Uroptychus laperousazi, 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 : 47-49

Uroptychus laperousazi n. sp. ( Fig. 12 )

Type material. HOLOTYPE: SAM C6084 , ovigerous female (8.4 mm), 231 km S of Eucla, Great Australian Bight , South Australia, 33°45’S, 129°17’E, 999–1110 m, Stn 28, FV Adelaide Pearl, K. Gowlett­Holmes, 1 Aug 1988 . PARATYPES: SAM C6085 , 1 male (10.9 mm), type locality ; SAM C6073 , 9 males (6.8–10.1 mm), 13 females (5.5–10.0 mm), 222 km S of Eucla, Great Australian Bight , South Australia, 33°39’S, 129°50’E, 984– 1015 m, from black coral, FV Longva, K. Gowlett­Holmes, 12 Dec 1989 .

Diagnosis. Carapace excluding rostrum distinctly broader than long; lateral margins slightly crenulate, distinctly convex, broadest posterior to midlength; with short, anteriorly directed anterolateral spine. Rostrum triangular, about half length of remaining carapace. Outer orbital angle produced to small tooth, not extending anteriorly beyond anterolateral spine. Dorsum unarmed. Sternite 3 not depressed, anterior margin with deep V­shaped emargination. Basal antennal segment without outer spine; ultimate and penultimate segments armed; antennal scale extending almost to apex of ultimate peduncle segment. Pereopods 2–4 similar; propodi not broadened distally, with 8 or 9 movable spines on distal flexor margin, distalmost paired; dactyli lined with 6–9 triangular, obliquely directed teeth on flexor margin.

Description. Carapace: Breadth exceeding length (excluding rostrum). Lateral margins slightly crenulate, distinctly convex, broadest posterior to midlength; with short, anteriorly directed anterolateral spine; posterior fifth with low, indistinct ridge. Rostrum triangular, apex sharp, about half length of remaining carapace, margins with 1 or 2 minute spines. 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 one­third as long as broad; distal portion posteriorly emarginate, about twice length of proximal portion.

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

Antenna: Basal segment without outer spine. Peduncle not reaching 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 1 or 2 small spines on distal extensor margin and 2 or 3 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 twice 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. Carpus slightly longer than merus and shorter than propodal palm. Merus and ischium without tubercles on inner proximal margin; ischium with small spine on outer margin.

Pereopods 2–4: Setose, becoming shorter distally; carpi and meri unarmed. Propodi not broadened distally, with 8 or 9 movable spines on distal flexor margin, distalmost paired. Dactyli lined with 6–9 triangular, obliquely directed teeth on flexor margin. Carpi of pereopods 2–3 about 0.6 merus length and 0.6 propodus length. Carpus of pereopod 4 about 0.7 merus length, about 0.5 propodus length.

Ovum : 1.3 mm diameter.

Etymology. Named after Thierry Laperousaz, South Australian Museum, Adelaide, for his hospitality during many visits to the museum.

Remarks. Uroptychus laperousazi n. sp. strongly resembles U. latus n. sp. but differs in lacking the outer spine on the basal antennal segment. Uroptychus laperousazi also differs from U. latus in having a sharp instead of rounded rostral apex, but that character should be treated with caution until further specimens become available. The apex of the rostrum is may have been damaged.

Uroptychus laperousazi and U. latus also resemble U. patulus n. sp. in the short, broad carapace and broad V­shaped anterior sternal emargination, but differ in having well spaced, upright spines, instead of short, triangular serrations on the inner margins of the dactyli of pereopods 2–4.

Distribution. Presently known only from the Great Australian Bight, south of Eucla, South Australia at 984–1110 m depth.

Figures

FIGURE 12. Uroptychus laperousazi n. sp., holotype female, 8.4 mm, SAM C6084. 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 = 2 mm, C– F = 1 mm, G–H = 0.5 mm.