Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891

Ng, Peter K. L., Devi, Suvarna & Kumar, Appukuttannair Biju, 2018, The genus Parilia Wood-Mason, in Wood-Mason & Alcock, 1891, with description of a new species and establishment of a new genus for P. tuberculata Sakai, 1961 (Crustacea, Brachyura, Leucosiidae), Raffles Bulletin of Zoology 66, pp. 300-319 : 301

Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891

( Figs. 1A , 2A , 3A , 4A, B , 5 A–C, 6A, 7A, B, 8A–D, 9A, B)

Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891: 264 ; Wood-Mason, 1892: pl. 5 fig. 3, 3a; Alcock & Anderson, 1894: 177; Alcock, 1896: 198; Alcock, 1899: 28, pl. 4 fig. 1; Tirmizi & Serène, 1971: 30, text fig. 4 fig. 1; Tirmizi & Serène, 1971: 30, text fig. 4; Ng et al., 2008: 92; Krishnamoorthy, 2009: 2; Huys et al., 2014: 16; Lakshimi Pillai et al., 2013: 72, unnumbered colour figure; Prema et al., 2018: 112 , figs. 1, 2, 4A–D, F, 5A–G.

Parilia (sic) alcocki – Lloyd, 1907: 3.

Material examined. 14 males (largest 70.6 × 52.2 mm, smallest 43.0 × 36.5 mm), 10 ovigerous females (largest 47.4 × 38.8 mm, smallest 41.2 × 34.4 mm) ( CASAU) , 1 male (66.1 × 57.4 mm), 2 ovigerous females (45.2 × 37.0 mm, 41.5 × 35.6 mm) ( ZRC 2017.215 ), Pazhayar fish landing center, 11°21′30.28″N 79°49′39.83″E, Tamil Nadu, southeast India, 549 m, coll. M. Prema, 14 March 2017; 1 young male (24.8 × 23.4 mm) ( ZRC 2017.216 ), fishing port, Tuticorin, Tamil Nadu, Southeast India, coll. A.B. Kumar et al., March 2017 .

Diagnosis. Carapace transversely subovate ( Figs. 1A , 2A , 3A ); dorsal surface covered with numerous small granules ( Fig. 3A ); branchial regions prominently swollen laterally and dorsally ( Figs. 1A , 2A , 3A , 4A ); surface of carapace, chelipeds and ambulatory legs smooth or covered with small tubercles and granules; adult cephalothorax box-like in frontal view ( Figs. 1A , 2A , 3A , 4A , 6A ); frontal region set back such that part of buccal cavity and third maxillipeds visible in dorsal view, frontal lobes distinctly triangular ( Fig. 3A ); exopod of third maxilliped in adult very broad, appears foliaceous ( Figs. 4B , 5A, C ); surfaces of chelipeds and ambulatory legs covered with small tubercles and granules ( Figs. 1A , 2A , 6A ); G1 very elongate, distal part prominently flared, subdistal lateral projection dorso-ventrally flattened ( Fig. 8 A–C); female sternopleonal cavity with prominent projection between vulvae ( Fig. 9B ). Indian Ocean.

Remarks. Prema et al. (2018) redescribed and figured this species at length and there is no need to elaborate on its taxonomy here. Parilia alcocki is distinct among congeners in possessing a transversely ovate carapace which is very swollen, and an exopod of the third maxilliped which is so broad in adults that it appears foliaceous.

Distribution. Known from the east coast of India and Bay of Bengal ( Wood-Mason & Alcock 1891; Wood-Mason, 1892; Alcock & Anderson, 1894; Alcock, 1896; Alcock, 1899; Huys et al., 2014; Krishnamoorthy, 2009; Lakshimi Pillai et al., 2013; Prema et al., 2018), Arabian Sea ( Lloyd, 1907) including Pakistan ( Tirmizi & Serène, 1971). The species occurs at depths between 128–457 m (Alcock, 1896, 1899; Lloyd, 1907; Prema et al., 2018).

Figures

Fig. 1. Overall view. A, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, male (66.1 × 57.4 mm) (ZRC 2017.218), India; B, P. major Sakai, 1961, male (70.0 × 69.0 mm) (ZRC 2001.552), Philippines; C, P. ovata Chen, 1984, male (31.6 × 43.3 mm) (ZRC 2017.219), Philippines; D, P. pattersoni, new species, holotype male (53.0 × 52.6 mm) (DABFUK), India.

Fig. 2. Overall view. A, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, female (45.2 × 37.0 mm) (DABFUK), India; B, P. major Sakai, 1961, female (48.3 × 49.2 mm) (ZRC 2001.552), Philippines; C, P. pattersoni, new species, paratype female (58.2 × 55.8 mm) (DABFUK), India.

Fig. 3. Dorsal view of carapace. A, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, male (66.1 × 57.4 mm) (ZRC 2017.218), India; B, P. major Sakai, 1961, male (70.0 × 69.0 mm) (ZRC 2001.552), Philippines; C, P. ovata Chen, 1984, male (31.6 × 43.3 mm) (ZRC 2017.219), Philippines; D, P. pattersoni, new species, holotype male (53.0 × 52.6 mm) (DABFUK), India.

Fig. 4. Frontal view of cephalothorax and third maxillipeds. A, B, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, male (66.1 × 57.4 mm) (ZRC 2017.218), India; C, D, P. major Sakai, 1961, male (70.0 × 69.0 mm) (ZRC 2001.552), Philippines; E, F, P. ovata Chen, 1984, male (31.6 × 43.3 mm) (ZRC 2017.219), Philippines; G, H, P. pattersoni, new species, holotype male (53.0 × 52.6 mm) (DABFUK), India.

Fig. 5. Right third maxilliped. A, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, male (66.1 × 57.4 mm) (ZRC 2017.218), India; B, P. alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, young male (24.8 × 23.4 mm) (ZRC 2017.216), India; C, P. alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, female (45.2 × 37.0 mm) (DABFUK), India; D, P. major Sakai, 1961, male (70.0 × 69.0 mm) (ZRC 2001.552), Philippines; E, P. major Sakai, 1961, female (48.3 × 49.2 mm) (ZRC 2001.552), Philippines; F, P. ovata Chen, 1984, male (31.6 × 43.3 mm) (ZRC 2017.219), Philippines; G, P. pattersoni, new species, holotype male (53.0 × 52.6 mm) (DABFUK), India; H, P. pattersoni, new species, paratype male (72.5 × 69.8 mm) (DABFUK), India; I, P. pattersoni, new species, paratype female (58.2 × 55.8 mm) (DABFUK), India.

Fig. 6. Outer view of right chela. A, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, male (66.1 × 57.4 mm) (ZRC 2017.218), India; B, P. major Sakai, 1961, male (70.0 × 69.0 mm) (ZRC 2001.552), Philippines; C, P. ovata Chen, 1984, male (31.6 × 43.3 mm) (ZRC 2017.219), Philippines; D, P. pattersoni, new species, holotype male (53.0 × 52.6 mm) (DABFUK), India.

Fig. 8. Gonopods. A–D, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, male (66.1 × 57.4 mm) (ZRC 2017.218), India; E–I, P. major Sakai, 1961, male (70.0 × 69.0 mm) (ZRC 2001.552), Philippines; J–M, P. ovata Chen, 1984, male (31.6 × 43.3 mm) (ZRC 2017.219), Philippines; N–S, P. pattersoni, new species, holotype male (53.0 × 52.6 mm) (DABFUK), India. A, E, J, N, left G1 (ventral view); O, left G1 (dorsal view); B, F, K, P, distal part of left G1 (ventral view); C, G, H, L, Q, R, distal part of left G1 (dorsal view); D, I, M, S, left G2. Scales: A, D, E, I, J, M, N, O, S = 2.0 mm; B, C, F–H, K, L, P–R = 0.5 mm.

Fig. 9. Female pleon and sternopleonal cavity. A, B, Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, female (45.2 × 37.0 mm) (DABFUK), India; C, D, P. major Sakai, 1961, female (48.3 × 49.2 mm) (ZRC 2001.552), Philippines; E, F, P. pattersoni, new species, paratype female (58.2 × 55.8 mm) (DABFUK), India