Eucodonium Hartlaub, 1907

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 : 49

Genus Eucodonium Hartlaub, 1907

Eucodonium Hartlaub, 1907: 71 ; Mayer, 1910: 68; Schuchert, 1996: 89; Bouillon et al., 2006: 147. Type species: Eucodonium brownei Hartlaub, 1907 .

Diagnosis. As in the family diagnosis.

Discussion. The genus Eucodonium is similar to Cytaeis Eschscholtz, 1829 , Hydractinia van Beneden, 1841 and Plotocnide Wagner, 1885 by having four perradial nematocyst clusters embedded in the mouth margin. But it is distinguished from Cytaeis by oral tentacles simple, situated on/or very near mouth rim, from Hydractinia by mouth with four distinct lips elongated to form perradial mouth armed with one or many distinct cnidocyst clusters, from Plotocnide by the cnidome contains desmonemes and stenoteles (Hand & Kan, 1961) justifying assignment to the Capitata Tubulariidae incertae sedis.

Key to medusae of all known Eucodonium species.

1 Four perradial marginal bulbs and four tentacles present; tentacles with terminal swelling; mouth with 4 inconspicuous perradial lips, eaching containing a group of about 100 nematocysts ....................................................................... E. brownei Hartlaub, 1907 Two perradial marginal bulbs and two tentacles present; tentacles with terminal swelling..................................................................2 2 Two opposite perradial tentacles very long and thin, length up to 3 times bell height, with numerous prominent brown spots at irregular intervals ................................................................................................ E. longitentaculatum Xu, Huang & Wang sp. nov. Two opposite perradial tentacles short ................................................................................................................................................. 3 3 Gastric peduncle broad conical, half as long as manubrium; oral tube long, about the same length as that of the stomach ..................

.................................................................................................................................. E. bitentaculatum Xu, Huang & Guo, sp. nov. Gastric peduncle short and broad, shorter than the length of manubrium; oral tube short, about shorter than the length of stomach....

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

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