Patiriella occidens O'Loughlin & Waters & Roy 2003, sp. nov.

Patiriella occidens sp. nov. Figures 1 (as ‘western’), 5a–f, 7d Patiriella gunnii W.— Hart et al., 1997: 1848–1861, figs 1–4, tabs 1, 2.— Byrne et al., 1999: 188–194, figs 1, 3D, 6 (non Patiriella gunnii (Gray, 1840)). Material examined. Holotype. Western Australia, Perth, Cottesloe, on reef amongst algae, 1 m, L. Marsh, 29 Dec 2001, WAM Z8951 (MOL 151). Paratypes. Type locality and date, NMV F92971 (1, cleared) (MOL 150); Albany, Cape Vancouver, Quaranup, amongst boulders, 1 m, L. Marsh, 13 Dec 2001, WAM Z8949 (1) (MOL 148); under boulder, 1 m, WAM Z8950 (1) (MOL 149); Cockburn Sound, Woodman Point, under rocks, 1 m, L. Marsh, 1 Jan 2002, WAM Z8953 (3) (MOL 154–156). Other material (selected for molecular confirmation, distribution and depth data). Vic. Port Fairy, causeway beach, NMV F73149 (1). SA. Victor Harbour, The Bluff wharf, NMV F92975 (1) (MOL 67); Cape Jervis, rocky shallows, NMV F74638 (1) (MOL 182); Kangaroo I., Eastern Cove, rocky shallows, NMV F71862 (2) (MOL 181); Gulf Saint Vincent, Glenelg, SAM K1932 (3); Yorke Peninsula, Edithburg, 0–4 m, SAM K1904 (3); Sir Joseph Banks Group, 0–1 m, SAM K1899 (2); Eyre Peninsula, Point Labatt, 0–1 m, SAM K1907 (1); Nuyts Archipelago, 14 m, SAM K1898 (2). WA. E of Hopetoun, Mason Bay, East Mason Point, granite/dolerite with algae and seagrass, 0–3 m, WAM Z9470 (1); Cheyne Bay, under stones, WAM Z9479 (6); Two Peoples Bay, WAM Z9576 (2); Albany, Middleton Beach, under rocks, WAM Z9478 (2); Torbay, Mutton Bird I., under boulders, intertidal, WAM Z9474 (2); Kilkarnup, Cape Mentelle, WAM Z9466 (1); Cowaramup Bay, under boulders, 0–1 m, WAM Z9400 (1); Yallingup, limestone reef, under boulders with P. ‘brevispina’ (= P. gunnii here), WAM Z9396 (4); Cape Naturaliste, under intertidal granite boulders, WAM Z9405 (2); Geographe Bay, Dunsborough, WAM Z9402 (1); Rockingham, Point Peron, H.L. Clark, Oct 1929, WAM Z9440-2 (3); SAM K712 (3); Rottnest I., reef, WAM Z9530 (9); Trigg I., reef platform, WAM Z9454 (1); Yanchep, reef, WAM Z9433 (1); Port Gregory, N of Geraldton, top of reef in pool, NMV F73179 (1); Kalbarri (Murchison River), reef top, WAM Z9413 (2). Description (dry and cleared specimens). Up to R = 38 mm; 4–9 rays, predominantly 6 (292 of 331 AM, SAM, TM and WAM specimens with 6 rays, 25 with 7 rays, 9 with 8 rays, 3 with 5 rays, 1 with 4 rays, 1 with 9 rays); form variable from 6 distinct pointed rays with interradial margin deeply incurved (common for larger specimens) to subhexagonal (rare except for smaller specimens); body flat orally, flattened dome aborally, acute angle at margin; madreporite conspicuous; lacking pedicellariae; gonopores abactinal. Abactinal surface slightly uneven; papulate areas more extensive than non-papulate areas; secondary plates numerous, very irregular in size and form; proximal radial and interradial plates fairly openly imbricate; proximal papular spaces fairly large, frequently 2–6 secondary plates and 6–7 papulae in proximal papular spaces outside disc when R = 30 mm (2–4 secondary plates and 4–6 papulae when R = 20 mm); abactinal plates crescentic in papulate areas, carinally with double notch and proximal lobe; carinal series frequently regular from close to disc to end or near end of rays, doubly papulate for at least three quarters ray length when R = 20 mm and larger; distal interradial non-papulate plates closely imbricate, domed, rounded proximally; disc variably distinct, bordering plates variably regular crescentic radial plates and smaller interradial plates, disc frequently obscured by irregular large plates within and distal to disc; abactinal plates granular, covered by glassy convexities, lacking spine-bearing ridge; abactinal spinelets frequently twice as long as wide, variable form, most frequently columnar, sometimes slightly widened or narrowing distally, sometimes with slight waist, truncate and prominently spinous distally, typically up to 0.48 mm long when R = 30 mm (0.36 mm when R = 20 mm), distributed over projecting surface of plates; superomarginal plates aligned longitudinally with inferomarginal plates; lacking internal superambulacral plates between ambulacrals and actinals; distal abactinal and actinal interradial plates with internal tapered vertical contiguous projections. Projecting inferomarginal plates form margin, frequently 8–11 spinelets per plate when R = 20–30 mm; actinal plates in regular series, curving acutely from furrow to margin, some proximal actinal areas not calcified; actinal interradial spines generally thick, long, digitate, distally spinous; actinal interradial proximal plates with 1–2 spines, distally 2 (rarely 3) shorter, digitate to slightly bulbous, distally spinous spines; adradial row of actinal interradial proximal plates with predominantly 1 thick digitate spine, rarely 2, typically about four fifths length of subambulacral spines, some slightly bulbous; adambulacral proximal plates with 1–3, predominantly 2, thick subambulacral spines, frequently unequal, form variable from digitate to slightly bulbous to subcapitate to spatulate to widending distally, minutely spinous distally; furrow spines slender, tapering, webbed, 2–4 per plate proximally, predominantly 3, minutely spinous distally, subequal in length with subambulacral spines; suboral spines rare (at least 1 suboral spine on 23 of 307 AM, SAM, TM and WAM specimens examined; more than 10 suborals on 2 of 307); oral spines 4–6, predominantly 5. Live colour. Very variable abactinally; commonly dark coloured disc, sometimes red; frequently grey appearance; sometimes fairly uniform grey or red or blue-green or grey-blue or blue or brown or orange, sometimes with black or white flecks; some with rays, interradii and margin coloured differently, or with colour patches; frequently mottled with grey, white, green, red, brown, blue, orange, mauve, black. Distribution. Port Fairy (Vic.) continuous to Kalbarri (WA); predominantly on reef flat, sometimes with seagrass; 0–14 m (molecular confirmation for Victor Harbour (SA) to Perth (WA)). Etymology. From occidens (Latin, as a noun in apposition) meaning “west” and referring to the westerly distribution in southern Australia. Remarks. Hart et al. (1997) and Byrne et al. (1999) found from molecular evidence that specimens of Patiriella ‘gunnii’ from eastern and western Australia had divergent lineages. The western material was collected from Margaret River in WA (L. Marsh, pers. comm.). Western Australian specimens are confirmed by molecular and morphological evidence and described here as Patiriella occidens sp. nov. Grice and Lethbridge (1988) reported on the reproductive and developmental biology of Patiriella ‘gunnii’. Since the research was based on material collected from the region of Perth, it is assumed here that the species was not P. gunnii but probably the readily found and collected new species P. occidens (used hereafter for P. ‘gunnii’ from western Australia). It is improbable that the collections included the cryptic P. medius, which is sympatric with P. occidens in the Perth region. Grice and Lethbridge (1988) found that spawning by P. occidens occurred in late summer and early autumn. Spawning is thus later than P. oriens (see below), a factor which may be significant in the maintenance of genetic identity in these similar species. P. occidens is found most frequently on intertidal reef platform, a habitat frequently occupied by P. calcar. This potential competitive factor may have resulted in the absence of P. calcar in most of the distribution range of P. occidens. The combination of morphological characters which distinguishes P. occidens from other six-rayed Patiriella species is: frequently distinct long rays; carinal series of plates frequently doubly papulate for at least three-quarters ray length; abactinal spinelets frequently columnar, distally slightly swollen and spinous, and creating a very coarsely spinous surface appearance; normal absence of suboral spines; subambulacral spines projecting significantly above furrow and actinal interradial spines; actinal interradial spines digitate; up to about 11 spinelets per inferomarginal plate. The limited live colour data available for confirmed determinations indicates that grey or brown or blue are frequently evident abactinally, and red infrequently.

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