Ceramaster patagonicus Sladen 1889

Ceramaster patagonicus (Sladen, 1889)

(Figure 2 A–G)

Sladen, 1889: 269, pl. 46, figs 3–4, pl. 44, figs 3–4. (as Pentagonaster patagonicus)

Perrier, 1891: K127, pl. 12, figs 3a–b (as Pentagonaster austrogranularis)

Verrill, 1899: 195 (as Mediaster patagonicus)

Verrill, 1899: 195 (as Pseudarchaster patagonicus)

Fisher, 1911: 214, pl. 37, fig. 4,, pl. 38, figs 1–2, pl. 40, fig. 3; 1940: 118; Djakonov, 1950: 48, figs. 27, 48; Bernasconi, 1963: 8, pl. 1, figs. 1–2, pl.2, fig. 3; Baranova & Belyaev 1968: pl. 17, fig. 2; Tommasi, 1970: 12, fig. 36; Lambert, 1978: 62; Anderson et al., 1993: 502; Branch et al., 1993: 44 (illustr.); A.M. Clark, 1993: 249; Rowe & Gates, 1995: 65; O’Hara, 1998: 179, pl. 1d.; H.E.S. Clark in Clark & McKnight, 2001: 33; Stampanato & Jangoux, 2004: 4, 6 (as Ceramaster patagonicus)

McKnight, 1973: 178, fig. 4; 1984: 142; A.M. Clark, 1993: 249 (as Ceramaster lennoxkingi)

Clark & Downey, 1992: 236 (as Ceramaster grenadensis patagonicus)

Range. Broadly distributed. Bering Sea, Aleutian Islands, Alaska to British Columbia, Gulf of California to southern Australia (North of Macquarie Island), New Zealand and outlying areas (Bounty Islands and Macquarie Island). South Atlantic from near Cape Horn, Straits of Magellan, Falkland Islands, Falkland Plateau, Burdwood Bank. South Indian Ocean: Crozet Island, Kerguelen, Marion and Prince Edwards. 18–1125 m.

Material examined. Strait of Magellan. USNM E13497 East of Cape Froward, Strait of Magellan, Chile. 53°56’S, 71° 15’W, 256– 320 m. Coll. R/V Eltanin, USARP, 6 Feb 1964. (1 dry spec. R=5, r=3.3). USNM 1081976 Desolacion Island, Strait of Magellan. 52°53’S, 74° 05’W to 52°50’S, 74°10’W, 522– 544 m. Coll. R/V Eltanin, USARP, 1 April 1966. (2 dry specs. R=5.2, r=2.8; R=4.4, r=2.6); USNM 1082906 Strait of Magellan, west mouth, 52°41’S, 74°35’W, to 52°45’ S, 74°28’W, 188– 247 m. Coll. R/V Eltanin, USARP, 6 Jan 1966 (1 dry spec. R=4.4, r=2.9); USNM 112246 Cape Froward, Strait of Magellan, Chile. 53°38’48S, 70° 55’ 06W, 101– 119 m. Coll. R/V Eltanin, USARP, 6 Feb 1964. (1 dry spec. R=4.6, r=3.4); USNM 1123437 Strait of Magellan, west mouth, 52°53’S, 74°09’W, 523– 539 m. Coll. R/V. Eltanin, USARP, 7 Dec. 1965. (1 dry spec. R=4.6, r=3.2); USNM 1083028 Clarence Island, Strait of Magellan. 53°51’S, 71° 36’W to 53°50’S, 71° 41’W 256– 269 m. Coll. R/V Eltanin, USARP, 1 April 1966 (2 dry spec. R=2.5, r=1.6, R=3.4, r=2.1). USNM 119201 Strait of Magellan, west mouth of Strait, 52°53’S, 74°09’W, 523– 539 m. Coll. R/V Eltanin, USARP. 7 Dec. 1965. (1 dry spec. R=5.0, r=2.9). South Pacific (including New Zealand & Australia). USNM 1084435, Southeast Pacific. 60°24’S, 115° 01’W to 60°15’S, 114°48’W, 4978–5043 m. Coll. R/V Eltanin, USARP, 2 May 1966 (1 dry spec. R=3.8, r=2.6); USNM 1120452, Off Chile. 52°43’S, 74°31’W, 188– 247 m. Coll. R/V Eltanin, USARP, 6 Dec. 1965. (1 dry spec. R=4.0, r=2.9); USNM 1121285, South Pacific Ocean. 54°47’59’S, 129°48’W, 549 m. Coll. R/V Eltanin, USARP, 7 Nov. 1964 (1 dry spec. R=1.6, r=1.2); USNM 1122408, Macquarie Ridge, North of Macquarie Island 54°32’S, 159°59 E., 112– 124 m., Coll. R/V Eltanin, USARP, 15 Feb. 1967 (5 dry specs. R=4.2, r=2.7; R=7.4, r=5.0; R=9.3, r=6.3; R=6.7, r=4.6; R=7.0, r=5.2). USNM 1122413 East of Macquarie Island 54°31’S, 159°00 E, 110 m. Coll. R/V Eltanin, USARP, 18 June 1968 (8 dry specs. R=6.3, r=4.0; R=7.2, r=5.3; R=7.8, r=5.4; R=6.0, r=3.9; R=7.2, r=4.8; R=9.9, r=6.2; R=8.6, r=5.5; R=7.8, r=5.3). South Atlantic. USNM 1079801 Burdwood Bank, Scotia Sea, South Atlantic. 54°43’S, 56°37’W to 54°42’S, 56°39’W, 339– 357 m. Coll. R/V Eltanin, USARP, 14 March 1966. (1 dry spec. R=5.6, r=3.4). Indian Ocean. MNHN EcAs 10705, Crozet Island, 46°02’S, 49°49’E, 240 m. Coll. N. O. Marion Dufresne MD 30, st. CP 145 (1 dry spec. R= 5.3, r= 4.0). MNHN EcAs 10708, Crozet Island 46°39’S, 51°51’E, 365 m. Coll. N. O. Marion Dufresne MD 30, st. CP 221 (1 dry spec. R= 8.4, r= 6.5). Southern Ocean. USNM 1082742 Off Hermit Island, outside of Arthur Harbor, Palmer Archipelago 64°47’24’S, 64°06’ 54’W, 120– 165 m. Coll. R/V Hero, USARP, 26 Jan 1972 (4 dry specs. R=5.3, r=2.9; R=4.4, r=2.6; R=4.5, r=2.9; R=5.3, r=2.9).

Description. Body flattened, pentagonal (R/r=1.1–1.5), with weakly curved to nearly linear interradial arcs.

Abactinal plates hourglass shaped in profile with enlarged base and enlarged flattened top (i.e., tabulate), plate surface hexagonal to quadrate to irregular in outline, often with discrete angular edges (Fig. 1 B). Abactinal plates in well-defined rows. Carinal series is flanked by several ordered rows forming angular regions becoming more crowded interadially and more irregular closer to the contact with the superomarginal plate series. Granules covering each plate, eight to 80 in number. Peripheral granules, four to 40 in number, angular, discrete from central granules, which are rounder. Distinction between peripheral and central granules is especially evident on radial and proximal disk regions. Granular covering interradially is more homogeneous with less distinction between peripheral and central granular covering. Fasciolar grooves between abactinal plates well-developed, especially over radial and proximal disk regions. Each plate surrounded by individual papulae, six total with one per side of each plate.

Marginal plates, 26–28 per interradius (armtip to armtip) (Fig. 2 A). Superomarginal and inferomarginal series slightly offset from one another forming a zigzag contact (Fig. 2 C), which is especially evident distally on arms. Both series quadrate in shape with angular corners. Distalmost superomarginal plates in contact along midline on one edge in smaller specimens (<R=2.5) and in some larger specimens from the Macquarie Island region. Superomarginal plates with variably sized bare spot on each plate, facing abactinally. Bald spot is variably sized, ranging from small round patch to large area dominating surface of plate. The latter is commonly found on distal superomarginal plates adjacent to the terminal. Remainder of the plate is depressed relative to this bald spot and covered with granules, 40–200, which are round to polygonal, crowded, forming flush surface with bald spot. Granules forming weak to discrete periphery, 15–80 per plate. Inferomarginal plates similar but with smaller bald spots on each plate. Granules 40–200 total, round to polygonal, crowded with weakly defined perhiphery, 15–80 per plate. Granules from superomarginals and inferomarginals becoming confluent laterally. Shallow fasciolar grooves present between marginal plate series. Bivalved tong-like pedicellariae presence or absence on marginal plates is variable. Tendency is for pedicellariae to be present in larger specimens (R> 6.0 cm) but absent in smaller ones, although some large individuals lack pedicellariae. When present, pedicellariae abundance also seems associated with larger specimens (Fig. 2 D).

Actinal plates arranged in four to eight well-defined chevrons composed of quadrate plates with angular edges (Fig. 2 F). Plate shape more strongly defined proximally becoming more irregular distally, adjacent to inferomarginal plate contact. Each plate covered with round to irregularly shaped granules, five to 35, crowded to evenly spaced. Peripheral granules, 15–25, round to quadrate, discrete from central granules eight to twelve. Granules more densely packed adjacent to mouth becoming more widely distributed adjacent to inferomarginal contact (Fig. 2 F). Fasciolar grooves between actinal plates weakly expressed.

Furrow spines blunt, three to four, round, to triangular to quadrate in cross-section (Fig. 2 E). Larger individuals with relatively thick spines. Subambulacral spines, two to three, rounded quadrate in cross-section, about half the length but approximately identical thickness of furrow spines, forming one to two irregular rows of granules adjacent to subambulacral spines intermediate between furrow spination and actinal granules. These granules, two to five, approximately 70–85% of length of subambulacrals, quadrate to triangular in cross-section. Each row of adambulacral spination separated by a discrete space. Oral plates with furrow spines, five to six, with one large blunt furrow spine from each plate projecting into oral region. Oral spination is crowded. These spines, triangular and paired up against one another. Oral plate surface covered with eight to 19 spines, blunt, triangular, quadrate in cross section. Spination on oral plates is widely spaced and appears to be continuous with spacing observed on adambulacral plates.