Macrobrachium perspicax (Holthuis, 1977) Mantelatto & Pileggi & Pantaleão & Magalhães & Villalobos & Álvarez, 2021

Mantelatto, Fernando L., Pileggi, Leonardo G., Pantaleao, Joao A. F., Magalhaes, Celio, Villalobos, Jose Luis & Alvarez, Fernando, 2021, Multigene phylogeny and taxonomic revision of American shrimps of the genus Cryphiops Dana, 1852 (Decapoda, Palaemonidae) implies a proposal for reversal of precedence with Macrobrachium Spence Bate, 1868, ZooKeys 1047, pp. 155-198 : 155

Macrobrachium perspicax (Holthuis, 1977) comb. nov.

Bithynops perspicax Holthuis, 1977: 182, figs 3, 4. - Reddell 1981: 108, fig. 15 (map). - Villalobos 1982: 217 (list). - Holthuis 1986: 606 (list). - Álvarez et al. 1996: 110, chart 12.2 (list). - Pereira 1997: 47, table 6 (list). - Fransen et al. 1997: 16 (catalog). - Jayachandran 2001: 17. - Mejía-Ortiz et al. 2013: 32, table 1 (list).

Bithinops perspicax . - Sbordoni et al. 1977: 52, pl. 3 [error].

Cryphiops (Bithynops) perspicax . - Villalobos Hiriart et al. 1989: 165, figs 1, 7a, c, 8b. - Villalobos-Hiriart et al. 1993: 281, table 5 (list). - Hobbs III 1994: 98 (list). - Fransen et al. 2010: 30, Appendix III (list). - De Grave and Fransen 2011: 316 (catalog). - Álvarez et al. 2011: 258, fig. 2c. - Palacios-Vargas and Reddell 2013: 43 (list). - Palacios-Vargas et al. 2014-2015: 22. - Quiroz-Martínez et al. 2014: table S1 (list). - Alvarez and Villalobos 2016: 250, table 8.1 (list).

Cryphiops perspicax . - Palacios-Vargas 2006: 7 (list). - Baldari et al. 2010: 48, fig. 1 (map), 52, table 1. - Mantelatto et al. 2020: 916 (key).

Material examined.

Mexico - Chiapas • 16 males, tl 31.1-43.3 mm, 16 ovigerous females, tl 21.6-35.5 mm; Municipality of La Trinitaria, Ruinas de Chincultik, Cenote La Cueva ; 07 Apr. 1986; J.L. Villalobos-Hiriart, J.C. Nates-Rodríguez, A. Cantú-Díaz Barriga leg; CNCR 7898 .

Description.

Rostrum. Short, directed downwards, reaching joint between second and third articles of antennular peduncle; upper margin with 5-8 teeth regularly spaced, first one at level or slightly behind posterior edge of orbit; lower margin with 1-3 teeth.

Cephalon. Scaphocerite 2.6 × as long as wide, outer margin straight.

Carapace: Smooth, with minute punctuations; antennal spine small, slightly overreaching lower portion of orbit; hepatic spine absent. Lower orbital angle subacute, moderately pronounced.

Pereiopods . P1 slender, reaching with entire chelae or small part of carpus beyond scaphocerite; fingers slightly longer than palm; chelae 2/3 length of carpus. P2 moderately robust, with spines, equal in form and size, reaching with proximal third of carpus beyond scaphocerite; ischium evidently shorter than merus; merus as long as carpus; carpus as long as palm, with basal constriction; propodus 2.2 × as long as dactylus, 2 × as long as carpus; palm inflated, nearly 3 × as long as high; fingers slightly shorter (0.8) than palm, with numerous small spinules, not gaping, tips crossing, cutting edges with two similar denticles closer to proximal portion. P3-P5 with all joints covered with row of small spinules on lower margin; P3 reaching with entire dactylus beyond scaphocerite, propodus 2 × as long as dactylus, propodus nearly 2 × as long as carpus, propodus slightly longer than merus; P4 reaching with tip of dactylus end of scaphocerite, propodus 3 × as long as dactylus, propodus nearly 2 × as long as carpus, propodus slightly longer than merus; P5 reaching with tip of dactylus half-length of scaphocerite, propodus 3 × as long as dactylus, propodus nearly 2 × as long as carpus, propodus slightly longer than merus.

Pleon. Smooth, somite 5 with posteroventral angle of pleuron acute; somite 6 nearly 2 × as long as somite 5. Inter-uropodal sclerite without keel-shaped pre-anal carinae.

Pleopods. PL2 with appendix masculina nearly 2 × as long as appendix interna.

Uropods. Exopodite with mobile spines as long as spiniform projection of outer margin.

Telson. Broad, smooth, slightly longer than abdominal somite 6, bearing two pairs of dorsal spinules close to posterior margin of telson. Posterior margin ending in moderately acute triangular point, with several plumose setae and two pairs of posterior spinules, inner pair overreaching end of telson.

Size.

See in material examined.

Color.

Body translucid with orange punctuations.

Type locality.

México, Chiapas, Municipality of La Trinitaria, Cenote La Cueva, Ruinas de Chincultik, altitude 1,480 m.

Distribution.

Only known from the type locality ( Holthuis 1977; present paper).

Life cycle.

Exclusive of inland waters, therefore independent of brackish waters to complete its life cycle. The eggs are few and large: 1.9-2.5 mm ( Villalobos Hiriart et al. 1989). Its larval development is not known but given the characteristics of the eggs, it should be abbreviated, following the same pattern of congeners inhabiting continental waters ( Magalhães and Walker 1988; Pereira and García 1995).

Remarks.

Among the epigean forms of this group of species with abbreviated development and without hepatic spine, M. perspicax comb. nov. can be distinguished from M. candango nom. nov., comb. nov. and M. alevillalobosi nom. nov., comb. nov. by the total length of the body, and by the similar form and size of the second pereiopod and the proportion of its articles (Table 2 ). Specimens of M. perspicax comb. nov. are generally smaller (31.1-43.3 mm) than those of the other two species; the second pereiopods are shorter, do not present heterochely like M. candango nom. nov., comb. nov. and the chelae are slender, the palm is 3 × as long as high, and the dactylus is slightly shorter.