Two new genera and nine new species of hydroids (Cnidaria: Hydrozoa) from off New Caledonia Author Galea, Horia R. text European Journal of Taxonomy 2015 2015-08-31 135 1 19 journal article 22396 10.5852/ejt.2015.135 4ebe05f4-f39b-4770-85c2-8de0fcda0cb3 2118-9773 3785289 F5F578C8-4CA7-4ADA-9DAF-0DA5170E9F9F Hincksella similis sp. nov. urn:lsid:zoobank.org:act: DBF94D6B-02BA-4364-B599-A411A95D8EC5 Fig. 5 G–H; Table 3 Diagnosis Stems simple, monosiphonic; nodes indistinct; each internode with a distal hydrotheca; the latter long, tubular, distinctly facing outward, finely and densely striated on free adcauline wall and lower part of abcauline wall. Etymology From the Latin similis , meaning "similar", on account of its resemblance to H. pusilla Ritchie, 1910 . Material examined Holotype NEW CALEDONIA : campaign Norfolk 1, station DW1722, 23°18’ S , 168°10’ E , 540 m , 26 Jun. 2001 ; sterile, 2.2 cm high stem (IK-2012-10300). Description Colony erect, 2.2 cm high, arising from creeping, tortuous, branching stolon. Stem monosiphonic, unbranched; basal part 9 mm long, ahydrothecate; remainder of stem divided by means of indistinct nodes; each equivalent of internode rather short, slightly geniculate to almost collinear, each bearing a hydrotheca distally. Hydrothecae tubular, given off at an angle of c . 65–70° with internode, long axis slightly sigmoid; abcauline wall markedly curved where hydrotheca becomes free; aperture rounded, rim even, slightly flared; renovations occasional; perisarc of hydrotheca finely and densely striated, especially on free adcauline side and proximal part of abcauline wall. Gonotheca unknown. Large macrobasic heteronemes (none seen discharged), with parallel walls and rounded ends, and with straight or slightly curved longitudinal axes, occur abundantly in coenosarc. Remarks The alternate, long, tubular, non-operculate hydrothecae and the large nematocysts scattered in the coenosarc place this species, with little doubt, in the genus Hincksella Billard, 1918 . This species resembles both H. pusilla Ritchie, 1910 , through the shape of its hydrothecae, and H. neocaledonica sp. nov. through their striations. However, the former is a much smaller species (see dimensions in Galea 2010 : table 3), while the latter has comparatively longer and more geniculate internodes, its hydrothecae are given off at more acute angles, their free part is shorter, and the striations extend over the whole perisarc of the colony.