Antennella sinuosa, Agís & Vervoort & Ramil, 2009

Agís, José Ansín, Vervoort, Willem & Ramil, Fran, 2009, Hydroids of the family Halopterididae (Cnidaria, Hydrozoa) collected in the western Pacific by various French expeditions, Zoosystema 31 (1), pp. 33-61 : 39

Antennella sinuosa n. sp.

( Fig. 2 ; Table 3)

TYPE MATERIAL. — New Caledonia. MUSORSTOM 4, stn CP 155, 18°52.8’S, 163°19.5’E, 500-570 m, 15.IX.1985, single detached stem, no gonothecae, holotype ( MNHN Hy 1294).

ETYMOLOGY. — The specific name sinuosa refers to the sinuose shape of the abcauline wall of the hydrotheca.

DISTRIBUTION. — This material comes from a single station near New Caledonia and was collected between 500 and 570 m.

DESCRIPTION

Stem reaching 16.5 mm in height. Basal part, with signs of damage and posterior regenerations, divided in several internodes by straight nodes; last internode with three nematothecae and ending with a distal oblique node.

Rest of stem heteromerously segmented by alternating oblique and transverse nodes, sometimes indistinct.Hydrothecate internodes with a hydrotheca and three nematothecae: one mesial infracalycine and two laterals. Intermediate internodes with a single nematotheca in proximal part.

Hydrotheca cylindrical and deep, rim smooth and tilted towards abcauline side. Abcauline wall sinuous, slightly convex in basal half and concave above. Adcauline wall straight and adnate in ¾ of its length; rest of adcauline wall free, straight or slightly concave.

All nematothecae two-chambered.Mesial inferior nematotheca immovable, not reaching the hydrothecal base; upper chamber with adaxial wall lowered down to bottom of chamber. Lateral nematothecae placed on distinct apophyses, movable, reaching hydrothecal rim, with adcauline margin of upper chamber scooped. Nematothecae on ahydrothecate internodes similar to mesial inferior ones, but with longer adaxial wall and movable.

Gonothecae not observed.

REMARKS

This species is characterised by the morphology of its hydrothecae, which are cylindrical with the abcauline wall convex in its basal part and concave above, and the adcauline wall straight with the distal ¼ free.

In spite of the fact that the New Caledonian material lacks gonothecae, it is described as a new species here because of the morphology of the hydrothecae, with their sinuous abcauline wall, which is unknown in the other species of this genus.

Figures

FIG. 2. — Antennella sinuosa n. sp., MUSORSTOM 4, stn CP 155: A, first internode of stem, lateral view; B, internodes from distal part of stem, lateral view. Scale bar: 0.1 mm.