Pseudorhombila octodentata Rathbun, 1906

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 : 3

Pseudorhombila octodentata Rathbun, 1906

( Figs. 1A–E , 4A–B , 5 )

Pseudorhombila octodentata Rathbun, 1906: 91 . — Rathbun, 1918: 43, figs. 17, 18, pl. 14. — Chace, 1940: 48. — Guinot, 1969a: 704, figs. 113–115, pl. 3, fig. 2. — Gómez and Ortiz, 1976: 9 (in list). — Hernández Aguilera, 1982: 2, figs. 1A, 2A, 3A, 4A, 5A, 6A. — Coelho and Coelho-Filho, 1993: 560 (in list). — Martínez-Iglesias and Gómez, 1994: 26, figs. 1–3. — Hendrickx, 1995: 14, figs. 1A, 2A, 3D. — Melo, 1996: 413. — Boschi, 2000: 122 (in list). — Melo, 2010: 47 (in list). — Boos et al. 2012: 1026 (in list). Material examined. 1 male (CL = 50.7 mm; CW = 40.13 mm), Revizee/NE (Cruzeiro 3), R/V Natureza col., Sergipe, Station #3, (10°41’S 36°19’W), 27 October 2000, 130 m, gravel bottom, MOUFPE: 19993.

Geographic distribution. Western Atlantic: Cuba (Punta Alegre), Lesser Antilles, Dominica, and Brazilian states of Sergipe (present record), Rio de Janeiro, São Paulo, and Rio Grande do Sul ( Melo, 1996; 2010; Boos et al., 2012) ( Fig. 5 ).

Remarks. The characteristics of the examined material were consistent with the original description provided by Rathbun(1906) and additional taxonomic information provided by Guinot (1969a) and Hernández Aguilera (1982) for specimens collected in the islands of Central America. Pseudorhombila octodentata differs from the other species occurring in Brazil ( P. quadridentata ) in the following characters: antero-lateral margin with four teeth (vs. two teeth in P. quadridentata ) ( Figs. 1A ; 2A ); ocular peduncle with acute lateral granules (vs. less pronounced in P. quadridentata ); the external surface of the third maxilliped is granulated(vs. smooth or little granulated in P. quadridentata ) ( Figs. 1C ; 2C ); merus of the third ambulatory legs with strong and acute spines (vs. granulated in P. quadridentata ); the first and second pleonal somites are corrugated (vs. only the first pleonal somite is corrugated in P. quadridentata ) ( Figs. 1D ; 2D ); well-developed gonopod 1 (G1), convergent at midline of thoracic sternum, slightly curved, and with few spines at the tip (vs. strongly curved, with several spines at the tip,and showing an apex elevation in P. quadridentata ) ( Fig. 4A–D ) (see more details in Guinot, 1969a; Hernández Aguilera, 1982). Pseudorhombila octodentata presents a similar geographic distribution to that of P. quadridentata ( Fig. 5 ), although P. octodentata does not occur in the Gulf of Mexico, only in the South and Southwest regions of Brazil (see P. octodentata distribution topic).However, considering the vertical distribution, P. quadridentata occurs more commonly in shallow waters (between 20 and 64 m) (see remarks under P. quadridentata ), and P. octodentata has a bathymetric distribution between 180 and 329 m ( Chace, 1940; Gómez and Ortiz, 1976; Martínez-Iglesias and Gómez, 1994). The examined specimen was found at 130 m, thus providing a new shallow record for this species. It is also the first record of this species in the Northeast region of Brazil.

Figures

Figure 1. Pseudorhombila octodentata Rathbun, 1906, male; dorsal habitus (A), thoracic sternum, abdominal somites and telson (B), frontal view (C), pleonal somites 1–3, right cheliped (P1) (D), 130 m, MOUFPE: 19993. Scale bar: 1 cm.

Figure 2. Pseudorhombila quadridentata (Latreille,1828), male; dorsal habitus (A), thoracic sternum, abdominal somites and telson (B), frontal view (C), pleonal somites 1–3, right cheliped (P1) (D), 114 m, MOUFPE: 19994. 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.