Eucodonium longitentaculatum

Mao Lin, Zhenzu Xu, Jiaqi Huang, Donghui Guo & Chunguang Wang, 2016, Taxonomic notes on Hydroidomedusae (Cnidaria) from South China Sea I: Family Eucodoniidae (Anthomedusae), Zoological Systematics 41 (1), pp. 48-53 : 52

Eucodonium longitentaculatum Xu, Huang & Wang, sp. nov.

( Figs 3 , 9 )

Material examined. Holotype ( TIO 013 ), Beibu Bay of South China Sea, station J67 (18°21'N, 108°40'E), depth 32m, 31 July 2006, coll. Donghui Guo.

Diagnosis. Umbrella with low, rounded apical process; gastric peduncle short and broad, shorter than the length of manubrium; oral tube short; mouth with 4 inconspicuous perradial lips, each containing a group of nematocysts; two opposite perradial tentacles, very long and thin, length up to 3 times bell height, with numerous prominent brown spots at irregular intervals.

Description. Medusa with bell-shaped umbrella, 1 mm in height, 0.8 mm in width, with low and rounded apical process, lateral walls thin; manubrium on well-formed peduncle, gastric peduncle short and broad, shorter than the length of manubrium, oral tube short, inconspicuous; manubrium length 3/4 of bell cavity, cylindrical, mouth quadrangular with 4 inconspicuous perradial lips, each containing a group of nematocysts; medusa buds arise from middle region of stomach; 4 narrow radial canals and circular canal present; two opposite perradial marginal bulbs containing blackish brown pigment granules, with two very long and thin tentacles, length up to 3 times bell height, with numerous prominent brown spots at irregular intervals and with a distinct terminal knob, two other opposite marginal bulbs no present; no ocelli present; velum narrow.

Distribution. Beibu Bay of South China Sea.

Etymology. The specific name is from the Latin longitentaculatum , meaning long-tentacles, referring to the morphology of the tentacles, which are very long and thin tentacles.

Remarks. The new species can be distinguished from the other species of Eucodonium by: 1) two very long and thin tentacles, length up to 3 times bell height, with numerous brown spots at irregular intervals; 2) gastric peduncle short and broad; 3) oral tube inconspicuous; 4) 4 inconspicuous perradial lips, each containing a group of nematocysts.

Funding This study was supported by Global Climate Change and Ocean Atmosphere Interaction Research (GASI-01- 02-02-03, GASI-01-02-04, GASI-01-02-02-01), the Marine Biological Sample Museum of the Chinese Offshore Investigation and Assessment, and the National Basic Research Program of China (2011CB403604).

Figures

Figures 1 – 3. Eucodonium spp., lateral view. 1. E. bitentaculatum Xu, Huang & Guo, sp. nov. 2. E. brevistyle Xu, Huang & Lin, sp. nov. 3. E. longitentaculatum Xu, Huang & Wang, sp. nov. Scale bars = 0.5 mm.

Figures 4 – 9. Eucodonium spp. 4 – 6. E. bitentaculatum Xu, Huang & Guo, sp. nov. 7 – 8. E. brevistyle Xu, Huang & Lin, sp. nov. 9. E. longitentaculatum Xu, Huang & Wang, sp. nov. 4, 7, 9. Lateral view. 5, 8. Gonads, dorsal view. 6. Gonads, lateral view. Scale bars = 0.5 mm.