Sertularella valdiviae Stechow, 1923b

Horia R. Galea, Dirk Schories, Verena Häussermann & Günter Försterra, 2017, Taxonomic revision of the genus Sertularella (Cnidaria: Hydrozoa) from southern South America and the subantarctic, with descriptions of five new species, Revue suisse de Zoologie 124 (2), pp. 255-321 : 306

Sertularella valdiviae Stechow, 1923b

Figs 12G, H , 17 I-L, 18 A-D; Table 26

Sertularella valdiviae Stechow, 1923b: 11 . – Stechow, 1925: 471, fig. 31. – Ruthensteiner et al., 2008: 23.

Sertularella jorgensis El Beshbeeshy, 2011: 136 , fig. 43 (syn. nov.). – Soto Àngel & Peña Cantero, 2015: 994, fig. 7E-F.

non Sertularella jorgensis . – Galea, 2007: 63, fig. 14G, H. – Galea et al., 2007c: 312, fig. 4B [= Sertularella tenella ( Alder, 1856) ].

Sertularella gayi parva . – Blanco, 1968: 217, pl. 4 figs 8-11; 1994: 199 [non Sertularella gayi ( Lamouroux, 1821) var. parva Billard, 1925 ].

Material examined: ZSM 20050521; French Southern and Antarctic Lands, 7 km west off St. Paul, -38.66667° -77.64333°, 672 m, coll. Deutsche Tiefsee ( Valdivia ) Expedition 1898-1899, Stn. 165; 03.01.1899; microslide ( Fig. 12G ) comprising five colony fragments of Sertularella valdiviae Stechow, 1923 , 3-23 mm high, one of which is fertile and bears 8 empty gonothecae. – ZSM 20050522; French Southern and Antarctic Lands, 7 km west off St. Paul, -38.66667° -77.64333°, 672 m; 03.01.1899; coll. Deutsche Tiefsee ( Valdivia ) Expedition 1898-1899, Stn. 165, microslide ( Fig.

12H) comprising three colony fragments (one of which bearing a gonotheca) of S. valdiviae , 6-14 mm high. – ZMH C11886; FRV Walther Herwig, Stn. 257, Argentine Shelf, -53.93333° -63.85000°, depth not recorded; 06.02.1971; several sterile, erect stems of Sertularella jorgensis El Beshbeeshy, 2011 , up to 5 mm high, showing terminal stolonization, as well as a number of stolonal hydrothecae on the same hydrorhiza, both with remains of coenosarc only. – ANT XIX/5 ID.91; RV Polarstern, cruise ANT XIX/5, Stn. 253, Elephant I., -61.40050° -55.41200°, 276-282 m; 25.04.2012; sterile colony composed of several stems up to 3.5 cm high [material studied by Soto Àngel & Peña Cantero (2015), as S. jorgensis ].

Description: Monosiphonic, slender, irregularly and sparingly-branched stems, up to 4 cm high, arising from creeping, filiform hydrorhiza; prisarc smooth or with 2-3 basal twists above origin from stolon. Stems and branches divided into long, geniculate internodes; nodes oblique, not always clearly demarcated; a hydrotheca confined to the distal end of each internode. Branches arising from below a stem hydrotheca, not always strictly laterally, but shifted on to the anterior or posterior sides of the stem, giving the colony a three-dimensional appearance; up to 4th order branching observed; branches with similar structure as that of stem; 1 st internode comparatively longer than subsequent ones, and provided with 1-2 basal twists. Hydrothecae biseriate, alternate, distant from one another, occasionally not strictly coplanar; rather long, tronconical to almost tubular, adnate for a varied length, from 1/2 to 2/5th fused with the corresponding internode; abaxial wall slightly concave to straight, free adaxial wall with 2-4 wrinkles extending towards abaxial wall; 4 small, triangular marginal cusps separated by shallow embayments; a 4-flapped operculum; rim occasionally renovated; hydranths with 14-18 tentacles. Gonothecae given off from below the bases of cladial hydrothecae, elongated-ovoid, significantly tapering below, distally rounded, devoid of a neck region and perisarcal projections, walls with 4-6 transverse wrinkles.

Dimensions: See Table 26.

Remarks: By comparing parts of El Beshbeeshy’s (2011) and Soto Àngel & Peña Cantero’s (2015) materials assigned to S. jorgensis to the type of S. valdiviae Stechow, 1923b , it appears that there are no morphological differences between them (compare Fig. 17I, J and K, respectively). Both nominal species prove coterminous, with S. valdiviae having priority over El Beshbeeshy’s species. The gonothecae, not already known in S. jorgensis , are only present in the St. Paul material.

Distribution: Argentina – Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off the southeastern coast of Isla de los Estados ( Blanco, 1968; 1994, both as S. gayi parva )]; scattered records from the Argentine Shelf, ranging between 42°-46° S ( El Beshbeeshy, 2011, as S. jorgensis ). Between Península Mitre and the Falkland Is. ( El Beshbeeshy, 2011, as S. jorgensis ). Scotia Arc – South Sandwich Is., Elephant I. ( Soto Àngel & Peña Cantero, 2015, as S. jorgensis ). French Southern and Antarctic Lands – St. Paul ( Stechow, 1923b, 1925).

Figures

Fig. 12. (A) Sertularella (?) hermanosensis El Beshbeeshy, 2011. Likely a fragment of this species mounted on slide, as part of the type material of S. implexa (Allman, 1888). (B) Sertularella implexa (Allman, 1888), fragment from type colony mounted on slide. (C) Sertularella juanfernandezensis Galea, sp. nov., identified as S. polyzonias (Linnaeus, 1758) by Jäderholm (1910). (D) Sertularella robusta Coughtrey, 1876, identified as S. tenella (Alder, 1857) by Ritchie (1907). (E, F) Sertularella subantarctica Galea, sp. nov. Materials identified as S. allmani Hartlaub, 1901 by Jäderholm (1910, 1905) (E, F, respectively). (G, H) Sertularella valdiviae Stechov, 1923 a, two slides prepared from type colony.

Fig. 18. (A-D) Sertularella valdiviae Stechow, 1923 b (continued). Hydrothecae from ANT XIX / 5 ID. 91 (A), ZSM 20050522 (B) and ZSM 20050521 (C). Gonothecae from the latter source (D). (E) Sertularella vervoorti El Beshbeeshy, 2011, internode with hydrotheca. Scale bars: 200 μm (A-C, E), 500 μm (D).