Macrobrachium candango nom. nov., 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 candango nom. nov. comb. nov.

Cryphiops brasiliensis Gomes Corrêa, 1973: 169, figs 1-26. - Rodríguez 1981: 47 (in list). - Coelho and Ramos-Porto 1985: 407, 409 (table II). - Ramos-Porto and Coelho 1990: 98. - Pereira 1997: 21, fig. 18B, 47, table 6 (in list). - Ramos-Porto and Coelho 1999: 330 (catal.). - Melo 2003: 332, figs 180, 181. - Pileggi and Mantelatto 2010: 197 (table 1). - Mantelatto et al. 2016: 261 (in list). - Mantelatto et al. 2020: 915 (in key), fig. 23.102C.

Cryphiops (Bithynops) brasiliensis . - Villalobos Hiriart et al. 1989: 164, fig. 6b, d. - De Grave and Fransen 2011: 316 (catal.).

Material examined.

Holotype: Brazil - Distrito Federal • male, cl 18.2 mm; Brasília, riacho da Granja do Ipe ; 13 Sep. 1966; Emílio Varolli (SUDEPE) leg.; M.M.G. Corrêa det.; MNRJ 903.

Additional material examined.

Brazil - Distrito Federal • 1 ovigerous female, cl 15.6 mm, [allotype]: Brasília, riacho da Granja do Ipê; 13 Sep. 1966; Emilio Varolli (SUDEPE) leg.; M.M.G. Corrêa det.; MNRJ 6464 • 1 male, cl 17.93 mm, 2 females, cl 15.3, cl 15.3 mm; Brasília, riacho da Granja do Ipe ; 23 Feb. 1972; M.M.G. Corrêa leg.; MNRJ 2668 • 1 male, cl 14 mm, 2 females, cl 12.6, cl 13.8 mm; Brasília, córrego Taquara, Reserva Ecológica do IBGE ( Instituto Brasileiro de Geografia e Estatística); 05 Aug. 2014, F.L. Mantelatto, L.G. Pileggi, F.L. Carvalho leg.; CCDB 5894 • 2 males, cl 22.9, cl 23.9 mm; Brasília, córrego Onça, upper Paraná River basin; 18 Aug. 1988; E.C. Lopes leg.; CCDB 5895 • 2 males, cl 21.7, cl 24.4 mm; Brasília, córrego Taquara, Onça, upper Paraná River basin; 18 Aug. 1988; E.C. Lopes leg.; CCDB 5896 • 2 females, cl 13.8, cl 14 mm, 5 juveniles, cl 4.4 to 6.2 mm; Brasília, riacho da Granja do Ipê, rio Roncador , Reserva Ecológica do IBGE ( Instituto Brasileiro de Geografia e Estatística); 05 Aug. 2014, F.L. Mantelatto, L.G. Pileggi, F.L. Carvalho leg.; CCDB 5897 • 2 males, cl 9.49, cl 10.23 mm, 2 females, cl 11.34, cl 11.70 mm, 4 juveniles, cl 4.55 to 6.30 mm; Brasília, riacho da Granja do Ipe , 22 Feb. 2008, F.L. Mantelatto, E.C. Mossolin leg.; CCDB 2195 .

Description of the holotype.

Rostrum. Moderately high, nearly straight, distal end slightly directed upwards, reaching end of antennular peduncle, and little before the distal margin of scaphocerite; upper margin convex over orbit, with seven teeth, first and sometimes the second, slightly behind posterior edge of orbit; lower margin with one tooth.

Cephalon. Scaphocerite 2.5 × as long as wide; outer margin slightly concave. Epistome forming two lobes; lobes with laterally arranged carinae.

Carapace. Anterolateral region slightly roughened; hepatic spine absent. Lower orbital angle obtuse, strongly pronounced.

Pereiopods . P1 reaching with almost half length of carpus beyond scaphocerite; fingers as long as palm; carpus 1.5 × as long as chelae, 1.5 × as long as merus; articles with scattered setae, fingers with tufts of setae. P2 similar in shape, different in size; largest one reaching with distal portion of merus beyond scaphocerite; smallest one reaching with distal end of carpus beyond scaphocerite, with fingers as long as palm; all articles with sparse setae and spines. Larger cheliped with ischium nearly as long as merus, with spinulation as in palm; merus as long as carpus, swollen, with spinulation as in palm; carpus slightly shorter than palm, swollen, with strong basal constriction; spinulation as in palm; propodus 2.5 × as long as dactylus, 2 × as long as carpus; palm with upper surface slightly compressed, somewhat swollen, covered with spinules, nearly 3 × as long as high; fingers 2/3 as long as palm, with numerous spinules; cutting edge of dactylus with large tooth in proximal third, slightly lower tooth in between large tooth and proximal part; cutting edge of fixed finger with tooth opposing two teeth of dactylus, with row of three denticles between proximal part and this tooth. P3-P5 smooth, except for sparse setae and spinules along lower margin of propodus; propodus nearly 2 × as long as carpus; propodus slightly shorter than merus; P3 reaching with half-length of dactylus beyond scaphocerite, propodus 2 × as long as dactylus; P4 reaching with tip of dactylus end of scaphocerite, propodus 2.5 × as long as dactylus; P5 reaching with tip of dactylus half-length of scaphocerite, propodus 2.5 × as long as dactylus.

Pleon. Smooth. Somite 5 with posteroventral angle of pleuron rectangular, not spinose; somite 6 1.5 × as long as somite 5. Inter-uropodal sclerite with strong, keel-shaped pre-anal carinae.

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

Uropods. Exopodite with mobile spines slightly shorter than spiniform projection of outer margin.

Telson. Broad, smooth, 1.5 × as long as abdominal somite 6, bearing two pairs of dorsal spinules, first pair slightly behind middle portion of telson, second pair located closer to first pair than to posterior margin. Posterior margin distinct, ending in acute point, with several plumose setae and two pairs of posterior spinules, inner pair reaching end of telson.

Etymology.

The specific epithet Cryphiops brasiliensis was used by Gomes Corrêa (1973) to refer to the type locality of the species, Brasília, the capital of Brazil. To keep that intention, we rename the species using the word Macrobrachium candango , a demonym referring to those who are native to Brasília.

Size.

See in material examined.

Color.

From colorless to light brown, with dark brown carapace, mimicking the color of the substrate where they inhabit.

Type locality.

Brazil, Distrito Federal, Brasília, Riacho da Granja do Ipê.

Distribution.

Endemic of inland waters from Central Brazil (Distrito Federal) ( Gomes Corrêa 1973; present paper).

Life cycle.

Exclusive of inland waters, therefore independent of brackish waters to complete its life cycle. The fecundity is low, 38-61 eggs, and the eggs are large, their volume ranged from 4.41 to 7.71 mm3 (Nogueira et al. under revision). Its larval development is not known but given its fecundity and egg size, it should be abbreviated, following the same pattern of congeners inhabiting continental waters ( Magalhães and Walker 1988; Pereira and García 1995).

Remarks.

Gomes Corrêa (1973) named Cryphiops brasiliensis a species from the vicinities of Brasília, Brazil. This specific epithet, however, was already used by Heller (1868) for a species of Macrobrachium described from the state of Mato Grosso, Brazil. With the synonymization of both genera, these specific names become secondary homonyms. We, therefore, propose the name Macrobrachium candango nom. nov., comb. nov. as a replacement name for Cryphiops brasiliensis Gomes Corrêa, 1973.

We examined specimens from three lots used by Gomes Corrêa (1973) to describe C. brasiliensis and deposited at the MNRJ: the holotype (MNRJ 903: male, cl 18.2 mm) and two others labeled as allotype (MNRJ 6464: 1 ovigerous female, cl 15.6 mm) and paratypes (MNRJ 2668: 1 male, cl 17.9 mm, 2 females, cl 15.3 and cl 15.3 mm), although the author did not explicitly designate the latter two as type material. We had this material on loan, which was returned to MNRJ in July 2008. After the fire at the Museu Nacional do Rio de Janeiro in September 2018, the lot MNRJ 2668 is missing, but the other two, including the holotype, preserved in alcohol, are safe and in good condition (I.A. Cardoso, curator of Crustacea, pers. comm. to FLM, Nov 2020). When carrying out aquatic surveys in the region around the type locality, we (FLM, LGP) visited the Reserva Ecológica do IBGE ( Brasília, DF) and found a well-preserved collection of specimens (> 260, not listed herein) made during previous aquatic faunistic surveys in the area ( Takahashi et al. 2019). The main area of occurrence of this species is in a protected reserve, which may avoid possible impacts. This species was classified in the IUCN’s Data Deficient (DD) category ( Mantelatto et al. 2016). However, due to anthropic pressures in the region, future monitoring is necessary to evaluate its conservation conditions.