Coryne

Galea, Horia R., 2008, On a collection of shallow-water hydroids (Cnidaria: Hydrozoa) from Guadeloupe and Les Saintes, French Lesser Antilles, Zootaxa 1878, pp. 1-54 : 11-13

Coryne sp.

(fig. 3A–D)

Material examined. Stn. 3: 01.04.2008 —several colonies of various sizes, some with propagulae and/or medusa buds, on algae and concretions. Stn. 7: 25.03.2008 —a few sterile colonies, some hydranths with propagulae, on concretions ( MHNG INVE 60982); 29.03.2008 —a small, sterile colony, propagulae absent, on hydrocoral.

Description. Colonies stolonal, cauli relatively short (0.2–2.3 mm high); perisarc smooth, diameter gradually increasing from base (105–120 µm) towards distal end (170–260 µm). Hydranths cylindrical, 0.5–2.0 mm high, 300–325 µm wide, hypostome short, dome-shaped. Perisarc collar at hydranth base absent. One whorl of 4 tentacles around hypostome held nearly vertically; five additional, more or less distinct rows of lower tentacles scattered over 2/3–3/4 of body; a total of up to 26 tentacles per hydranth; all capitate, filiform tentacles absent. Oral tentacles with diameter of capitula exceeding those of lower tentacles (115–125 µm vs. 70–100 µm); stalks short and slightly tapering distally, length decreasing from distal to proximal row. Some stems with lateral, branch-like structures covered with perisarc, these irregularly ramified several times; propagulae budded off from open tips; 190–215 µm long, 115–125 µm wide. Gonophores developing among the lowest whorl of tentacles, the latter occasionally less numerous than in sterile specimens; liberated as free medusae; up to 8 buds per polyp. Medusa buds globular to pear-shaped; borne on short pedicels; 4 tentacle bulbs visible as brown patches, each with one red ocellus. No other structures could be examined. Some polyps simultaneously producing frustules and medusae. Color: white-milk to pale pink, hypostome of polyp and manubrium of medusa buds brownish. Cnidome of polyp and propagula (undischarged capsules): two size classes of stenoteles, large (17.8–20.8) × (13.6–14.7) µm and small (8.6–10.4) × (6.6–7.4) µm. Cnidome of medusa buds (undischarged capsules): desmonemes (6.4–7.1) × (3.7–4.1) µm; three distinct size classes of stenoteles, i.e. large (11.4–12.7) × (8.7–10.4) µm, medium-sized (9.3–10.7) × (6.6–8.4) µm, and small (7.1– 7.4) × (5.6–6.1) µm.

Remarks. This species, from areas with high water movement, exhibits two simultaneous modes of reproduction and dispersal: asexual, by massive production and release of frustules, and sexual, liberating free swimming medusae.

The formation of frustules in the genus Coryne has been rarely described, as for instance the South-African record by Millard (1975) of a dwarf, sterile form, provisionally assigned to C. pusilla Gaertner, 1774 .

Due to its peculiar mode of reproduction, the present material may belong to a new species, but I refrain in naming it until the adult medusa is known.

Distribution. Presently known from Guadeloupe and Les Saintes.