Acryptolaria disordinata, 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 : 283-284

Acryptolaria disordinata n. sp.

( Figs 7 ; 30 ; 31D ; Table 8)

TYPE MATERIAL. — NW New Caledonia. MUSORSTOM 4, stn DW 197, 18°51.3’S, 163°21.0’E, 560 m, 20.IX.1985, several stems up to 60 mm high on coral, with coppinia: 1 stem holotype (MNHN-Hy.2009-0159); 5 stems paratypes (RMNH-Coel. no. 31505).

OTHER MATERIAL EXAMINED. — NW New Caledonia. MUSORSTOM 4, stn CP 194, 18°52.8’S, 163°21.7’E, 550 m, 19.IX.1985, 7 stems up to 45 mm high ( MNCN 2.03/414). — Stn CP 195, 18°54.8’S, 163°22.2’E, 465 m, 19.IX.1985, 1 stem c. 40 mm high (MNHN- Hy.2009-0192). — Stn DW 197, 18°51.3’S, 163°21.0’E, 560 m, 20.IX.1985, 3 fragments up to 23 mm long (RMNH-Coel. no. 35506, slide 432).

ETYMOLOGY. — The specific name disordinata refers to the rather disordered disposition of the gonothecae in the coppinia. From the Latin verb “ordino”, to order, to arrange; the particle “dis” expresses the contrary. Adjective following the genus name in gender.

ECOLOGY AND DISTRIBUTION. — Acryptolaria disordinata n. sp. was collected at depths between 465 and 560 m off NW New Caledonia. It was found epibiotic on coral. Coppiniae were found in September.

DESCRIPTION

Flabellate, polysiphonic stems up to 60 mm high, frequently branched; up to third-order branches observed ( Fig. 31D ). Branching irregular and with anastomoses, but strictly in one plane, giving the colonies a flabellate appearance. Branches straight ( Fig. 7A ), but distinctly widening at the place where hydrotheca becomes free ( Fig. 7 A-C).

Hydrothecae alternately arranged in approximately one plane ( Fig. 7 A-C). Hydrotheca cylindrical and of a constant diameter throughout, only decreasing in diameter at its base ( Fig. 7 A-C). Hydrotheca smoothly curved outwards; adcauline wall adnate to internode for over two-thirds of its length (adnate/free ratio 2.5), convex over its whole length. Abcauline wall completely concave or straight at basal half, with strongly developed perisarc reaching as far downwards as the hydrotheca situated below. Hydrothecal aperture circular, oblique and directed upwards, at an angle of c. 20° with long axis of branches. Rim even, frequently with short renovations (up to seven observed).

Large nematocysts relatively very large and fusiform ( Fig. 30 ).

Female coppinia 12 mm long and 3 mm in maximum diameter, roughly fusifom, but with extensions on lower-order branches. Gonothecae set together, but not as tightly as in other species ( Fig. 7D ), consequently shape of gonotheca more variable and gonothecal walls fused to a varying degree. In general, gonothecae pear-shaped ( Fig. 7D ), with a main, swollen basal part and a long distal neck, provided with a distal, circular aperture. Rim even. Coppinia without defensive tubes. Planulae completing development outside gonothecae in an acrocyst.

REMARKS

In material from MUSORSTOM 4 stn DW 197, the stems grow side by side and anastomose, even with fusion of the coppiniae.

Acryptolaria disordinata n. sp. is characterized by the remarkable widening of the branch where the hydrotheca becomes free, by the cylindrical hydrothecae and by the disorderly arrangement of the gonothecae. It is allied to A. bathyalis n. sp. in the shape and size of the hydrotheca, but they differ because in the latter the branches are practically straight, the hydrothecae are less closely packed, the basal half of the abcauline hydrothecal wall remains parallel to the branch, the hydrotheca only curves outwards at the distal half, and because the nematocysts are distinctly smaller (21.6 × 8.5 µm).

Figures

FIG. 7. — Acryptolaria disordinata n. sp., from MUSORSTOM 4 stn DW 197: A, branch fragment showing hydrothecal arrangement; B, C, hydrothecae; D, part of coppinia. Scale bar: A, 600 μm; B-D, 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.