Parastacus varicosus Faxon, 1898

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 : 34-38

Parastacus varicosus Faxon, 1898

( Fig. 18–20 )

Parastacus varicosus Faxon, 1898: 685 , pl. 69. — Ortmann 1902: 293.—­ Riek, 1971:134,fig. 1a, d, e.—­ Buckup & Rossi, 1980:675, figs. 12-14,21.—­ Hobbs 1989: 80, fig. 367; 1991: 801, fig. 3d.—­ Buckup & Bond-Buckup 1994: 19.—­ Crandall & De Grave, 2017: 641.—­ Rogers et al. 2020: 876 (key), fig. 23.62A, C. —­ Huber et al. 2022: 275 (key).—­ De los Ríos-Escalante et al. 2022: 1131 (appendix), fig. 1q..—­ Huber et al. 2024: 13 (key).

Parastacus pilimanus .—­ Correa et al. 2013: 156, fig. 1, 2.

Type locality. Colima ( Mexico) [erroneous locality] .

Type material re-examined. Holotype, ♂, Colima ( USNM 4133 ) [Photos examined].

Material examined. Brazil, Santa Catarina: one male, Joinville, Estrada Timbé (direção Chaparral ) (26°12’30”S; 48°50’47”W), 19/II/2001, coll. L. Buckup & G. Bond-Buckup ( UFRGS 3067 ) ; one male and one female, Joinville, Estrada Timbé (direção Chaparral ) (26°12’30”S; 48°50’47”W), 20/II/2001, coll. L. Buckup & G. Bond-Buckup ( UFRGS 3066 ) ; one male, Joinville, Estrada Timbé (direção Chaparral ) (26°12’30”S; 48°50’47”W), 08/X/2003, coll. L. Buckup & G. Bond-Buckup ( UFRGS 2663 ) ; two males, Siderópolis, Jordão Baixo , 01/XII/19777, coll. L. Buckup ( UFRGS 271 ) ; one female and two juveniles, Maracajá, Canal de drenagem de fragmento florestal, sub-bacia do Rio Mãe Luzia , Bacia do Rio Araranguá (28°51’7,75”S; 49°25’45,72”W), 01/X/2019, coll. C. Feltrin ( UFRGS 6920 ) ; one male, Maracajá, Arroio no Parque Ecológico Maracajá (28°53’55,8”S; 42°25’43,8”W), 27/ IX/2019, coll. C. Fukakusa, J. Ferrer, J. Chucktaya & L. Malabarba ( UFRGS 6920 ) .

Brazil, Rio Grande do Sul: one male, Novo Hamburgo, Lomba Grande, Estrada da Integração , 27/X/1985, coll. G. Oliveira & J. Muller ( UFRGS 1354 ); five males, one female, Novo Hamburgo , Lomba Grande , Estrada da Integração , 28/IX/1985, coll. J. Muller ( UFRGS 1355 ); seven males, Novo Hamburgo , Lomba Grande , Estrada da Integração , 25/X/1985, coll. Guacira & Jackson ( UFRGS 2343 ); one sni, Novo Hamburgo , Lomba Grande , Estrada da Integração , coll. G. Oliveira & J. Muller ( UFRGS 879 ); four males, Fazenda do Sandro , Lomba Grande , Novo Hamburgo (- 29.7302545S; - 51.087590W), 25/XI/2018, coll. A.F. Huber & F.B. Ribeiro ( UFRGS 6656 ); six males, Canoas, floodplain of Sinus river , Tabaí-Canoas, 16/IX/1983 ( MCTP 981 ); one male, Porto Alegre, várzea do Rio Gravataí , 08/XI/2000, coll. Malabarba, Berg, Anza & Azevedo ( UFRGS 4790 ); six juveniles, Laguna dos Patos, Tavares, VI/2016, coll. L.E.K. Lanés, R. Godoy & V. Weber ( UFRGS 6413 ); one male, Taim, 21/XI/1979, coll. Helena ( UFRGS 2347 ); one female, Taim, 6–10/VII/1979, coll. P. Buckup, C. Souto & K. Leyser ( UFRGS 1370 ); six males, Pelotas, 22/VII1965 ( MZUSP 6934 ); one female , Rio Grande do Sul, coll. Hering ( BMNH 1983 :5); one male, Mostardas , 21/I/1977 ( UFRGS 281 ); one male, Gravataí, Fazenda Alencastro, 29/X/1976 ( UFRGS 280 ) .

Uruguay: one sni, Republica Oriental del Uruguay, 1897, coll. F. M. Rodriguez (MACN–In 4570–1); two males, Departamento de Rocha, Camino a laguna de Rocha (Frente al Velódromo), IV/1996 (FC–UDELAR 314); one male and one female, Departamento de Rocha (FC–UDELAR 355); one male and three juveniles, Rocha, Ruta 9 Pte Arroyo Valizas, Charco al Norte de La Carretera, 09/V/1981, coll. R. V. Ferreira, F. Achaval & J. Bergan (FCUDELAR 276); one sni, Bocas del Sarandi , III/1995 (FC–UDELAR 313); one sni, Departamento de Maldonado, Gruta de Salamanca , Ruta 13 entre Aigua y Velazquez (FC–UDELAR 384); one sni, Montevideo, Parque Centenario, XII/1938, coll. Carcelles, Alberto & M. Rosa (MACN–In 23568); three females and 19 males, Maldonado, IX/1927, coll. C.R. Mazzoni (MACN–In 17514) .

Argentina: one female with juveniles, Entre Ríos (MACN–In 30723) .

Diagnosis and description. Faxon (1898) and Buckup & Rossi (1980).

Remarks. This species also occurs in the municipality of Siderópolis—­ SC, being erroneously identified as P. saffordi by Buckup and Rossi (1980). Regarding the type locality, it is clearly erroneous as pointed out by Hobbs (1987) and Buckup & Rossi (1980), because the genus Parastacus only occurs in South America. The material listed by De los Ríos Escalante (2022) from the locality of Cova do Touro (29°52’S 51°00’W) used in the study of Silva-Castiglioni et al. (2008) was analyzed and does not correspond to P. varicosus , and are considered to be an undescribed species. Additional morphological characters not mentioned in previous descriptions include: eyes large ( Fig. 18A, B, C ); front wide ( Fig. 18A, B ); epistome anterolateral section with a very sharp conical projection ( Fig. 19A ); antennal scale lateral margin straight ( Fig. 19D ); antennule internal ventral border of basal article with one sharp spine ( Fig. 19A ); mandible with cephalic molar process molariform and caudal molar process bicuspidate or tricuspidate, incisor lobe with nine teeth; the third tooth from the anterior are the largest ( Fig. 19E ); SLP4 smallest and separeted to each other, medial keel present and not inflated; SLP5 widely separeted to each other, median keel present and not inflated; SLP6 larger than SLP4 and SLP5 with slightly concave dorsal surface, medial keel present and inflated; SLP7 largest and with slightly concave surface, median keel present and slightly inflated; SLP8 smaller than SLP7, median keel absent, vertical arms of paired sternopleural bridges close to each other in the superior portion, bullar lobes not visible ( Fig. 19B, C ); male cuticle partition present. Specimens collected in Joinville (state of Santa Catarina) lack the tufts of long setae present in the inner margin of cheliped merus, carpus, and propodus. However, there is not enough morphological evidence to group these individuals into another species. Parastacus varicosus is morphologically similar to P. saffordi as mentioned before, but it can be distinguishable by the serrated externally branchiocardic grooves, longer merus, propodus, and dactylus of chelipeds and by the anteriomedian lobe of epistome with acute apex.

Distribution. Brazil: states of Rio Grande do Sul and Santa Catarina ( Buckup and Rossi, 1980; 2003); Uruguay: departments of Montevideo, Maldonado and Rocha; Argentina: Province of Entre Ríos) ( Ribeiro et al. 2020).

Color of living specimens. Rostrum, cephalothorax anterior and lateral regions olive green. Dorsal pleon with dark green longitudinal lines interspaced by darkish yellow lines, tailfan light green, dark green or greenish brown. Chelipeds light green with a dark green line in lateral margins in palm and fingers. Pereiopod pairs 2–5 light green or dark green ( Fig. 20D, E ).

Habitat and Ecology. Swamps and wetlands away from temporary or permanent water bodies and sometimes in streams, where they can build shallow burrows in the margins with or without chimneys ( Buckup & Rossi, 1980) ( Fig. 20A–C ). Burrows of P. varicosus can be identified as type 1a, b according to Horwitz and Richardson’s (1986) classification and the species can be considered a tertiary burrower based on Hobbs’ (1942) classification ( Ribeiro et al. 2020).

Figures

FIGURE 18. Parastacus varicosus Faxon 1898: A—­ habitus, dorsal view (UFRGS 281); B—­ cephalon, dorsal view (UFRGS 1354); C—­ cephalon, lateral view (UFRGS 1354); D—­ female pleonal somites, dorsal view (UFRGS 3066); E—­ first to third male pleonal pleura (UFRGS 1354); F—­ first to third female pleonal pleura (UFRGS 3066); G—­ tailfan (UFRGS 281). Scale bars: A—­ 10 mm, B, C, D, E—­ 5 mm.

FIGURE 19. Parastacus varicosus Faxon 1898. A—­ epistome (UFRGS 1354); B—­ thoracic sternites and gonopores (UFRGS 1354); C—­ thoracomere 8, caudal view (UFRGS 1353); D—­ antennal scale, lateral view (UFRGS 1355); E—­ mandible (UFRGS 1354); F—­ third maxilliped, ventral view (UFRGS 1354); G—­ third maxilliped, dorsal view (UFRGS 1354); H—­ first pereiopod, lateral view (UFRGS 1355); I—­ first pereiopod, dorsal view (UFRGS 1355); J—­ second pereiopod, lateral view (UFRGS 1354). Scale bars: A, C, F, G, H, I—­ 5 mm; B, J—­ 10 mm; D, E—­ 2.5 mm.

FIGURE 20. Parastacus varicosus Faxon, 1898: habitat and living specimens. A—­ Habitat, backwater in the municipality of Novo Hamburgo, state of Rio Grande do Sul, Brazil; B—­ chimney; C—­ single opening; D—­ living specimen in nature; E—­ living specimen in aquarium. White arrows indicate burrow openings.