Phialella cf. quadrata ( Forbes, 1848 )

Galea, Horia R., 2007, Hydroids and hydromedusae (Cnidaria: Hydrozoa) from the fjords region of southern Chile, Zootaxa 1597 (1), pp. 1-116 : 39-42

Phialella cf. quadrata ( Forbes, 1848)

(fig. 9B–F, table 6)

Thaumantias quadrata Forbes, 1848: 43 , pl. 9 fig. 2.

Leptoscyphus tenuis Hincks, 1868: 197 , pl. 34 fig. 2.

Campanulina repens Hincks, 1868: 189 , pl. 38 figs 1, 1A.

Eucope globosa Mayer, 1910: 235 .

Phialella quadrata: Russell, 1953: 315 , figs 196–200, pl. 16 figs 4–6, pl. 17 fig. 5; Ralph, 1957: 848, fig. 8G–I; Kramp, 1959: 152, fig. 200; 1961: 180; 1968: 84, fig. 226; Fagetti, 1973: 40, pl. 3 figs C–D; Goy et al., 1991: 114, fig. 37; Cornelius, 1995a: 177, fig. 39; Vervoort & Watson, 2003: 28; Bouillon et al., 2004: 170, figs 91F–J, 92A–C.

? Phialella quadrata: Millard & Bouillon, 1973: 43 , fig. 5G–J;

Campanulina quadrata: Naumov, 1969: 335 , fig. 201

Campanulina turrida Millard, 1975: 139 , fig. 45B.

? Campanulina chilensis Hartlaub, 1905: 589 , figs L 2, M 2 b, N 2; Stechow, 1923: 128; Leloup, 1974: 3, fig. 1A–B; Stepanjants, 1979: 42, pl. 7 fig. 7.

? Phialella chilensis: Naumov & Stepanjants, 1962: 76 , fig. 3; Vervoort, 1972a: 38, fig. 10; Millard, 1977: 5, fig. 1A; El Beshbeeshy, 1991: 47, fig. 8; Blanco et al., 2000a: 271, figs 4–5.

Material examined. Stn. CHL 02 —04.iii.2005, S79 (13–20 m): a sterile colony, with both stolonal and erect growth forms, up to 6 mm high, epizoic on Symplectoscyphus sp. ( MHNG INVE 53279); S80 (13–20 m): a sterile colony, with both stolonal and erect growth forms, epizoic on Symplectoscyphus filiformis ( MHNG INVE 53285); S77 (20 m): a fertile colony, with both stolonal and erect growth forms, epizoic on Symplec- toscyphus filiformis ( MHNG INVE 53273). Stn. MEL 02 —06.iii. 2005, 15 m, S81: a sterile colony, with both stolonal and erect growth forms, epizoic on Symplectoscyphus filiformis . Stn. MEL 03 —08.iii.2005, 20– 30 m, S82: small, stolonal colonies, epizoic on Obelia dichotoma and Symplectoscyphus filiformis ; S90: a sterile colony, with both stolonal and erect growth forms, epizoic on Symplectoscyphus filiformis . Stn. CFA — 14.iii. 2006, 15 m, S125: sterile colonies, with both stolonal and erect growth forms, epizoic on Bougainvillia pyramidata or epiphytic on algae. Stn. CCO — 09.iii.2006, S144 (18 m): one sterile colony, epizoic on Symplectoscyphus sp. ; S140 (0–20 m): a small, stolonal colony, epizoic on Parascyphus repens , sterile. Stn. CPA — 09.iii. 2005, 15 m, S170: several sterile colonies, with both stolonal and erect growth forms, less than 1 cm high, epizoic on Symplectoscyphus subdichotomus . Stn. GDA — 07.iii. 2006, 11 m, S126: a small, sterile colony with both stolonal and erect growth forms, epizoic on Symplectoscyphus subdichotomus . Stn. CVI — 06.iii.2006, 15– 25 m, S128: one sterile colony, mainly stolonal but also with some small, erect shoots, on crab carapace. Plankton —off the Huinay Scientific Field Station, 02.xi.2006, 30–0 m, one poorly-preserved medusa.

Type locality. Firth of Forth , Great Britain .

Description. Colony stolonal or with erect shoots, up to 1 cm high, or with both arrangements in the same colony. Erect form with sympodial growth. Stems and branches annulated throughout, especially at origin of branches, or with portions of smooth or slightly wrinkled perisarc. Branches arising at acute angles from stem or low order branches. Hydrotheca small, of campanulinid type, thin walled, shorter than pedicel, oblongovoid, widest in middle, tapering slightly above and below, with thin diaphragm; distal third comprising membranous, conical pleated operculum, composed of several triangular flaps, forming a pointed roof; operculum without crease-line basally. Hydrotheca not sharply demarcated from pedicel. Hydranths are present in some specimens, but generally not extended and not well-preserved; therefore, the presence of an intertentacular web could not be checked. Gonothecae borne on stolon; ovoid, with basal part tapering into a short, twisted pedicel; apical part truncated and provided with circular aperture. Gonothecal contents badly preserved, comprising a single opaque, globular mass, occupying nearly the whole lumen.

The only poorly-preserved medusa specimen observed will not be described here. For a complete description, see Russell (1953).

Remarks. The polyp stage of P. chilensis Hartlaub, 1905 is similar to that of P. quadrata ( Forbes, 1848) , and they seem impossible to separate using morphological criteria. Vervoort (1972a) assigned his material from the Strait of Magellan to P. chilensis and found that the basal part of the hydrothecae was asymmetrical and had straight, conical walls, widening sightly from the base onwards. However, in his original description, Hartlaub (1905) figured the hydrothecae with either straight, conical walls (fig. L 2 c) or oblong-ovoid (figs L 2 b, M 2 b, N 2). Moreover, Leloup (1974) pointed out the variability in the shape of hydrothecae in his Chilean material. Therefore, this character has probably no taxonomic significance.

Gonothecae of P. chilensis have been found only a few times ( Naumov & Stepanjants 1962, Blanco et al. 2000a), and they are similar to those described for P. quadrata . Despite these resemblances, several authors ( Naumov & Stepanjants 1962, Vervoort 1972 a, Millard 1977, El Beshbeeshy 1991, Blanco et al. 2000a) kept both species separated, waiting until the mature medusa of the former is reared to maturity.

However, only two medusae belonging to genus Phialella have been reported from South America, namely P. quadrata ( Fagetti 1973, Palma et al. 2007, present study) and P. falklandica Browne, 1902 ( Vanhöffen 1913, Kramp 1959 and 1968, present study). Therefore, it seems reasonable to assume that the hydroid identified as P. chilensis must be the benthic stage of one of the two species of medusae. The hydroid of P. falklandica is still unknown, but hydroids belonging to genus Phialella are not expected to differ much. The present material is here assigned to P. quadrata . Comparative measurements of P. chilensis and P. quadrata hydroids are listed in table 6.

World distribution. The hydroid stage of P. chilensis was reported from the Strait of Magellan ( Vervoort 1972a), Antarctica ( Naumov & Stepanjants 1962), Auckland and Crozet Island ( Millard 1977) and Japan ( Stechow 1923). Both the hydroid and medusa stages of P. quadrata are widespread in coastal waters of Atlantic and Indo-Pacific Oceans ( Cornelius 1995a).

Records from Chile. The hydroid stage of P. chilensis was previously recorded from Calbuco ( Hartlaub 1905), Coquimbo Bay, north of Golfo de Ancud, Strait of Magellan and Seno Ultima Esperanza ( Leloup 1974). The present hydroid material was collected roughly between 43° and 52° S. The medusa stage of P. quadrata occurs along the entire Chilean coast ( Fagetti 1973, Palma et al. 2007).

Table 6 continued