Uroptychus latus, 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 : 49-52

Uroptychus latus n. sp. ( Fig. 13 )

Type material. HOLOTYPE: NMV J17059 , ovigerous female (9.3 mm), 63 km S of Point Hicks, Bass Strait , Victoria, 38°22.66’S, 149°18.41’E, 1073 m, 3.5 m beam trawl, SLOPE 68 , G. Poore et al., 25 Oct 1988.

Diagnosis. Carapace excluding rostrum distinctly broader than long; lateral margins smooth or slightly irregular, distinctly convex, broadest posterior to midlength; with short, anteriorly directed anterolateral spine; outer orbital angle produced to small tooth, not extending anteriorly beyond anterolateral spine; dorsum unarmed. Rostrum trianguloid, apex rounded, about one­third length of remaining carapace, margins unarmed. Sternite 3 not depressed, anterior margin with deep V­shaped emargination; outer lobes of emargination obtusely angled, crenulate. Basal antennal segment with outer spine; ultimate and penultimate segments armed; antennal scale extending almost to apex of ultimate peduncle segment. Pereopods 2–4 propodi not broadened distally, with 7–9 movable spines on distal flexor margin, distalmost paired; dactyli lined with 8–10 triangular, obliquely directed teeth on flexor margin.

Description. Carapace: Breadth greater than length (excluding rostrum). Lateral margins smooth or slightly irregular, distinctly convex, broadest posterior to midlength; with short, anteriorly directed anterolateral spine; posterior fifth with low, indistinct ridge. Rostrum trianguloid, apex rounded, about one­third length of remaining carapace, margins unarmed. Outer orbital angle produced to small tooth, not extending anteriorly beyond anterolateral spine. Dorsum minutely punctate, finely but sparsely­setose, unarmed. Pterygostomian flap with anterior spine.

Sternum: Plastron broader than long, slightly widening posteriorly. Sternite 3 (at base of maxilliped 3) not depressed, anterior margin with deep V­shaped emargination; outer lobes of emargination obtusely angled, crenulate. Sternite 4 (at base of pereopod 1) with obtuse, crenulate anterolateral margin, extending anteriorly to about midlength of emargination of sternite 3.

Abdomen: Segments minutely punctate. Telson about half as long as broad; distal portion posteriorly emarginate, about 1.5 times length of proximal portion.

Eye: Cornea not dilated, about one­third length of peduncle; not reaching to proximal half of rostrum.

Antenna: Basal segment with outer spine. Peduncle extending almost to apex of rostrum. Flagellum about 1.5 times as long as peduncle. Ultimate and penultimate segments armed; ultimate segment about 1.5 times length of penultimate segment. Antennal scale wider than opposite peduncular segments, extending almost to apex of ultimate peduncle segment.

Maxilliped 3: Dactylus and propodus unarmed. Extensor margin of carpus with small distal tubercle. Merus with small spine on distal extensor margin and 1 or 2 small spines on distal flexor margin. Crista dentata finely serrate for almost full length of ischium, not extending onto basis.

Pereopod 1 (cheliped): Slender, subcylindrical; about 3 times carapace length; setose. Propodus with palm about 3.5 times as long as high, about twice as long as pollex. Fingers crossing, occlusal margins finely dentate; occlusal margin of dactylus with obtuse process proximally; occlusal margin of pollex with low prominence distal to midlength. Carpus longer than merus and shorter than propodal palm. Merus and ischium without tubercles on inner proximal margin; ischium low triangular projection on outer margin.

Pereopods 2–4: Setose, similar, becoming shorter distally; carpus and merus unarmed; carpus of pereopods 2–3 about 0.5 merus length and 0.6 propodus length; carpus of pereopod 4 about 0.6 merus length, about 0.5 propodus length. Propodi not broadened distally, with 7–9 movable spines on distal flexor margin, distalmost paired. Dactyli lined with 8– 10 fixed, triangular, obliquely directed teeth on flexor margin.

Ovum : 1.3 mm diamater.

Etymology. Named latus , from the Latin for ‘broad’, alluding to the broad carapace of the species.

Remarks. U. latus n. sp. resembles U. laperousazi n. sp. and U. patulus n. sp. in the short, broad, carapace and broad V­shaped anterior sternal emargination. Characters distinguishing the three species are outlined under the account of U. laperousazi n. sp.

Distribution. Known only from eastern Bass Strait, Victoria, at 1073 m depth.

Figures

FIGURE 13. Uroptychus latus n. sp., holotype female, 9.3 mm, NMV J17059. A, dorsum. B, anterior carapace, right lateral. C, cheliped ischium, proximal right lateral. D, telson. E, sternum. F, maxilliped 3, right lateral. G, crista dentata, right. H, antenna, right ventral. Scale A–B = 3 mm, C– F = 1.5 mm, G–H = 0.8 mm.