Uroptychus flindersi, Ahyong & Poore, 2004

Ahyong, Shane T. & Poore, Gary C. B., 2004, The Chirostylidae of southern Australia (Crustacea: Decapoda: Anomura), Zootaxa 436 (1), pp. 1-88 : 37-40

Uroptychus flindersi n. sp. ( Fig. 9 )

Type material. HOLOTYPE: SAM C6071 , ovigerous female (10.9 mm), 47 km W of Richardson Point , Tasmania, 41°14’S, 144°07’E, 520 m, demersal trawl, stn 45, FV Soela, W. Zeidler, 19 Oct 1984 . PARATYPES: NMV J23880 , 1 male (10.0 mm), off NW Tasmania, 41°32.30’S, 144°22.20’E, 556 m, trawl, S01/85/23, 29 Jan 1985 ; SAM C6068–6069 , 1 male (8.5 mm), 2 ovigerous females (8.6–10.9 mm), 46 km W of Richardson Point , Tasmania, 500 m, demersal trawl, stn 51, FV Soela, W. Zeidler, 20 Oct 1984 ; SAM C6070 , 1 male (11.6 mm), 167 km E of Cape Arid , Western Australia, 34°09’S, 124°55’E, 620–714 m, trawled, stn 12, FV Adelaide Pearl, K. Gowlett­Holmes et al., 30 Jul 1988 .

Diagnosis. Carapace excluding rostrum distinctly longer than broad; lateral margins with anterolateral spine and distinct, bifid spine at base of cervical groove followed by 7 or 8 small teeth or serrations. Rostrum sharply triangular, less than half as long as remaining carapace. Dorsum unarmed except for cluster of minute spinules above lateral bifid spine. Sternite 3 strongly depressed, anterior margin narrow, with pair of median spines. Eyestalks reaching beyond midlength of rostrum. Antennal basal segment with acute tooth on outer margin; ultimate peduncle segment with small distal spine; penultimate segment unarmed. Antennal scale extending to apex of ultimate peduncle segment. Merus of the third maxilliped with distolateral spine. Pereopods 2–4 propodus not broadened distally, with 9–11 movable spines on flexor margin, distalmost paired; dactylus with 9 or 10 triangular, obliquely directed, corneous teeth on flexor margin.

Description. Carapace: Length (excluding rostrum) distinctly greater than breadth. Lateral margins subparallel; with strong anteriorly directed anterolateral spine and distinct, bifid spine at base of cervical groove followed by 7 or 8 small teeth or serrations. Rostrum sharply triangular, less than half as long as remaining carapace, margins unarmed. Outer orbital angle produced to small acute spine extending about to level of anterolateral spines. Dorsum smooth and unarmed except for cluster of minute spinules above lateral bifid spine; rostrum with broad, shallow concavity; posterior quarter with shallow lateral ridge. Pterygostomian flap with small anterior spine.

Sternum: Plastron about as long as broad, widening posteriorly. Sternite 3 (at base of maxilliped 3) strongly depressed, anterior margin narrow, with pair of median spines; outer lobes of emargination rounded, with short tooth on outer basal margin. Sternite 4 (at base of pereopod 1) with distinct anterolateral tooth extending anteriorly to level of base of emargination of sternite 3; margins irregular.

Abdomen: Segments glabrous. Telson length exceeding half breadth; distal portion posteriorly emarginate, about 1.8 times length of proximal portion.

Eye: Cornea moderately dilated, about half­length of peduncle; reaching beyond midlength of rostrum.

Antenna: Basal segment with acute tooth on outer margin. Peduncle extending to distal quarter of rostrum. Flagellum about twice as long as peduncle. Ultimate segment about 3 times length of penultimate segment; with small distal spine. Penultimate segment unarmed. Antennal scale wider than opposite peduncular segments, extending to apex of ultimate peduncle segment

Maxilliped 3: Carpus and merus with small distal tooth of extensor margin. Crista dentata distinctly and evenly serrate, extending onto basis.

Pereopod 1 (cheliped): About 3.5 times carapace length; segments glabrous dorsally and sparsely setose. Propodus with scales; palm about 3 times as long as high, about twice as long as pollex. Fingers crossing, occlusal margins dentate and each with obtuse process proximally. Carpus longer than merus and as long as propodal palm. Carpus, merus and ischium rugose ventrally, with distinct scales. Ischium with large distolateral spine.

Pereopods 2–4: Sparsely setose, similar, slightly decreasing in length posteriorly. Meri with spinose distal margins. Carpi about two­thirds propodi lengths; that of pereopods 2–3 with small distal spines on extensor margin; that of pereopod 4 unarmed. Propodi not broadened distally, with 9–11 movable spines on flexor margin, distalmost paired. Dactyli with 9 or 10 fixed, triangular, obliquely directed, corneous teeth on flexor margin.

Ovum : 1.5 mm diameter.

Etymology. Named after the English explorer, Matthew Flinders (1774–1814), the first to circumnavigate Australia, and after whom the Flindersian biogeographic subprovince ( Knox 1963, Womersley 1990) was named. The distribution of U. flindersi generally corresponds to the Flindersian subprovince.

Remarks. Uroptychus flindersi n. sp. most closely resembles U. sibogae Van Dam, 1933 , from Indonesia and U. longioculus Baba, 1990 , from Madagascar in having elongate eyestalks, the relatively broad and dorsally excavate rostrum, laterally spinose carapace and the arrangement of dactylar spines on the walking legs. The new species resembles U. longioculus and differs from U. sibogae in the following: the postorbital carapace length is distinctly longer than instead of about as long as wide; the merus of the third maxilliped bears a distolateral spine; the notch between the anterior submedian spines of the third sternite is distinctly shallower; the eyes do not reach the apex of the rostrum; the basal antennal segment bears an acute outer tooth; and the ultimate segment of the antennal peduncle bears a distal spine. Uroptychus flindersi resembles U. sibogae and differs from U. longioculus in the following features: the merus of the first walking leg is shorter than instead of longer than the postorbital carapace length; and the spination of the lateral margin of carapace in the posterior portion is less pronounced. Uroptychus flindersi differs from both U. longioculus and U. sibogae in having scales and tubercles on the ventral surface of the carpus and merus of the cheliped, and in having a bifid instead of single lateral carapace spine at the base of the cervical groove.

Distribution. Northwestern Tasmania and the vicinity of Cape Arid, Western Australia, at 520–714 m depth.

Figures

FIGURE 9. Uroptychus flindersi n. sp., holotype female, 10.9 mm, SAM C6071. A, dorsum. B, anterior carapace, right lateral. C, cheliped right proximal ventral. D, telson. E, sternum. F, maxilliped 3, right lateral. G, crista dentata, right. H, antenna, left ventral. A–C = 5 mm, D–F = 2.5 mm, G–H = 1.3 mm.