Uroptychus worrorra, Mccallum, Anna W. & Poore, Gary C. B., 2013

Mccallum, Anna W. & Poore, Gary C. B., 2013, Chirostylidae of Australia’s western continental margin (Crustacea: Decapoda: Anomura), with the description of five new species, Zootaxa 3664 (2), pp. 149-175 : 169-170

Uroptychus worrorra sp. nov.

( Figs. 10 , 12 I)

Type material. Holotype: Female, ovigerous (cl 10.0 mm), Western Australia, off the Kimberley plateau (13°15.9'S, 123°22.45'E – 13°16.35'S, 123°21.4'E), 394– 390 m, 0 7 Jul 2007 (stn SS05/2007 180), CSIRO acquisition number 0 38, NMV J61766 .

Paratypes: Collected with holotype, 2 males (cl 9.7, 9.6 mm) 2 ovigerous females (cl 10.0, 7.8 mm), NMV J56119 .

Diagnosis. Carapace excluding rostrum broader than long; width between anterolateral margins 0.6 times that of broadest carapace width; lateral margins with anterolateral spine and 7 or 8 lateral spines (5 large); dorsum smooth, with numerous setose scales; gastric region without epigastric spines or tubercles. Rostrum narrow triangular, about half remaining carapace length. Sternite 3 anterior margin concave, with pair of small or obsolescent submedian spines separated by U-shaped notch. Antennal peduncle ultimate article about 1.7 times as long as penultimate article; both articles with distal spine. Antennal scale extending beyond ultimate article of peduncle. Chelipeds slender, 3–4 times carapace length. Pereopods 2–4 similar; merus and carpus with setose scales; propodus not broadened distally, flexor margin ending in pair of spines preceded by 4–5 movable spines; dactylus with 14–16 closely spaced, obliquely directed corneous spines, penultimate markedly broader than others.

Description. Carapace: Carapace excluding rostrum, 0.8 times as long as wide; width between anterolateral margins 0.6 times that of broadest carapace width; lateral margins moderately convex, divergent, with strong anteriorly directed anterolateral spine and 7 or 8 lateral spines; anterior 2 lateral spines small, third spine large, slender, at base of indistinct cervical groove, with small spine at base; remaining spines large and slender, decreasing in size posteriorly; outer orbital angle with small spine; dorsum smooth, with numerous setose scales, and a few spine like tubercles in hepatic region; dorsal surface without depression between indistinct gastric and cardiac regions. Rostrum sharp triangular, about 0.4 as long as remaining carapace, lateral margins smooth. Pterygostomian flap anterior margin with small spine.

Sternum: Plastron about as long as wide, slightly widening posteriorly. Sternite 3 anterior margin concave, with pair of small or obsolescent submedian spines separated by U-shaped notch; anterolateral angle acute, lateral margin with 1 or 2 small spines. Sternite 4 with anterolateral margins spinose, reaching anteriorly to submedian spines of sternite 3; surface with one continuous row of setae along transverse ridge.

Abdomen: Somites smooth, with scattered setae. Telson 3 times as long as wide; distal portion medially emarginate, about 1.5 times as long as proximal article.

Eyes: Cornea not dilated, about one-third length of peduncle; extending beyond midlength of rostrum.

Antenna: Peduncle extending to distal quarter of rostrum. Article 2 with outer spine; ultimate article about 1.7 times as long as penultimate article, both with slender distal spine at least 1/3 length of article. Antennal scale 1.75 times broader than ultimate peduncle article, reaching third segment of flagellum.

Maxilliped 3: Dactylus and propodus unarmed. Carpus with 2 small spines on extensor surface and 2 distal extensor spines. Merus with 1 small spine on extensor surface and 2 distal extensor spines. Ischium with crista dentata denticulate along entire length of margin, spines closely set distally. One distal spine on basis.

Pereopod 1 (cheliped): With rows of setose scales and tubercles; about 3.3 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: Moderately setose, similar, decreasing in size posteriorly; pereopod 3 merus length 0.9 times that of pereopod 2 merus; pereopod 4 merus length 0.95 that of pereopod 3 merus. Meri and carpi with setose scales. Meri with distal flexor spine; carpi with distal extensor spine. Propodi not broadened distally, flexor margin ending in pair of spines preceded by 2–4 movable spines on distal flexor margin. Dactyli exceeding half propodus length; with 14–16 closely spaced, obliquely directed corneous spines, penultimate markedly broader than others.

Ovum: 0.9 mm (~ 50 eggs).

Colour. Body pale, pereopods pale pink.

Etymology. After the indigenous Worrorra people of the Kimberley (noun in apposition).

Distribution. North-western Australia, off the Kimberley plateau, 390– 394 m.

Remarks. Uroptychus worrorra closely resembles U. cardus Ahyong & Poore, 2004 , U. dentatus Balss, 1913 , and U. occultispinatus Baba, 1988 . The new species differs from U. occultispinatus in having 3–6 spines instead of one movable spine on distal flexor margin of the propodi of the walking legs, and in the shape of the lateral spines on the carapace which are more slender and long in U. worrorra . Uroptychus dentatus and U. cardus both differ from U. worrorra as they possess a transverse field of spines or granules across the gastric region of the carapace. In addition, U. cardus is sparsely setose on the cheliped and has a shorter rostrum (0.4 vs 0.5 remaining carapace); and U. dentatus lacks a distinct notch on the sternum, lacks anterolateral spines on sternite 4, and lacks spines on the carpus and merus of the third maxilliped (Baba, 1990). The type locality of U. dentatus is off the east African coast at 1079 m (now Somalia). The species has been recorded subsequently from Madagascar by Baba (1990) and the southern Nias Canal, west of Sumatra, Indonesia (Doflein & Balss, 1913). The Indonesian Valdivia material comprises two juvenile males which differ from adults in the smooth non-granulose carapace, the first pereopods having a few ventral spinelets, and fewer setae on the body and appendages, real differences from similar-sized specimens from Madagascar (Baba, 1990). Their locality suggests these juveniles may belong to U. worrorra , although the presence of spinules on pereopod 1 may warrant a new species.

Figures

FIGURE 10. Uroptychus worrorra sp. nov., female (10.0 mm), NMV J 61770. A, carapace and abdomen, dorsal. B, carapace, lateral. C, sternum, anterior. D, telson. E, right antenna, ventral. F, maxilliped 3, merus and ischium, right, lateral. G, maxilliped 3 basis and ischium, right, ventral. H, pereopod 1, left. I, pereopod 1, proximal ventral. J – L, Pereopods 2 – 4. Scales = 1 mm.

FIGURE 12. A, Uroptychus spinirostris (Ahyong and Poore, 2004), NMV J 61768. B, Uroptychus ciliatus (Van Dam, 1933), NMV J 55998. C, Uroptychus flindersi Ahyong & Poore, 2004, NMV J 54995. D, Uroptychus joloensis Van Dam, 1939, NMV J 57247. E, Uropychus nigricapillis Alcock, 1901, NMV J 57245. F, Uroptychus scandens Bendedict, 1902, NMV J 57249. G, Uroptychus taylorae sp. nov. NMV J 55000. H, Uroptychus vandamae Baba, 1988, NMV J 57248. I, Uroptychus worrorra sp. nov., NMV J 56119.