Patiriella medius, O'Loughlin & Waters & Roy, 2003

O'Loughlin, P. M., Waters, J. M. & Roy, M. S., 2003, A molecular and morphological review of the asterinid, Patiriella gunnii (Gray) (Echinodermata: Asteroidea), Memoirs of Museum Victoria 60 (2), pp. 181-195 : 184-187

Patiriella medius sp. nov.

Figures 1 (as ‘central’), 4a–f, 7c

Material examined. Holotype. Victoria, Port Fairy , Griffith I., rocky shallows, 0–2 m, M. O’Loughlin and M. Mackenzie, 29 Dec 2001, NMV F92986 ( MOL 72 ).

Paratypes. Type locality and date, NMV F92987 (3) (MOL 73, 74, 79) ; NMV F92988 (2 dry, 2 cleared) (MOL 69, 70, 75, 76) .

Other material (selected for molecular confirmation, distribution and depth data). Vic. W of Wilsons Promontory, Walkerville South, Bear Gully, NMV F71869 (1); Western Port, McHaffie Point, NMV F93174 (4); Flinders, ocean platform, NMV F93171 (2); Port Phillip Bay, Popes Eye, 5–12 m, NMV F93730 (1); Point Addis, 8–13 m, NMV F93165 (3) (MOL 170, 172); “Mullet Holes”, 10 km NE Apollo Bay, 0–2 m, NMV F92990 (3) (MOL 94–96); Port Fairy, Griffith I., rocky shallows, NMV F83593 (2) (MOL 50); NMV F93164 (1) (MOL 176); NMV F87171 (1) (MOL 177); Portland, Nelson Bay, 24 m, NMV F73193 (2). Tas. Port Arthur, below low tide, TM H809 (1); Bass Strait, Waterhouse Passage, rocky shallows, NMV F71872 (1) (MOL 46); Tamar River, Greens Beach, TM H1107 (21); Somerset, near Burnie, under rocks at low tide, WAM Z9394 (5); Rocky Cape, 5 m, NMV F92989 (2) (MOL 211). SA. Cape Jaffa, 14–20 m, SAM K1938 (2); Kangaroo I., Western River, 8–10 m, SAM K1917 (1); Gulf Saint Vincent, Fleurieu Peninsula, Rapid Bay jetty, 8–12 m, NMV F93166 (4) (MOL 163–165); Normanville, rocky shallows, NMV F93163 (4) (MOL 104–107); F93167 (1) (MOL 103); Port Noarlunga, under stones, 1 m, WAM Z9390 (1); Yorke Peninsula, Edithburg, Troubridge Light, 18 m, TM H1359 (1); Sir Joseph Banks Group, 3–14 m, SAM K1923 (3); Investigator Group, 6–8 m, SAM K1901 (1); Eyre Peninsula, near Streaky Bay, Point Westall, rocky shallows, NMV F71856 (1 cleared) (MOL 47, 57); Nuyts Archipelago, 34 m, SAM K1933 (1). WA. Hopetoun, east of jetty, rock platform, NMV F73201 (3); Cheyne Bay, intertidal reef, WAM Z9472 (1); Yallingup, under boulders with P. ‘brevispina’ (= P. gunnii here) and P. ‘gunnii’ (= P. occidens here), 0–1 m, WAM Z9477 (5); Cape Naturaliste, 9 m, WAM Z9404 (1); Dunsborough, Eagle Bay, under rock, 10 m, NMV F93172 (1); Bunbury, 4 km N, WAM Z9411 (1); Fremantle, Halls Bank, under rock, 8 m, NMV F73178 (1).

Description (dry and cleared specimens). Up to R = 38 mm; 5–7 rays, predominantly 6 (134 of 145 SAM, TM and WAM specimens with 6 rays, 9 with 7 rays, 2 with 5 rays); form variable from 6 short predominantly pointed rays with interradial margin incurved, to hexagonal; body flat orally, flattened dome aborally, acute angle at margin; madreporite conspicuous; lacking pedicellariae; gonopores abactinal.

Abactinal surface even; papulate areas slightly more extensive than non-papulate areas; secondary plates few, very irregular in size and form; proximal radial and interradial plates fairly closely imbricate; proximal papular spaces not large, frequently 1–3 secondary plates and 2–4 papulae in proximal papular spaces outside disc when R = 20–30 mm; abactinal plates crescentic in papulate areas, carinally with double notch and proximal lobe; carinal series variably regular from close to disc to near end of ray, rarely doubly papulate beyond half ray length; distal interradial non-papulate plates closely imbricate, domed, rounded proximally; disc variably distinct, bordering plates variably regular crescentic radial and smaller interradial plates, frequently obscured by irregular large plates within and distal to disc; abactinal plates granular, covered by glassy convexities, lacking spine-bearing ridge; abactinal spinelets with variable form, subcolumnar to narrowing and rounded distally with swollen base, minutely spinous distally, typically about 0.36 mm long when R = 30 mm (0.30 mm when R = 20 mm), distributed over projecting surface of plates; superomarginal plates aligned distally 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, widely rounded distally, frequently 10–14 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 fairly slender, tapered, short; actinal interradial proximal plates with 1–4 spines (predominantly 2–3), distally 2–4 very short tapered spines (frequently 3), minutely spinous distally; adradial row of actinal interradial proximal plates with predominantly 2 tapered spines, minutely spinous distally, significantly shorter than subambulacral spines (about half to two-thirds length); adambulacral proximal plates with frequently 2–3 thick tapered subambulacral spines, minutely spinous distally, frequently unequal, form variable from digitate to spatulate to distally bulbous, commonly slightly longer than furrow spines; furrow spines slender, webbed, tapering, predominantly 3–4 (sometimes 5) per plate proximally when R = 20 mm and larger, minutely spinous distally; suboral spines frequently present (at least 1 suboral spine on 68 of 115 AM, SAM and TM specimens examined; 10–12 suboral spines on 42 of 115 specimens); oral spines 5–7, predominantly 6.

Live colour. Abactinally very variable; dark-coloured disc not reported; frequently overall maroon red or red or reddish brown appearance, sometimes fairly uniform pale brown or orange or pink, sometimes with red or mauve or orange or brown or cream or white flecks; a few with margin or rays and interradii coloured differently, or with colour patches; some mottled with dark red, red, maroon, mauve, brown, orange, white; actinally typically off-white with prominent maroon flecking.

Distribution. Walkerville South (W of Wilsons Promontory, Vic.), Bass Strait, Tas., continuous to Fremantle (WA); under rocks; 0–34 m (molecular confirmation for Point Addis (Vic.) to western Eyre Peninsula (SA)).

Etymology. From medius (Latin, as a noun in apposition) meaning “between the two”, and referring to a distribution across southern Australia between the most easterly distribution of Patiriella oriens sp. nov. (below) and the most westerley distribution of Patiriella occidens sp. nov. (below).

Remarks. The combination of characters which distinguishes P. medius from other six-rayed species of Patiriella is: rarely doubly papulate carinally for more than half ray length; abactinal spinelets small and fine; frequent presence of some sub-oral spines; adradial row of actinal interradial spines up to about two-thirds the length of subambulacral spines; actinal interradial spines short, thin. The limited live colour data available for confirmed determinations indicates that maroon red is a common abactinal overall colour, with no reports of grey or blue or a black disc.

Figures

Figure 1. One of 1000+ optimal MP trees (863 steps) derived from analysis of CO1 sequence data. Numbers at nodes are bootstrap percentages based on 500 replicate analyses. MOL codes refer to specimens obtained for the current study. AM codes refer to Australian Museum specimens. Previously published sequences (Hart et al., 1997) are indicated in bold. Geographic origin of samples is indicated: Tasmania (T), Victoria (V), New South Wales (N), South Australia (S), Western Australia (W).