Acryptolaria inversa, 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

Acryptolaria inversa n. sp.

( Figs 13 ; 30 ; 31J ; Table 14)

TYPE MATERIAL. — Loyalty Islands. MUSORSTOM 6, stn DW 476, 21°09.36’S, 167°56.40’E, 300 m, 22.II.1989, 1 stem c. 53 mm high with coppinia, holotype (MNHN-Hy.2009-0164) ; 1 fragment c. 24 mm long, paratype (RMNH-Coel. no. 35130, slide 692).

OTHER MATERIAL EXAMINED. — New Caledonia. DRAGUE 3, New Caledonia area, exact position unknown, 1 fragment c. 38 mm long.

Loyalty Islands. MUSORSTOM 6, stn DW 391, 20°47.35’S, 167°05.70’E, 390 m, 13.II.1989, 3 stems up to 41 mm high on sponge, with coppinia ( MNCN 2.03 /417). — Stn DW 398, 20°47.19’S, 167°05.65’E, 370 m, 13.II.1989, 1 stem c. 80 mm high (RMNH-Coel. no. 31513). — Stn DW 399, 20°41.80’S, 167°00.20’E, 282 m, 14.II.1989, 7 stems up to 35 mm high, on coral (MNHN-Hy.2009-0195); 1 fragment c. 21 mm long (slide MNHN-Hy.2009-0152). — Stn DW 422, 20°26.20’S, 166°40.31’E, 257 m, 16.II.1989, 8 stems up to 40 mm high, with coppinia (RMNH-Coel. no. 31514). — Stn DW 423, 20°25.85’S, 166°40.50’E, 280 m, 16.II.1989, 1 stem c. 28 mm high on coral ( MNCN 2.03 /418). — Stn DW 424, 20°24.30’S- 166°24.70’E, 599 m, 17.II.1989, 1 stem c. 30 mm high (MNHN-Hy.2009-0196). — Stn CP 464, 21°02.30’S, 167°31.60’E, 430 m, 21.II.1989, 1 stem c. 35 mm high ( MNCN 2.03 /419). — Stn DW 477, 21°07.98’S, 167°54.69’E, 550 m, 22.II.1989, 1 fragment c. 32 mm long in slide ( MNCN 2.03 /396) .

ETYMOLOGY. — The specific name “ inversa ” refers to the downwards growth of part of the hydrotheca. It is an adjective in feminine gender. From the Latin noun “inversio”, reverse.

ECOLOGY AND DISTRIBUTION. — Acryptolaria inversa n. sp. comes from the Loyalty Islands where it was collected at depths from 257 to 599 m, being epibiotic on corals and sponges. Coppiniae were found in February. One sample originates from an uncertain locality in the New Caledonian area.

DESCRIPTION

Stems up to 80 mm high. Branching scarce ( Fig. 31J ) and irregular, but more or less in one plane; branches straight ( Fig. 13A ).

Hydrothecae alternately arranged, approximately in one plane ( Fig. 13A ); mainly cylindrical ( Fig. 13 A-C), diameter only decreasing clearly in their basal part and distinctly increasing at the hump. Hydrotheca twice strongly curved: markedly curved downwards at approximately basal third and frequently being parallel to the adnate part for a short distance ( Fig. 13C ) after which it turns upwards at about the middle of the adcauline wall ( Fig. 13 A-C). Adcauline wall extremely convex at basal half, with a strongly marked inflexion point at the middle of the adcauline length where it is concave ( Fig. 13 A-C). Distal third of adcauline wall more or less straight. Abcauline wall straight at basal fourth, parallel to branch, then strongly curved outwards and downwards, forming a distinct hump ( Fig. 13 A-C); later on abcauline wall becoming convex and finally straight ( Fig. 13 A-C). The hump of the abcauline wall may be free ( Fig. 13C ), but it is usually in contact with the basal portion of the abcauline wall and frequently both parts are fused ( Fig. 13A, B ). Adcauline wall free from internode for almost two-thirds of its length (adnate/ free ratio c. 0.7). Hydrothecal aperture circular, oblique, upwardly directed. Rim even, frequently with renovations (up to 10) ( Fig. 13C ).

Large nematocysts relatively small and fusiform ( Fig. 30 ).

Coppinia fusiform, 5 mm long and about 2 mm in diameter, deprived of defensive tubes ( Fig. 13D ). Gonothecae bottle-shaped, diameter increasing from basal part to approximately two-thirds of their length, then decreasing to form a fairly long neck provided with a distal, circular aperture ( Fig.13D ). Rim even, but frequently provided with one or two renovations ( Fig. 13D ). Gonothecae closely set, walls fused for about two-thirds of gonothecal height.

REMARKS

Acryptolaria inversa n. sp. is easily recognizable by the peculiar shape of the hydrotheca, partially directed downwards, frequently even becoming parallel to the adnate part and then running obliquely upwards. They are provided with a large abcauline hump which may be fused with the basal part of the abcauline wall.

Figures

FIG. 13. — Acryptolaria inversa n. sp.: A, branch fragment showing hydrothecal arrangement; B, C, hydrothecae; D, coppinia fragment showing gonothecae; A, B, from MUSORSTOM 6 stn DW 422; C, D, from MUSORSTOM 6 stn DW 476. 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.