Typhlocarcinodes Alcock, 1900

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 : 54

Typhlocarcinodes Alcock, 1900

Typhlocarcinodes Alcock, 1900: 326 .— Tesch 1918: 226 (part).— Ng 1987: 91 (part).— Ng et al. 2008: 76 (part).

Diagnosis. Carapace subovate; dorsal surface convex, covered with scattered very small granules; regions separated by deep grooves; front with margin indistinctly divided into 2 lobes, rounded, surface with longitudinal groove, lined with long setae obscuring margin; anterolateral margin arcuate, granular, hirsute, with 2 low but distinct teeth, lined with dense setae; anterolateral margins not distinctly separated from subparallel posterolateral margins. Epistome narrow, partially sunken. Basal antennal article 3 rectangular, longer than wide; article 4 slender, dorsoventrally flattened, twice as long as broad, margins with long plumose setae. Basal antennular article rectangular; antennules folding almost vertically. Basal antennular article large, rectangular, mobile; in large oblique antennular fossa; antennular articles folded into fossa. Eyes mobile; cornea small, pigmented. Third maxillipeds relatively short, stout, closing buccal cavern; merus semicircular, anterolateral angle rounded; exopod relatively narrow, with long flagellum. Outer surface of palm covered by numerous granules. Propodus, dactylus of last ambulatory leg long. Male thoracic sternum relatively wide, st1, 2 completely fused to form subtriangular plate, st3, 4 visibly separated by shallow oblique grooves joining at end of sterno-abdominal cavity; sternoabdominal cavity reaching to imaginary line joining base of coxae of chelipeds; penis sits in distinct groove between st7, 8, completely covered by transversely elongated mobile subrectangular plate which is fused to penis; large part of st8 exposed when abdomen closed, broadly rectangular in shape; press-button mechanism for holding male abdomen present as small sharp tubercle on anterior third of st5. Male abdomen with a1 reaching to cx5, lateral parts tapering to sharp edge, somite appearing subtriangular; lateral margin of a3 produced, forming triangular structure; a3–5 fused, with sutures shallow, but just visible. Gl relatively stout, distal surfaces with scattered spinules; G2 as long as G1, distal segment half length of basal segment.

Remarks. The history of the generic name was discussed earlier under the family. A poorly understood species and genus, its systematic position has been uncertain (see Ng 1987; Ng et al. 2008; Guinot et al. 2013), mainly because the key sternal and abdominal characters, so important in resolving goneplacoid classification, have not been reported until now. The condition of the penis, male thoracic sternum, male and female abdomens, and gonopods leave no doubt that the affinities of Typhlocarcinodes are with acidopsids. The most unusual character must surely be the form of the penis, which has a subrectangular plate that fits into the groove between st7 and st8, thereby protecting it from the external environment, unlike other raouliines ( Fig. 38C ). This penial plate, however, remains mobile, being part of the penis. Typhlocarcinodes is also unusual among raouliines in having the eyes mobile (fused with the orbits for the others). The antennal articles are also relatively longer, with article 4 less conspicuously dorsolateral flattened and the setation along the margins less dense ( Figs. 6F , 37B , 38B ). The structures of the epistome (partially sunken; Fig. 38B ); merus of the third maxilliped (with the anterolateral margin rounded, Fig. 5L ); basal antennal article (short, wider than long, Fig. 6F ), and the position of the vulvae (not next to the median longitudinal groove, Fig. 4H ), however, affirm its classification in the Raouliinae as defined at present.

Figures

FIGURE 4. Female thoracic sterna, abdomens and vulvae. A, B, Raoulia piroculata (Rathbun, 1911), lectotype female (7.3 × 5.5 mm) (USNM 41359a), Amirante Is., Indian Ocean; C, D, Caecopilumnus crassipes (Tesch, 1918), female (13.0 × 11.0 mm) (MZB), Lombok, Indonesia; E, F, Thecaplax capillosa gen. et. sp. nov., paratype female (12.7 × 10.5 mm) (ZRC 2013.1714), Lombok, Indonesia; G, H, Typhlocarcinodes integrifrons (Miers, 1881), paralectotype female (7.0 × 5.4 mm) (NHM 81.24b), Goree I., Senegal.

FIGURE 5. Right third maxillipeds. A, Acidops cessacii (A. Milne-Edwards, 1878), syntype female (14.1 × 10.0 mm) (NHM 99.3.23.66) Cape Verde (laterally inverted); B, Parapilumnus cristimanus (A. Milne-Edwards, 1873), male (16.3 × 12.5 mm) (ZRC 2003.90), Nansha Is. (Spratly Is.), South China Sea (laterally inverted); C, Raoulia limosa Ng, 1987, holotype male (8.3 × 6.3 mm) (ZMUC M58), off Marongas, Jolo, Philippines; D, Raoulia piroculata (Rathbun, 1911), lectotype female (7.3 × 5.5 mm) (USNM 41359a), Amirante Is., Indian Ocean; E, Raoulia galea sp. nov., holotype male (9.4 × 7.4 mm) (ZRC 2000.0980), Phuket, Thailand; F, Raoulia fortis sp. nov., holotype male (12.0 × 9.2 mm) (MNHN), Santo, Vanuatu (laterally inverted); G, Raoulia calva sp. nov., holotype male (6.6 × 5.2 mm) (ZRC 2013.1721), Society Is., French Polynesia; H, Caecopilumnus hirsutus (Borradaile, 1902), male (7.1 × 5.6 mm) (ZMA 261027), Flores, Indonesia (laterally inverted); I, Caecopilumnus crassipes (Tesch, 1918), male (11.8 × 10.1 mm) (ZRC 2013.1710) Lombok, Indonesia; J, Caecopilumnus loculatus sp. nov., holotype male (8.0 × 6.7 mm) (ZRC 2013.1723), Moorea, French Polynesia (laterally inverted); K, Thecaplax capillosa gen. et. sp. nov., holotype male (11.6 × 9.5 mm) (MZB), Lombok, Indonesia; L, Typhlocarcinodes integrifrons (Miers, 1881), lectotype male (8.5 × 6.9 mm) (NHM 81.24a), Goree I., Senegal.

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 37. Typhlocarcinodes integrifrons (Miers, 1881), dorsal views. A, lectotype male (8.5 × 6.9 mm) (NHM 81.24a), Goree I., Senegal; B, paralectotype female (7.0 × 5.4 mm) (NHM 81.24b), Goree I., Senegal.

FIGURE 38. Typhlocarcinodes integrifrons (Miers, 1881), lectotype male (8.5 × 6.9 mm) (NHM 81.24a), Goree I., Senegal. A, anterior thoracic sternum and sterno-abdominal cavity; B, frontal view of carapace; C, posterior thoracic sternum; D, outer view of right chela; E, outer view of left chela.