Acryptolaria medeae, 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 : 299-300

publication ID	https://doi.org/ 10.5252/z2010n2a5
DOI	https://doi.org/10.5281/zenodo.4551890
persistent identifier	https://treatment.plazi.org/id/03E5636A-FFBC-FF86-FF1F-514E7750FAED
treatment provided by	Felipe
scientific name	Acryptolaria medeae
status	sp. nov.

Treatment

Acryptolaria medeae View in CoL n. sp.

( Figs 16 View FIG ; 30 View FIG ; 32B View FIG ; Table 17)

TYPE MATERIAL. — NW New Caledonia. MUSORSTOM 4, stn CP 195, 18°54.8’S, 163°22.2’E, 465 m, 19.IX.1985, 1 stem 70 mm high, with coppinia, holotype (MNHN- Hy.2009-0166); 1 stem c. 23 mm high, paratype (RMNH- Coel. no. 31518).

OTHER MATERIAL EXAMINED. — Stn DW 197, 18°51.3’S, 163°21.0’E, 560 m, 20.IX.1985, 2 stems up to 80 mm high ( MNCN 2.03/424).

ETYMOLOGY. — The specific name medeae is a dedication to Medea Peña Sancho, daughter of the first author; “medeae” is a noun in genitive singular.

ECOLOGY AND DISTRIBUTION. — Acryptolaria medeae n. sp. was collected at depths between 465 and 560 m off NW New Caledonia.

DESCRIPTION

Palm-shaped stems up to 80 mm high ( Fig. 32B View FIG ), with the appearance of gorgonids and a disc-shaped hydrorhiza for attachment to hard substratum. Branching extremely abundant (up to sixth-order branches observed) and irregular, but strictly in one plane. Stem deprived of branches for the first few millimetres and then with continuous branching with numerous anastomoses, giving stems the aspect of a mesh. Branches slightly sinuous ( Fig. 16A View FIG ).

Hydrothecae alternately arranged in approximately one plane ( Fig. 16A, B View FIG ), almost cylindrical, but imperceptibly widening basally ( Fig. 16A, B View FIG ); later diameter sharply decreasing at hydrothecal base. Hydrotheca gently curved outwards; adcauline wall adnate to internode for over two-thirds of its length (adnate/free ratio 2.6), convex. Abcauline wall straight or convex at basal half, concave at distal half, with a strong development of the perisarc which is strongly reduced just over hydrotheca underneath ( Fig. 16A, B View FIG ). Hydrothecal aperture circular, oblique and directed upwards, forming an angle of c. 40° with long axis of branches. Rim even, sometimes with short renovations (up to 13 observed).

Large nematocysts relatively large and ovoid ( Fig. 30 View FIG ).

Coppinia fusiform, 22 mm long and 3 mm in diameter, consisting of closely set ( Fig. 16C View FIG ), flaskshaped gonothecae provided with a long distal neck ending in a circular aperture with even rim ( Fig. 16C, D View FIG ). Gonothecal walls coalesced with strong development of the perisarc ( Fig. 16D View FIG ); defensive tubes absent.

REMARKS

Acryptolaria medeae n. sp. is characterized by the gorgonian-like appearance of the stems, much branched in one plane and with many anastomoses which give them a compact aspect, the strong development of perisarc at the abcauline wall of the hydrotheca, and the fairly wide gonothecae. The large nematocysts are abundant.

This new species is close to A. disordinata n. sp. in stem structure, being much branched in one plane, and by the presence of a strong perisarc development in the abcauline hydrothecal wall. Nevertheless they distinctly differ in the nematocysts which in A. disordinata n. sp. are larger (25.6 × 9.4 µm). Furthermore in the latter the branches strongly widen where the hydrothecae become free, the strong development of perisarc of the abcauline wall reaches the hydrotheca situated below, the cylindrical hydrothecae are larger and, finally, the gonothecae are in a chaotic disposition in the coppinia.