Tregouboviopsis Guo, Xu & Huang 2017, gen. nov

Genus Tregouboviopsis Guo, Xu & Huang, gen. nov. Type species: Tregoubovia perradialis Xu, Huang & Du, 2012. Diagnosis. Ptilocodiidae medusae spherical; without tentacles; bell margin with nematocyst ring from which originate didermic centripetal tracks running meridionally on exumbrella; manubrium large, mouth quadratic with simple and long, unbranched oral tentacles, arising above mouth rim, unarmed terminal nematocyst clusters, and with ring nematocysts along the whole length of the oral tentacles; gonads very large, covering perradial on manubrium well, with mescenteries; without ocelli. Hydroid. Unknown. Remarks. The species Tregoubovia perradialis Xu, Huang & Du, 2012 is originally described under the genus Tregoubovia by the distinctness of simple unbranched oral tentacles, without marginal tentacles and exumbrella with didermic centripetal tracks. By reexamining the type specimens, its positions of oral tentacles and gonads are different from Tregoubovia atentaculata Picard, 1958, the type species of the genus. T. atentaculata has 4 oral arms extending directly from the perradial corners of mouth margin, with one terminal nematocyst clusters; gonads on interradial manubrium (Fig. 5), while T. perradialis has 4 oral tentacles arising above mouth rim, unarmed terminal nematocyst clusters, and with ring nematocysts along the whole oral tentacles; gonads on perradial manubrium (Figs 6–7). Therefore, the species T. perradialis is removed from the genus Tregoubovia and a new genus Tregouboviopsis Guo, Xu & Huang, gen. nov. is erected to accommodate it. Etymology. The genus name is derived from the Latin tregouboviopsis, meaning Tregoubovi-opsis, referring to external characters of both genera are nearly resemble.