Crinitocinus, Ng & Rahayu, 2014

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2014, Revision of the family Acidopsidae Števčić, 2005, and the systematic position of Typhlocarcinodes Alcock, 1900, Caecopilumnus Borradaile, 1902, and Raoulia Ng, 1987, with descriptions of two new genera and five new species (Crustacea: Brachyura: Goneplacoidea), Zootaxa 3773 (1), pp. 1-63 : 15

Crinitocinus gen. nov.

Diagnosis. Carapace dorsal surface with numerous short setae arranged in clumps of 4–8, relatively close to each other; with scattered low granules; lateral margins with longer setae; anterolateral margin with 3 low lobiform teeth (excluding triangular external orbital tooth), without associated grooves on carapace ( Figs. 9A , 10A, B ). Frontal margin relatively broad, with 2 broad convex lobes ( Figs. 9A , 10A, B ). Basal antennal article quadrate ( Fig. 11D ). Eye relatively short, not tapering, cornea large, rounded, pigmented ( Fig. 12A ). Male anterior thoracic sternum proportionately wide ( Figs. 9B , 11F ). Cutting edges of fingers dentate; base of dactylus of major chela with large cutting tooth, even in females ( Fig. 9D )

Etymology. The genus name is an arbitrary combination of the Latin crinitus for “hairy,” with the ending of Carcinus . Gender masculine.

Remarks. Crinitocinus gen. nov. most closely resembles Parapilumnus , especially in the carapace shape and armature, as well as the structure of the eyes. Crinitocinus gen. nov., however, differs markedly in two key characters: the male anterior thoracic sternum is proportionately wider ( Figs. 9B , 11F ) (proportionately narrower in Parapilumnus ; Fig. 8D ), and the cutting edges of the fingers are dentate and the base of the dactylus of the major chela has a large cutting tooth, even in females ( Fig. 9D ) (cutting edges of the fingers of both chelae are blade-like in Parapilumnus ; Fig. 8B ). The arrangement of setae on the adult carapace is also different. The setae are in clumps of 3 or 4 and uniformly distributed but more spread out on the dorsal surface in Parapilumnus , ( Fig. 8A, B ). In adult Crinitocinus gen. nov., the setae are in clumps of 4–8, somewhat more unevenly distributed but closer to each other ( Fig. 10B ). The dorsal carapace surface is covered with prominent small rounded granules in Parapilumnus , ( Fig. 8A, B ) but in Crinitocinus gen. nov. the surface only has scattered low granules which are not prominent ( Fig. 9A , 10A, B ).

Compared to Acidops , Crinitocinus gen. nov. differs in having less and shorter setae on the carapace ( Figs. 9A, C, D , 10A, B ) (denser and longer setae in Acidops ; Figs. 7A–C ); the setae on the ambulatory legs is denser and coarser, almost completely obscuring the outlines of the articles ( Fig. 12C ) (less dense and not completely covering the articles in Acidops ; Fig. 12F ); the anterolateral teeth are low and do not have associated grooves on the carapace ( Figs. 9A , 10A, B ) (with short shallow grooves on the carapace starting from the anterolateral teeth in Acidops ; Fig. 7A, C ); the basal antennal article is more quadrate ( Fig. 11D ) (more elongated in Acidops ; Fig. 6A ); the eye is relatively shorter and not tapering towards the large rounded cornea ( Fig. 12A ) (elongated, pear-shaped, tapering prominently to a small ovate cornea in Acidops ; Fig. 12D ); the male anterior and female thoracic sterna are proportionately wider ( Figs. 9B , 11F , 12B ) (proportionately narrower in Acidops ; Figs. 7E , 12E ); the lateral margins of the female telson is gently sinuous ( Fig. 12B ) (distinctly convex in Acidops ; Fig. 12E ); and the cutting edges of the fingers are dentate and the base of the dactylus for the major chela has a large cutting tooth, even in females ( Fig. 9D ) (the cutting edges of the fingers of both chelae are dentate in Acidops , without any obvious cutting tooth; Fig. 7F ).

Figures

FIGURE 6. Left antennae and antennules. A, Acidops cessacii (A. Milne-Edwards, 1878), male (11.3 × 8.1 mm) (ZRC 1998.58), Ascension; B, Parapilumnus cristimanus (A. Milne-Edwards, 1873), male (16.3 × 12.5 mm) (ZRC 2003.90), Nansha Is. (Spratly Is.), South China Sea; C, Raoulia fortis sp. nov., holotype male (12.0 × 9.2 mm) (MNHN), Santo, Vanuatu; D, Caecopilumnus crassipes (Tesch, 1918), male (12.9 × 11.4 mm) (ZRC 2013.1711), Lombok, Indonesia; E, Thecaplax capillosa gen. et sp. nov., paratype male (13.2 × 10.7 mm) (MZB), Lombok, Indonesia; F, Typhlocarcinodes integrifrons (Miers, 1881), lectotype male (8.5 × 6.9 mm) (NHM 81.24a), Goree I., Senegal. Abbreviations: at3 and at4 = basal antennal articles 3 and 4, respectively; bs = basal antennal article; ba = basal antennular article. Scales = 0.5 mm.

FIGURE 7. A, Acidops fimbriatus (Stimpson, 1871), female (19.7 × 14.9 mm) (MNHN-IU-2013-9470), Clipperton I.; B-G, Acidops cessacii (A. Milne-Edwards, 1878). B, syntype female (14.1 × 10.0 mm) (NHM 99.3.23.66), Cape Verde; C, G, female (12.6 × 9.9 mm) (ZRC 1998.58), Ascension; D, E, male (11.3 × 8.1 mm) (ZRC 1998.58), Ascension. A–D, overall dorsal views; E, anterior thoracic sternum and male abdomen; F, right chela; G, left chela. C by A. Anker.

FIGURE 8. A, B, Parapilumnus cristimanus (A. Milne-Edwards, 1873), male (10.2 × 7.6 mm) (IOCAS SSFVI2-2), Nansha Is. (Spratly Is.), South China Sea; C, D, Parapilumnus oryctus Ng, 2002, holotype male (12.3 × 10.5 mm) (ZRC 2002.174), Guam. A, C, dorsal views; B, frontal view showing chelae, antennae and antennules; D, anterior thoracic sternum and male abdomen.

FIGURE 9. Crinitocinus alcocki (Borradaile, 1902). A–C, holotype male (5.6 × 4.8 mm) (CUMZ I.63692), Suvadiva Atoll, Maldives; D, male (4.5 × 4.3 mm) (CUMZ I.63694), Amirante Is.. A, dorsal view; B, anterior thoracic sternum and male abdomen; C, left chela; D, right chela.

FIGURE 10. Crinitocinus alcocki (Borradaile, 1902). A, male (4.5 × 4.3 mm) (CUMZ I.63694), Amirante Is.; B–D, female (13.2 × 9.9 mm) (MNHN IU-2013-865), Madang, New Guinea. A, B, dorsal views; C, left third maxilliped; D, female thoracic sternum and vulva.

FIGURE 11. A–C, Acidops cessacii (A. Milne-Edwards, 1878), male (10.0 × 7.7 mm) (MNHN), Cape Verde; D–G, Crinitocinus alcocki (Borradaile, 1902), holotype male (5.6 × 4.8 mm) (CUMZ I.63692), Suvadiva Atoll, Maldives; H, Crinitocinus alcocki (Borradaile, 1902), male (4.5 × 4.3 mm) (CUMZ I.63694), Amirante Islands; I–K, Crinitocinus alcocki (Borradaile, 1902), male (carapace 11.1 × 8.8 mm) (ZRC 2013.1800), Hawai‘i. A, B, G1; C, G2; D, left antenna and antennule; E, right third maxilliped; F, male anterior thoracic sternum; G, H, male abdomens; I, damaged left G1 (proximal parts broken off); J, distal part of left G1; K, left G2. Scales: D–H, I, K = 0.5 mm; J = 0.05 mm. A–C after Guinot & Ribeiro (1962: figs. 27a, b, 28).

FIGURE 12. A–C, Crinitocinus alcocki (Borradaile, 1902), female (13.2 × 9.9 mm) (MNHN IU-2013-865), Madang, New Guinea; D–F, Acidops cessacii (A. Milne-Edwards, 1878), female (12.6 × 9.9 mm) (ZRC 1998.58), Ascension. A, D, right orbits and eyes (partially denuded); B, E, female anterior thoracic sterna and abdomens; C, F, right third and fourth ambulatory legs.