Sertularella leiocarpa ( Allman, 1888 )

Horia R. Galea, Dirk Schories, Verena Häussermann & Günter Försterra, 2017, Taxonomic revision of the genus Sertularella (Cnidaria: Hydrozoa) from southern South America and the subantarctic, with descriptions of five new species, Revue suisse de Zoologie 124 (2), pp. 255-321 : 288-289

Sertularella leiocarpa ( Allman, 1888)

Fig. 13L, M ; Table 15

Sertularia leiocarpa Allman, 1888: 52 , pl. 25 figs 1, 1a.

Sertularella leiocarpa . – Stechow, 1925: 477, fig. 35. – Galea, 2015: 9, fig. 3P.

Material examined: HRG-1056; Tristan da Cunha group of islands, E of Inaccessible I., -37.32000° 12.60000°, 160 m, coll. British Antarctic Survey, Stn. 80, lot DB12-0340; 24.05.2013; a ca. 5 cm high, sterile stem bearing a single side branch.

Description: Colonies up to ca. 7.5 cm high, arising from thin hydrorhizal fibers. Stems mono- or lightly polysiphonic basally, moderately stiff, giving rise to roughly alternate, coplanar side branches; stems and branches divided into moderately long, slender, geniculate internodes by means of indistinct oblique nodes; a hydrotheca confined to the distal end of each internode; side branches given off irregularly, directly (no apophyses present) and laterally from below a stem hydrotheca; up to 2nd order branches. Hydrothecae long, tubular, adnate for ca. 1/3rd their length to the corresponding internode, then curving gently outwards; abaxial wall almost straight, free adaxial wall slightly convex proximally, then nearly straight for most of its length; aperture facing outwards, provided with 4 small, triangular cusps separated by very shallow embayments; usually without intrathecal, submarginal cusps, but occasionally 2-4 present, one below each embayment; a 4-flapped operculum. Gonothecae arising from the stem internodes at level of hydrothecal bases, on opposite side to hydrotheca; spindle-shaped, walls entirely smooth, apically 3-4 short spines.

Dimensions: See Table 15.

Remarks: The colony shape and the gonotheca are illustrated by both Allman (1888) and Millard (1975). Although generally absent, internal, submarginal hydrothecal cusps may occasionally occur ( Vervoort, 1966; Gili et al., 1989).

Distribution: Tristan da Cunha group of islands, Namibia, New Caledonia, New Zealand, as well as scattered records from the south and southeast Indian Ocean ( Galea, 2015).

Figures

Fig. 13. (A-D) Sertularella implexa (Allman, 1888). Colony fragments from holotype material (A) and Vervoort (1972, as S. picta) (B). Hydrothecae from the same sources (C and D, respectively). (E, F, H, I) Sertularella juanfernandezensis Galea, sp. nov. Portions of colonies from SMNH 123883 (E) and ZMB Cni 4421 (F), and comparison with S. polyzonias (Linnaeus, 1758) HRG- 0550 (G). Hydrothecae from the same sources (H, I and J, respectively). (L, M) Sertularella leiocarpa (Allman, 1888). Portion of colony (L) and hydrotheca (M) from HRG- 1056. Scale bars: 200 μm (C, D, H-J, M), 500 μm (K), 1 mm (A, B, E-G, L).