Stylaster parageus columbiensis Lindner & Cairns

Cairns, Stephen D. & Lindner, Alberto, 2011, A Revision of the Stylasteridae (Cnidaria, Hydrozoa, Filifera) from Alaska and Adjacent Waters, ZooKeys 158, pp. 1-88 : 45-47

Stylaster parageus columbiensis Lindner & Cairns ssp. n. Figs 21B23 A–J

Allopora campyleca Fisher, 1938: 506, in part (specimen from Alb-4230).

Type material.

Holotype: FOMC 1162 (209), male colony, dry, and SEM stubs 1389-91, USNM 1122462 (Fig. 22B). Paratypes: Alaskan Leader 21-108, 54°27'N, 133°55'48"W, 215-563 m, 10 Jul 2002, 1 male, USNM 1122483; Alb-4230, 55°N, 131°W, 198-439 m, 7 Jul 1903, 1 male, USNM 76815 (paratype of Allopora campylecus); FOMC 1158 (206), 48°07'546"N, 125°05'46"W, 246 m, 10 Jul 2008, 1 male in alcohol, USNM 1122465; FOMC 1159 (161), 48°07'56"N, 125°05'45"W, depth unknown, 10 Jul 2008, 3 males, USNM 1122472; FOMC (162), 48°07'56"N, 125°05'46"W, depth unknown, 10 Jul 2008, 1 male in alcohol, USNM 1122471; FOMC 1159 (166), 48°07'46"N, 125°05'41"W, 273 m, 10 Jul 2008, 1 male in alcohol, USNM 1122473; FOMC 1159 (169), 48°07'48"N, 125°05'41"W, 264 m, 10 Jul 2008, 1 male in alcohol, USNM 1122467; FOMC 1162 (203 and 205), 48°08'26"N, 125°11'28"W, 265 m, 12 Jul 2008, 2 males in alcohol, USNM 1122464, and -68; Lindner, coll., AL470 (41), Race Rocks, near Sooke Community, Straits of Juan de Fuca, British Columbia, depth unknown, Jul 2002, 1 male, USNM 1096625; Lindner, coll., AL466 (25), off Triangle Island, British Columbia, depth unknown, 1 male in alcohol, USNM 1096628; Ropos 956 (103), 48. 15605°N, 124.9973°W, 288 m, 30 May 2006, 1 male, USNM 1117117; Ropos 957 (116), 48°08'42"N, 125°11'26"W, 285 m, 31 May 2006, 1 female in alcohol, SEM stub 1402, USNM 1117112. Type locality. 48°08'31"N, 125°11'01"W (off Cape Flattery, Washington), 273 m.

Etymology.

Named for the region from which it is primarily known: British Columbia.

Material examined.

Types.

Description.

Corallum shape and branching similar to that of typical subspecies: bushy or flattened bushy with delicate terminal branches. Holotype 7 cm tall and 7 cm wide, with a basal branch diameter of 10.1 × 8.1 mm; largest corallum (USNM 1096625, Fig. 21B) 8.5 × 8.0 cm, with a massive basal branch diameter of 3 cm. Commensal spionid worm tubes absent. Coenosteum reticulate-granular in texture, the coenosteal strips 50-60 µm wide, bordered by slits about 10 µm wide, the strips originally covered with irregularly-shaped nodules that are subsequently covered with smoother granular coenosteum (Fig. 23E shows the transition). Coenosteum white.

Cyclosystems occur exclusively on edges of distal branches, but also on anterior face of larger-diameter branches. Cyclosystems circular to elliptical in shape, the larger axis ranging from 1.1 to 1.5 mm, the abaxial edge slightly raised above coenosteum; gastropores circular, 0.45-0.50 mm in diameter. Gastropore tubes somewhat inflated in upper half, changing to a narrow cylinder proximally; a well-developed ring palisade present as in the typical subspecies, the narrow pointed gastrostyle tip projecting through the ring palisade constriction into upper chamber (Fig. 23G) and thus easily visible from above. Gastrostyles elongate-lanceolate (Fig. 23D), occupying lower half of gastropore tube, and up to 0.67 mm in length, having a H:D ratio of 3.1-3.7.

Dactylotomes 0.09-0.10 mm in width, the inner slit short but longer than that of typical subspecies. Dactylostyles well developed, the cylindrical elements up to 38 µm in height and about 14 µm in diameter. Range of dactylopores per cyclosystem 6-13 (n = 50, average = 9.38 (σ = 1.43), and mode = 9). Supernumerary dactylopores rare. Pseudosepta 0.17-0.28 mm in width; diastemas uncommon.

Female ampullae (Fig. 23I) smooth superficial hemispheres 0.9-1.0 mm in diameter, with lateral efferent pores about 0.23 mm in diameter. Male ampullae (Fig. 23J) superficial swellings up to 0.5 mm in diameter, with small apical efferent pores. Both types of ampullae clustered on anterior and posterior faces.

Remarks.

Subspecies columbiensis resembles the typical subspecies in many ways, including colony shape and branching, and ring palisade shape, but also differs in a number of small but consistent characteristics (Table 2). Subspecies columbiensis has larger cyclosystems and gastropores, a slightly higher average number of dactylopores per cyclosystem, a more commodious upper gastropore chamber and deeper dactylotome slits, and a more elongate gastrostyle that is easily seen from above. Dixon Entrance appears to be the border between the two subspecies, the typical subspecies occurring to the north and columbiensis occurring to the south of this body of water. Because of the overall similarity of the two taxa, and their consistent minor differences, including their geographic separation, columbiensis is considered as a subspecies or Stylaster parageus . Of 16 colonies examined, 15 are male and one is female.

Distribution.

Entire coast of British Columbia (Canada) from Dixon Entrance to off Cape Flattery, Washington (USA); 246-285 m.