Acryptolaria laertesi, 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 : 294-297

Acryptolaria laertesi n. sp.

( Figs 14 ; 30 ; 31K ; Table 15)

TYPE MATERIAL. — Loyalty Islands. MUSORSTOM 6, stn DW 425, 20°24.30’S, 166°24.80’E, 594 m, 17.II.1989, 1 stem c. 75 mm high, holotype (MNHN-Hy.2009-0165); 1 stem fragment c. 20 mm high, paratype (RMNH-Coel. no. 35137, slide 699).

ETYMOLOGY. — The specific name “ laertesi ” is a dedication to Laertes Peña Sancho, son of the first author; it is a noun in genitive singular.

ECOLOGY AND DISTRIBUTION. — Acryptolaria laertesi n. sp. was collected at a depth of 594 m in the Loyalty Islands area.

DESCRIPTION Stem c. 75 mm high. Branching irregular and scarce ( Fig. 31K ); only seven, very short (up to 8 mm long) primary branches present. Branches roughly straight, with an almost unnoticeable zigzag ( Fig. 14A ).

Hydrothecae alternately arranged in two planes forming an obtuse angle ( Fig. 14A ); approximately cylindrical, but with a clear decrease of diameter at basal adnate part ( Fig. 14 ); minimum diameter at base. Distal part of hydrotheca practically straight. Hydrotheca strongly curved outwards, adnate for about half of its adcauline length (adnate/free ratio 1.1). Adcauline wall convex, straight at distal part; abcauline wall broadly concave, straight at distal part. Hydrothecal aperture circular, oblique and directed upwards, forming an angle of c. 30° with long axis of branch. Rim even, with numerous renovations (up to 12). Large nematocysts relatively very large and fusiform ( Fig. 30 ). Coppinia not observed.

REMARKS Acryptolaria laertesi n. sp. is easily recognizable by the colony structure, with just a few short primary branches and by shape and size of both hydrothecae and nematocysts. Acryptolaria laertesi n. sp. has extremely long and thin nematocysts (ratio 4.1). It has in fact the longest nematocysts in the genus Acryptolaria , together with A. tortugasensis , though in this species they are wider (29.3 × 9.9 µm). Acryptolaria laertesi n. sp. resembles A. encarnae n. sp. in the shape of the hydrothecae, but in the latter the hydrothecae are broadly cylindrical, slightly smaller, more strongly directed outwards and free for a smaller proportion. Moreover, in A. encarnae n. sp. the branches are straight and the large type of nematocysts is much smaller (19.9 × 7.5 µm). In the shape of the hydrothecae, A. laertesi n. sp. approaches A. corniformis , but in the latter the hydrothecae are much larger and less curved outwards. Moreover, it has much smaller nematocysts (12.3 × 4.3 µm in the holotype).

Figures

FIG. 14. — Acryptolaria laertesi n. sp., from MUSORSTOM 6 stn DW 425: A, branch fragment showing hydrothecal arrangement; B, C, hydrothecae. Scale bar: A, 600 μm; B, C, 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.