Oratosquillina gravieri

Oratosquilla gravieri

Squilla oratoria.—Gravier, 1937:183 [part].—Dawydoff, 1952: 145 [part; not Squilla oratoria de Haan, 1844].

MATERIAL.—Baie d'Along [Yung Ha Long, 20°55′N, 107°05′E], Gulf of Tonkin, North Viet Nam; Dawydoff, leg.; Oct 1931; holotype: 1 , TL 92 mm (MNHNP).

DESCRIPTION.—Size moderate, total length less than 100 mm. Body appearing smooth, minutely punctate under magnification.

Eye (Figure 6b) of moderate size, cornea bilobed, set obliquely on stalk. Eyes not extending to end of first segment of antennular peduncle. Corneal index 394.

Antennular peduncle almost as long as carapace. Dorsal processes of antennular somite produced into anterolaterally directed spines.

Rostral plate (Figure 6a) with length and width subequal, appearing elongate, lateral margins converging on rounded apex. Median carina absent.

Anterior width of carapace less than half median length. Anterolateral spines of carapace (Figure 6a) extending to, but not overreaching, base of rostral plate. Median carina interrupted at anterior bifurcation, branches of bifurcation distinct. Intermediate carinae turning toward laterals, not extending to anterior margin.

Dactylus of claw with 6 teeth (one claw of holotype regenerating, with 8 teeth), outer margin sinuous, with low, obtuse projection basally. Dorsal ridge of carpus (Figure 6c) undivided. Inferodistal angle on outer face of merus produced into slender spine.

Exposed thoracic somites (Figure 6d) each with unarmed submedian and intermediate carinae. Lateral process of fifth somite bilobed, anterior lobe a slender, anteriorly directed spine, posterior lobe smaller, triangular, apex acute but not sharp, directed laterally. Lateral process of sixth somite strongly bilobed, anterior lobe acute, slender, triangular, posterior lobe larger, triangular, apex acute but not spined. Lateral process of seventh somite bilobed, anterior lobe slightly shorter than that of sixth somite, triangular, posterior lobe larger, triangular, apex acute, unarmed.

Submedian carinae subparallel on fifth abdominal somite. Abdominal carinae spined as follows: submedian 5–6, intermediate 4–6, lateral 3–6, marginal 1–5.

Telson flattened, longer than broad. Prelateral lobe longer than margin of lateral tooth. Denticles (Figure 6e) subquadrate or rounded, unarmed, 4, 5, 1. Ventral surface with short postanal keel.

Uropod broad, proximal segment of exopod subequal in length to distal, with 9 movable spines on outer margin, distalmost short, not extending to midlength of distal segment. Lobe on outer margin of inner spine of basal prolongation (Figure 6f) small, narrower than adjacent spine, margin concave, apex rounded.

COLOR.—Pattern not distinctive in holotype. Posterior margins of carapace, posterior 3 thoracic and anterior 5 abdominal somites each with line of dark pigment. Bases of marginal teeth of telson dark. Dark spot at articulation of segments of uropodal exopod, pigment extending onto inner half of distal segment, endopod with distal third dark.

MEASUREMENTS.—Only specimen examined, male holotype, TL 92 mm. Other measurements of holotype: CL 20.1, anterior width 9.1; cornea width 5.1; antennular peduncle length 19.6; rostral plate length 3.0, width 3.1; telson length 17.4, width 15.7.

DISTRIBUTION.—Known only from the type-locality, the Baie d'Along, Gulf of Tonkin.