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Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa
No full textCairns, Stephen D., Zibrowius, Helmut (2013): Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa. Zootaxa 3691 (1): 1-57, DOI: 10.11646/zootaxa.3691.1.
Stylaster
No full textStylaster (Species group A) Diagnosis. Species of Stylaster having cyclosystems arranged on all surfaces of the branch; branch tips usually blunt. Formerly called Allopora.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on page 21, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
Stenohelia venusta Cairns & Zibrowius, 2013, sp. nov.
No full textStenohelia venusta sp. nov. Figs. 3 A, 17 A–K, 30 ? Stylaster minimus, Hickson & England, 1909: 346 (Mauritius). Etymology. From the Latin venustus, meaning beautiful, elegant, and graceful, a name that could be given to virtually any stylasterid. Types and Type Locality. Holotype: MN SM 232, female colony (in alcohol), SAM, and SEM stubs 1682 – 83 (USNM). Paratypes: MN SM226, 1 male colony, SAM; MN SM232, 3 female and 3 male colonies, SAM, and SEM stub 1681 (USNM); PF 1915, 1 male colony, SAM H 1463; PF 13395, 2 branches, SAM H 2820; PF 13476, 3 male branches, SAM H 1228; Anton Bruun 8—420 A, 1 male colony (dry) and 1 male colony (in alcohol), USNM 76773. Type Locality: 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 syntype of S. tiliatus, Siboga 105, USNM 77280. Description. Colonies are uniplanar and relatively small, the largest specimen (the holotype, Fig. 3 A) only 4.6 cm in height and 2.6 cm in 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. 17 D, E). The coenosteum is white. Cyclosystems are unifacial in arrangement, unilinearly positioned on the anterior face (Fig. 17 A). They are elliptical to irregular in shape, up to 1.3 mm in greater diameter and about 0.8–0.9 mm in lesser diameter, the greater diameter usually oriented perpendicular to the branch axis (Figs. 17 B, C). Based on 50 cyclosystems, the range of dactylopores per cyclosystem is 13–20; the average is 16.46 (ơ = 1.74); and the mode is 16. Gastropores are also elliptical in shape, up to 0.35 mm in greater diameter and about 0.3 mm in 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 mm in diameter that supports a cylindrical distal portion, which is approximately 0.10 mm in diameter. A solid inner ring (the sphincter) constricts the tube at the transition point of the basal to distal portion of the style (Figs. 17 H, I). The illustrated style is 0.45 mm in 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. 17 F). 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. 17 J). 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. Female ampullae are superficial hemispheres 0.6–0.8 mm in diameter, arranged in close proximity on the posterior faces of terminal branches (Fig. 17 G); efferent pores are inconspicuous but are lateral in position, not opening within the gastropore tube. The male ampullae are smaller (0.35–0.50 mm diameter) 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. 17 K). Comparisons. Among the 11 other species in the genus, Stenohelia venusta is most similar to S. tiliata (Hickson & England, 1905), originally described and still known only from the Sulu Sea at 275 m. Examination of the syntype of S. tiliata shows it to have 15–16 dactylopores per cyclosystem, irregularly-shaped cyclosystems, a rough reticulate coenosteal texture, lacking a ring palisade, and male ampullae about 0.5 mm in diameter. The only difference detectable between the two species is that S. venusta has dactyloglossae, whereas S. tiliata has typical dactylostyles composed of aligned pillars. One must keep in mind, however, that S. tiliata is 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 venusta also bears a resemblance to S. conferta Boschma, 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. venusta differs in having a higher number of dactylopores per cyclosystem, and in having dactyloglossae. Hickson & England (1909) reported Stylaster minimus from Mauritius, which heretofore was the only record of this genus in the Indian Ocean, the type locality for Stylaster (= Stenohelia) minimus being the Philippines at 1089 m. They did not supply any substantive description or illustrations for this specimen. Distribution. Known from the continental shelf and slope off South Africa from Cape Blaize to northern Eastern Cape Province (Fig. 30) (159–710 m); off Kenya (140 m),? Mauritius (Hickson & England, 1909), 140– 710 m.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on pages 36-38, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
Gyropora africana Boschma 1960
No full textGyropora africana Boschma, 1960 Fig. 1 H, 23 Gyropora africana Boschma, 1960 a: 423 –433, pl. 1, figs. 1–9, text-figs. 1 a–d; 1966 b: 112 (listed).—Vervoort & Zibrowius, 1981: 13, 26– 27 (lectotype designation).—Cairns, 1983 b: 466, figs. 13 A–H, 24 J, 25 L (redescription).—Cairns & Macintyre, 1992: 100–101 (mineralogy). Types and Type Locality. A lectotype was designated from the syntype series of two specimens by Vervoort & Zibrowius (1981) UCTES TRA 151, which is now cut in two pieces and deposited at Naturalis Biodiversity Centre (Coel. 13749). The smaller paralectotype cannot be found. Type Locality: 34 ° 51 ’S, 19 ° 35 ’E (off Cape Agulhas, South Africa), 22 m. Material Examined. Lectotype; specimen from BM 1977.8. 5.1, Cape of Good Hope (Cairns 1983 b); Valdivia 95, 6 branches, ZMB; PF 2675, 1, SAM H 1235. Remarks. This species is known from only four locations, two of them reported herein, all from shallow water off South Africa. The Valdivia specimen, collected 62 years before the original description, was only a km from the type locality. The species was adequately described and figured by Boschma (1960 a) and Cairns (1983 b), and thus no additional SEM illustrations are included. Being a monotypic genus, the generic diagnosis is sufficient for its identification. Distribution. As for the genus (Fig. 23).Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on page 20, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
FIGURE 18 in Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa
No full textFIGURE 18. Stenohelia spinifera, male holotype from PF13479, SAM H1461: A, stereo view of cyclosystems and tall nematopore tubes. B–C, individual cyclosystems and tall nematopore tubes. D, pseudosepta. E–F, rough reticulate coenosteal texture. G–H, nematopore tubes. I, a dactyloglossa. J, cross section of an internal male ampulla. K, stereo view of a gastrostyle, but with a broken tip. L, cross section of male ampullae, and a broken gastrostyle. M, spination on the gastrostyle.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on page 39, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
Stylaster griseus Cairns & Zibrowius, 2013, sp. nov.
No full textStylaster griseus sp. nov. Figs. 2 C, 13 A–M, 28 Etymology. Named griseus (Latin, meaning grey), for the colour of the coenosteum. Types and Type Locality. Holotype: PF 13063, colony of indeterminate gender, SAM H 1459. Paratypes: MN SM163, 3 poor fragments, SAM; MN SM179, 1 female colony (in alcohol), SAM, and SEM stub 1701 (USNM); MN SM180, 1 colony base, SAM; MN SM184, 22 worn fragments, SAM; MN SM185, 1 male and 3 indet. colonies (in alcohol), SAM, and SEM stub 1715 (USNM); PF 808, 1 colony, indet., SAM H 1231; PF 907, 1 male and 3 indet. colonies, SAM H 1467; PF 13654, 2 female and 1 male colonies, SAM H 1460, and SEM stub 1699–1700 (USNM); UCTES SCD289, 1 female colony, RMNH 15820; UCTES SCD296, 1 male colony, RMNH 15826. Type Locality: off Hood Point Lighthouse (Eastern Cape Province), South Africa, 90 m. Material Examined. Types. Description. Colonies are of moderate size, robust, uniplanar, and sparsely branched, the largest colony (the holotype, Fig. 2 C) 7 cm tall and 6 cm wide, with a basal branch diameter of 14.1 mm. Branching is dichotomous but not regular, the blunt, cylindrical branch tips 2–4 mm in diameter. There are no polynoid commensals. The coenosteal texture is a fine reticulate-granular, the strips ranging from 53–72 µm in width, each covered with small, irregularly-shaped granules (Fig. 13 D, F). Nematopores were not observed. The colonies are light grey to light brown in colour, and chalky white when dead. Cyclosystems (Fig. 13 B) are uniformly arranged on all branch surfaces, although sometimes arranged in longitudinal rows up to 15 cyclosystems in length. Cyclosystems are slightly raised above the coenosteum and circular in shape, 0.9–1.13 mm in diameter. Based on 50 cyclosystems, the range of dactylopores per cyclosystem is 7–12; the average is 9.22 (ơ = 1.30); and the mode is 9. Diastemas occur occasionally but are rarely wider than two pseudosepta. The gastropore is circular (about 0.43 mm in diameter), and the deep gastropore tube is cylindrical, as much as 1.4 mm in depth. The base of the gastrostyle is a short cylinder about 0.35 mm in diameter, which supports a discoidal torus that is 0.40–0.50 mm in diameter. Above the torus is a tall slender apical spine, the entire gastrostyle measuring up to 0.64 mm in height (Figs. 13 F, G). At the level of the base of the apical spine the gastropore tube constricts as a sphincter (a continuous in structure like a low belt about 68 µm in width and 36 µm in height, not composed of discrete cylindrical elements, Figs. 13 F, G). The dactylotomes are 0.09–0.13 mm in width, and the pseudosepta are 0.07–0.25 in width, their upper surfaces convex (Fig. 13 C). Each dactylopore contains 1–3 dactyloglossae, usually getting larger with greater depth in the pore. The dactyloglossae are semi-circular (or broadly tongue-shaped), about 0.08–0.10 mm wide and 0.09 mm in height, and about 20 µm thick, although their outer margins appear to be the thickest (Figs. 13 H–L). The larger uppermost dactyloglossae occlude about onethird of the dactylopore. Female ampullae are primarily internal, hardly seen in surface view, and are about 0.9 mm in internal diameter, opening via an efferent pore into the upper chamber of an adjacent gastropore tube. Male ampullae are also primarily internal, but can be seen in apical view as small (0.35–0.40 mm in diameter) mounds, each with a small apical efferent pore (Figs. 13 A, M). Comparisons. Stylaster griseus is quite similar to S. bithalamus in many characters, and, after examination of more specimens, may prove to be a subspecies or just a distinctive form of the latter. The species are similar in coenosteal texture, in lacking nematopores, their female and male ampullar shapes, gastrostyle shape, and presence of dactyloglossae, as well as overlapping in distribution and depth range. S. griseus, however, seems to consistently differ (Table 1) in having, a gray to light brown corallum, blunt branch tips, a slightly higher average and modal number of dactylopores per cyclosystem, and in lacking polynoid gall tubes. Distribution. Known only from off the continental shelf off the Eastern Cape Province (Fig. 28), 80– 155 m.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on pages 28-30, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
Conopora tenuiramus Cairns & Zibrowius, 2013, sp. nov.
No full textConopora tenuiramus sp. nov. Figs. 3 E–F, 20 A–N, 25 Etymology. From the Latin tenuis (thin) and ramus (branch), an allusion to the slender terminal branches of this species; treated as a noun in apposition. Types and Type Locality. Holotype: MN SM 228, female colony, SAM, and SEM stubs 1690, 1693 (USNM). Paratypes: MN SM162, 4 branch fragments, gender indeterminate, SAM; MN SM228, 2 male branches, SAM; MN SM232, 2 dead male branch fragments, SAM, and SEM stub 1690 (USNM); PF 14306, 1 female colony, SAM H 1455. Type Locality: 32 ° 29.5 ’S, 28 ° 57.1 ’E (continental slope north of East London, off northern Eastern Cape Province), 650– 700 m. Material Examined. Types. Reference Material: Broch’s (1936) Mauritius specimen of C. tenuis and C. major (ZMC). Description. Colonies are uniplanar and relatively small, the holotype (Fig. 3 F) only 3.8 cm tall and 2.4 cm broad, with an intact basal branch having a diameter of 2.75 mm. However, larger colonies are known (PF 14306), which are up to 6 cm long and 1.1 cm in diameter, most of the main branch diameter consumed with a polynoid gall tube. Regardless of the size of the colonies, the distal branches are invariable delicate and thin, usually less in diameter than the cyclosystems they support. All colonies support a commensal polynoid gall tube (Figs. 3 E, F), which is prominent in the basal part of the main branches, often forming a web-like membrane that seems to envelope the lower branches. Branching is dichotomous, nodes occurring at almost every cyclosystem, producing a highly ramified and often anastomotic colony. The coenosteal texture is a well-defined linear-imbricate (Figs. 20 G–I), the strips being 70–80 µm in width, with about 65 platelet leading edges per mm, although parts of some colonies appear to have a smooth (worn?) texture (Fig. 20 J). The platelets are somewhat roughened by having low longitudinal ridges. The branch and polynoid gall tube coenosteum, ampullae, and pseudosepta are densely covered with low nematopore mounds, the pores on the coenosteum and ampullae 20–40 µm in diameter (Fig. 20 K) and the mounds up to 30 µm in height, whereas those on the pseudosepta are usually slightly larger (35–45 µm in diameter) and flush with the coenosteum, and arranged one to a pseudoseptum (Fig. 20 C, E). The colonies are white. Cyclosystems are unifacially arranged on all branches in a linear manner, elliptical to slightly irregular in shape (Figs. 20 B–D), and 1.0– 1.4 mm in greater diameter. Based on 40 cyclosystems, the range of dactylopores per cyclosystem is 13–19; the average is 16.0 (ơ = 1.13); and the mode is 15. The gastropore tube is double chambered (Fig. 20 F), the lower chamber flattened, about 0.45 mm in diameter and 0.15 mm in height, separated from the upper spherical chamber by a delicate gastropore ring constriction of about 0.26 mm diameter. The upper chamber is about 0.35 mm in diameter, above which the gastropore tube is flanked with dactylotomes. Dactylotomes range from 75–80 µm in width, the pseudosepta being slightly wider and more variable in width, ranging from 0.10–0.21 mm. The tops of the pseudosepta are flat to slightly convex. Female ampullae are massive swellings (up to 1.6 mm in diameter), sometimes even hemispherical, but often partially submerged in the coenosteum, most clustered in the coenosteum forming the polynoid gall tube (Fig. 20 L). Efferent pores are well defined, lateral in position, and about 0.25–0.30 mm in diameter. Male ampullae are also clustered in the polynoid gall tube coenosteum and frequently internal, only seen in a cross sectional break of the polynoid gall tube coenosteum (Figs. 20 M, N). They are about 0.4–0.7 mm in internal diameter; their efferent pores were not observed. Comparisons. Only one other species of Conopora has unifacially-arranged cyclosystems (but see below), C. unifacialis Cairns, 1991 (from New Zealand). Conopora tenuiramus is easily distinguished from that species by its thicker pseudosepta, lesser number of dactylopores per cyclosystem, polychaete commensalism, and gastropore tube shape. But, Conopora tenuiramus is also similar to C. laevis (Studer, 1878), especially in its delicate colony shape, polychaete commensalism, nematopore distribution, and ampullar shape, but C. tenuiramus can be distinguished by having unifacially arranged cyclosystems, more dactylopores per cyclosystem, and thinner branches. Although similar, the specimen reported from Mauritius by Broch (1936) as C. tenuis Hickson & England, 1905, has smaller cyclosystems and female ampullae, hemispherical female ampullae, and a mixture of unifacial and sympodially arranged cyclosystems. Conopora tenuiramus was also compared to Broch’s (1936) C. major Hickson & England, 1905, also collected from off Mauritius. Both species have unifacial cyclosystems, a polynoid commensal, and similarly-sized cyclosystems and ampullae, but Broch’s specimens differ in having female efferent pores that open within the gastropore tube, and frequently having enlarged (widened) pseudosepta in the abcauline position of the cyclosystem, resembling incipient lids characteristic of Crypthelia. Distribution. Continental shelf and slope off southeastern South Africa from Cape Seal (Western Cape Province) to northern Eastern Cape Province (Fig. 25), 146– 650 m.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on pages 42-43, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
FIGURE 14 in Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa
No full textFIGURE 14. Stylaster amphiheloides (A, male syntype, USNM 85785; B, E–F, H–J, female from PF2819A, SAM H1462; male from K–L, MN SM328, SAM): A, stereo view of a cyclosystem. B–C, reticulate-granular coenosteal texture. D, stereo view of a damaged cyclosystem showing some dactyloglossae. E–F, dactyloglossae. G, stereo view of a gastrostyle from above. H, stereo view of a gastrostyle and sphincter. I, elongate gastrostyle and sphincter. J, longitudinal fracture of gastropore tube showing a female efferent pore. K–L, male ampullae.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on page 31, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
FIGURE 20 in Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa
No full textFIGURE 20. Conopora tenuiramus (A–L, female holotype, MN SM228, SAM; M–N, male paratype, MN SM232, SAM): A, unifacially arranged cyclosystems. B–D, cyclosystems showing the regular placement of one nematopore per pseudoseptum (C is a stereo pair). E, nematopores on outer edges of each pseudoseptum. F, stereo view of double-chambered gastropore tube. G– I, linear-imbricate coenosteal texture. J, transition of linear-imbricate to smooth coenosteal texture. K, a single nematopore mound. L, female ampulla and efferent pore. M, transverse section though several male ampullae lodged in polynoid gall tube coenosteum. N, longitudinal section of male ampullae in polynoid gall tube coenosteum.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on page 44, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
Errinopsis Broch 1951
No full textGenus Errinopsis Broch, 1951 Errinopsis Broch, 1951 b: 40.—Boschma, 1956 a: F 104.—Cairns, 1983 a: 77–78; 1983 b: 455–457; 1992, 540: 545; Type Species. Errinopsis reticulum Broch, 1951 b, by original designation. Diagnosis. Colonies uniplanar to bushy, branching highly anastomotic (fenestrate), often with multiple attachments to substrate. Coenosteal texture a mixture of reticulate-granular and coarsely imbricate. Gastro- and dactylostyles uniformly arranged on branches. Gastrostyles present; dactylopore spines dimorphic, mound-like and horseshoe-shaped, the dactylotome facing downward (adcauline) as in Errina; dactylostyles absent. Ampullae superficial with lateral or apical efferent pores. Discussion. This is a rarely reported genus consisting of only two species, previously known only from Subantarctic South America. Holocene Distribution. Off southern South America and South Africa, 250– 771 m.Published as part of Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, pp. 1-57 in Zootaxa 3691 (1) on page 18, DOI: 10.11646/zootaxa.3691.1.1, http://zenodo.org/record/28423
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