Quollastria ornata

Oratosquilla ornata

HOLOTYPE.—1 , 43.5 mm; China Sea, off Hong Kong; 21°53’N, 115°51′E; 62 fathoms; sand, green mud; Albatross Station 5309; 4 November 1908; USNM 77939.

DIAGNOSIS.—Rostral plate as long as broad, appearing elongate, lacking median carina, apex rounded; eye large, cornea set obliquely on stalk; corneal index 426; anterior width of carapace less than half median length; median carina of carapace interrupted at base of bifurcation, bifurcation opening anterior to dorsal pit; raptorial claw with 6 teeth, dorsal ridge of carpus entire, inferodistal margin of outer face of merus at most angled; mandibular palp and 4 epipods present; lateral process of fifth thoracic somite produced into an anterior spine and a posterior angled lobe; lateral processes of sixth and seventh thoracic somites bilobed, anterior lobe of process of sixth somite truncate laterally, almost as large as posterior lobe; lateral carinae of abdomen not bicarinate; abdominal carinae spined as follows: submedian 5–6, intermediate 3–6, lateral 2–6; telson without supplementary dorsal tubercles; telson denticles 4, 8, 1; proximal segment of exopod longer than distal; inner spine of basal prolongation of uropod with sharp spine on outer margin, proximal margin of spine concave.

DESCRIPTION.—Dorsal surface of body pitted, rugose. Eye large, cornea bilobed, set very obliquely on stalk; eyes not extending to end of first segment of antennular peduncle; ocular scales truncate, inclined laterally, separate mesially; anterior margin of ophthalmic somite flattened; corneal index 426.

Antennular peduncle slightly shorter than carapace; dorsal processes of antennular somite flattened, directed anterolaterally.

Antennal scale slender, curved, elongate, more than half as long as carapace.

Rostral plate slender, length and width subequal, appearing elongate, upturned lateral margins converging on rounded apex; median carina absent.

Carapace narrowed anteriorly, anterior width less than half median length; anterolateral spines strong but not extending to base of rostral plate; median carina interrupted at base of anterior bifurcation, branches of bifurcation distinct; distance from dorsal pit to anterior bifurcation less than distance from bifurcation to anterior margin; portion of median carina posterior to cervical groove with anterior bifurcation; intermediate carinae not extending to anterior margin; posterolateral margin of carapace evenly curved, not angled anteriorly; median posterior margin of carapace with triangular projection.

Dactylus of raptorial claw with 6 teeth, outer margin of dactylus evenly curved; dorsal ridge of carpus undivided; inferodistal margin of outer face of merus with unarmed angular lobe.

Mandibular palp and 4 epipods present.

Exposed thoracic somites with irregular submedian and intermediate carinae; lateral process of fifth somite bilobed, anterior lobe a slender spine, outer margin convex, directed anteriorly, posterior lobe short, bluntly triangular, directed laterally; lateral process of sixth somite bilobed, anterior lobe truncate, almost as large as posterior, apex acute but not spined; lateral process of seventh somite bilobed, anterior lobe triangular, posterior lobe larger, triangular; ventral keel of eighth somite erect, triangular, apex rounded.

Anterior 5 abdominal somites each with 8 carinae, submedians slightly divergent on each somite; sixth somite with 6 pairs of carinae; abdominal carinae spined as follows: submedian 5–6, intermediate 3–6, lateral 2–6, marginal 1–5; sixth somite with small ventrolateral spinule in front of articulation of each uropod and with median tubercle on posterior margin of sternum.

Telson flattened, longer than broad, with 6 elongate marginal teeth; prelateral lobes present, not markedly projecting laterally, shorter than lateral carina; dorsal surface of telson ornamented with median carina and carinae of marginal teeth, supplementary tubercles or carinae absent; median carina low, sharp, with obscure anterior notch and long distal spine; outer submedian denticle rounded, remainder sharp, 4, 8, 1; ventral surface of telson with short but prominent postanal keel.

Uropods slender, elongate, proximal segment of exopod longer than distal, with 9 graded spines on outer margin, distalmost not extending to mid-length of distal segment; endopod slender, inner margin concave; lobe on inner spine of basal prolongation of uropod a slender erect spine, margin concave.

COLOR.—Completely faded in holotype.

MEASUREMENTS.—Female holotype, TL 43.5 mm, only known specimen; other measurements, in mm: carapace length 9.8; anterior width of carapace 4.0; cornea width 2.3; rostral plate length 1.4, width 1.4; telson length 8.2, width 6.9.

DISTRIBUTION.—Known only from the type locality, off Hong Kong in the China Sea, at a depth of 62 fathoms.

Woodmasoni Group

Members of this group can be characterized by their broad, smooth carapace, with the anterior width of the carapace greater than one-half its median length and with the branches of the anterior bifurcation of the median carina of the carapace poorly developed or completely absent. The species assigned to this group include O. woodmasoni (Kemp, 1911), O. massavensis (Kossmann, 1880), O. hesperia (Manning, 1968), and O. tweediei, described below. Only two of the species, O. massavensis and O. hesperia, have the telson ornamented with dorsal tubercles on each side of the median carina of the telson. As in the species of the Oratoria Group, the carpus of the claw is tuberculate in members of the Woodmasoni Group.

In all four of the species placed in this group the body is relatively smooth, not so tuberculate as in O. oratoria, and the carapace is noticeably broader than in any of the other species in the genus. The carapace of O. woodmasoni is comparatively the broadest; in that species, the anterior width, at the base of the anterolateral spines, is usually greater than one-half the length of the carapace and rostral plate combined. In the other three species, the anterior length is greater than one-half the median length of the carapace, excluding the rostral plate.

Further investigation may show that there are several additional species in this complex; Chopra (1934), Holthuis (1941), and Manning (1966) all reported material from different localities that differs from Kemp’s (1913) account of O. woodmasoni based primarily on material from India.

Oratosquilla massavensis is not known to occur in the Indian Ocean adjacent to the Red Sea, but it is apparently very abundant in the latter area (Holthuis, 1967). It has been recorded from Viet Nam by Serène (1953, 1954); but in view of its apparent occurrence only in the Red Sea, Serène’s records may be based on another undescribed species with a broad carapace, smooth body, and dorsal tubercles on the telson.