Sertularella robusta Coughtrey 1876

Sertularella robusta Coughtrey, 1876

Figs 12D, 15 N-R; Table 22

Sertularella robusta Coughtrey, 1876: 27, pl. 3 fig. 6. – Leloup, 1960: 234, fig. 7. – Blanco, 1968: 215, pl. 4 figs 4-7. – p.p. Vervoort, 1972: 129, figs 40A, 41A. – Leloup, 1974: 33, fig. 27. – Blanco, 1976: 42, pl. 4 figs 1-3; 1994: 200. – Galea, 2007: 66, fig. 15E-I. – Galea et al., 2009: 2, 4. – p.p. El Beshbeeshy, 2011: 144, fig. 46A-D.

non Sertularella robusta. – p.p. Vervoort, 1972: 129, fig. 40B (= Sertularella microtheca Leloup, 1974). – p.p. El Beshbeeshy, 2011: 144, fig. 46E-H (= S. microtheca). – Soto Àngel & Peña Cantero, 2015: 996, fig. 7G [= (?) Sertularella tenella (Alder, 1856)].

Sertularella tenella. – Jäderholm, 1905: 31, pl. 12 fig. 8. – Ritchie, 1907: 78. – p.p. Rees & Thursfield, 1965: 138. – Blanco, 1963: 173, figs 7-8 [non Sertularella tenella (Alder, 1856)].

Sertularella stepanyantae El Beshbeeshy, 2011: 20 [new name for Vervoort’s (1972, p. 129) record of S. robusta Coughtrey, 1876; nomen nudum].

Material examined: HRG-0626; Chile, Región de los Lagos, southern Chiloé, west of Punta Inio, -43.39300° -74.11769°, 26 m, coll. HSFS, HF6, lot A565; 22.02.2008; male colony composed of both stolonal and erect stems, up to 5 mm high, epizoic on Symplectoscyphus milneanus (d’Orbigny, 1842). – HRG-0356; Chile, Región de Magallanes y de Antártica Chilena, Punta Arenas, Faro San Isidro, -53.78174° -70.97391°, 10 m, coll. D. Schories, lot PTA002; 25.02.2010; colony composed of numerous sterile stems, up to 15 mm high. – HRG-0797; Chile, Región de los Ríos, north of Corral, Chaihuin, -39.95730° -73.60245°, 6-12 m, coll. D. Schories; 06.03.2012; sterile stolonal colony epizoic on Halecium sp. – HRG- 0788; Chile, Región de Aysén, west of Canal Messier, -47.86020° -74.76023°, 5.3 m, coll. HSFS, HF13, lot C176; 16.03.2012; small colony composed of both stolonal hydrothecae and up to 4 mm high erect stems, bearing single male gonotheca. – HRG-1099; Chile, Región de los Lagos, Roca Gloria, -45.662433° -73.849266°, 20 m, coll. HSFS, HF21, lot #99; 05.04.2014; rich, fully fertile (male) colony composed mainly of stolonal hydrothecae and, occasionally, of short, erect stems (2-4 hydrothecate internodes), epizoic on Symplectoscyphus filiformis (Allman, 1888). – HRG- 1173; Chile, Región de los Lagos, southern Chiloé, Isla Yencouma, -43.4193° -74.0818°, 10 m, coll. HSFS, HF22, lot #65; 18.01.2015; a male colony composed of mostly stolonal hydrothecae, and a few, up to 3 mm high, erect stems. – NMSZ 1959.33.499; Burdwood Bank, -54.41667° -57.53333°, ca. 102 m, coll. Scottish National Antarctic (Scotia) Expedition 1902-1904; 01.12.1903; microslide (Fig. 12D) comprising 4 sterile stem fragments, 6-8 mm high, one of them branched once [material studied by Ritchie (1907, as S. tenella), and listed by Rees & Thursfield (1965, p. 138)].

Description: Stolonal hydrothecae or short, erect, unbranched or sparingly-branched stems arising from creeping, branching, filiform hydrorhiza. A varied number of annuli at the stem bases, immediately above origin from stolon. Stems and side branches, when present, exclusively monosiphonic, divided into moderately-long, geniculate internodes by means of oblique nodes slanting in alternate directions. A hydrotheca, or a hydrotheca and a lateral apophysis immediately below its basis, confined to the distal end of each internode; basally, a twist. Branches arise irregularly (every 1-7 stem hydrothecae) and in the same plane as the stem; up to 2nd order branching observed; structure similar to stem, though 1 st internode comparatively longer than subsequent ones. Hydrothecae biseriate, alternate, coplanar; flask-shaped, swollen basally, adnate for 2/5th their adaxial length; surface provided by 4-6 transverse ridges; rim with 4 small, triangular, equally-developed cusps separated by deep, rounded embayments; 3 distinctive, plate-shaped, internal projections of perisarc below the hydrothecal aperture (2 latero-adaxial, 1 abaxial); operculum composed of 4 triangular flaps forming a pyramidal roof. Gonothecae arising from below the hydrothecal bases; broadly ovoid, surface with 6-7 transverse ribs, aperture apical, surrounded by 4 pointed cusps; external acrocysts in female.

Dimensions: See Table 22.

Remarks: The typical shape of a stolonal colony is illustrated in Galea (2007, fig. 15E), and of an erect stem in Galea (2007, fig. 15F). The gonothecae are illustrated in Galea (2007, fig. 15G, I).

Distribution: Chile – Región de los Ríos [north of Corral (present study)]; Región de los Lagos [around Isla Grande de Chiloé (Leloup, 1974; Galea et al., 2009); Golfo de Ancud (Leloup, 1974); Roca Gloria (present study)]; Región de Aysén [Guaitecas Archipelago (Leloup, 1974; Galea, 2007); Canal Puyuhuapi (Galea et al., 2009); Canal Messier (present study)]; Región de Magallanes y de la Antártica Chilena [Canals Castillo, Copihue, Pasaje, and Pitt Chico, as well as Angostura Inglesa and Isla Camello (Galea, 2007); around Punta Arenas (present study); Magellan Strait (p.p. Vervoort, 1972)]. Patagonia – no localities given (Leloup, 1960). Argentina – Provincia de Río Negro [Golfo de San Matías (Blanco, 1994)]; Provincia de Santa Cruz [Puerto Deseado, Bahía Uruguay (Blanco, 1963, as S. tenella)]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [Argentinean waters off the northern coast of Isla Nueva, Tierra del Fuego (Blanco, 1968); off the eastern entrance of the Magellan Strait (Blanco, 1976); south of Sloggett Bay, Beagle Canal (Jäderholm, 1905, as S. tenella; p.p. Vervoort, 1972); around Península Mitre (p.p. Vervoort, 1972)]; numerous scattered records from the Patagonian Shelf, between 40°-54° S (p.p. El Beshbeeshy, 2011). Between Tierra del Fuego and the Falkland Is. (p.p. Vervoort, 1972). Burdwood Bank (Ritchie, 1907, as S. tenella).