Acryptolaria intermedia, Peña Cantero & Vervoort, 2010

Peña Cantero, Álvaro L. & Vervoort, Willem, 2010, Species of Acryptolaria Norman, 1875 (Cnidaria, Hydrozoa, Lafoeidae) collected in the Western Pacific by various French expeditions, with the description of nineteen new species, Zoosystema 32 (2), pp. 267-332 : 292-293

Acryptolaria intermedia n. sp.

( Figs 12 ; 30 ; 31I ; Table 13)

TYPE MATERIAL. — Norfolk Ridge. CHALCAL 2, stn DW 76, 23°40.50’S, 167°45.20’E, 470 m, 30.X.1986, several stems, up to 24 mm high, from communal stolonal fibers: 1 stem holotype (MNHN-Hy.2009-0163) ; several stems paratype (RMNH-Coel. no. 31510).

ETYMOLOGY. — The specific name “ intermedia ” refers to the presence of intermediate features between A. angulata and A. bulbosa ; it is an adjective in femine gender.

ECOLOGY AND DISTRIBUTION. — Acryptolaria intermedia n. sp. was collected at a depth of 470 m in the Norfolk Ridge area.

DESCRIPTION

Stems up to 24 mm high ( Fig. 31I ). Branching irregular, but usually in one plane, and scarce, though branches up to third order are present. Branches straight or slightly sinuous ( Fig. 12A, B ), with anastomoses.

Hydrothecae alternately arranged in one plane ( Fig. 12A, B ), tubular, roughly cylindrical, with a distinct decrease in diameter at their base ( Fig. 12 ). Hydrotheca curved twice: strongly outwards at distal part of adnate portion, becoming more or less perpendicular to adnate part, and markedly upwards consecutively, usually shortly after the adnate wall becomes free. Abcauline wall with a distinct inflexion point at about half its length, forming a shallow embayment at that point, accompanied by an internal perisarc cusp ( Fig. 12 ). Basal part of abcauline wall straight, parallel to branch; distal part slightly convex or straight too. Adcauline wall adnate for over half of its length (adnate/free ratio c. 1.7); adnate part convex; free part concave proximally becoming straight distally. Hydrothecal aperture circular, oblique and slightly directed upwards; rim even, sometimes with renovations.

Large nematocysts relatively very small and spherical ( Fig. 30 ).

Coppinia not observed.

REMARKS

At first glance, Acryptolaria intermedia n. sp. resembles A. bulbosa in the shape of the hydrothecae. Nevertheless they are clearly different species as the latter has bigger hydrothecae, much bigger nematocysts (20.7 × 6.7 µm) and the internal perisarc cusp at the abcauline hydrothecal embayment is absent. In the size of the nematocysts, A. intermedia n. sp. is closer to A. angulata (15.9 × 8.6 µm), but they differ in the shape and size of the hydrotheca; A. intermedia n. sp. lacks the characteristic sharp invagination of the adnate adcauline wall of A. angulata and has distinctly smaller hydrothecae (cf. Table 31).

Above, when dealing with A. bulbosa , we have indicated that material described either as A. rectangularis (cf. Gravier-Bonnet 1979; Millard 1967, 1968) or as A. angulata (cf. Hirohito 1995) could belong to A. bulbosa or to A. intermedia n. sp. but that it is necessary to study the cnidome to properly identify this material.

Figures

FIG. 12.— Acryptolaria intermedia n.sp., from CHALCAL 2 stn DW 76: A, B, branch fragments showing hydrothecal arrangement and hydrothecae; C, D, hydrothecae. Scale bar: 250 μm.

FIG. 30. — Outline drawings of the large type nematocysts of Acryptolaria species discussed in the present report. Scale bar: 30 μm.

FIG. 31. — Colony shape and branching in Acryptolaria Norman, 1875: A, A. angulata (Bale, 1914), from MUSORSTOM 6 stn DW 487;B, A. bathyalis n. sp., holotype, MUSORSTOM 6 stn CP 419; C, A. bulbosa (Stechow, 1932), from MUSORSTOM 6 stn CP 419; D, A.disordinata n.sp.,holotype,MUSORSTOM 4 stn DW 197;E, A. encarnae n. sp., holotype,MUSORSTOM 6 stn CP 464;F, A.flabelloides n. sp., from SMIB 4 stn DW 36; G, A. gemini n. sp., holotype, GEMINI stn DW 60; H, A. infinita n. sp., holotype, MUSORSTOM 4 stn DW 197; I, A. intermedia n. sp., holotype, CHALCAL 2 stn DW 76; J, A. inversa n. sp., holotype, MUSORSTOM 6 stn DW 476; K, A. laertesi n. sp., holotype, MUSORSTOM 6 stn DW 425. Scale bars: A, C, F, G, I, 10 mm; B, D, E, H, J, K, 20 mm.