar Basin), R / V Seward Johnson col. , Rio Grande do Norte, Station #MT-52 (04°44’S 36°25’W), date: 23 May 2011, 180 m of depth, gravel bottom, MOUFPE : 19231.

Geographic distribution. Western Atlantic :Brazilian states of Rio Grande do Norte (Potiguar Basin — present record) and Santa Catarina ( Tavares and Gouvêa, 2013) ( Fig. 5 ) .

Remarks. The characteristics of the R. meridionalis specimens were consistent with the original description provided by Tavares and Gouvêa (2013), who listed some morphological differences between the only two described species of the genus Robertsella . The species of R. meridionalis can be distinguished from R. mystica by the following characters: strongly def lexed frontal region of carapace ( Fig. 3B ) (vs. a distinctly less deflected frontal region of carapace in R. mystica ); densely and coarsely tuberculate cheliped ischial ridge (vs. less tuberculate cheliped ischial ridge); the merus of the pereiopods P2–P5 is densely and coarsely tuberculate ventrally (vs. the merus of the ventral surface of P2–P5 is smooth); the abdominal suture5/6is well above the thoracic sternal suture 6/7 ( Fig. 3C ) (vs. abdominal suture 5/6 and thoracic sternal suture 6/7 aligned with each other); portion of the thoracic sternite 8 not covered by the lateral expansion of the third abdominal somite ( Fig. 3C ) (vs. proportionally larger)(see more characteristics in Tavares and Gouvêa, 2013). The genus Robertsella was recorded only once in the original description of R. meridionalis provided by Tavares and Gouvêa (2013), specifically from the southern region of Brazil (state of Santa Catarina) from a depth of 400 m. Thus, the present work provides a second report of the species R. meridionalis from Brazil (Northeast region - Potiguar Basin) at about 4,200 km distance from the type locality and increases the bathymetric distribution range for this species to 180– 400 m.

Figures

Figure 3. Robertsella meridionalis Tavares and Gouvêa, 2013, male; dorsal habitus (A), Carapace, dorsal view (B),thoracic sternum, pleonal somites and telson (C), right cheliped (P1) (D), carpus detail (E), 180 m, MOUFPE: 19231. Scale bar: 1 cm.

Figure 4. Gonopod 1 (G1) of male specimens: Pseudorhombila octodentata Rathbun, 1906 (A), P. octodentata (G1) distal region in detail (B), Pseudorhombila quadridentata (Latreille, 1828) (C), P. quadridentata (G1) distal region in detail (D), Robertsella meridionalis Tavares and Gouvêa, 2013 (E), R. meridionalis (G1) distal region in detail (F). Scale bar: 0.5 mm.

Figure 5. Geographic distribution of the Pseudorhombilidae from the Western Atlantic: Pseudorhombila octodentata Rathbun, 1906 (circle); P. quadridentata (Latreille, 1828) (square); Robertsella meridionalis Tavares and Gouvêa, 2013 (star). Black symbols = previous records; Gray symbols = new records.