Cryptodromia mariae Ihle, 1913

Mclay, Colin L., 2001, Dynomenidae and Dromiidae (Decapoda, Brachyura) from Guam, Philippine Islands, Tonga and Samoa, Zoosystema 23 (4), pp. 807-856 : 834-835

Cryptodromia mariae Ihle, 1913

Cryptodromia mariae Ihle, 1913: 38 , pl. 1, figs 5, 6. — Buitendijk 1950: 61. — Sakai 1983: 3, pl. 5, fig. A. — McLay 1993: 199 (key).

MATERIAL EXAMINED. — Western New Guinea. Siboga Expedition , stn 164, 1°42.5’S, 130°47.50’E, 32 m, 1 8.0 × 8.7 mm, 1 (ovig.) 11.4 × 12.1 mm (Syntypes) ( ZMA, De 102.952).

Philippine Islands. Sulu Archipelago, Albatross, stn D 5146, 5°46.40’N, 120°48.40’E, 44 m, 16.II.1908, 1 7.8 × 8.2 mm ( USNM).

SIZE. — Only two males and five females are known. The syntypes are the largest known for both sexes: 8.0 × 8.7 mm for males and 11.4 × 12.1 mm for females ( Ihle 1913). Sakai (1983) gave measurements of 11.5 × 11.5 mm but not the sex of the specimen. The syntype female is ovigerous, carrying 30 eggs, diameter= 1.1 mm. These relatively large eggs suggest that C. mariae may well have abbreviated development.

DEPTH. — The syntypes were collected from 32 m and other specimens have been collected from the intertidal. The Philippine specimen came from 44 m and thus extends the known depth range.

DISTRIBUTION. — New Guinea, Singapore, and Japan. C. mariae is a new record for the Philippine Islands.

DESCRIPTION

Carapace longer than wide, evenly convex, smooth, regions not defined, branchial groove not distinct. Transverse groove behind cardiac region marked in female. Body covered with short soft tomentum. Rostrum tridentate, medi- an tooth acute, very small and strongly deflexed, although visible dorsally. Lateral rostral teeth large, projecting, horizontally direct- ed, broadly triangular, separated by U-shaped sinus. Frontal groove not marked. Anterolateral margin begins at level of orbital corner bears two or three small, sub-acute teeth, number can be different on each side, depending upon development of second tooth. Second tooth can be represented by a thin edentate flange. First tooth largest, close to postorbital corner, second tooth smallest (may be absent), mid-way between first and third teeth. Margin between second and third teeth concave. Posterolateral tooth indistinct. Posterolateral margins parallel, posterior margin convex.

Supraorbital margin shallowly concave, interrupted mid-way by small supraorbital tooth. Postorbital corner slightly produced, small orbital fissure separates infraorbital lobe which bears an acute tooth mid-way, only just visible dorsally.

First article of antennule as wide as long in maximum dimensions but narrowed at base and increasing in width distally; second article longer than wide, and along rest of antennule, folded tightly under orbital margin. Basal antennal article wider than long, beaked medially, not gaping; second article much longer than wide, medial corner produced, curved, on which third article is inserted at an angle; third and fourth articles as wide as long. Exopod fixed to second article, tip bilobed, reaching as far as joint between third and fourth article. Sub-hepatic area smooth, concave. Bases of third maxilliped closely approximated. Palp exposed, as long as merus plus one-third of basis. Crista dentata variable: in female syntype eight small teeth on left third maxilliped but on right, five broader distal teeth with proximal border unarmed. In male syntype six small evenly spaced teeth increasing in size distally on right, but on left teeth are grouped distally. Female sternal sutures 7/8 end wide apart on low rounded tubercles joined by narrow ridge just behind chelipeds.

Chelipeds small, carpus with several tubercles on outer surface: superior inner border has small blunt tubercle mid-way and similar larger tubercle at distal corner; inferior border with a larger tubercle and smaller tubercle above it; distal bor- der has two large tubercles. Propodus has one large proximal tubercle, two small tubercles midway on outer face and large projecting tubercle at base of dactyl; superior inner margin produced as small blunt lobe. Fingers naked, white, gaping, cutting edges armed with six blunt teeth, only last three interlocking.

P2 and p3 as long as chelipeds, slender, distal borders of articles produced, angular especially carpi. Dactyli long and curved, inner margins have five small spines increasing in size distally.

P4 and p5 reduced, p4 shortest, dactyli short, strongly curved, opposed by single propodal spine, and spine on outer propodal margin. P5 sub-dorsal.

Male and female telsons wider than long, posterior margin rounded. Posterolateral corners of fourth and fifth abdominal segments produced as subacute lobes. Median area more strongly convex on fourth to sixth segments with small blunt median distal tubercle, larger on last segment. Uropods well-developed, visible externally, occupying onethird of lateral margin in female. Abdominal locking mechanism in male consists of uropods fitting in front of serrated ridge on coxae of p2. No locking mechanism in mature female.

DISCUSSION

A full re-description, based on the male and female syntypes, is given above because the original has not been brought up to date since Ihle (1913). Present day descriptions of dromiids utilize a greater range of characters than formerly. Besides the two original specimens, only five other specimens have been recorded until now. Buitendijk (1950) reported two females, from the vicinity of Singapore, which she compared with Ihle’s syntypes. Variation in anterolateral teeth both within and between specimens was noted. Sakai (1983) reported three specimens from Japan in which the second anterolateral tooth was apparently absent. Distinctive features of C. mariae are the carapace, which is longer than wide, the very small median rostral tooth, scarcely visible from above, tubercles on last three abdominal segments, and the long and slender propodi and dactyli of p2 and p3.