Ancylomenes magnificus ( Bruce, 1979 )

Prakash, Sanjeevi, Kumar, Thipramalai Thangappan Ajith & Subramoniam, Thanumalaya, 2015, Notes on some Indo-Pacific Caridean shrimps (Crustacea: Decapoda: Caridea: Palaemonidae and Gnathophyllidae) particularly from India, Zootaxa 3914 (4), pp. 456-466 : 459-460

Ancylomenes magnificus ( Bruce, 1979)

( Figure 3A )

Restricted synonymy

Perclimenes magnificus Bruce, 1979: 195 –207, figs. 1–5; pl. 1A–C. Marin et al. 2004: Ancylomenes magnificus Okuno and Bruce, 2010: 99 .

Material examined. 11 individuals: 6 males and 5 females (3 ovigerous) (tl 26–34 mm, cl 3–7 mm), India, Tamilnadu, Tuticorin, Van Island (8o50’12.61”N 78o14’08.80”E), depth 2–3 m, on Entacmaea quadricolor , coll. T. T. Ajith Kumar, 15th March 2013, ( MBRC /ZSI M1-54).

Diagnosis based on the collected material. Medium sized shrimp, moderately robust with smooth carapace and abdomen. Rostrum well developed, tapering and distally acute, extending to the intermediate segment of antennular peduncle, dorsal margin with 8 teeth’s and ventral margin with single teeth surrounded by short plumose setae. Epigastric spines present and supra-orbital spine absent. Antennal spines are small and acute. Third abdominal segment humped and moderately produced, fifth segment is longer than the sixth, slightly compressed. Pleura of first three segments are bluntly rounded; fourth segment is broad and fifth produced posterior. Telson is straight, tapering posteriorly with two pairs of small dorsal spines. Uropods are well developed with numerous setae, exopod with convex lateral margin terminating with acute tooth and movable spine medially. Transverse diaresis is present and endopods are slightly narrower than the endopod.

Eyes well developed with large bulbous cornea and accessory pigment spot is visible. Stylocerite acute and well developed, statocyst normally developed. Antenna robust with developed lateral spine. Third maxilliped with slender endopod, antepenultimate segment longer and slightly curved, median border with long plumose setae.

First pereiopods are normal, palm of the chela cylindrical and compressed, fingers of palm unequal and cutting edges of dactyli with hooked tips and numerous setae. Second pereiopods are robust, well developed and subequal, palm smooth and flattened cutting edges of dactyli with short hooked tips and numerous setae, presence of distal spine on the carpus. Merus and ischium unarmed. Ambulatory legs are slender with distinct unguis, third pereiopod with the presence of four ventro-lateral spines. Fourth and fifth pereiopods are similar. Pleopods are normal.

Color pattern. Female. Transparent body and rostrum white, saddle-like transverse bands of white color, edged anteriorly and posteriorly with deep red color. The dorsal hump of the third abdominal segment bears a large pear-shaped white patch surrounded by deep purple margin. Fourth and fifth segments also bear a small oval white patch. Pleuron of first three segments possesses white patches edged with deep red color. Transverse red bands are also visible through the transparent abdomen, presence of small red oval shaped band on the ventral side of fourth and fifth segment. Antenna and antennules are white. Eye cornea margined with slightly purplish with black spot and stalks white. First and second pereiopods are entirely white, first pereiopod with fingers blue, posterior margin of carpus and anterior margin of merus are slightly bordered with blue. Second pereiopods with deep purple on the fingers of dactyli, anterior and posterior borders of propodus, carpus, merus with purple or blue. Ambulatory legs are white; dactylus and anterior half of propodus are slightly reddish. Anterior border of telson and last abdominal segment red, exopod of the uropods with small distinct deep purple spot, endopods are white except the posterior margin with slight yellowish tinge.

Male. Transparent body and rostrum white, saddle-like white transverse bands are absent instead presence of four transverse bands on the ventral side, which is visible through the transparent body. Dorsal hump of third abdominal segment bears a small distinct patch anteriorly margined with red. Fourth and fifth abdominal segment with oval shaped white patch dorsally. Other color patterns are similar as in female specimen.

Host. These shrimps are associated with a variety of invertebrates like Catalaphyllia plicata (Scleractinia) and Dofleinia armata (Actiniaria) ( Bruce, 1979). Also associated with hydroid Aglaophenia whiteleggei, Octocorallia Lobophyton sp., Plerogyra sp., actiniarians Entacmaea quadricolor , Antheopsis maculata , Macrodactyla sp., and Cerianthus sp. ( Marin et al., 2004; Okuno and Bruce, 2010). In the present study, A. magnificus was found associated with sea anemone Entacmaea quadricolor .

Distribution. Heron island, Australia, Philippines, Indonesia, southern Japan, Papua New Guinea, Andaman Sea and New Caledonia. ( Marin et al., 2004; Bruce, 2007; Okuno and Bruce, 2010). Now in India.

Remarks. Discovery of Ancylomenes magnificus in Tuticorin, Tamilnadu constitutes the first record of this species in Indian waters. Present specimen agrees well with the description of Bruce (1979) except some changes on the color patterns. The saddle-like transverse bands are margined with red color in our specimen compared to the deep purple color in the type material (cf. Bruce, 1979; pg. 203). The color variations of adult female and adult male are explained in detail. A. magnificus is closely related to A. holthuisi , but readily distinguished by the characteristic color patterns (but see Bruce, 1979 for detailed explanation).

Figures

FIGURE 3. A, Ancylomenes magnificus Bruce, ovigerous female (dorsal view) from Gulf of Mannar; B, A pair of Periclimenes brevicarpalis Schenkel (dorsal view) with a host anemone Heteractis magnifica from Lakshadweep; C, P. s o ror Nobili, ovigerous female (dorsal view) on the ventral side of cushion sea star Culcita sp. from Lakshadweep; D. same (dorsal view).