Albunea occulta Boyko, 2002

Marimuthu, P., Kumaralingam, S., Jayaraj, K. A., Equbal, Jawed & Ganesh, T., 2015, First record of Albunea occulta (Boyko) (Crustacea: Decapoda: Albuneidae) from the Andaman Islands, India, Zootaxa 4027 (1), pp. 135-139 : 135-136

Albunea occulta Boyko, 2002

( Figs. 2–3 )

Albunea occultus Boyko, 2002: 313 –320, fig. 100, 101.

Albunea occulta . — Boyko & McLaughlin, 2002: 141, 143.

Material examined. ZSI/ ANRC #10283, 1 male, cl 17.5 mm, cw 18.0 mm, OP 5.0 mm, coll. P. Marimuthu, 7 October 2013, Burmanallah, Andaman Island; ZSI/ ANRC #10659, 1 immature female, cl 13.0 mm, cw 13.5 mm, OP 3.0 mm, coll. P. Marimuthu & J. Equbal, 28 April 2014, Corbyn’s Cove, Andaman Island.

Remarks. The two specimens (a male and female) collected have distinctive morphological structures and show normal sexual dimorphism in telson form. The specimen collected from Corbyn’s Cove is an immature female ( Figs. 2 A– F).

The key characteristics of the specimens identifyinmg them as A. occulta are as follows: two antennae with long plumose setae with well-developed mandibles; the antennal segment I with dorsodistal spine confirms the characters for genus Albunea ; CG1 separated into anterior and posterior elements; the pereopod I dactylus is curved and tapering; the pereopod III dactylus heel is acute; the male telson is spatulate and broadly triangular with the distal margin having a closely rounded median projection and row of long simple setae on either side of the median groove. The telson of the female is flattened, and ovate, with a median groove similar to the male and the distal margin slightly produced medially ( Fig. 3 ). Other characteristic morphological structures are as follows: the anterior margin has 10 large spines on either side of the ocular sinus; CG11 is present as single long element; the distal segment of the ocular peduncle is elongate and subtriangular; the heel on the dactylus of pereopod II is produced and curved; the dactylus of pereopod IV is sinuous from the base to the tip. Coloration of specimens differed (♂—orange and ♀ —ash green); both were found in the sandy intertidal region up to 2–3 m from the low water mark.

Worldwide studies on sand crabs are very scarce due to their peculiar habits ( Osawa & Fujita 2012; Boyko 2002). They are apparently restricted to sandy sediments, without too much shell debris or other coarser particles which could preclude easy burrowing. Earlier workers reported A. occulta from Japan and Australia ( Asakura 1995; Boyko 2002; Osawa et al. 2010), and has been found at depths of 2–3 meters, similar to A. speciosa in the Hawaiian Islnads ( Boyko 1999). A closely related species, A. symmysta , has been reported from the east coast of India, Philippines, Indonesia and Australia ( Boyko 2002). The Andaman and Nicobar Islands, one of the greatest archipelagoes in the world has a highly diversified marine fauna and may be regarded as a hotspot of biodiversity. The present study is the first report of A. occulta from Indian coastal regions, particularly in Andaman Islands. These findings provide new information on the marine infauna of the Andaman region and open the way for further studies.

Figures

FIGURE 2. Albunea occulta Boyko, 2002: A – C, male, cl 17.5 mm, cw 18.0 mm. D – F, female, cl 13.0 mm, cw 13.5 mm. A, D, dorsal view; B, E, anterior carapace and ocular peduncles; C, F, telson.

FIGURE 3. Albunea occulta Boyko, 2002: A – C, male, cl 17.5 mm, cw 18.0 mm. D, cl 13.0 mm, cw 13.5 mm. A, carapace and ocular peduncles; B, left cheliped; C – D, telson.