Eutima gegenbauri ( Haeckel, 1864 )

Peter Schuchert, 2017, Systematic notes on some leptomedusa species with a description of Neotima galeai n. spec. (Hydrozoa, Cnidaria), Revue suisse de Zoologie 124 (2), pp. 351-375 : 361-362

Eutima gegenbauri ( Haeckel, 1864)

Octorchis gegenbauri Haeckel, 1864: 331 . – Russell, 1953:

367, fig. 233-23, pl. 22 fig. 4.

Eutima gegenbauri . – Neppi & Stiasny, 1913: 48. – Kramp, 1959a: 161, fig. 221. – Kramp, 1961: 195. – Cornelius, 1995: 228, fig. 52.

Eutima (Octorchis) gegenbauri . ‒ Kramp, 1933: 588, fig. 58. ‒

Russell, 1970: 260, figs 23s-24s.

Liriopsis campanulatus Claus, 1877: 11 .

Octochandra canariensis Haeckel, 1879: 198, pl. 13 fig. 1.

Octochandra germanica Haeckel, 1879: 198 , pl. 13 figs 3-8.

Material examined: MHNG-INVE-31748; 2 specimens; France, Villefranche-sur-Mer , Ligurian Sea, Mediterranean, 43.686°N 07.317°E, 0 m depth; collection date 04.05.2001; DNA isolate 009; 16S sequence FJ550515 , COI MF000489 , 18 S FJ550600 , 28S FJ550456 . ‒ MHNG-INVE-89881;> 10 specimens; Sweden, Kristineberg , 58.243849°N 11.432305°E, 0 m depth, collection date 03.10.2014 ; DNA isolate 1062; 16S sequence KY363964 , COI MF000515 ; for archived photos see Table 1.

Diagnosis: Umbrella 10-20 mm wide when mature, almost hemispherical. Apical jelly thick (up to 1/2 of bell height), gastric peduncle very long, 2-3 times the bell height, conical, with very broad base. Velum narrow. 4 radial canals. Stomach tubular, with four lips, rim with a few folds. Elongate gonads along radial canals subdivided, 4 on peduncle beginning near stomach, 4 gonads on subumbrellar parts of radial canals reaching to bell margin, thus a total of 8 gonads. 8-16 tentacles without distinct bulbs, relatively thick and stiff, not coiling; between tentacles marginal warts, about 60-80 in total, with nematocysts, each wart with an adaxial, conical papilla, usually 1-2 lateral cirri, but these often rudimentary or lost, with a few nematocysts. Papillae with nematocysts. 6-8 statocysts, irregularly placed, with 6-12 concretions.

No distinct colours or denser tissues greenish.

Polyp stage: see Cornelius (1995).

Distribution: North-western Europe up to mid-Norway; Mediterranean; Canary Islands; Morocco, North Carolina. Type locality: Nice, Mediterranean.

Remarks: The marginal warts have an easily visible adaxial, conical papilla. They have reportedly no excretory pore, but this could not be verified in the present material and needs further examination by histological sections (comp. Russell, 1953: 372).

Vannucci (1957) thought that Eutima curva could be conspecific with E. gegenbauri , a proposal which was not followed by subsequent authors. DNA sequences of material of E. curva from New Zealand were clearly distinct from E. gegenbauri ( Leclère et al., 2009; Schuchert et al., 2017).

Genus Neotima Petersen, 1962 emended

Diagnosis: Eirenidae medusa with large gastric peduncle, four radial canals, 4-8 statocysts, tentacle bulbs or bell margin without cirri, bulbs without excretory papillae, without cordyli, with marginal warts, gonads on entire length of radial canals, either undivided or interrupted in middle part. Hydroid unknown.

Remarks: It was necessary to modify slightly the diagnosis of this genus ( Bouillon et al., 2006) in order to accommodate the new species described below which has subdivided gonads. The alternative solution, to propose a new genus name, seemed less desirable. Moreover, other genera of the family, like Eutima , are also composed of species with entire or subdivided gonads.

The genus Eutima McCrady, 1859 differs from the genus Neotima by the presence of lateral cirri on the marginal warts ( Bouillon et al., 2006). The generic subdivision of the Eirenidae Haeckel, 1879 is likely highly artificial and needs a taxonomic revision.

Figures

Fig. 10. Eutima gegenbauri, after living Mediterranean specimen. (A) Lateral view. (B) Schematic drawing of bell margin seen from adaxial.