Symplectoscyphus filiformis ( Allman, 1888 )

Galea, Horia R., 2007, Hydroids and hydromedusae (Cnidaria: Hydrozoa) from the fjords region of southern Chile, Zootaxa 1597 (1), pp. 1-116 : 68-69

Symplectoscyphus filiformis ( Allman, 1888)

(fig. 16A–I, table 26)

Sertularia filiformis Allman, 1888: 51 , pl. 24 fig. 1.

Sertularella filiformis: Nutting, 1904: 97 , pl. 23 figs 1–3; Hartlaub, 1905: 636, fig. B 4. Material examined. Stn. CHL 02 —04.iii.2005, S80 (13–20 m): several fertile colonies, up to 7.5 cm high (MHNG INVE 53283). S77 (20 m): several fertile colonies, about 3.5 cm high (MHNG INVE 53272). Stn. COM 02 —12.i.2005, 12.5 m, S68: several sterile fragments, up to 3 cm high, on rock. Stn. COM 03 — 25.ii.2005, 15– 25 m, S70: several colonies and fragments, up to 5 cm high, all sterile (MHNG INVE 53257); S63: several sterile fragments, up to 4 cm high, 2 slides (MHNG INVE 53245); S65: several sterile colonies, about 4 cm high, 3 slides (MHNG INVE 53249). Stn. COM 05 —15.xi. 2001, 20 m, S71: numerous sterile fragments, about 3 cm high, 3 slides (MHNG INVE 53259). Stn. COM 07 —20.i.2006, 20– 25 m, S167: several sterile fragments, up to 4.5 cm high. Stn. COM 08 —25.xii. 2004, 7 m, S67: several fertile colonies, 6–7 cm high, 4 slides (MHNG INVE 53251). Stn. COM 09 —04.v. 2005, 38 m, S33: several fertile colonies and fragments, up to 6 cm high (MHNG INVE 53195). Stn. MEL 01 —08.iii.2005, 10– 15 m, S75: one sterile colony, 3.5 cm high, 3 slides (MHNG INVE 53266); S76: one sterile colony, less than 1 cm high, epizoic on Sertularella argentinica (MHNG INVE 53270). Stn. MEL 02 —06.iii. 2005, 15 m, S81: several colonies about 7 cm high, mostly sterile, but few gonothecae present in some parts. Stn. MEL 03 —08.iii.2005, 20– 30 m, S82: several fertile colonies, up to 7.5 cm high (MHNG INVE 53293); S90: several sterile colonies, mostly fragmentary, up to 2.5 cm high.

Type locality. Puerto Hambre (Port Famine), Patagonia, Chile .

Description. Bushy colonies arising from a rhizoid stolon, firmly attached to substrate; erect, monosiphonic, up to 7 cm high, branched in one plane; transparent to white in color. Dense assemblages generally composed of numerous colonies developing in parallel planes and interconnected by branches anastomosed at their tips. Branching pseudodichotomous, each branch arising generally every 2 or 3 consecutive hydrothecae. Stem and branches delimited into internodes by weak constrictions of perisarc above each hydrotheca; in some parts of colonies these may become invisible. Internodes long and straight. Branches inserted laterally below stem hydrothecae, thus becoming axillar and introducing a bend in longitudinal axis of stem, giving it a zigzag appearance; the situation is similar for the side branches which branch again. Hydrothecae biseriate, alternate, in same plane. Hydrotheca best described as tubular, with ad- and abcauline walls quite parallel. Free part of adcauline wall straight; length same as adnate part. Abcauline wall convex, with inflexion point in middle. Rim with three rounded cusps (one adcauline and two laterals) delimited by three relatively shallow embayments; 1–4 renovations present. Closing apparatus composed of three triangular flaps. Foramen visible below hydrothecal base. In some hydrothecae, an oblique septum present. Gonothecae numerous in some colonies, arising below hydrotheca; with 7–9 transverse frills, not spirally disposed; perisarc between frills with longitudinal striations; adnate part of gonotheca flattened. Terminal tube cylindrical, sometimes with slight constriction in middle part, aperture round, at end of tube. Gonothecal contents not seen, all gonothecae empty. Gonotheca male = female?

Remarks. The size of gonothecae and their number of frills is variable among colonies. The distinctive trait of this species is the presence of a cylindrical, narrow, terminal tube. In some cases, the gonothecae of S. subdichotomus ( Kirchenpauer, 1884) may closely resemble those of S. filiformis (see Blanco 1969).

Hydroid epibionts. Bougainvillia pyramidata ( Forbes & Goodsir, 1851) ; Phialella cf. quadrata ( Forbes, 1848) ; Filellum serratum ( Clarke, 1879) ; Hebella striata Allman, 1888 ; Halecium delicatulum Coughtrey, 1876 ; Campanularia cf. hincksii Alder, 1856 ; Clytia linearis ( Thornely, 1900) ; Clytia paulensis ( Vanhöffen, 1910) ; Obelia dichotoma ( Linnaeus, 1758) .

World distribution. Probably endemic to Chilean Patagonia ( Hartlaub 1905).

Records from Chile. Symplectoscyphus filiformis was previously reported from Puerto Hambre ( Hartlaub 1905). The present material was collected between 42°09' S and 43°56' S, the latter latitude being probably the most southerly limit for this species along the Chilean coast .