Sertularella gaudichaudi ( Lamouroux, 1824 )

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 : 275-281

Sertularella gaudichaudi ( Lamouroux, 1824)

Figs 1 H-K, 8J, 9, 10; Tables 9, 10

Sertularia gaudichaudi Lamouroux, 1824: 615 , pl. 90 figs 4, 5. – Van Praët, 1979: 901, fig. 47 (reexamination of schizoholotypes).

Sertularella gaudichaudi . – Bedot, 1905: 105. – Billard, 1909: 317, fig. 4A (reexamination of the holotype). – Bedot, 1910: 360; 1912: 354; 1916: 204; 1918: 238. – Billard, 1924: 61 (reexamination of the holotype). – Van Praët, 1979: 901, fig. 47. – Ramil et al., 1992: 518, fig. 15 (reexamination of schizoholotypes).

non Sertularella gaudichaudi . – Cornelius, 1979: 282, fig. 20 [= S. ellisii ( Deshayes & Milne-Edwards, 1836) , S. fusiformis ( Hincks, 1861) , and S. mediterranea Hartlaub, 1901 ]. – García Corrales et al., 1980: 30, fig. 10 [= S. ellisii ( Deshayes & Milne-Edwards, 1836) ]. – Gili et al., 1989: 101, fig. 26B, C (= S. cf. mediterranea Hartlaub, 1901 ).

Sertularella gaudichaudii . – Kirchenpauer, 1884: 38 (incorrect subsequent spelling).

Sertularia picta Meyen, 1834: 201 , pl. 34 figs 1-3 (syn. nov.). – Hartlaub, 1901: 77, pl. 5 fig. 14, pl. 6 figs 17, 18 & 20 (reexamination of the cotype). – Jäderholm, 1903: 282. – Nutting, 1904: 90, pl. 20 figs 5-7. – Bedot, 1905: 105; 1910: 361. – Hartlaub, 1905: 645, fig. L4. – Billard, 1922: 106, fig. 2B. – Stechow, 1923a: 187, fig. B1 (reexamination of cotype). – Naumov & Stepanjants, 1962: 88. – Blanco, 1963: 175, figs 3-4. – (?) Millard 1971: 405, fig. 6A; 1977: 25, fig. 6A-D. – Blanco, 1994: 199. – Branch & Williams, 1993: 12, text-fig. – El Beshbeeshy, 2011: 138, fig. 44.

non Sertularella picta . – Blanco, 1967: 112, pl. 3 figs 1-7 (= Sertularella mediterranea Hartlaub, 1901 ). – Millard, 1971: 405, fig. 6B (= S. subantarctica Galea , sp. nov.). – Vervoort, 1972: 113, figs 34, 35C [= Sertularella implexa ( Allman, 1888) ]. – Vervoort, 1972: 114, fig. 35A, B (= Sertularella fuegonensis El Beshbeeshy, 2011 ).

Sertularella protecta p.p. Hartlaub, 1901: 79, pl. 6 figs 21-26 (syn. nov.). – Hartlaub, 1905: 652, fig. R4. – Billard, 1924: 62. – p.p. Jäderholm, 1903: 282. – Rees & Thursfield, 1965: 135.

(?) Sertularella margaritacea Allman, 1885: 133 , pl. 7 figs 3, 4. – Nutting, 1904: 95, pl. 22 fig. 1. – Hartlaub, 1905: 657, fig. V4. – Bedot, 1916: 208; 1918: 240. – Billard, 1924: 60.

Sertularella allmani. – Naumov & Stepanjants, 1962: 86 (non Sertularella allmani Hartlaub, 1901 ).

Sertularella antarctica . – p.p. Jäderholm, 1903: 283 (non Sertu- larella antarctica Hartlaub, 1901 ).

Sertularella contorta . – p.p. Hartlaub, 1901: 83 (non Sertularel- la contorta Kirchenpauer, 1884 ).

Sertularella polyzonias . – p.p. Vanhöffen, 1910: 322 [non Ser- tularella polyzonias ( Linnaeus, 1758) ].

Material examined: ZMH C04172; Chile, Región de Magallanes y de la Antártica Chilena, Isla Lennox, coll. Michaelsen no. 181; 22.12.1892; fertile colony (stranded on beach) with multiple fascicled stems, up to ca. 7.5 cm high [material examined by Hartlaub (1901, p. 79) and assigned by him to S. picta ( Meyen, 1834) ]. – ZMH C04173; Chile, Región de Magallanes y de la Antártica Chilena, Lennox Cove, coll.

Michaelsen no. 182; 24.12.1892; fertile colony with multiple monosiphonic stems, up to 4 cm high, on kelp (type of S. protecta Hartlaub, 1901 ). – SMNH 123894; Chile, Región de Magallanes y de la Antártica Chilena, Lennox Cove, coll. Swedish Tierra del Fuego Expedition 1895-1896; 05.02.1896; microslide ( Fig. 1J ) containing 2 badly preserved, fertile colony fragments, both ca. 2.5 cm high [material identified by Jäderholm (1903) as S. protecta Hartlaub, 1901 ]. – SMNH 123881; Chile, Región de Magallanes y de la Antártica Chilena, Isla Lennox, 18-45 m, coll. Swedish Tierra del Fuego Expedition 1895-1896; 07.02.1896; microslide ( Fig. 1H ) containing 3 colony fragments 1.7-2.0 cm high, two of which bear gonothecae [material identified by Jäderholm (1903) as S. picta ( Meyen, 1834) ]; with small, epizootic colony of Halecium annuliforme Galea & Schories, 2012a , bearing an incipient gonophore of unassignable sex. – SMNH 123837; Chile, Región de Magallanes y de la Antártica Chilena, Isla Nueva, coll. Swedish Tierra del Fuego Expedition 1895-1896; 07.02.1896; microslide ( Fig. 1I ) containing a ca. 6 cm high, fertile colony fragment [material identified by Jäderholm (1903) as S. antarctica Hartlaub, 1901 ; a second identification, contorta , was subsequently added to the label]. – NMSZ 1959.33.472; Patagonia; microslide ( Fig. 1K ) comprising 2 colony fragments, 0.5 and 1.0 cm high, the largest bearing 2 gonothecae [material belonging to Ritchie’s collection, identified by Stechow as S. protecta Hartlaub, 1901 , and listed by Rees & Thursfield (1965, p. 135)]. – ZMB Cni1122; Chile, coll. Philippi, no additional data; a very fragmented, badly preserved fertile colony composed of numerous pieces up to 1.6 cm high, with fascicled portions of stem [material studied by Hartlaub (1901) and assigned by him to S. contorta Kirchenpauer, 1884 ]. – ZMB Cni946; French Southern and Antarctic Lands, Kerguelen Is., Royal Sound, coll. Deutsche Südpolar (Gauss) Expedition 1901-1903; 01.01.1902; a fully fertile (male) colony, 3 cm high [material studied by Vanhöffen (1910), as S. polyzonias ].

Description: Slender, straggling, repeatedly branched, tangled colonies, up to 21 cm high, with mono- or polysiphonic stems and branches; these divided by oblique nodes into internodes of highly variable length, from short to exceedingly long and slender; each internode with a couple of spiral twists proximally, a hydrotheca distally, and a short, lateral apophysis below its base; apophyses alternate, supporting side branches with the same structure as the stem, though internodes generally shorter; first internode with 2-4 spiral twists basally. Side branches and hydrothecae shifted on to one side (“anterior”) of the colony, the two rows forming a moderately wide angle. Hydrothecae short, flask-shaped, distinctly swollen adaxially; abaxial wall straight or nearly so; free adaxial wall convex for most of its length, becoming concave below aperture; margin with 4 short, triangular, unequally-developed cusps: abaxial one generally produced, occasionally less so; adaxial one the shortest; lateral ones asymmetrical, the “anterior” one comparatively shorter than “dorsal” one; rim generally thickened; internal, submarginal cusps of varied development: from absent, to 2 latero-adaxial, to a complete set of 3 (one abaxial and 2 latero-adaxial); a variously developed perisarc plug at the end of the adnate adaxial wall, forming an incomplete foramen for the passage of the hydranth. Gonothecae borne on both stems and branches; broadly ovoid, with 3-4 transverse ridges in distal half, smooth in the lower half; aperture on short collar surrounded by generally 4 blunt spines (occasionally 3-5).

Dimensions: See Table 9.

Remarks: The holotype colony of Sertularia gaudichaudi , stored in Caen, France, and reexamined earlier by Billard (1909; 1922), was lost during WWII ( Redier, 1967). However, two schizoholotype slides (MNHN H.L. 615 & 616) were prepared by Billard from that colony ( Van Praët, 1979), and were reexamined subsequently by Ramil et al. (1992). Unfortunately, those slides could not be located for the purpose of the present study (A. Andouche, Muséum national d’Histoire naturelle, Paris, pers. comm.).

The cotype of Sertularia picta was reexamined by Hartlaub (1901) and Stechow (1920; 1923a), who provided additional information and more accurate illustrations.

The synonymy between these two nominal species was suspected by Meyen (1834), Kirchenpauer (1884), Hartlaub (1901; 1905), Bedot (1910), Billard (1909; 1910), and Galea & Schories (2012b). In contrast, Stechow (1920) and Billard (1922) provided arguments in favor of their specific separation, but their reliability could be contested in light of the new data available in the subsequent literature, and through the present observations. Stechow, who compared the redescription of S. gaudichaudi given by Billard (1909) with the cotype of S. picta , emphasized the following differences: 1) Lamouroux’ species does not have hydrothecae with thickened rims, a statement invalidated later on by Billard (1922), who showed that this character is inconstant, an opinion equally shared by us; 2) the abaxial cusp is conspicuously produced in S. picta , although it is now recognized that its shape varies within the same colony (present study); 3) the gonothecae of S. picta have only wavy walls, while those of S. gaudichaudi are clearly transversely ringed, an argument not only contradicted by several observations ( Blanco 1963; present study, material ZMH C04172), but also recognized as dependent on their state of maturation.

Billard (1922), for his part, emphasized the following distinguishing characters exhibited by S. picta : 1) the conspicuously hypertrophied abaxial hydrothecal cusp described by Stechow (1920), which is now recognized as a variable character; 2) the comparatively thickened hydrothecal rim, although the distalmost, youngest hydrothecae have evidently unthickened rims; 3) the more conspicuous internal, submarginal cusps, though it was demonstrated that this is an inconstant character ( Blanco 1963); 4) the broad perisarcal plug at the base of the hydrotheca, although obvious differences are seen in the hydrothecae from various, or even the same, colonies (present study).

It appears, therefore, that none of the arguments provided by Stechow and Billard are reliable specific characters. In addition, a comparison of the available data ( Table 10 ) and illustrations ( Fig. 10 ) from various sources based on the examination of the types of both nominal species demonstrate, with little doubt, that they are coterminous, with Lamouroux’s species having priority.

A typical, fully formed colony of S. gaudichaudi is illustrated by both Lamouroux (1824) and Billard (1922), while the gonotheca is depicted in a number of papers, e.g. Billard (1909), Stechow (1923a, as S. picta ), Ramil et al. (1992), and El Beshbeeshy (2011, as S. picta ). The habit of the stem varies in this species, and could be either monosiphonic ( Blanco, 1963; El Beshbeeshy, 2011; specimen ZMH C04173 examined here) or polysiphonic (material ZMH C04172 examined here).

Type material of S. protecta [not designated by Hartlaub (1901), but indicated on the label of sample ZMH C04173] is characterized by: 1) the occurrence of long (up to 2 mm) internodes among the otherwise most numerous, much shorter stem internodes; 2) the profuse branching, with almost every stem internode giving rise to a side branch, the latter alternate in position; 3) short and conspicuously adaxially-swollen hydrothecae. The perisarc of this material is comparatively hypertrophied with respect to that of sample ZMH C04172 assigned to S. picta by Hartlaub himself, giving the colony a more “peculiar”, rigid appearance. The higher occurrence of short vs. long internodes does not justify the placement of this species close to S. allmani as suggested by Hartlaub, because long internodes have never been observed in the latter. On the contrary, their presence is a typical feature of S. gaudichaudi , and their length may reach as much as 4 mm (e.g. SMNH 123881 and 123894).

Two other specimens, one from Elizabeth I. (Magellan Strait) and the other from South Georgia were also assigned to S. protecta by Hartlaub. The former is possibly no longer extant in ZMH (H. Roggenbuck, pers. comm.) and, for the latter, there is no certainty whether it is the same specimen as ZMH C04384, now recognized as a distinct species, S. subantarctica Galea , sp. nov.

The Chilean material collected by Philippi and assigned by Hartlaub (1901, p. 83) to S. contorta Kirchenpauer, 1884 was reexamined, and should be better assigned to the present species. Indeed, quite long internodes ( Fig. 9E) co-occur with otherwise uniformly short internodes in some stem fragments.

Billard (1924) reexamined the type of Sertularella margaritacea Allman, 1885 and noted the presence of a thickened hydrothecal rim, of a conspicuous abaxial cusp, as well as the apparent lack of internal, submarginal projections of the perisarc. In addition, the branching pattern illustrated in the original account ( Allman, 1885, pl. 7 fig. 3) fits those provided by both Lamouroux (1824) and Billard (1922) for S. gaudichaudi . Although not evident from his pl. 7 fig. 4, Allman also stated that the hydrothecae of his species were “distant” and this is, indeed, noticeable on the lower part of the stem and a couple of side branches, suggesting that both short and long internodes occur within the same colony, which is a character typically exhibited by S. gaudichaudi .

Distribution: Chile – Región de Magallanes y de la Antártica Chilena [Isla Navarino ( Hartlaub, 1901; 1905, both as S. picta ); Isla Lennox ( Hartlaub, 1901; 1905, as both S. picta and S. protecta ; Jäderholm, 1903, as S. picta ); Lennox Cove ( Hartlaub, 1901; Jäderholm, 1903; both as S. protecta ); Cape Horn ( Billard, 1922, as S. picta ); Isla Nueva ( Jäderholm, 1903, as S. antarctica ); Magellan Strait ( Allman, 1885, as S. margaritacea )]. Patagonia – no exact locality ( Rees & Thursfield, 1965, as S. protecta ). Argentina – scattered records from the Argentine Shelf between ca.

47° S and the east of Península Mitre ( El Beshbeeshy, 2011); Provincia del Chubut [Puerto Madryn ( Blanco, 1963, as S. picta )]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [Isla de los Estados ( Blanco, 1994, as S. picta ); eastern coast of Tierra del Fuego ( Meyen, 1834, as S. picta )]. Between Tierra del Fuego and the Falkland Is. ( Naumov & Stepanjants, 1962, as S. allmani ). Falkland Is. ( Lamouroux, 1824; Meyen, 1834, as S. picta ) and off their eastern coast ( El Beshbeeshy, 2011). French Southern and Antarctic Lands – Kerguelen Is. ( Vanhöffen, 1910, as S. polyzonias ; Naumov & Stepanjants, 1962, as S. picta ; Millard, 1977, as S. picta ); Crozet Shelf ( Millard, 1977, as S. picta ). (?) South African Subantarctic Islands: Marion I. ( Millard, 1971; Branch & Williams, 1993; both as S. picta ), Prince Edward I. ( Branch & Williams, 1993, as S. picta ).

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. 10. Comparison of the type materials of Sertularella gaudichaudi (Lamouroux, 1824) (A-E) and S. picta (Meyen, 1834) (F-K) illustrated by various authors, as follows: Lamouroux (1924) (A, C), Meyen (1834) (F, H, I), Hartlaub (1901) (G, K), Billard (1909) (D), Billard (1922) (E) and Stechow (1923) (J).

Tables

Table 10. Comparison of the available data on type materials of S. gaudichaudi (Lamouroux, 1824) and S. picta (Meyen, 1834). “ Ba ” stands for Billard (1909), “ Bb ” for Billard (1922), “ Bc. ” for Billard (1924), “ H ” for Hartlaub (1901), “ L ” for Lamouroux (1824), “ M ” for Meyen (1834), and “ R ” for Ramil et al. (1992).

	Sertularella gaudichaudi (Lamouroux, 1824)	Sertularella picta (Meyen, 1834)
Origin of the specimens	Vicinity of the Falkland Islands (L)	Eastern coast of Tierra del Fuego and the Falkland Islands (M).
Colony structure	Shrub-like, 1.5 to 2 inches high, with numerous alternate branches (L). Holotype 6.5 cm high, as high as broad, flabelliform, profusely and irregularly ramified (Bb)	“6 to 8 inches, and over” (M). Growth very ample, reminiscent of Obelia longissima (H).
Habit of the stem	Lightly fascicled (Bb)	Lightly fascicled (H).
Color	Greenish yellow to bluish green; hydranths pale blue (L)	“of a beautiful yellow, sometimes pale red” (M)
Internodes	Long, with the hydrothecae “very remote from each other” (L). Proximally with 1-2 annuli, not always distinct (Ba).	Typically very long, geniculate, strikingly resembling those of S. gaudichaudi (H).
Branches	With several annuli at origin from stem (Ba). Branchlets pinnately arranged, originating from below bases of successive hydrothecae, occasionally every 2-4 hydrothecae (Bb).	Each stem internode provides an origin for a side branch (H). Branches “strongly annulated” basally (i.e. several annuli) (H).
Hydrothecae	Not in the same plane (Ba, Bb), angle varying between 90-180° (Bb); adnate for 1/3rd, swollen adaxially, aperture on a constricted neck region, rim thickened though not always so (Bb); abcauline cusp produced; 3 internal, submarginal cusps (2 latero-adaxial, 1 abaxial) (Ba, Bb), not always present (Bc).	Not in the same plane (H). Adnate for 1/3rd, swollen adaxially, rim thickened (H). Perisarc thickened (M).
Gonothecae	Profuse, nearly globular, walls transversely annulated in upper half (L, Ba, Bb); aperture surrounded by 3-4 blunt cusps, indistinct in young thecae (Ba, Bb)	Wall annulated, with 4 apical projections (M), the latter not always obvious (H).