Stylaster stejnegeri (Fisher, 1938)

Cairns, Stephen D. & Lindner, Alberto, 2011, A Revision of the Stylasteridae (Cnidaria, Hydrozoa, Filifera) from Alaska and Adjacent Waters, ZooKeys 158, pp. 1-88: 31-32

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Stylaster stejnegeri (Fisher, 1938)


Stylaster stejnegeri (Fisher, 1938)   Figs 11C14 A–J

Allopora stejnegeri   Fisher, 1938: 518-519, pl. 42, figs 2-2b, pl. 56.- Boschma 1957: 28.

Stylaster stejnegeri   : Cairns 1983b: 429.- Wing and Barnard 2004: 11, 28.- Heifetz et al. 2005 " 134, 137 (listed).- Stone and Shotwell 2007: 108 (listed).-Jameison et al. 2007: 224 (listed).

Type material.

Holotype, 1 female colony, and SEM stub 1500, dry, USNM 43271 (Fig. 11C). Type locality.Albatross 4777: 52°11'N, 179°49'E (Petrel Bank, Aleutian Islands), 79-95 m.

Material examined.



The holotype (Fig. 11C) is a small, arborescent colony 6 cm in height and 7 cm in width, with a basal branch diameter of 9.3 mm. Branches cylindrical and blunt tipped, the tips measuring 3-5 mm in diameter. Coenosteum reticulate-granular in texture, coenosteal strips 50-55 µm wide, separated by slits 13-15 µm wide. Coenosteum also covered with small papillae (nematopores). Binary spionid worm tubes present along branch axes. Coenosteum light orange to pink.

Cyclosystems on all sides of branches, circular, 1.0-1.2 mm in diameter. Gastropores circular, 0.35-0.45 mm in diameter. Gastropore tube cylindrical and usually slightly curved such that gastrostyle tip is not visible from apical view; ring palisade absent. Gastrostyle lanceolate.

Cyclosystems flush to only slightly raised above coenosteum; surface of pseudosepta porous. Dactylotome width 0.08-0.11 m. Range of dactylopores per cyclosystems 5-11 (n = 50, average = 6.46 (σ = 1.03), and mode = 6). Small (0.11-0.14 mm diameter), circular supernumerary dactylopores fairly common (Fig. 14A-C). Dactylostyles rudimentary (Fig. 14H).

Female ampullae (Fig. 14A, I–J) superficial hemispheres up to 1.1 mm in diameter, often bearing low ridges radiating from their apex. Male ampullae unknown.


Although only one specimen is known of this species, it does appear to be distinctive. Perhaps most similar to Stylaster brochi   , it differs from that species in having flush cyclosystems, fewer dactylopores per cyclosystem, and ridged female ampullae (Table 2).


Known only from one specimen from the type locality.