Gangliostoma abaxialispura

Type materials. Holotype (TIO 032), China, south of Taiwan Strait, Station ZD-MJK 535 (26 ° 09 ’ N, 120 ° 45 ’ E), depth 67 m, sampling depth 67 – 0 m, 20 July 2006, coll. Peng Xiang. Diagnosis. The species is diagnosed by following: umbrella nearly disk shaped, apex jelly very thick; manubrium very broad, with a basal circular row of as many papillae as radial canals; with 8 marginal tentacles, tentacular bulbs with a distinct abaxial spurs upwards over margin of bell; with 6 rudimentary bulbs and 6 statocysts between the tentacles. Description. Umbrella 5.0 mm in height, 8.0 mm in width, nearly disk shaped, apex jelly very thick, thinning towards margin; with very broad manubrium which devoid of a peduncle, about half as wide as diameter of umbrella, with a basal circular row of as many as papillae as radial canals; without subumbrella gelatinous papillae; with 32 simple radial canals, oral lips short, less numerous than radial canals; gonads extending along whole length of radial canals, but not connected to ring canal; with 8 well-developed hollow marginal tentacles, about 1 / 4 as many as number of radial canals, tentacular bulbs large, nearly spherical-like with a distinct abaxial spurs upwards over margin of bell; no ocelli; with 6 rudimentary bulbs between tentacles, medium one larger than other two or three; with many statocysts of same number as rudimentary bulbs; velum broad. Distribution. Taiwan Strait, China. Etymology. The specific name derived from the Latin abaxialispura, meaning abaxial-spur, in reference to the morphology of tentacular bulbs with an abaxial spur. Remarks. This new species has following characters which are in common with Gangliostoma Xu, 1983: medusa with a very broad manubrium, with a basal circular row of papillae of the same number as the radial canals. Before the work, only two species of Gangliostoma, G. dayaensis and G. guangdongensis, are known (Xu, 1983; Bouillon et al., 2006; Du et al., 2010; Xu et al., 2014). The new species can be distinguished from other two by following: 1) umbrella with 8 marginal tentacles, about 1 / 4 as many as the number of radial canals; 2) each tentacular bulbs with a distinct abaxial spurs, without excretory papillae; 3) with 6 rudimentary bulbs and 7 statocysts between the tentacles.