Uroptychus cardus, 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 : 31-34

Uroptychus cardus n. sp. ( Fig. 7 )

Uroptychus sp. MoV2676.– Poore, Hart, Taylor & Tudge, 1998: 69.

Type material. HOLOTYPE: NMV J44744 , female (15.9 mm), J1 Seamount, 82.5 km SSE of SE Cape, Tasmania, 44°14.4’S, 147°21.6’E, 1200 m, epibenthic sled, T. Stranks et al., 27 Jan 1997 . PARATYPES: NMV J44743 , 1 female (12.2 mm), J1 Seamount, Tasmania, 83.8 km SSE of SE Cape, 44°16.2’S, 147°19.8’E, 987 m, epibenthic sled , T. Stranks et al., 27 Jan 1997 ; NMV J39633 , 2 ovigerous females (14.1–14.7 mm), J1 Seamount, 83.8 km SSE of SE Cape, Tasmania, 44°16.2’S, 147°19.8’E, 987 m, epibenthic sled , T. Stranks et al., 27 Jan 1997 .

Diagnosis. Carapace excluding rostrum longer than broad; lateral margin with anterolateral spine and 7 or 8 lateral spines; dorsum rugose, with numerous setose scales or tubercles, with transverse field of 11–19 spines across epigastric region, laterally largest. Rostrum triangular. Sternite 3 anterior margin deeply concave with narrow U­shaped median notch. Antennal basal segment with outer spine; ultimate and penultimate segments with distal spine. Antennal scale extending beyond ultimate segment of peduncle. Cheliped rugose and sparsely setose. Pereopods 2–4 similar; merus with setose scales; propodus not broadened distally, with 5–7 movable spines on distal flexor margin, distalmost paired; dactylus with 16–20 small, closely spaced, obliquely directed corneous spines, penultimate markedly broader than others.

Description. Carapace: Length (excluding rostrum) greater than breadth. Lateral margins convex, divergent; with strong anteriorly directed anterolateral spine and 7 or 8 lateral spines. Anterior 2 lateral spines small, third spine large, stout, at base of indistinct cervical groove, remainder spines stout, decreasing in size posteriorly. Rostrum triangular, about 0.4 as long as remaining carapace, lateral margins smooth, dorsally with shallow concavity. Outer orbital angle obtuse. Dorsum rugose, with numerous setose scales or tubercles, with transverse field of 11–19 spines across epigastric region, with largest spines either side of midline. Pterygostomian flap with acute anterior angle and small spinules or scales 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 U­shaped median notch, anterolateral angle acute, flanked by 1 or 2 small spines. Sternite 4 (at base of pereopod 1) with anterolateral margins acute, produced anteriorly to base of spine on lateral margin of sternite 3.

Abdomen: Segments glabrous. Telson half as long wide; distal portion medially emarginate, about 1.5 times as long as proximal segment.

Eye: Cornea not dilated, about two­thirds length of peduncle; not reaching beyond midlength of rostrum.

Antenna: Basal segment with outer spine. Peduncle extending to distal third of rostrum. Ultimate segment about twice as long as penultimate segment, both with distal spine. Antennal scale wider than opposite peduncular segments, extending beyond ultimate segment of peduncle.

Maxilliped 3: Dactylus and propodus unarmed. Carpus with 2 or 3 small spines on extensor surface and distal extensor spine. Merus with 2–4 spines on distal flexor margin and larger distal flexor spine. Ischium with crista dentata denticulate along entire margin, becoming finest distally.

Pereopod 1 (cheliped): Sparsely setose; about 3.5 times carapace length. Propodus with irregular, setose scales; palm 3 times as long as high, about twice as long as pollex. Fingers crossing, occlusal margins dentate and each with low process proximally. Carpus and merus covered with setose scales or small spines; with larger spinules on distal margin. Inner margin of merus with 2 rows of stout spines. Ischium with slender distolateral spine.

Pereopods 2–4: Similar, slightly decreasing in length posteriorly. Meri and carpi with setose scales. Meri with upper and distal flexor spine on pereopods 2–3. Propodi about 2.5 times length of carpus, not broadened distally, with 5–7 movable spines on distal flexor margin, distalmost paired. Dactyli exceeding half propodus length; with 16–20 small, closely spaced, obliquely directed corneous spines, penultimate markedly broader than others.

Ovum : 1.4 mm diameter.

Etymology. Named cardus , from the Latin meaning ‘thistle’, alluding to the rugose or spiny dorsal and lateral surfaces of the carapace and chelae of the species.

Remarks. Uroptychus cardus n. sp. closely resembles U. dentatus Balss, 1913 , described from Indonesia, and U. occultispinatus Baba, 1988 , from Japan and the Philippines. The new species differs from U. occultispinatus in having a transverse field of strong spines across the gastric region of the carapace, in bearing 2 or 3 spines on the flexor margin of the merus of the third maxilliped in addition to the distal extensor and distal flexor spines, and in having 5–7 instead of 1 movable spines on distal flexor margin of the propodi of the walking legs. Uroptychus cardus differs from U. dentatus in having a transverse field of spines across the gastric region of the carapace, and in bearing spines on the carpus and merus of the third maxilliped. In contrast to U. cardus , U. dentatus bears a row of small tubercles or granules on the gastric region of the carapace and lacks spines on the carpus and merus of the third maxilliped ( Baba 1990).

Uroptychus cardus differs from all other Australian congeners that have marginal carapace spines in having a rugose, tuberculate dorsum and in the higher number of spines lining the flexor margins of the dactyli of pereopods 2–4 (16–20 vs. 6–11). Uroptychus cardus was listed by Poore et al. (1998) as “ Uroptychus sp. MoV2676”, one of numerous decapods collected from the seamounts off southeastern Tasmania by the RV Southern Surveyor in 1997.

Distribution. Known only from “J1” Seamount, southern Tasmania at 987–1200 m depth.

Figures

FIGURE 7. Uroptychus cardus n. sp., holotype female, 15.9 mm NMV J44744. A, dorsum. B, anterior carapace, right lateral. C, cheliped right proximal ventral. D, sternum. E, telson. F, maxilliped 3, right lateral. G, crista dentata, right. H, antenna, right ventral. A–C = 5 mm, D–F = 2.5 mm, G–H = 1.3 mm.