Uroptychus nowra, 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 : 63-66

Uroptychus nowra n. sp. ( Fig. 18 )

Type material. HOLOTYPE: NMV J17064 , female (rostrum broken; orbital carapace length 6.4 mm), off Nowra , New South Wales, 35°00.00’S, 151°16.30’E, 1100 m, SLOPE 9 , 5 m otter trawl, M. Gomon et al., 15 Jul 1986.

Diagnosis. Carapace excluding rostrum broader than long; lateral margins convex, divergent; with strong anteriorly directed anterolateral spine and 9 lateral spines; anterior 2 lateral spines small, third spine large, stout, at base of indistinct cervical groove, followed by 2 small spines and 4 large spines. Rostrum triangular, distinctly exceeding half remaining carapace length; ventrally carinate; lateral margins with at least 1 or 2 spinules. Outer orbital angle produced to a small spine. Dorsum minutely granular, sparsely setose laterally, unarmed except for a minute spine above each anterolateral spine. Sternite 3 anterior margin deeply concave with narrow median notch flanked either side by a small spine. Basal antennal segment with inner and outer spine. Ultimate segment of antennal peduncle about twice as long as penultimate segment, both with distal spine. Antennal scale extending almost to midlength of ultimate segment of peduncle. Pereopod 2 distinctly more slender than pereopod 4. Pereopod 4 dactylus with 12 small, closely spaced, obliquely directed corneous spines, penultimate markedly broader than others.

Description. Carapace: Breadth greater than length (excluding rostrum). Lateral margins convex, divergent; with strong anteriorly directed anterolateral spine and 9 lateral spines. Anterior 2 lateral spines small, third spine large, stout, at base of indistinct cervical groove, followed by 2 small spines and 4 large spines. Rostrum triangular, broken but distinctly exceeding half the remaining carapace length; ventrally carinate; lateral margins with at least 1 or 2 spinules. Outer orbital angle produced to a small spine. Dorsum minutely granular, sparsely setose laterally, unarmed except for a minute spine above each anterolateral spine. Pterygostomian flap with slender anterior spine and small spinules on proximal surface.

Sternum: Plastron about as long as wide, slightly widening posteriorly. Sternite 3 (at base of maxilliped 3) depressed, anterior margin deeply concave with narrow median notch flanked either side by a small spine, anterolateral angle acute, outer margin irregular. Sternite 4 (at base of pereopod 1) with anterolateral margins acute, not produced anteriorly, margins irregular with 2 or 3 small spines.

Abdomen: Segments setose. Telson about half as long as broad; distal portion posteriorly emarginate, about twice length of proximal portion.

Eye: Cornea not dilated, about two­thirds length of peduncle; partially concealed by rostrum.

Antenna: Basal segment with inner and outer spine; ultimate segment about twice as long as penultimate segment, both with distal spine. Antennal scale with outer spine at midlength, wider than opposite peduncular segments, extending almost to midlength of ultimate segment of peduncle.

Maxilliped 3: Dactylus and propodus unarmed. Carpus with small distal extensor tooth. Merus with 2 spines on distal flexor margin and distal extensor spine. Ischium with crista dentata finely and evenly denticulate along proximal three­quarters.

Pereopod 1 (cheliped): Slender, at most 3.5 times carapace length; all segments rugose and sparsely setose. Propodus with irregular, setose scales; palm about eight times as long as high, about three times as long as pollex. Fingers crossing, occlusal margins dentate and each with low process proximally. Carpus as long as propodal palm, sparsely covered with setose scales; upper distal margin with distinct spine flanked on either side by smaller spine. Merus sparsely covered with setose scales; distal margins spinous. Ischium with serrated inner and spinous outer distal margin.

Pereopods 2–4: Pereopod 3 unknown. Pereopod 2 distinctly more slender than pereopod 4; merus extensor margin denticulate; carpus unarmed, slightly exceeding half length of merus, longer than propodus; propodus smooth, with 3 movable spines on distal flexor margin, distalmost paired; dactylus about two­thirds as long as propodus, with 2 distal spines and fine distal setae. Pereopod 4 merus with denticulate extensor and flexor margins, most pronounced dorsally; carpus slightly exceeding one­third merus length about half propodus length, with 3 spines on extensor margin; propodus with 3 movable spines on distal flexor margin, distmost paired; dactylus exceeding half propodus length, with 12 small, closely spaced, obliquely directed corneous spines, penultimate markedly broader than others.

Ovum : 1.4 mm diameter.

Etymology. Nowra is an Aboriginal word meaning black cockatoo; this species is named for the city of that name, owing to its proximity to the type locality; noun in apposition.

Remarks. Uroptychus nowra n. sp. is a member of the spinimarginatus group ( Baba 1977a) characterised by the laterally directed carapace spines and strongly elongate rostrum. The first walking leg in U. nowra is distinctly more slender than the second walking leg, with the dactylus unarmed on its flexor margin indicating a close relationship to U. albatrossae Baba, 1988 , U. benedicti Baba, 1977a , U. grandirostris Yokoya, 1933 , U. mortenseni Van Dam, 1939 and U. spinulifer Van Dam, 1940 . Uroptychus nowra differs from U. mortenseni in lacking the dense covering of fine setae on the carapace and legs, from U. spinulifer and U. benedicti in lacking the covering of dorsal spinules on the carapace, and from U. albatrossae and U. grandirostris in the short antennal scale which reaches almost to the midlength instead of beyond the apex of the distal peduncle segment.

Distribution. Known only from off Nowra, New South Wales, at 1100 m depth.

Figures

FIGURE 18. Uroptychus nowra n. sp., holotype female, orbital carapace length 6.4 mm, NMV J17064. A, dorsum. B, anterior carapace, right lateral. C, cheliped, proximal right lateral. D, sternum. E, telson. F, maxilliped 3, right lateral. G, crista dentata, right. H, antenna, right ventral. Scale A–C = 4 mm, D–F = 2 mm, G–H = 1 mm.