Permanotus purpureus ( Gordon, 1934 )

Prakash, S. & Marimuthu, N., 2020, Notes on some crinoid associated decapod crustaceans (Crustacea: Decapoda) of Lakshadweep Archipelago, Central Indian Ocean, Zootaxa 4766 (1), pp. 86-100 : 94

Permanotus purpureus ( Gordon, 1934)

( Fig 4e )

Restricted synonymy:

Harrovia purpurea Gordon, 1934: 67 , Figs. 33d, 34, 35. 1939: 266. Holthuis, 1953: 6. Serene et al., 1958: 198–199, 240, Figs. 7C, 14. Nagai and Nomura 1988: 221. Castro, 1989: 98. Takeda & Marumura 1994: 26, Fig. 2

Harrovia bituberculata Shen et al., 1982: 146 [Chinese text], 149 [English text], Fig. 4 –9, 4–11, pl. 2: Fig. 12.

Permanotus purpureus Chia and Ng, 1998 , 46(2): 546–553, figs. 29–31.

Material examined. Single male (cl 3.8 mm, carapace width 5.2 mm), India, Lakshadweep, Bangaram Island, 10 o 55.681’N 72 o 13.083’E, depth 13m, on Phanogenia gracilis , 20 November 2018 (ZSI/ Crustacea /C8032/2).

Short Description. Carapace distinctly broad, rostrum short, inner surpaorbital teeth distinct but small, separated from frontal margin by longitudinal groove, numerous flat tubercles along the frontal margin, gastric and protogastric regions distinct. Cardiac regions slightly swollen, hepatic regions depressed, dorsal surface of carapace covered with very thin pubescence. Anterolateral and posterolateral margins demarcated. Antennules folding obliquely, antenna free and reaching to orbit, antennal basal segment rectangular. Pterygostomial regions granulated. Third maxilliped quadrate, ischium rectangular, merus squarish, exopod reaching the antero-external edge of merus. Abdomen seven segmented, sutures visible in all segments. Chelipeds smooth, carpus without spines, chelae slender and elongated, fingers not carinate. Merus of the first ambulatory leg slender, dactylus elongated, merus smooth on the anterior margins.

Coloration. In Permanotus purpureus , carapace was dominated by dark brown and light bands. Major pereiopods with dark and pale bands running longitudinally from coxa to dactyl. Tip of the dactylus pale. Other pereiopods like a major claw with the dark and pale band. Third maxillipeds were dark with setae pale.

Distribution. Widely distributed in the Indo-Pacific: From Central Pacific to Japan, southwest Pacific, Sulawesi, Papua New Guinea, Australia and Malaysia, Indonesia, Marshall, Taiwan, Tasman Sea and Western Indian Ocean ( Gordon 1934, Holthuis, 1953, Shen et al., 1982, Stevcic et al. 1988, Nagai and Nomura, 1988, Castro 1989, Takeda and Maramura 1994, Chia and Ng, 1998, Ng and Jeng, 1999). Now from India ( Lakshadweep).

Host. Associated with a different type of crinoids ( Chia and Ng, 1998). Our specimen was collected with Phanogenia gracilis in the Bangaram Island, Lakshadweep.

Remarks. Permanotus purpureus is a distinct and widely distributed species in the Indo-Pacific. The coloration of our specimen agrees well with the description of Nagai and Nomura (1998). Previously confused with Harrovia purpurea Gordon, 1934 , however, P. purpureus can be easily distinguished based on its rostrum being short and the presence of tubercles on the gastric region of carapace. Recently, Chia and Ng (1998) transferred it to the monotypic genus and currently considered as a synonym of Harrovia bituberculata ( Shen, Dai & Chen,1982) .

Figures

FIGURE 2. Host crinoids of crustacean decapods collected from the Lakshadweep group of Islands. a. Comaster multifidus (Müller, 1841); b–c. Phanogenia gracilis (Hartlaub, 1893); d. Phanogenia distincta (Carpenter, 1888); e. Phanogenia gracilis (Hartlaub, 1893); f. Stephanometra indica (Smith, 1876); g. Phanogenia multibrachiata (Carpenter, 1888); h. Phanogenia gracilis (Hartlaub, 1893); i. Stephanometra tenuipinna (Hartlaub, 1890).

FIGURE 4. Crustacean decapods associated with crinoids collected from the Lakshadweep Islands. a. Synalpheus carinatus (De Man, 1888), lateral view; b. S. comatularum (Haswell, 1882), lateral view; c. S. stimpsonii (De Man, 1888), lateral view; d. Palaemonella pottsi (Borradaile, 1915); e. Permanotus purpureus (Gordon, 1934).