Rimapenaeus constrictus ( Stimpson, 1874 )

Cardoso, Irene & Terossi, Mariana, 2022, Molecular analyses reveal two lineages under the name Rimapenaeus constrictus (Stimpson, 1874) (Decapoda, Dendrobranchiata, Penaeidae), Zootaxa 5150 (2), pp. 282-292 : 284-286

Rimapenaeus constrictus ( Stimpson, 1874)

Penaeus constrictus Stimpson 1874: 135 .

Trachypeneus constrictus — Hay & Shore 1918: 378, pl. 25, fig. 9; Schmitt 1935: 131; Williams 1965: 31, fig. 21.

Trachypenaeus constrictus —A. Milne Edwards & Bouvier 1909: 232, figs. 60–63; pl. 5, figs. 7–10; pl. 6, figs. 1, 2; Chace 1972: 9; Huff & Cobb 1979: 43 (complete synonymy), fig. 26; Perez Farfante 1988: 17 (Key), figs. 26–27, A-C, D; Williams 1984: 38, figs. 20, 21.

Material examined. USA, Florida: UF 3725 , Key Largo , 1 female, CL 16.7mm; UF 28522 , off Jacksonville , 1 juvenile (genetic voucher), CL 7.1mm; UF 28511 , off Jacksonville , 1 male (genetic voucher), CL 10.5mm; UF 28509 , off Jacksonville , 1 female (with spermatophore plug), CL 18.5mm; UF 28510 , off Jacksonville , 1 female (with spermatophore plug), CL 19.1mm. Brazil , Rio de Janeiro (RJ) and São Paulo (SP): MNRJ 25229 , Baía de Guanabara , Rio de Janeiro, RJ, 3 females (genetic vouchers), CL 14.2–15.1mm; MNRJ 30198 , Baía de Guanabara , Rio de Janeiro, RJ, 8 females (genetic voucher), CL 10.1–13.5mm; MNRJ 30199 , Enseada de Ubatuba , Ubatuba, SP, 26 females (11 with spermatophore plug), CL 13.3–21.9mm; DZ/ UFRGS 6929 , Enseada de Ubatuba , Ubatuba, SP, 13 females (genetic voucher) (9 with spermatophore plug), CL 10.5–18.5mm and 2 males, CL 12.3–14.4mm .

Diagnosis. Rostrum with usually 7 to 9 teeth along entire dorsal margin, without teeth on ventral margin; carapace with two longitudinal sutures; with almost entire dorsal region and anterior part of sides densely setose; branchial region sparsely setose ( Figs. 2A , 4A ). Abdomen naked except for bands of setae flanking dorsal keel of last 2 or 3 segments. Males with protuberance on sternite 13–14 goblet-shaped, constricted posteriorly. Petasma with inner lamellae soldered together and folded, diverging at the tip, forming two hard, lunate processes with distolateral corners greatly produced as hornlike projections; with two strong hook setae at lamellae divergence point ( Figs. 2C , 4C ). Appendix masculina (pleopod 2) subquadrate with rows of small stout setae at distal margin ( Figs. 3B , 5C ). Thelycum anterior margin of plates of sternite 14 strongly convex, evenly rounded, notched in middle; anterior margin of median protuberance on sternite 13 convex or subangulate ( Figs. 4B , 5F ). Exopods of fifth pair of pereopods long, reaching, or almost reaching level of distomesial extremity of basis and telson with 2 rounded carinae, tapering to short acuminate tip, armed on either side with one stout seta ( Figs. 3C, D and 5E, G ).

Remarks. All diagnostic features of R. constrictus , including that mentioned in Pérez Farfante (1988) key, were analyzed in all examined specimens from both lineages. Small distinctions were observed in some specimens, but none clear pattern that allows the morphological separation of the two lineages found in molecular data was observed. At the present level of morphological observation, these distinctions from specific diagnosis were considered intraspecific variations once that they were observed also between specimens from the same locality. The main intraspecific variation observed was in protuberance on sternite 13–14 of males that according to Perez Farfante (1988) is goblet-shaped, constricted posteriorly. The same was observed herein in some Ubatuba (São Paulo) specimens ( Fig. 5A ) but in Florida and other Ubatuba (São Paulo) specimens it is almost rounded, not acute anteriorly and not constricted posteriorly ( Figs. 3A , 5B ). The appendix masculina (pleopod 2) was not described previously to this species, but none variation was observed between the examined material. At the thelycum, the middle notch on plates of sternite 14 is wider in specimens with the spermatophore plug inserted ( Figs. 2B , 5D ).

Figures

FIGURE 2. Rimapenaeus constrictus—UF 28509, Jacksonville, Florida, USA, female (CL 18.5 mm):A. Cephalothorax, lateral view; B. Thelycum with spermatophore, ventral view. UF 28511, Jacksonville, Florida, USA, male (CL 10.5 mm): C. Petasma, posterior view.

FIGURE 3. Rimapenaeus constrictus—UF 28511, Jacksonville, Florida, USA, male (CL 10.5 mm): A. Thoracic sternites 13–14; B. Appendix masculina (pleopod 2). UF 28509, Jacksonville, Florida, USA, female (CL 18.5 mm): C. Exopod of fifth pereopod (right); D. Telson, dorsal view, terminal spine lost.

FIGURE 4. Rimapenaeus constrictus—MNRJ 30198, Canal Central, Baía de Guanabara, Rio de Janeiro, Brazil, female (CL 10.1 mm): A. Cephalothorax, lateral view; B. Thelycum, ventral view. MNRJ 30199, Enseada de Ubatuba, São Paulo, Brazil, male (CL 12.3 mm): C. Petasma, posterior view.

FIGURE 5. Rimapenaeus constrictus—MNRJ 30199, Enseada de Ubatuba, São Paulo, Brazil, male (CL 12.3 mm):A. Thoracic sternites 13–14. Male (CL 14.4 mm): B. Thoracic sternites 13–14; C. Appendix masculina (pleopod 2). Female (CL 17.7 mm): D. Thelycum with spermatophore, ventral view. Female (CL 20 mm): E. Exopod of fifth pereopod (right and left); F. Thelycum, ventral view. MNRJ 30198, Canal Central, Baía de Guanabara, Rio de Janeiro, Brazil, female (CL 10.1 mm): G. Telson, dorsal view.