Eucheilota medusifera? ( Torrey, 1902 )

Altuna, Álvaro, 2008, The life cycle of Eucheilota medusifera? (Torrey, 1902), comb. nov. [= Campalecium medusiferum] (Cnidaria: Hydrozoa: Lovenellidae) from the Bay of Biscay (northeastern Atlantic), including a description of the adult medusa, Zootaxa 1856, pp. 1-15 : 3-5

Eucheilota medusifera? ( Torrey, 1902) comb. nov.

( Figures 1–3 )

? Campalecium medusiferum Torrey, 1902: 48 , pl. 3, figs. 26–29.

Halecium Torreyi Motz-Kossowska, 1911: 331 , figs. 5g, h, m, t.

Halecium Torreyi var. intermedia Motz-Kossowska, 1911: 333 , figs. 6g, t.

Haleciella microtheca HadŽi, 1914: 51 .

Campalecium medusiferum: Huvé 1954: 183 , pl.7, figs. 23–27, pl.8, fig. 28; Isasi & Saiz 1986: 69; Bouillon et al. 2004: 162, figs. 87C-E.

? Eucheilota cirrata: Brinckmann 1959: 82 , figs. 1a–b, 2d–e, 3.

Non Campalecium cirratum: Millard & Bouillon 1975: 7 , figs. 2C–E.

Campalecium medusiferum ?: Boero 1981: 188, figs. 5A–D.

? Mitrocomium cirratum: Calder 1991: 25 , figs.15a–b, 16a–b. Mitrocomium cirratum: Altuna 1992 /1993: 44, figs. 1A–G. Non Lovenella cirrata: Bouillon et al. 2004: 165 , fig. 88I.

The polyp ( Figure 1 )

This species has been described also after Bay of Biscay material by Altuna (1992/1993) as Mitrocomium cirratum Haeckel, 1879 following Calder (1991). His description is completed here with remarks on the soft parts of the live animals.

Colony stolonal with numerous pedicels arising from a tubular and profusely ramified hydrorhiza 60–80 µm wide. Live hydranths whitish. Fully extended hydranth 1.8–2.0 mm long, tubular, or slightly thicker below the tentacles [70–80 µm (proximally at hydrothecal rim); 100–120 µm (below tentacles)]. Hypostome small and dome-shaped, having a single row of 22–28 amphicoronate tentacles (16–26 x 260–640 µm), with a basal intertentacular web with big sausage-like cnidocysts. Tentacles with 13–21 clusters of cnidocysts, which are not present in the basal portion covered by the membrane. Gonothecae curved (1000–1300 µm), arising from hydrothecal pedicels, with a thin pedicel (60–80 µm), widening gradually, and ending in a more or less truncated summit (186–260 µm); they contain 4–5 medusa buds. Stolonization frequent; stolons arising from hydrorhiza or from the hydrophores carrying 1–2 polyps.

Figures

FIGURE 1. Eucheilota medusifera? (Torrey, 1902). A) Hydrothecae and a developing gonangium; note the accumulation of cnidocysts in the distal end of the latter. B) Hydrotheca and stolon; a new hydranth is budding. C) A detail of the intertentacular web showing the typical sausage-like cnidocysts; these may be lacking in some polyps. D) Sausage-like merotrichous haploneme. The real armature of this cnidocyst very likely consists of a dextral helix of two or three separate strands of small spines with several coils; there could be minute spines in the distal tube as well. Scale bar: 100 µm (A, B); 21 µm (D); C, not at scale.

FIGURE 2. Eucheilota medusifera? (Torrey, 1902). Newly released medusa. A) A specimen seen from above (exumbrellar cnidocysts not drawn). B) Side view; note the equatorial band of cnidocysts. C) A perradial bulb; note the rudimentary developing cirrus in the right side of the bulb. Three kinds of cnidocysts can be seen: minute atrichous isorhizas in the tentacle, merotrichous haplonemes in the bulb and basitrichous haplonemes in the exumbrella. D) A developing perradial bulb with lateral cirrus and the typical terminal cluster of merotrichous haplonemes. E) An interradial thickening with central cirrus. F) Exumbrellar basitrichous haploneme (frontal and side views) and a small merotrichous haploneme of the cirri. Adult medusa. G) Umbrellar margin with a statocyst with six statoliths in a single row forming a semicircle. Scale bar: 66 µm (C, D, E); 20 µm (F); B, width = 725 µm; height = 640 µm; A, G, not at scale.

FIGURE 3. Eucheilota medusifera? (Torrey, 1902). Adult medusa (30 days old), height = 1.8 mm; width = 4.0 mm.