Parastacus pilimanus (von Martens, 1869 )

Ribeiro, Felipe Bezerra & Araujo, Paula Beatriz, 2024, Taxonomic review of the genus Parastacus Huxley, 1879 (Decapoda: Astacidea: Parastacidae) with description of five new species, Zootaxa 5455 (1), pp. 1-84 : 15-16

Parastacus pilimanus (von Martens, 1869)

( Fig. 6–8 )

Astacus pilimanus von Martens, 1869: 15 , pl. 2, fig. 1.

Parastacus pilimanus .—­ Huxley 1879:771 [by implication].—­ Faxon 1898: 683, 684.—­ Moreira 1901: 16, 80.—­ Ortmann 1902: 292.—­ Faxon 1914: 405.—­ Riek 1971:133.—­ Buckup and Rossi 1980:665, figs. 2-4, 8, 21.—­ Hobbs 1989: 80, fig. 366; 1991: 801, fig. 3e.—­ Buckup & Bond-Buckup, 1994: 19.—­ Collins et al. 2008: 254, fig. 1c.—­ Crandall & De Grave 2017: 641.—­ Rogers et al. 2020: 879 (key), fig. 23.66A.—­ Huber et al. 2022: 276 (key).—­ De los Ríos-Escalante et al. 2022: 1130 (appendix), fig. 1m —­ Huber et al. 2024: 14 (key).

Type material re-examined. Lectotype (designated by Bond-Buckup & Buckup 1994). One snd, Brazil, Rio Grande do Sul, Porto Alegre (30°2’S; 51°12’W), coll. Hensel ( MNB 3323 ) . Paralectotypes. Brazil, Rio Grande do Sul —­ one snd, same data as lectotype ( MNB 3323 ) ;

Material examined. Brazil, Rio Grande do Sul —­ one male, Rio Grande do Sul, coll. Ihering ( BMNH 1886.1 ) ; three males, Porto Xavier, Ijuí river , 22/VI/1989 ( MCTP 1378 ) ; one male, Pirapó, Ijuí river , 22/VI/1989 ( MCTP 1348 ) ; one male, Santiago, Rota 1 ( UFRGS 2310 ) ; one male, Itaqui , 1914, coll. E. Garbe ( MZUSP 949 ) ; two males, Garruchos (28°7’43.93”S; 55°31’10.85”W), 17/IX/2013, coll. F. B. Ribeiro & K. M. Gomes ( UFRGS 5787 ) ; one male, Garruchos, Barreiro (-28.12838’S; -55.5181’W), 19/IX/2013, coll. F. B. Ribeiro & K. M. Gomes ( UFRGS 6503 ) ; one female, São Borja, Arroio do Barreiro , 28/II/1988 ( MCTP 1308 ) ; one male, São Borja, Arroio do Barreiro , 21/IV/1989 ( MCTP 1350 ) ; three males, São Borja, Arroio Barreiro , 23/VI/1989 ( MCTP 1370 ) ; one juvenile, São Borja, Rio Gabju (afluente do rio Iamaquã ), ponte com BR 472, 13/X/1987, coll. G. Bond, N. F. Fontoura, D. Schosler & F. Bento ( UFRGS 1368 ) ; one male and one female, Maquiné, Estrada do Ligeiro , 02/VIII/1999, coll. F. G. Becker, T. Finker & P. Colombo ( UFRGS 6233 ) ; four males, Santa Cruz, Pardo River (29°42’S; 52°25’W) ( MNB 3447 ) ; one female, São Sebastião do Caí , IV/1997, coll. M. Verdade ( UFRGS 2191 ) ; two males, Faxinal do Soturno , coll. N. Fontoura, G. F. Rey & M. P. Barros ( MCTP 1915 ) ; two males and one juvenile, Faxinal do Soturno , 28/VII/1995 ( MCTP 1653 ) ; one male, Montenegro, affluent of Maratá stream, 15/V/2001, coll. D. Pereira ( UFRGS 3204 ) ; one male, Manoel Viana , 28/VII/1998, coll. J. Ferzola & P. Ferzola ( UFRGS 2697 ) ; one female, Vale Vêneto (29°38’33”S; 53°33’02”W), 2012, coll. M. M. Dalosto ( UFRGS 5779 ) ; three males and one female, Vale Vêneto , XI/2012, coll. M. M. Dalosto ( UFRGS 6073 ) ; one male, Santa Maria , CISM (29°45’12.58”S; 53°51’13.6°W) ( UFRGS 5780 ) ; one female, Santa Maria, Base Aérea (29° 49’27.33”S; 53°37’19.506”W), 2012, coll. M. M. Dalosto ( UFRGS 5784 ) ; one male, Alvorada , 04/X/1999 ( MCTP 2150 ) ; four males, Alvorada, IFRS Campus Alvorada , 08/VIII/2017, coll. K.M. Gomes ( UFRGS 6510 ) ; one male, Alegrete, Rio Ibirapuitã , 25/II/1982, coll. B. Irgang ( UFRGS 542 ) ; one male, Alegrete, REBIO Ibirapuitã (29°55’14.3”S; 55°56’02”W), 19/IX/2013, coll. K. M. Gomes & F. B. Ribeiro ( UFRGS 6914 ) ; four males and 18 juveniles, Restinga Seca , 28/III/1995 ( MCTP 1650 ) ; one female, Uruguaiana, Barragem e Rio Touro Passo , 14–18/X/1985, coll. P. Lucena & Marchini ( UFRGS 1376 ) ; one female, Uruguayana , 1914, coll. E. Garbe ( USNM 50671 ) ; two females, São Gabriel (30°34’16.86”S; 54°29’42.22”W), 21/ IX/2012, coll. K. M. Gomes ( UFRGS 5786 ) ; one male, São Gabriel (30°34’16.86”S; 54°29’42.22”W), 21/IX/2012, coll. K. M. Gomes ( UFRGS 5785 ) ; one male, Quaraí, affluent of the river Garupá , BR-293, 12/XI/1987, coll. G. Bond-Buckup ( UFRGS 2339 ) ; one male, Quaraí, affluent of the river Garupá , 12/XI/1987; coll. G. Bond, N. Fontoura & F. Bento ( UFRGS 2345 ) ; one female, Dom Pedrito , 05/III/1957, coll. C. P. Coreto ( UFRGS 1374 ) ; two female, Rio Grande, Estação Ecológica do Taim , 09/VI/1975, coll. L. Buckup ( UFRGS 276 ) ; one male and one female, Bagé , 22/VIII/1987 ( UFRGS 2350 ) ; one male, Bagé, Estância Santa Odessa , IV/2004, coll. Filho ( UFRGS 4792 ) ; one male, Rio Grande, Estação Ecológica do Taim , 09/VI/1975, coll. L. Buckup ( UFRGS 6616 ) ; one male and one female, Rio Grande, Estação Ecológica do Taim , 09/VI/1975, coll. L. Buckup ( UFRGS 277 ) ; 12 males, one female and 28 juveniles, Rio Grande, Estação Ecológica do Taim , 07/VIII/1976 ( UFRGS 205 ) ; six males, Rio Grande, Estação Ecológica do Taim , 19/IX/1998, coll. G. Bond-Buckup & C. Jara ( UFRGS 2413 ) ; one female and one juvenile, Rio Grande, Povo Novo, Estrada do Brete , coll. A. L. F. Santos ( UFRGS 3169 ) ; one male, Rio Grande, Povo Novo, Estrada do Brete , 23/VII/1982, coll. A. L. F. Santos ( UFRGS 3170 ) .

Uruguay —­ four males and one juvenile (MNHN-As 361) ; one male, Río Negro, Estância Morgan , 20/XII/1968, coll. C. S. Carbonell ( FC-UDELAR 165 ) ; 2 sni, Gruta del Palacio , 20/XI/1991 (FC-UDELAR w/n); one sni, Lavalleja, 20/VI/1981, coll. F. Amestoy ( USNM 177853 ) ; one sni, Rocha, 20/VIII/1981, F. Amestoy ( USNM 177854 ) ; two sni, 31/XII/1986, leg. ( USNM 219130 ) ; one sni, 1921, F. Felipponi ( USNM 62318 )

Argentina —­ two males, Marte Caseros, Corrientes (MACN-In 19817); one sni , Santo Tomé, Corrientes , coll. A. Nani VII/1947 (MACN-In 6592); one snd, Mercedes, Corrientes, coll. V. C. Pedera (FCEN-UBA w/n); one female, Catamarca, coll. E. Boman (MACN–In 30838) .

Diagnosis and description. von Martens (1869) and Buckup and Rossi (1980).

Remarks. Additional characters not mentioned in the original description by von Martens (1869) or in the redescription by Buckup and Rossi (1980) are: eyes small ( Fig. 6A, B, C ); front narrow ( Fig. 6A, B ); epistome anterolateral section with a conical projection ( Fig. 6A ); antenna when extended back reaching S2; antennal scale lateral margin curved ( Fig. 7D ); antennule internal ventral border of basal article unarmed ( Fig. 7A ); mandible with cephalic molar process molariform and caudal molar process bicuspidate, incisor lobe with nine teeth; the third tooth from the anterior is the largest ( Fig. 7E ); SLP4 and SLP5 equal in size and separated to each other with median keel not inflated; SLP6 conical and with two concavities on surface and larger than SLP4 and SLP5, median keel present and inflated; SLP7 largest and with a concave surface, median keel present and inflated; SLP8 smaller than SLP 7, median keel absent, vertical arms of paired sternopleural bridges close to each other, bullar lobes not visible ( Fig. 8B, C ); male cuticle partition present. As von Martens (1869) did not designate a holotype, Buckup & Bond-Buckup (1994) designated the largest specimen of lot MNB 3323 as the lectotype, with Porto Alegre as the type-locality. This species is morphologically similar to P. fluviatilis , P. laevigatus and P. pilicarpus in having the cutting edge of cheliped fingers covered by dense tufts of long setae and triangular rostrum, but it differs from both in having irregular lines of verrucous tubercles in the dorsal margin of cheliped dactylus and longer rostrum with apex V-shaped.

Color of live specimens. Rostrum, cephalothorax anterior and lateral regions, chelipeds, dorsal pleon and tailfan olive-green or dark green. Pereiopod pairs 2–5 light greenish brown to dark greenish brown ( Fig. 8A ).

Habitat. Streams, floodplain rivers, and flooded grasslands ( Buckup and Rossi 1980; Ribeiro et al. 2020) ( Fig. 8B ). Burrows can reach a depth of up to one meter and with several branches and small chimneys ( Fig. 8C ) ( Buckup and Rossi 1980). Burrows of P. pilimanus can be identified as type 2 according to Horwitz and Richardson’s (1986) classification and the species can be considered a secondary burrower based on Hobbs’ (1942) classification ( Ribeiro et al. 2020).

Distribution. Brazil: State of Rio Grande do Sul; Argentina: Provinces of Catamarca, Entre Ríos, Corrientes and Santa Fé; Uruguay: Departments of Rivera, Rocha, Cerro Largo, Federación and Flores ( Ribeiro et al. 2020).

Figures

FIGURE 6. Parastacus pilimanus (von Martens, 1869): A—­ habitus, dorsal view (UFRGS 277); B—­ cephalon, dorsal view (UFRGS 277); C—­ cephalon, lateral view (UFRGS 277); D—­ female pleonal somites, dorsal view (UFRGS 277); E—­ first to third male pleonal pleura (UFRGS 277); F—­ first to third female pleonal pleura (UFRGS 277); G—­ tailfan (UFRGS 277). Scale bars: A, C, D, E—­ 1 cm; B, F, G—­ 5 mm.

FIGURE 7. Parastacus pilimanus (von Martens, 1869): A—­ epistome (UFRGS 277); B—­ thoracic sternites and gonopores (UFRGS 277); C—­ thoracomere 8, caudal view (UFRGS 277); D—­ antennal scale, lateral view (UFRGS 277); E—­ mandible (UFRGS 277); F—­ third maxilliped, ventral view (UFRGS 277); G—­ third maxilliped, dorsal view (paratype 4); H—­ first pereiopod, lateral view (UFRGS 277); I—­ first pereiopod, dorsal view (UFRGS 277); J—­ second pereiopod, lateral view (UFRGS 277). Scale bars: A, C, F, G, I, J—­ 5 mm; B, H—­ 1 cm; D, E—­ 2.5 mm.

FIGURE 8. Parastacus pilimanus (von Martens, 1869), living specimen and habitat:A—­ living specimen; B—­ habitat, wetland in the municipality of Uruguaiana, state of Rio Grande do Sul, Brazil; C—­ burrow opening with chimney. White arrow indicates burrow opening. Scale bar: A—­ 10 mm.