Sertularella

Galea, Horia R. & Schories, Dirk, 2012, Some hydrozoans (Cnidaria) from Central Chile and the Strait of Magellan, Zootaxa 3296, pp. 19-67 : 40-41

Sertularella ? implexa ( Allman, 1888)

(pl. 3F, fig. 4F–J, table 3)

Sertularia implexa Allman, 1888: 54 , pl. 26, figs 1, 1a.

Sertularella polyzonias — El Beshbeeshy, 1991: 179, fig. 45. — El Beshbeeshy, 2011: 141, fig. 45 [not S. polyzonias (Linnaeus, 1758) ].

Material examined. Stn. FSI — 04.i.2011, S36 (40 m): a small, sterile fragment, 7 mm long, epizoic on Symplectoscyphus magellanicus ; 05.i.2011, S11 (40 m): obviously a single bushy colony coming as several fertile stems detached from substrate, up to 5.5 cm high (MHNG-INVE-79627); 07.i.2011, S03 (40 m): a sterile, branched fragment, 2 cm high, on worm tube.

TABLE 3. Measurements of Sertularella cf. implexa ( Allman, 1888) , in µm. *Calculated from El Beshbeeshy's (2011) fig. 45.

Description. Hydrorhiza missing, but stems above stolon comprising an ahydrothecate basal part of variable length, with several basal wrinkles; stems monosiphonic; perisarc slightly brownish in older parts, becoming transparent in younger ones. Above base, stems divided into internodes by means of oblique constrictions of the perisarc; stem and branches of geniculate appearance. Branching pattern irregular, side branches arising every 1–8 stem hydrothecae, and branching again several times; branches arise laterally from the base of a hydrotheca and are in the same plane with the higher-order branches; in rare instances, branches may be given off from within the hydrothecae. As the branching develops further, branches undergo a little torsion to accommodate newly-formed branches, so that the branching pattern of the colony appears as three-dimensional, though rather laterally compressed. Stems and branches of similar structure, except for the first internode of each side branch, which is comparatively longer than the others and has a couple of basal wrinkles. Following internodes rather long, with a distal hydrotheca. Axis of hydrotheca making an angle of about 20° with that of internode. Hydrotheca adnate for 1/3rd of its length; free adaxial side considerably swollen basally, decidedly convex, becoming concave towards aperture; abcauline side longer than others, straight or nearly so basally, becoming convex distally, where it forms a neck region, which further widens to form the aperture; the latter tilted outwards and upwards; no internal cusps. Gonothecae borne on stems and branches, arising from below bases of hydrothecae. Ovoid in general outline, walls wrinkled, wrinkles more obvious distally, becoming less marked proximally; aperture surrounded by 3–4 pointed perisarc projections. Gonothecae spent, sex could not be ascertained.

Remarks. The present material is provisionally assigned to S. implexa ( Allman, 1888) , pending the reexamination of the type specimen (if still extant) of this species. There is no doubt that the material assigned to S. polyzonias (Linnaeus, 1758) by El Beshbeeshy (2011) is conspecific with ours.

Through the shape of its hydrothecae, this species shows several similarities to both S. fuegonensis El Beshbeeshy, 2011 and S. sanmatiasensis El Beshbeeshy, 2011 . However, the colonies of the former are strictly coplanar, the hydrothecae are more closely-set and less deep, and are provided with internal cusps (Galea 2007), whilst those of S. sanmatiasensis have more wrinkled free adaxial walls and shorter neck regions ( El Beshbeeshy 2011).

Distribution in Chile. The present records are from the Strait of Magellan.

World records. Between Cape Virgins and the Falkland Islands ( Allman 1888), off the Argentinean provinces of Santa Cruz and Chubut, and around Falkland Islands ( El Beshbeeshy 2011).