Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa Cairns, Stephen D. Zibrowius, Helmut Zootaxa 2013 3691 1 1 57 6ZLJW [151,378,860,886] Hydrozoa Stylasteridae Stenohelia Animalia Anthoathecata 35 36 Cnidaria species venusta sp. nov.   Etymology.From the Latin venustus, meaning beautiful, elegant, and graceful, a name that could be given to virtually any stylasterid.   Typesand TypeLocality. Holotype: MNSM232, female colony (in alcohol), SAM, and SEM stubs 1682–83(USNM). Paratypes: MNSM226, 1 malecolony, SAM; MNSM232, 3 femaleand 3 malecolonies, SAM, and SEM stub 1681 (USNM); PF1915, 1 malecolony, SAM H1463; PF13395, 2 branches, SAM H2820; PF13476, 3 malebranches, SAM H1228; Anton Bruun8—420A, 1 malecolony (dry) and 1 malecolony (in alcohol), USNM 76773. TypeLocality: 32°14.9’S, 29°10.4’E, 620–650 m(off Umtata, northern Eastern Cape Province).   Material Examined. Types. Reference Material, fragment of male syntypeof  S. tiliatus,  Siboga105, USNM 77280.   Description.Colonies are uniplanar and relatively small, the largest specimen (the holotype, Fig. 3A) only 4.6 cmin height and 2.6 cmin width, with a basal branch diameter of 4.5 mm; branch anastomosis occurs occasionally. The coenosteum is covered with reticulate strips 50–60 µm in width, each strip covered with small irregularlyshaped granules ( Figs. 17D, E). The coenosteum is white. Cyclosystems are unifacial in arrangement, unilinearly positioned on the anterior face ( Fig. 17A). They are elliptical to irregular in shape, up to 1.3 mmin greater diameter and about 0.8–0.9 mmin lesser diameter, the greater diameter usually oriented perpendicular to the branch axis ( Figs. 17B, C). Based on 50 cyclosystems, the range of dactylopores per cyclosystem is 13–20; the average is16.46 (ơ = 1.74); and the mode is 16. Gastropores are also elliptical in shape, up to 0.35 mmin greater diameter and about 0.3 mmin lesser diameter. The gastropore tube is long (up to 1.6 mm) and invariably bent about 90° just beneath the gastropore. The gastrostyle occupies only the lower 30% of the tube, and is composed of a lower section about 0.21 mmin diameter that supports a cylindrical distal portion, which is approximately 0.10 mmin diameter. A solid inner ring (the sphincter) constricts the tube at the transition point of the basal to distal portion of the style ( Figs. 17H, I). The illustrated style is 0.45 mmin height, and is covered with small spines. The dactylotomes are fairly consistent in width (60–70 µm), whereas the pseudosepta are somewhat irregular in width, ranging from 64–145 µm wide ( Fig. 17F). The tops of the pseudosepta range from slightly convex to slightly concave. Each dactylopore contains 1–3 dactyloglossae, the uppermost being at the level of the coenosteal surface, and thus most easily seen in damaged cyclosystems ( Fig. 17J). The dactyloglossae are tongue-shaped, about 60–70 µm in surface dimensions, and about 8–10 µm thick, each blocking approximately 70–80% of the dactylopore tube.   FIGURE 17.  Stenohelia venusta( A–J, female holotype, MNSM232, SAM; K, male paratype, MNSM232, SAM): A, unifacially arranged cyclosystems; B, a cyclosystem. C, stereo view of a cyclosystem showing some dactyloglossae. D–E, reticulate granular coenosteal texture. F, several pseudosepta. G, female ampullae. H, stereo view of an elongate gastropore tube and its gastrostyle. I, stereo view of a gastrostyle and its massive sphincter. J, stereo view of a dactyloglossa. K, stereo view of male ampullae. Female ampullae are superficial hemispheres 0.6–0.8 mmin diameter, arranged in close proximity on the posterior faces of terminal branches ( Fig. 17G); efferent pores are inconspicuous but are lateral in position, not opening within the gastropore tube. The male ampullae are smaller ( 0.35–0.50 mmdiameter) and conical in shape, with a small (about 35 µm diameter), irregularly-shaped apical efferent pore. The male ampullae tend to cluster on the posterior side of the branches ( Fig. 17K).  Comparisons.Among the 11 other species in the genus,  Stenohelia venustais most similar to  S. tiliata(Hickson & England, 1905), originally described and still known only from the Sulu Sea at  275 m.Examination of the syntypeof  S. tiliatashows it to have15–16 dactylopores per cyclosystem, irregularly-shaped cyclosystems, a rough reticulate coenosteal texture, lacking a ring palisade, and male ampullae about 0.5 mmin diameter. The only difference detectable between the two species is that  S. venustahas dactyloglossae, whereas  S. tiliatahas typical dactylostyles composed of aligned pillars. One must keep in mind, however, that  S. tiliatais known only from one specimen, and the taxonomic value of dactyloglossae is yet to be determined. Regardless, these two species would appear to be sister species, if not conspecific.   Stenohelia venustaalso bears a resemblance to  S. confertaBoschma, 1968, known only from the Antipodes Islands at 1335 m. They are similar in coenosteal texture, cyclosystem shape, and in lacking a typical ring palisade, but  S. venustadiffers in having a higher number of dactylopores per cyclosystem, and in having dactyloglossae. Hickson & England(1909) reported  Stylaster minimusfrom Mauritius, which heretofore was the only record of this genus in the Indian Ocean, the typelocality for  Stylaster(= Stenohelia) minimusbeing the Philippinesat 1089 m. They did not supply any substantive description or illustrations for this specimen.   Distribution.Known from the continental shelf and slope off South Africafrom Cape Blaize to northern Eastern Cape Province (Fig. 30) ( 159–710 m); off Kenya( 140 m),? Mauritius(Hickson & England, 1909), 140– 710 m.