Sertularella contorta Kirchenpauer, 1884

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 : 268-271

Sertularella contorta Kirchenpauer, 1884

Figs 1 E-G, 6 , 7 A-H; Table 5

Sertularella contorta Kirchenpauer, 1884: 39 , pl. 15 figs 2, 2a. – p.p. Hartlaub, 1901: 83, pl. 4 fig. 26, pl. 6 figs 14-16 (reexamination of the cotype). – Nutting, 1904: 85, pl. 18 figs 7-9. – Hartlaub, 1905: 647. – Jäderholm, 1905: 31, pl. 12 figs 9-10. – Ritchie, 1907: 76. – Bedot, 1916: 202; 1918: 236. – Billard, 1924: 61. – p.p. Rees & Thursfield, 1965: 133.

(?) Sertularella lagena Allman, 1876: 114 . – Allman, 1879: 283, text-fig. – Studer, 1879: 120. – Kirchenpauer, 1884: 40. – Bedot, 1912: 355; 1916: 207; 1918: 240. – Stechow, 1925: 475, fig. 34.

non Sertularella ? lagena . – Galea & Schories, 2012a: 41, fig. 4K-L (= Sertularella antarctica Hartlaub, 1901 ).

Sertularella polyzonias . – p.p. Jäderholm, 1910: 4. – p.p. Vanhöffen, 1910: 322 [non Sertularella polyzonias ( Linnaeus, 1758) ].

Material examined: NMSZ 1921.143.1351.C; Falkland Is., Cape Pembroke, coll. Scottish National Antarctic ( Scotia ) Expedition 1902-1904, shore; 01.1903-01.1904; a profuse, fertile (female) colony with numerous stems, up to 4.5 cm high, on pneumatocyst of Macrocystis pyrifera [material studied by Ritchie (1907), and listed by Rees & Thursfield (1965, p. 133)]. – NMSZ 1921.143.1351.D; Falkland Is., Cape Pembroke, coll. Scottish National Antarctic ( Scotia ) Expedition 1902-1904, shore; 01.1903-01.1904; a fertile (female) colony composed of several stems, up to 6 cm high, on Macrocystis pyrifera [material studied by Ritchie (1907), and listed by Rees & Thursfield (1965, p. 133)]. – SMNH 123884; Falkland Is., Port William, 5 m, Swedish Magellanic Expedition 1907- 1909, coll. C. Skottsberg; 10.02.1908; microslide ( Fig. 1E ) containing several fragments (up to 1.3 cm high) of a fertile colony, assigned by Jäderholm (1910) to Sertularella polyzonias ( Linnaeus, 1758) . – SMNH 123851; Falkland Is., Port William, 40 m, coll. Swedish South Polar Expedition 1901-1903, Stn. 39; 04.07.1902; microslide ( Fig. 1G ) containing 2 species: 1) on the lefthand side, a ca. 2 cm high, fertile colony assigned to the present species by Jäderholm (1905), re-illustrated herein in Fig. 6C, I ; 2) on the right-hand side, two sterile colonies fragments, 1.3 and 1.5 cm high, assignable to S. subantarctica sp. nov. (see below), but identified by Jäderholm (1905) as S. allmani Hartlaub, 1901 , and illustrated by him in his pl. 12 fig. 11, re-illustrated herein in Fig. 16K, O). – ZMB Cni945; French Southern and Antarctic Lands, Kerguelen Is., Observatory Bay, coll. Deutsche Südpolar (Gauss) Expedition 1901- 1903; 15.02.1902; a sterile, fragmentary colony, 2.5 cm high [material studied by Vanhöffen (1910), as S. polyzionias ]. – ZMN Cni620; French Southern and Antarctic Lands, Kerguelen Is., Port Gazelle, coll. Deutsche Tiefsee ( Valdivia ) Expedition 1898-1899; 28.12.1898; a fully fertile (male) colony, 2.5 cm high. – ZSM 20050442; French Southern and Antarctic Lands, Kerguelen Is., coll. Deutsche Tiefsee ( Valdivia ) Expedition 1898-1899, Stn. 160; 28.12.1898; microslide ( Fig. 1F ) containing two fertile (female) colony fragments, 9 and 13 mm high [material identified by Stechow (1925) as S. lagena Allman, 1876 ].

Description: Colonies erect, bushy, up to 6 cm high in inspected material (but up to 8 cm in the type), arising from dense mat of branching, intertwined stolonal fibers. Stems and basal parts of side branches either monosiphonic or fascicled in older colonies; divided into regular, slightly geniculate, rather short internodes by means of oblique constrictions of the perisarc; each internode with a couple of proximal twists, a distal swelling, and a hydrotheca, or a hydrotheca and a short, lateral apophysis below its base, confined to its distal part; branching pattern more or less regular, with generally every two consecutive apophysisbearing internodes separated by a couple of internodes not supporting side branches; occasionally, only one apophysis-bearing internode is given off, instead of two consecutive ones, or successive apophysisbearing internodes or couples of them are separated by 1 or 3 (instead of 2) internodes devoid of apophyses ( Fig. 7A ). Branching pattern of side branches similar to that of stem, though more irregular, with much spaced successive branchlets; proximal most internode generally slightly longer than subsequent ones, and provided with 2-3 spiral twists basally; branching up to at least 6th order. Basalmost side branches generally longer, hence more developed, than uppermost ones. Branches and hydrothecae shifted on to one side of the stem and forming an angle of less than 90°. Hydrothecae flask-shaped, distinctly swollen adaxially, adnate for about 1/3rd or less to corresponding internode; abaxial wall slightly concave to nearly straight for most of its length; free adaxial wall sigmoid, convex in middle; hydrotheca expanding below rim on both ab- and adaxial sides; rim thickened, provided with 4 triangular cusps, of which the abaxial one is distinctly produced, and the laterals asymmetrical; three internal, submarginal cusps (2 latero-adaxial and 1 abaxial) of varied development, sometimes absent. Gonothecae arising from below the hydrothecal bases; male similar to female; broadly ovoid, tapering below, transversely wrinkled, distally with 4 short spines. The perisarc of the colony may be either thin or thick.

Dimensions: See Table 5.

Remarks: Although quite succinct, the description of Sertularella contorta given by Kirchenpauer (1884) does not allow an indisputable identification to be made in the absence of a reexamination of the type material (N.B.: this material could not be found in ZMB, where Kirchenpauer’s “herbarium” was recently located; C. Lüter, pers. comm.). Some statements provided in the original account proved inaccurate, as for example the lack of unilateral arrangement of the hydrothecae, which was subsequently disputed by Hartlaub (1901). The latter author reexamined the (then extant) cotype material, and provided more accurate details on its morphology, allowing a somehow easier identification of this species. The materials NMSZ 1921.143.1351.C&D assigned to S. contorta by Rees & Thursfield (1965), and reexamined here, agree with the available data on this species.

Sertularella contorta comes close to S. gaudichaudi ( Lamouroux, 1824) through the shape (but not the size) of its internodes, and both the shape and size of its hydrothecae. Indeed, the length of the internodes in the later varies considerably (from short to exceedingly long), while it is uniformly short in the present species (this feature results also from Kirchenpauer’s pl. 15 fig. 2). In addition, the mode of branching of S. contorta recalls that met with in S. allmani (with stem internodes devoid of lateral apophyses intercalating among those bearing these structures), while S. gaudichaudi exhibits a much denser branching pattern (with almost every stem internode bearing an apophysis supporting a branch). However, these differences should, perhaps, not be regarded as purely species-specific, especially given that a quite limited number of samples corresponding to both nominal species have been examined in the frame of the present study. Future collecting and molecular analyses are expected to clarify their relationships.

The Chilean material collected by Philippi and assigned by Hartlaub (1901) to the present species, although quite similar morphologically, should be better assigned to S. gaudichaudi ( Lamouroux, 1824) owing to the presence of long stem internodes among the otherwise short ones (see remarks under the latter species).

Distribution: Falkland Is. ( Kirchenpauer, 1884; Jäderholm, 1905; Ritchie, 1907; Jäderholm, 1910, as S. polyzonias ). Le Maire Strait ( Kirchenpauer, 1884). French Southern and Antarctic Lands – Kerguelen Is. ( Allman, 1876; 1879, both as S. lagena ; Vanhöffen, 1910, as S. polyzonias ; Stechow, 1925, as S. lagena ; present study).

Figures

Fig. 1. (A, B) Sertularella allmani Hartlaub, 1901. Two holotype slides of Sertularia secunda Allman, 1888 (= Sertularia unilateralis Allman, 1888). (C) Sertularella blanconae El Beshbeeshy, 2011, material identified as S. gayi (Lamouroux, 1821) by Jäderholm (1903). (D) Sertularella clausa (Allman, 1888), holotype slide. (E, F) Sertularella contorta Kirchenpauer, 1884 identified as S. polyzonias (Linnaeus, 1758) by Jäderholm (1910) (E) and S. lagena Allman, 1876 by Stechow (1925) (F), respectively. (G) Slide material studied by Jäderholm (1905), containing S. contorta (colony on the left-hand side) and S. subantarctica Galea, sp. nov. (colony on right-hand side), the latter identified by him as S. allmani. (H-K) Sertularella gaudichaudi (Lamouroux, 1824). Slide materials identified as S. picta (Meyen, 1834) (H), S. antarctica Hartlaub, 1901 (I) and S. protecta Hartlaub, 1901 (J) by Jäderholm (1903); as S. protecta by Stechow, according to Rees & Thursfield (1965) (K).

Fig. 6. Sertularella contorta Kirchenpauer, 1884 (part). Colony fragments from NMSZ 1921.143.1351. C (A), NMSZ 1921.143.1351. D (B), SMNH 123851 (C), SMNH 123884 (D) and ZSM 20050442 (E). Hydrothecae from NMSZ 1921.143.1351. C (F-H) and SMNH 123851 (I). Scale bars: 200 μm (F-I), 1 mm (A-E). ►

Fig. 7. (A-H) Sertularella contorta Kirchenpauer, 1884 (continued). Mode of branching (A). Hydrothecae from NMSZ 1921.143.1351. D (B), SMNH 123884 (C) and ZSM 20050442 (D). Gonothecae from NMSZ 1921.143.1351. C (E), NMSZ 1921.143.1351. D (F), SMNH 123851 (G) and SMNH 123884 (H). (I-L) Sertularella cruzensis El Beshbeeshy, 2011. Colony fragments from holotype (I) and Vervoort (1972, as S. conica) (J). Hydrothecae from the same sources (K and L, respectively). (M, N) Sertularella curta Galea & Schories, 2014. Portion of stem with basal part of a side branch from MHNG-INVE- 86236 (M), and hydrotheca from HRG- 0721 (N). Scale bars: 200 μm (B-D, K, L, N), 500 μm (E-H), 1 mm (I, J, M).