Parastacus quasimodo, Ribeiro & Araujo, 2024

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 : 68-72

Parastacus quasimodo sp. nov.

( Figs. 43–45 , Table 4)

Holotype. male, Brazil, Rio Grande do Sul, Caraá (29°42’26.39”S; 50°17’27.41”W), 04/XII/2012, coll. M.P. Almerão ( MZUSP 45370 );

Paratypes. Brazil, Rio Grande do Sul —­ 1–5: five males, same data as holotype ( UFRGS 6440 ) .

Etymology. The species’ name is derived from the fictional character “Quasimodo”, the deformed hunchback from the novel Notre-Dame de Paris by Victor Hugo; used as a noun in apposition. We also suggest the common name “Quasimodo crayfish” for this species.

Diagnosis. Rostrum wider than long, apex ending in an upwards spine. Pleon S3 longer than S2 with an elevation resembling a humpback.

Description.

Rostrum: triangular, wider than long (RL 83.2% of RW), short (11.1% of CL), not reaching the half of the second article of the antennular peduncle ( Fig. 43A–C ). Dorsum upwards, apex inverted “U”-shaped, ending in a upwards spine ( Fig. 43B, C ). Few plumose setae on lateral margins. Rostral carinae straight, prominent and narrow, extending back to carapace, slightly surpassing rostral basis, rostral carinae sides slightly convergent and rostral carinae basis slightly divergent ( Fig. 43B, C ).

Cephalon: CeL 66% of CL. Eyes small (CMW 51.6% of OW); suborbital angle> 90°, unarmed ( Fig. 43C ). Front narrow (FW 39.5% of CW). Postorbital carinae longer than rostral carinae (RCL 65.9% of POCL) and weakly prominent. Lateral cephalic edge with some tubercles and sparse setation ( Fig. 43A–C ).

Thorax: carapace laterally compressed, deep and narrow (CD 57.3% of CL; CW 46.2% of CL). Cervical groove weakly U-shaped. Branchiocardiac grooves conspicuous ( Fig. 43A ). Areola narrow, 4.3x as long as wide (33.6% of CL) ( Fig. 43A ).

Pleon: long and narrow (PL 70.8% of CL; PW 64.6% of CW), smooth, not covered by setae on pleural margins ( Fig. 43A ). Pleural somites with rounded posterior margins. S2 pleurae high and long without groove parallel to margin ( Fig. 43D, E, F ). S3 longer than S2 with an elevation ressembling a humpback.

Tailfan: telson uniformly calcified, subtriangular, longer than wide (TeW 76.6% of TeL), with small sharp spines on lateral margins; rounded distal margin with abundant long plumose setae and short simple setae. Dorsal surface with tufts of short setae and inconspicuous dorsomedian longitudinal groove ( Fig. 43E ). Uropod protopod bilobed, with rounded and unarmed margins; proximal lobe largest. Exopod lateral with a small spine, mid-dorsal carina few prominent, ending in a sharp spine. Transverse suture (diaeresis) straight, with ten dorsolateral spines (outer) and nine dorsolateral spines (inner) on right exopod and ten dorsolateral spines (outer) and eight dorsolateral spine (inner) on the left exopod. Endopod, mid-dorsal carina few prominent, ending in a small spine; lateral margin with one sharp spine at level of exopod transverse suture ( Fig. 43E ).

Epistome: anterolateral section with inconspicuous blunt conical projection. Posterolateral section smooth and with deep lateral grooves converging to the basis of the anteromedian lobe, and with longitudinal median groove. Anteromedian lobe pentagonal, 1.2x longer than wide, apex acute with serrated setae, reaching median part of antepenultimate article of antennal peduncle; dorsal surface straight, and basis with a shallow groove ( Fig. 44A ).

Thoracic sternites: SLP4 close to each other, median keel present and not inflated; SLP5 smallest and close to each other, median keel inflated; SLP7 largest and with surface slightly concave, median keel inflated, bullar lobes absent; SLP8 straight, median keel absent, vertical arms of paired sternopleural bridges close to each other, bullar not visible ( Fig. 44B, C ).

Antennule: internal ventral border of basal article with a sharp spine ( Fig. 44A ).

Antenna: when extended back reaching telson. Antennal scale widest at midlength, reaching the end of third antennal article,ASW 44.8% of ASL ( Fig. 44A, D ), lateral margin straight, spine strong and distal margin emarginate. Coxa with prominent carina and one blunt above the nephropore. Basis unarmed ( Fig. 44A ).

Mandible: cephalic molar process molariform, caudal molar process bicuspidate with one cephalodistal cusp and one small distoproximal cusp. Incisor lobe with nine teeth. The third tooth from the anterior margin is the largest ( Fig. 44E ).

Third maxilliped: ischium, ventral surface entirely covered by tufts of short and simple ( Fig. 44F ); dorsal surface glabrous ( Fig. 44G ). Crista dentata bearing 24 and 23 teeth in right and left ischium respectively. Merus ventral surface entirely covered by tufts of long and simple setae ( Fig. 44F, G ).

First pair of pereiopods (chelipeds): large and subequal, laterally flattened (RPrT 25.6% of RPrL; LPrT 25.1% of LPrL) ( Fig. 43A ). Ischium ventral surface with 14 tubercles. Merus: right merus (RML) 53.5% of propodus length (RPrL); left merus (LML) 50.9% of propodus length (LPrL); ventral surface with two longitudinal series of tubercles: inner series with 13 tubercles, outer 13 and mesial 12, arranged irregularly on right merus; inner series bearing 12 tubercles, outer 14 and mesial 13, arranged irregularly on left merus. Dorsal and midventral spines absent. Carpus not divided by a shallow transversal groove ( Fig. 44A ; Fig. 42I ). Internal dorsolateral margin with row of tubercles, increasing in size distally; inner surface without mesial tubercles. Carpal spine absent ( Fig. 44I ). Propodus width (RPrW and LPrW) 41.8% of length in right cheliped and 41.8% in left cheliped. Dorsal surface of palm with verrucous tubercles irregularly distributed ( Fig. 44H, I ). Inner margin without tubercles. Ventral surface bearing two rows of squamose tubercles, reaching the beginning of the fixed finger ( Fig. 42H ), right dactylus (RDL) 59.6% of propodus length (RPrL), left dactylus (LDL) 59.6% of left propodus (LPrL); dorsal surface with rows of setiferous punctuations ( Fig. 42I ). Cutting edge of fingers visible. Fixed finger with seven teeth with four large. Dactylus with eight teeth, the last two smallest ( Fig. 44H, I ).

Second pair of pereiopods: ventral and dorsal surface of carpus, propodus and dorsal surface of dactylus with sparse covering of simple long setae ( Fig. 44J ).

Gonopores: Presence of both genital apertures on coxae of third and fifth pairs of pereiopods. Female gonopores semi-ellipsoidal (maximum diameter 1.24 mm) with well-calcified membrane. Male gonopores rounded, opening onto apical end of a small, fixed, calcified and truncated phallic papilla, close to inner border of ventral surface of coxae of fifth pair of pereiopods. Male cuticle partition present ( Fig. 44B ).

Remarks. This species resembles P. brasiliensis in having large and laterally flattened chelipeds, but can be distinguished from that (and other) congeneric species by the S3 being longer than S2 with an elevation resembling a humpback.

Color of living specimens. Data not available.

Habitat and Ecology. Data not available.

Distribution. Brazil: state of Rio Grande do Sul ( Fig. 45 ).

Figures

FIGURE 42. Parastacus manezinho sp. nov., distribution in the state of Santa Catarina, southern Brazil.

FIGURE 43. Parastacus quasimodo sp. nov., A—­ habitus, dorsal view (holotype, MZUSP 45370); B—­ cephalon, dorsal view (holotype, MZUSP 45370); C—­ cephalon, lateral view (holotype, MZUSP 45370); D—­ first to third pleonal pleura (holotype); E—­ tailfan (holotype). Scale bars: A—­ 1 cm; B, C, D, E—­ 5 mm.

FIGURE 44. Parastacus quasimodo sp. nov., holotype and paratypes: A—­ epistome (holotype, MZUSP 45370); B—­ thoracic sternites and gonopores (holotype); C—­ thoracomere 8, caudal view (holotype, MZUSP 45370); D—­ antennal scale, lateral view (paratype 2, UFRGS 6440); E—­ mandible (paratype 2, UFRGS 6440); F—­ third maxilliped, ventral view (paratype 1, UFRGS 6440); G—­ third maxilliped, dorsal view (paratype 1); H—­ first pereiopod, lateral view (holotype, MZUSP 45370); I—­ first pereiopod, dorsal view (holotype, MZUSP 45370); J—­ second pereiopod, lateral view (holotype, MZUSP 45370). Scale bars: A, C—­ 2.5 mm; B, I—­ 5 mm; D, E—­ 2 mm; F, G—­ 5 mm; H, J—­ 1 cm.

FIGURE 45. Parastacus quasimodo sp. nov., distribution in the state of Rio Grande do Sul, Brazil.