Eucodonium brevistyle

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 : 51-52

Eucodonium brevistyle Xu, Huang & Lin, sp. nov.

( Figs 2 , 7–8 )

Material examined. Holotype ( TIO 009 ), Beibu Bay of South China Sea, Station H11 (18°17'N, 109°06'E), depth 20 m, 6 August 2006, coll. Donghui Guo. Paratype. Three specimens ( TIO 010–012 ), same data as holotype; two specimens ( TIO 020–021 ), East China Sea, Station 332 and 338 , August 2002.

Diagnosis. Unbrella nearly hemisphaerical, with slight rounded apical projection; gastric peduncle short and broad, shorter than the length of manubrium, manubrium cylindrical, oral tube short, about 1/2 length of manubrium, mouth quadrangular, with 4 inconspicuous perradial lips, each containing a row of numerous nematocysts; 2 opposite perradial marginal tentacles, short and thin, with ring nematocysts and a small terminal knob, marginal bulbs spherical-like, inside swelling, without ocelli, but containing red-brown pigment granules, and other 2 opposite marginal bulbs without tentacles.

Description. Umbrella nearly hemisphaerical, bell 0.9–1.0 mm in height, 0.4–0.8 mm in width, with slight rounded apical projection; jelly fairly thin; gastric peduncle very short and broad, shorter than the length of manubrium; manubrium large on broad gastric peduncle, oral tube short, about 1/2 of the length of manubrium; manubrium cylindrical, about 1/3 as long as bell cavity; mouth quadrangular, with 4 inconspicuous perradial lips, each containing a row of numerous nematocysts; medusa buds arise from interradial region of stomach; 4 very narrow radial canals and circular canal present; 2 opposite perradial marginal tentacles, short and thin, thread-like, extending to 1/3 the height of umbrella, with ring nematocysts and a small terminal knob containing nematocysts; marginal bulbs spherical-like, inside swelling, without ocelli, but containing red-brown pigment granules, and other 2 opposite perradial marginal bulbs without tentacles; velum narrow.

Distribution. Northern South China Sea (Beibu Bay), East China Sea.

Etymology. The specific name is from the Latin brevistyle , meaning brevi-style, referring to the short peduncle, which is shorter than the length of manubrium.

Remarks. This new species is close to E. bitentaculatum Xu, Huang & Guo, sp. nov., but differs from the latter by following: 1) a gastric peduncle shorter than the length of the manubrium; 2) two opposite perradial marginal tentacles short and thin, thread like, terminal knob without terminates in a thin fibrous appendage; 3) oral tube short, about 1/2 length of manubrium.

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.