Errinopora zarhyncha 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 : 18-21

Errinopora zarhyncha Fisher, 1938 Figs 5E9 A–L

Errinopora zarhyncha Fisher, 1938: 539-541, pl. 68, pl. 69, fig. 1.- Boschma 1957: 58.-Thomson and Chow 1955: 23, 30 (mineralogy).-Not Naumov 1960: 559.- Lowenstam 1964: 377 (mineralogy).- Lowe 1967: 82.- Cairns 1983b: 462.- Cairns and Macintrye 1992: 100-101 (mineralogy).- Cairns et al. 1999: 43 (listed).- Heifetz 2002: 22 (listed).- Wing and Barnard 2004:27, 57, fig. 27.- Lindner 2005: 123-127, fig. 4.2D, 4.10, 4.20 (redescription, key). - Heifetz et al. 2005: 133, 137 (listed).- Stone and Shotwell 2007: 108 (listed).- Jamieson et al. 2007: 224 (listed).- Lindner et al. 2008: 3, and supplemental Table S1: 3 (phylogeny and DNA sequences).

Errinopora zarhincha : Lowenstam 1964: 382-383 (misspelling).

Type material.

Holotype, Alb-3480, a dry male colony 14 cm in height, USNM 42874 (Fig. 5E). Paratypes: Alb-3480, 3 dry female branches, USNM 52247; Alb-3480, 1 branch, CAS 28186. Type locality.Alb-3480: 52°06'N, 171°45'W (Amukta Pass, Aleutian Islands), 518 m.

Material examined.

Shishaldin, 53°56'24'N, 179°49'31"E, 318 m, 14 May 2000, 1 male, USNM 1123447; Shishaldin, 54°54'05"N, 178°37.27'E, 410 m, 11 Feb 2000, 3 female branches, and SEM stubs 1542-43, USNM 1123448; Vesteraalen 941-59, 52°02'00"N, 172°12'W, 658 m, 14 Jun 1994, 3 branches of a female colony, both dry and in alcohol, USNM 96234; Vesteraalen 941-62, 51°58'N, 172°40'W, 207 m, 15 Jun 1994, 1 female, USNM 96233; Vesteraalen, 51°13'17"N, 179°05'57"E, 488 m, 4 Jun 2000, 1 male, USNM 1071915; 51°13'43"N, 179°49'31"E, 465-529 m, 13 Jun 2000, large male colony, USNM 1123446; Types.

Description.

Colonies uniplanar or multiplanar, robust, with fairly close dichotomous branching, leaving little space between branches; branch anastomosis occurs but uncommon. Largest colony 26 cm in height and 27 cm in width, with a massive basal branch 4.3 cm in diameter (USNM 1123446). Branches circular to slightly flattened in cross section, attenuating to thick (7-15 mm in diameter), blunt tips. Parasitic spionid polychaete worms form tubes along branch axes in two colonies (USNM 96233, 96234), the tubes Fig. 8 in cross section. Coenosteum quite porous in texture (Fig. 9 E–H), consisting of a reticulum of thin (25 µm), spinose ridges, separated by wide slits or series of pores. This texture also present on ampullae and dactylopore spines, in the latter the coenosteal strips forming longitudinal ridges. Coenosteum orange.

Dactylopore spines occur on all branch surfaces and are quite variable in orientation, sometimes forming rows of 10-13 spines laterally fused into a short tier on one side of a pore row (unilaterally), the dactylotomes usually facing upward (abcauline), but dactylopore spines also oriented with their dactylotomes facing downward (adcauline) or laterally, and occasionally are isolated; compound dactylopore spines common. Dactylopore spines quite large and thick-walled, up to 3 mm in height and 1.5 mm in width, the dactylotome occupying one-fourth to one-third width of spine; exterior surface longitudinally ridged. Small, circular, flush secondary dactylopores, measuring only 0.08-0.11 mm in diameter, occur on walls of dactylopore spines, often several on each spine. Whereas dactylopore spines are quite large, dactylostyles are small and thin, only about 30-35 um in width, bearing short spines up to 23 µm in length and 14 µm in diameter.

Gastropores circular and quite variable in size, up to 1.1 mm in diameter, often arranged linearly in valleys created by adjacent rows of dactylopores. Large gastropores often sit directly adjacent to much smaller ones; secondary gastropores about 0.38 mm in diameter. Gastropore fairly shallow, lacking a ring palisade, affording an easy view of base of pore, as the gastrostyle occupies only a small part of gastropore cavity. Ga strostyles lanceolate and slender, up to 0.9 mm in height, and bear longitudinal anastomosing ridges, the gastrostyle size commensurate with diameter of gastropore tube.

Female ampullae inconspicuous (Fig. 9J) and not common, rarely seen in cross section branch fracture. Female ampullae hemispherical, often overshadowed by tall dactylopore spines or becoming incorporated into dactylopore spines. Efferent pores elusive; when detectable they are lateral in position, and about 0.7 mm in diameter, but more often a spent female ampulla lacks its upper half or is simply a crater in the coenosteum, a function of its thin, porous coenosteal cover. Male ampullae equally inconspicuous (Fig. 9C), roughly hemispherical, highly porous, and only about 0.6-0.7 mm in diameter.

Remarks.

Errinopora zarhyncha is one of three species in the genus having a predominantly unilateral arrangement of dactylopore spines in which only one row of laterally fused spines (usually the proximal row) have their dactylotomes facing a gastropore or gastropore row, the other species being Errinopora nanneca and Errinopora dichotoma (see Dichotomous Key and Table 1). Errinopora zarhyncha differs from the other two species in having very tall dactylopore spines, relatively small dactylostyles, large robust colonies, and gastropore tubes that are much larger than their gastrostyles (see Dichotomous Key and Table 1). Naumov (1960) reported this species from the Kurile Islands, but based on his description in which he reports gastropore diameters of only 0.20-0.25 mm and dactylopore spines only 0.6 mm in height, we conclude that he is referring to a different, and as yet unknown species. Of the 8 lots of specimens examined, 4 are female, and 4 male. Coralla were determined to be calcitic by Thompson and Chow (1955) and Cairns and Macintrye (1992).

Distribution.

Endemic to Aleutian Islands in a somewhat disjunct distribution: Amchitka Pass, Bowers Bank, and off Seguam Island; 207-658 m.