Species of Acryptolaria Norman, 1875 (Cnidaria, Hydrozoa, Lafoeidae) collected in the Western Pacific by various French expeditions, with the description of nineteen new species Author Peña Cantero, Álvaro L. Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia / Fundación General, Universidad de Valencia, Apdo. Correos 22085, E- 46071 Valencia (Spain) alvaro. l. pena @ uv. es pena@uv.es Author Vervoort, Willem National Museum of Natural History, P. O. Box 9517, NL- 2300 RA Leiden (The Netherlands) vervoort @ naturalis. nnm. nl text Zoosystema 2010 2010-06-30 32 2 267 332 http://www.bioone.org/doi/abs/10.5252/z2010n2a5 journal article 8099 10.5252/z2010n2a5 f76e17a3-3bc3-43a8-ae33-6655aba3fa57 1638-9387 4521008 Acryptolaria minuta Watson, 2003 ( Figs 18 ; 30 ; Table 19 ) Acryptolaria minuta Watson, 2003: 163 , 164, fig.13A-C. — Peña Cantero et al. 2007: 256-258 , figs 11, 16C, tab. XI. MATERIAL EXAMINED . — Loyalty Islands . MUSORSTOM 6, DW 406, 20°40.65’S , 167°06.80’E , 373 m , 15.II.1989 , several stems up to 30 mm high, on hydroid stem (MNHN-Hy.2009-0201). — Stn DW 481, 21°21.85’S , 167°50.30’E , 300 m , 23.II.1989 , several stems up to 25 mm high, on sponge (RMHH-Coel. no. 31520). Norfolk Ridge. BIOCAL 1, stn DW 37, 22°59.990’- 23°00.079’S , 167°15.650’- 167°16.340’E , 350 m , 30.VIII.1985 , three stems up to 27 mm high, on gorgonian axis ( MNCN 2.03/425). ECOLOGY AND DISTRIBUTION. — So far Acryptolaria minuta was known only from the Macquarie Island area (52°59.4’- 53°02’S , 159°59’- 159°58.2’E ), where it was collected at a depth of 1422 m on a dead primnoid gorgonian ( Watson 2003 ). Our material was found at depths between 300 and 373 m in the Loyalty Islands and Norfolk Ridge areas where it was found epibiotic on a sponge, the axis of a gorgonian and a hydroid stem. FIG. 17. — Acryptolaria cf. minima Totton, 1930 , branch fragments showing hydrothecal arrangement and hydrothecae: A -C , from BIOCAL 1 stn DW 36; D , E , from BIOCAL 1 stn DW 51. Scale bar: 250 μm. DESCRIPTION Stems up to 30 mm high. Branching frequent and irregular,approximately in one plane;anastomoses may be present. Branches straight ( Fig. 18A, C, D ). Hydrothecae alternately arranged in one plane ( Fig. 18A, C, D ), tubular, roughly cylindrincal; diameter decreasing at basal part ( Fig. 18 ). Hydrotheca strongly curved outwards; adcauline wall adnate over approximately two-thirds of its length (adnate/free ratio 2.1), convex. Abcauline wall concave, but basally straight. Hydrothecal aperture circular and directed outwards, almost parallel to long axis of branches; rim even, with few renovations ( Fig. 18A ). TABLE 19. — Measurements of Acryptolaria minuta Watson, 2003 (in μm). Hydrothecae from BIOCAL 1 stn DW 37; nematocysts from MUSORSTOM 6 stn DW 481.

Range	Mean ± SD (n)
Hydrothecae
Length of abcauline wall	550-600	568.6 ± 20.3 (7)
Length of adcauline wall	710-800	762.1 ± 25.9 (7)
Length of free adcauline wall	225-280	247.9 ± 18.9 (7)
Length of adnate adcauline wall	480-550	514.3 ± 28.2 (7)
Ratio adnate/free adcauline wall	1.7-2.4	2.1 ± 0.2 (7)
Diameter at aperture	115-140	129.3 ± 6.8 (7)
Nematocysts
Larger group	17-19 × 7-8	18.5 ± 0.6 × 7.5 ± 0.4 (10)
Ratio	2.3-2.6	2.5 ± 0.1 (10)
Smaller group	6-7 × 3

Large nematocysts relatively small and ovoid ( Fig. 30 ). Coppinia not observed. REMARKS Peña Cantero et al. (2007) redescribed the holotype of Acryptolaria minuta composed of scarce material mounted on a slide. As indicated by those authors, Acryptolaria minuta is similar to A. minima in the size of the hydrothecae, though in the former the hydrothecae are larger and thinner, strongly curved outwards and with a much larger portion of the adcauline wall free. Moreover, the nematocysts are much smaller (25.8 × 9.8 Μm in the type material of A. minima ). Our material roughly agrees with Watson’s species. The slight difference in the size of the nematocysts (16.7 × 6.3 Μm in the type material) is considered to be less important as Peña Cantero et al. (2007) measured the nematocysts of the holotype of A. minuta in a mounted slide.