Uroptychus zeidleri, 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 : 82-85

Uroptychus zeidleri n. sp. ( Fig. 26 )

Type material. HOLOTYPE: SAM C6066 , ovigerous female (10.4 mm), 46 km W of Richardson Point , Tasmania, 41°15’S, 144°08’E, 520 m, scampi trawl, stn 51, FV Soela, W. Zeidler, 20 Oct 1984 . PARATYPE: SAM 6082 , 1 female (7.0 mm), type locality .

Diagnosis. Carapace excluding rostrum broader than long; lateral margins divergent; with anterolateral spine and 11–15 lateral spines; anterior 2 lateral spines small, third spine large, stout, at base of indistinct cervical groove, remainder stout, closely spaced, decreasing in size posteriorly; outer orbital angle produced to small acute spine; dorsum smooth, with transverse row of 9 or 10 epigastric spines. Rostrum sharply triangular, with 1 or 2 minute lateral spinules. Sternite 3 anterior margin deeply concave with U­shaped median notch, anterolateral angle crenulate, flanked laterally by short angular projection. Basal antennal segment with 1 or 2 small outer spines; ultimate and penultimate segments with distal spine. Antennal scale extending almost to apex of ultimate peduncle segment. Cheliped segments with setose scales or small spinules. Pereopods 2–4 similar; merus with small spines on extensor margin; propodus broadened distally, with 6 or 7 movable spines on flexor margin; dactylus with 8–10 strong, obliquely directed, corneous teeth on flexor margin.

Description. Carapace: Breadth greater than length (excluding rostrum). Lateral margins divergent; with strong anteriorly directed anterolateral spine and 11–15 lateral spines. Anterior 2 lateral spines small, third spine large, stout, at base of indistinct cervical groove, remainder stout, closely spaced, decreasing in size posteriorly. Rostrum sharply triangular, about half as long as remaining carapace, with 1 or 2 minute lateral spinules. Outer orbital angle produced to small acute spine. Dorsum smooth, with transverse row of 9 or 10 epigastric spines. Pterygostomian flap with strong anterior spine and small spinules of proximal surface.

Sternum: Plastron broader than long, widening posteriorly. Sternite 3 (at base of maxilliped 3) depressed, anterior margin deeply concave with U­shaped median notch, anterolateral angle crenulate, flanked laterally by short angular projection. Sternite 4 (at base of pereopod 1) with short, triangular anterolateral margins.

Abdomen: Segments glabrous. Telson about half as long as broad; distal portion posteriorly emarginate, longer than proximal portion.

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

Antenna: Basal segment with 1 or 2 small outer spines. Peduncle extending to distal quarter of rostrum. Flagellum about twice as long as peduncle. Ultimate segment twice as long as penultimate segment, both with distal spine. Antennal scale wider than opposite peduncular segments, extending almost to apex of ultimate peduncle segment

Maxilliped 3: Dactylus and propodus unarmed. Merus with 3 or 4 distal flexor spines and 1 distal extensor spine. Crista dentata finely denticulate proximally, becoming smooth on distal half of ischium.

Pereopod 1 (cheliped): Setose, about 3 times carapace length. Propodus with scales; palm 3–4 times as long as high, less than twice as long as dactylus. Fingers crossing, occlusal margins dentate and each with low process proximally. Carpus with setose scales or small spinules, distal margin spinose. Merus with setose scales or small spinules, distal margin spinose; inner margin with row of 2 or 3 large spines. Ischium with large distolateral spine and 2 rows of small spines on inner margin.

Pereopods 2–4: Setose, similar, slightly decreasing in length posteriorly. Meri with spinulose extensor margin and distal flexor spine. Carpi about two­thirds propodal length; that of pereopods 2–3 with small proximal spine on extensor margin; that of pereopod 4 unarmed. Propodi broadened distally, with 6 or 7 movable spines. Dactyli with 8–10 fixed, strong, obliquely directed, corneous teeth on flexor margin.

Ovum : 1.2 mm diameter.

Etymology. Named for Wolfgang Zeidler, formerly South Australian Museum, who collected the type material.

Remarks. Uroptychus zeidleri n. sp. closely resembles U. ensirostris Parisi, 1917 , from Japan (see redescription by Froglia 1987) in the shape of the carapace and rostrum, presence of a transverse row of epigastric spines, sternal morphology, armature of the chelae dactyli of the walking legs, and distally broadened propodi of the walking legs. The new species is readily distinguished from U. ensirostris in having distinctly more spinose lateral carapace margins, in bearing an outer spine on the basal antennal segment and in bearing a distal spine on the distal two antennal peduncle segments.

Of the known Australian species, U. zeidleri resembles U. calcar n. sp. and U. paracrassior n. sp. from New South Wales and Victoria in the lateral armature of the carapace and shape of sternites 3 and 4. Uroptychus zeidleri differs from U. calcar in having tuberculate instead of glabrous chelae, serrate instead of smooth dorsal margins of the pereopod 2–4 meri, in having a row of movable spines on the distal flexor margins of the pereopod 2–4 propodi, and in having obliquely instead of perpendicularly oriented dactylar spines on pereopods 2–4. Uroptychus zeidleri differs from U. paracrassior in having a transverse row of epigastric spines, in having more slender and more rugose chelae and in lacking the small paired median spines on the anterior margin of sternite 3.

Distribution. Presently known only from off Richardson Point, northwestern Tasmania at 520 m.

Figures

FIGURE 26. Uroptychus zeidleri n. sp., holotype female, 10.4 mm, SAM C6066. A, dorsum. B, anterior carapace, right lateral. C, cheliped, proximal right ventral. D, telson. E, sternum. F, maxilliped 3, right lateral. G, crista dentata, right. H, antenna, right ventral. Scale A–C = 5 mm, D–F = 2.5 mm, G–H = 1.3 mm.