Australocarcinus riparius Davie, 1988

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 140-146

Australocarcinus riparius Davie, 1988

( Figs. 93 A, B; 94A, G; 95A, B; 96A, B; 98A, B; 99A, B)

Australocarcinus riparius Davie, 1988: 260 , figs. 1‒3 [type locality: Queensland, Australia].— Davie & Guinot 1996: 279, fig. 7.— Jamieson & Guinot 1996: 289, figs. 1‒3, tab. 1.— Jamieson & Tudge, 2000: 64 [sperm ultrastructure].—Ng et al. 2008: 76 [in list].

Type material (not examined). Holotype male (cw 13.1 mm) (QM W13113), Australia, Queensland, Murray River .

Paratypes: 28 paratype males, 26 paratype females (QM W12915, QM W12891, QM W12895, QM W 12916, QM W13190-94), type locality.

Material examined. Australia, Queensland . 2 males (9.1 × 11.5 mm, 8.8 × 10.2 mm), 1 female (9.0 × 11.3 mm) ( ZRC 2006.167 ), McIvor River , northern Queensland, 15°07.2’S, 145°04.4’E, freshwater near road crossing, under rocks, in drying river bed fringing rainforest, 30 m elevation, P.F.J. Davie coll., 18.11.1992 ; 2 males, 1 female ( ZRC 2010.0070 ), same data as above.

Diagnosis. Carapace ( Fig. 93 A, B; Davie 1988: figs. 1D; 3) subquadrate, dorsally smooth, flat; 1.2‒1.3 wider than long; front strongly bilobed, with deep median cleft. Anterolateral margins arcuate, with elevated crest bearing 4 large, obtuse, upturned teeth. Orbits short. Epistome ( Fig. 94 A) compressed, posterior margin with median lobe with fissure, circular lateral margins without fissures. Eye peduncle short ( Fig. 94 A; Davie 1988: fig. 1D), does not fill orbit, mobile, cornea enlarged, pigmented. Third maxillipeds ( Fig. 94 G; Davie 1988: fig. 1C) leaving gap when closed; merus quadrate, auricular anteroexternal angle, ischium quadrate, slightly longer than merus. Chelipeds ( Figs. 93 A, B; 95A, B; Davie 1988: figs. 2A, B; 3) subequal in length, nearly similar in both sexes; cutting margins of both chelae with broad, shallow teeth, much larger in major chela. Short, triangular tooth on inner margin of cheliped carpus. Ventral surface of cheliped merus bordered by large tubercles. Proportionally short ambulatory legs ( Fig. 93 A, B; Davie 1988: fig. 3), meri unarmed, dorsal margins with long setae; P5 merus not reaching front when folded, P5 dactylus straight. Short tubercles on surface, margin of articles, long setae on proximal portions of meri. Fused thoracic sternites 1, 2 broadly triangular, proportionally wide, short. Male pleon ( Fig. 96 A, B; Davie 1988: fig. 1E) with lateral margins of somite 6, fused somites 3–5 slightly convex; postero-lateral regions slightly swollen; telson proportionally long. Male thoracic sternite 8 ( Fig. 96 B; Davie 1988: fig. 1F; Davie & Guinot 1996: fig. 7) proportionally short, rectangular; “supplementary plate” conspicuously narrow, short, rectangular. G1 (Fig. ( Fig. 98 A; Davie 1988: fig. 1B) stout, distal part with tapering tip, with short spinules. G2 ( Fig. 98 B; Davie 1988: fig. 1A) longer than G1, basal segment curved; distal segment slightly longer than basal segment, apex with lateral pointed tip. Somites of female pleon ( Fig. 99 A; Davie 1988: fig. 2C) with slightly convex lateral margins; telson proportionally long. Sterno-pleonal cavity of female ( Fig. 99 B) moderately deep, with conspicuously large vulvae relatively close together, covering full extent of thoracic sternite 5, round, thin lip on outer margin, soft membrane across, leaving proportionally small opening.

Remarks. Australocarcinus riparius can be morphologically distinguished from its two congeners by the presence of four large, dorsally upturned teeth on each anterolateral margin of its carapace ( Figs. 93 A; 94A; Davie 1988: figs. 1D; 3), whereas A. kanaka Davie & Guinot, 1996 , has three, dorso-ventrally flattened, wide teeth ( Fig. 93 C; Davie & Guinot, 1996: figs.1, 3A) and A. palauensis Davie & Guinot, 1996 , lacks any teeth along its anterolateral margins ( Fig. 93 D; Davie & Guinot, 1996: fig. 5A).

A female specimen (MNHN-B21888) had a small sperm plug ( Guinot et al. 2013: 42).

Distribution. Known only from Australia (Queensland); rivers and estuaries.

Figures

FIGURE 93. Overall dorsal view of species of Australocarcinus and Trogloplax. A, Australocarcinus riparius, Australia: male 8.8 × 10.2 mm (ZRC 2006.167); B, A. riparius, Australia: female 9.0 × 11.3 mm (ZRC 2006.167); C, Australocarcinus kanaka, New Caledonia: female 8.5 × 9.8 mm (ZRC 2009.111); D, Australocarcinus palauensis, Palau: holotype female (5.8 × 7.1 mm) (USNM 277853); E, F, Trogloplax joliveti, New Britain: holotype male 16.0 × 21.0 mm (MNHN-IU- 2014 - 10457) (after Guinot 1986: pl. 1 A, B); G, Trogloplax joliveti, New Britain: male 15.7 × 18.6 mm (ZRC 2015.294); H, Trogloplax joliveti, New Britain: female 14.1 × 16.8 mm (ZRC 2015.295).

FIGURE 94. Frontal view and third maxilliped of species of Australocarcinus and Trogloplax. A, Australocarcinus riparius, Australia: male 8.8 × 10.2 mm (ZRC 2006.167); B, Australocarcinus kanaka, New Caledonia: female 8.5 × 9.8 mm (ZRC 2009.111); C, D, Australocarcinus palauensis, Palau: holotype female (5.8 × 7.1 mm) (USNM 277853); E, Trogloplax joliveti, New Britain: male 15.7 × 18.6 mm (MNHN-B 20136); F, Trogloplax joliveti, New Britain: female 14.1 × 16.8 mm (ZRC 2015.295); G, Australocarcinus riparius, Australia: holotype male (after Davie 1988: fig. 1 C); H, Australocarcinus kanaka, New Caledonia: paratype female 9.5 × 11.1 mm (after Davie & Guinot 1996: fig. 3 C); I, Australocarcinus palauensis, Palau: holotype female (5.8 × 7.1 mm) (USNM 277853) (after Davie & Guinot 1996: fig. 5 B); J, Trogloplax joliveti, New Britain: holotype male 16.0 × 21.0 mm (MNHN-IU- 2014 - 10457) (after Guinot 1986: pl. 2 B).

FIGURE 96. Male anterior thoracic sternum and pleon of species of Australocarcinus. A, B, A. riparius, Australia: male 8.8 × 10.2 mm (ZRC 2006.167); C, D, A. kanaka, New Caledonia: paratype male 5.5 × 6.4 mm (after Davie & Guinot 1996: fig. 3 D, G).

FIGURE 98. Gonopods of species of Australocarcinus and Trogloplax. A, B, Australocarcinus riparius, Australia: holotype male (after Davie 1988: fig. 1 A, B); C, D, Australocarcinus kanaka, New Caledonia: holotype male 9.5 × 11.1 mm (after Davie & Guinot 1996: fig. 4); E, F, Trogloplax joliveti, New Britain: paratype male 20.0 × 27.0 mm (MNHN-IU- 2014 - 10458) (after Guinot 1986: pl. 2 F, G); G ‒ J, Trogloplax joliveti, New Britain: male 15.7 × 18.6 mm (ZRC 2015.294). Scales: G, J = 1.0 mm; H, I = 0.5 mm.

FIGURE 99. Female pleon and vulvae of species of Australocarcinus and Trogloplax. A, B, Australocarcinus riparius, Australia: female 9.0 × 11.3 mm (ZRC 2006.167); C, D, Australocarcinus kanaka, New Caledonia: female 8.5 × 9.8 mm (ZRC 2009.111); E, F, Australocarcinus palauensis, Palau: holotype female (5.8 × 7.1 mm) (USNM 277853); G, H, Trogloplax joliveti, New Britain: female 14.1 × 16.8 mm (ZRC 2015.295). A, C, E, G, thoracic sternum with pleon; B, D, F, H, female sterno-pleonal cavity with vulvae.