Hebella striata Allman, 1888

Galea, Horia R., Schories, Dirk, Försterra, Günter & Häussermann, Verena, 2014, New species and new records of hydroids (Cnidaria: Hydrozoa) from Chile, Zootaxa 3852 (1), pp. 1-50 : 6

Hebella striata Allman, 1888

( Fig. 1 C, D)

Material examined. HF7, Remolina, lat. -41.80727, long. -73.52517, 23.i.2009, 23 m, sample B244: colony on Eudendrium sp., several gonothecae present (MHNG-INVE-86207). HF16, East of Seño Contreras, lat. -50.34242, long. -75.2259, 24.iv.2013, 22 m, sample 579: colonies on Symplectoscyphus filiformis ( Allman, 1888) and Lafoea dumosa (Fleming, 1828) , one gonotheca found (MHNG-INVE-86206).

Remarks. Details on the trophosome of this species have been given in an earlier account (Galea 2007). Several gonothecae occur in the present material. They are large, tubular, tapering gradually basally into an indistinct pedicel of varied length. Distally truncated and covered by a thin layer of perisarc that is ruptured upon release of the gonophore, thus producing a four-flapped “operculum”. Elsewhere, the perisarc is transversely wrinkled, but the striations are coarser than on the hydrotheca, and fade off basally. In order to preserve the integrity of samples, only the depicted gonotheca ( Fig. 1 D) was measured: it is 2220 µm long and 510 µm wide just above the aperture. There is one gonophore per gonotheca, and no morphological details could be observed in this fairly well preserved material. In contrast, Hartlaub (1905) figured several medusa buds in a conspicuously curved gonotheca.

Distribution in Chile. The northern limit of this species is probably the Ancud Gulf and the Calbuco Channel ( Leloup 1974), while it reaches Tierra del Fuego in the South ( Hartlaub 1905).

World records. A subantarctic and Antarctic species ( Vervoort 1972, Millard 1977).

Figures

FIGURE 1. A, B: Hebella cf. scandens (Bale, 1888) — hydrotheca (A); gonotheca (B). C ‒ D: Hebella striata Allman, 1888 — hydrotheca (C); gonotheca (D). E, G, H: Phialella? falklandica Browne, 1902 — portion of erect stem (E) compared with that of P. quadrata (Forbes, 1848) (F); gonotheca seen laterally (G) and apically (H), compared with those of P. quadrata (I, stolonal; J, borne of stem). K, L: Silicularia? bilabiata (Coughtrey, 1876) — two hydrothecae (K); female gonotheca (L). M ‒ O: Silicularia rosea Meyen, 1834 — two hydrothecae (M) compared with specimens from Tristan da Cunha assigned to S. hemisphaerica (Allman, 1888) (P); female (N) and male (O) gonothecae, compared to homologous gonothecae (Q and R, respectively) from Tristan. S: Halecium corrugatissimum Trebilcock, 1828 — small stem with female gonotheca. Scale bars: 300 µm (A, B, E, F, S), 500 µm (C, D, G ‒ J), and 1 mm (K ‒ R).