Temnopleurus decipiens ( de Meijere, 1904 )

Hegde, Mahabaleshwar R. & Rivonker, Chandrashekher U., 2013, A new record of Temnopleurus decipiens (de Meijere, 1904) (Echinoidea, Temnopleuroida, Temnopleuridae) from Indian waters, Zoosystema 35 (1), pp. 97-111 : 100-101

Temnopleurus decipiens ( de Meijere, 1904)

Genocidaris decipiens de Meijere, 1904: 76 , pl. 16, figs 264-266.

MATERIAL EXAMINED. — Off Betul fishing jetty, Goa, west coast of India, 15°04’N, 73°55’E, 17-20 m depth, 17 specimens, test diameter ranging from 5.4 to 21.30 mm.

Representative specimens are preserved in 70% ethanol and have been deposited as voucher samples (N = 16) at the Marine Biology Laboratory, Department of Marine Sciences, Goa University.

TYPE LOCALITY. — Labuan Badjo, Flores and Saleh Bay, Indonesia.

HABITAT AND DISTRIBUTION. — Temnopleurus decipiens has been reported from the Philippines, the eastern Indian Ocean ( Clark & Rowe 1971; Marsh & Morrison 2004), the South China Sea ( Lane et al. 2000) and Western Australia ( Marsh & Morrison 2004; Fig. 6 ). Lane et al. (2000) reported this species from depths of 18-40 m around the coastal shelf waters of southern China. The present specimens of T. decipiens (as well as T. toreumaticus ) were found to inhabit a sandy and muddy bottom at 15-20 m depth along the near-shore coastal waters of Goa, but were absent in all estuarine trawls.

DESCRIPTION

Test small, dome-shaped (hemispherical), well sculptured with convex aboral surface; flattened oral surface with sunken peristome ( Fig. 2A ).HTD ranges from 5.42 to 21.30mm (Μ = 14.60± 4.78 mm) and VTD from 2.74 to 12.92 mm (Μ = 8.22 ± 3.15 mm); test width about twice its height (Μ VTD/ HTD ratio = 0.56:1).Test comprises of five pairs of alternately placed ambulacral and interambulacral plates, interambulacral plates placed at about the level of ambulacral plates ( Fig. 2C ). Colouration of the naked test light green to grey ( Fig. 2C ).

Ambulacral plates compound trigeminate, their pore-pairs bearing numerous tube feet (in living specimens) arranged in a straight line forming a single adradial band. Single primary tubercle of each ambulacral plate closed to the pore zone, surrounded by randomly scattered smaller secondary tubercles; tubercles imperforate and distinctly crenulated.

Interambulacral plates covering a slightly larger area of the test than the corresponding ambulacra. Each interambulacral plate having a central primary tubercle surrounded by smaller secondary and miliary tubercles that cover the remainder of the plate ( Fig. 3A ). Primary tubercles imperforate and distinctly crenulated. Wedge-shaped pits located at the angle of the suture, and arranged in a zig-zag manner along the middle of the interambulacrum; lateral extensions of the pits separating the interambulacral plates and reaching the pore-pair zone ( Fig. 3B ); sutural pits near the peristome also conspicuous ( Fig. 3C ).

Peristome large (PSD 35.18 ± 3.33% of HTD), roughly circular in outline with very feeble buccal notches; covered with soft skin, comprising of five pairs of buccal plates with buccal tube feet emanating from them.Aristotle’s lantern of the camarodont type (i.e., with a paired rod-like epiphysis bridging across the upper end of pyramid [ Fig. 3D ]).

Apical system dicyclic, relatively large, but smaller than the peristome (AD 25.14 ± 3.96% of HTD). Apical system with four equal-sized genital plates and one larger genital plate with madreporite. Inner part of each genital plate with small tubercles, outer part naked. The number of tubercles varying with the size of the specimens:1-2 tubercles in specimens <5 mm, whereas 3-4 tubercles in larger specimens. Genital plate wider than long (mean GPH:GPW = 0.87:1). Gonopore roughly circular, approximately ⅓ of genital plate size (GD 32.57 ± 7.40% of GPH) and located at the centre of each genital plate. Ocular plates oval-shaped, placed at the junction of two adjacent genital plates, not reaching the periproct margin; covered with 3-4 small tubercles. Conspicuous triangular pit present at the junction of the ocular plate with its two adjacent genital plates. Periproct roughly circular in outline, approximately �₇ of maximum test diameter (PPD 13.89 ± 2.17% of HTD), composed of brown plates; anal opening eccentric, located opposite genital plate “I”. Suranal plate conspicuous, located opposite the anus, covering approximately half the periproct ( Fig. 3E ). Spines thin, total length not exceeding maximum test diameter (SL 61.80 ± 11.74% of HTD), their surface covered with fine longitudinal ridges. Spine colouration white with alternating reddish or purple bands ( Fig. 4A ).

Figures

FIG. 6. — Geographical distribution of Temnopleurus decipiens (de Meijere, 1904) and Temnopleurus toreumaticus (Leske, 1778). Scale bar: 1 000 km.

FIG. 2. — A, B, oral views of Temnopleurus decipiens (de Meijere, 1904) (A) and Temnopleurus toreumaticus (Leske, 1778) (B); C, D, aboral views of T. decipiens (C) and T. toreumaticus (D). Scale bars: 10 mm.

FIG. 3.— Temnopleurus decipiens (de Meijere,1904):A, primary tubercle;B, interambulacrum;C, sutural pit near peristome;D, pyramid of Aristotle’s lantern; E, apical system. Scale bar: 10 mm.

FIG. 4. — Banding on spines of: A, Temnopleurus decipiens (de Meijere, 1904); B, Temnopleurus toreumaticus (Leske, 1778). Scale bars: 10 mm.