Allogalathea elegans ( Adams & White, 1848 )

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 : 94-95

Allogalathea elegans ( Adams & White, 1848)

Restricted synonymy:

Galathea elegans Adams & White, 1848 : plate 12, figure 7, Potts, 1915:83, figure 4, plate 1, figure 5, Barnard, 1950: 487, figures 91i–k, Lewinsohn, 1969: 123, figure 24.

Galathea longirostris Dana, 1852: 482 , Southwell, 1906: 220

Galathea longirostris Yokoya, 1936: 138 , figure 6.

Galathea deflexifrons Haswell, 1882: 761 .

Galathea grandirostris Stimpson, 1858: 90 , Stimpson, 1907: 234, Henderson, 1888: 119, plate 12, figure 3, Borradaile, 1900: 421.

Allogalathea elegans Baba, 1969: 6 , figure 1 (in part), Haig, 1973: 275 (in part), Haig, 1974: 447 (in part), Baba, 1977: 252 (in part), Poore, 2004: 231, figure 63e, plate 13g, Macpherson, 2008: 289 (in part), Baba et al. 2008: 53, figure 2B. Cabezas et al. 2011, 162: 256–259, fig. 2, 3.

Material examined. Four specimens: 3 females (cl 1.6, 1.8 and 1.9 mm, tl 4.8, 5.4, 5.7 mm), India, Lakshadweep, Kavaratti Island, 10 o 34.945’N 72 o 38.323’E, depth 25m, on Stephanometra indica , 08 February 2018 (ZSI/ Crustacea /C8033/2).

One female (cl 3.5 mm), India, Lakshadweep, Minicoy Island, 08 o 19.066’N 73 o 01.874’E, depth 22m, on Stephanometra tenuipinna , 28 November 2018 (ZSI/ Crustacea /C8034/2)

Short Description. Carapace excluding rostrum, as long as broad, dorsal surface horizontal from anterior to posterior, with distinct transverse striae bearing fine but coarse setae but cervical groove distinct. Gastric regions with four or five uninterrupted and one or two interrupted edges. Lateral margin of carapace with nine spines. Pterygostomial flap with setiferous striae, anterior margin bluntly produced. Abdominal somites two to four each with three uninterrupted transverse ridges on tergite, usually without scales in between. Eyestalk with short fine setae on the dorsal anterior extension, cornea moderately dilated. Major pereiopods squamous, subcylindrical, lateral and mesial margins straight, merus with spines on mesial and distodorsal margins, carpus mesial margin with row of spines, palm with mesial row of spines, lateral margin with spines continuing till fixed finger. Last four pereiopods relatively squamous and slender, somewhat compressed. Meri shorter posteriorly, dorsal margin with distodorsal spine and a row of well-developed spies proximally in second and third pereiopods, some minute spines on fourth pereiopod. Carpus with some dorsal spines on second and third, unarmed on fourth pereiopod. Propodus slightly longer than dactylus, extensor margin unarmed, flexor margin with six to ten slender movable spines. Dactylus subequal in length, slightly longer and ending in a curved, strong, sharp spine, flexor margins with prominent triangular terminal tooth preceded by four or five obsolescent teeth, each with seta-like movable spines.

Coloration. Allogalathea elegans has a uniformly dark brown stripes along with narrow light stripes running from the tip of the rostrum to the telson. Major pereiopods also show dark and light bands from coxa to propodus. Fingers of the major claw with a combination of dark and orange band, with white color at the tip. Second, third and fourth pereiopods with coxa, ishicum and merus dark brown, carpus and propodus dark, distal portion light, 2/3 rd of the dactylus light orange and curved tip white.

Distribution. Widely distributed in the Indo-Pacific: Mozambique, Red Sea, Madagascar, Taiwan, Philippines, Indonesia, Vanuatu, New Caledonia and Chesterfield Islands ( Cabezas et al. 2011). Now from India.

Host. Allogalathea elegans was previously documented with a variety of crinoid hosts ( Cabezas et al., 2011). Our specimens were collected from Stephanometra indica (Kavaratti Island) and S. tenuipinna (Minicoy Island) in the Lakshadweep.

Remarks. Allogalathea elegans was reported for the first time in India. A. elegans is close to A. babai , however, can be easily distinguished based on the following characters: i) Second to fourth pereiopods are longer and robust in A. elegans compared to A. babai ; ii) merus of the second pereiopod is four times longer than high in A. elegans compared to three times longer in A. babai ; iii) dorsal margin of meri on second to third pereiopods have well-developed spines A. elegans than small or no spines in A. babai ; iv) first pereiopod squamae on the dorsal side has only one spinule and few long setae compared to several spines and numerous setae in A. babai ; v) epipods present or sometimes absent in the first pereiopod in A. elegans whereas the epipods are always present in pereiopod 1 and sometimes on pereiopod 2 and 3 in A. babai . According to Cabezas et al., (2011), A. elegans reported from several other countries such as South Africa, Sri Lanka, Japan, Western and South-Western Australia, Queensland, Great Barrier Reef, and Fiji needs validation.