Paranubiella shenzhenensis Xu, Guo & Wang, 2019

Wang, Xuefeng, Lin, Kun, Xu, Zhenzu, Guo, Donghui & Huang, Jiaqi, 2019, Some new Hydroidomedusa (Cnidaria) from the northern South China Sea, Zoological Systematics 44 (3), pp. 191-205 : 194

Paranubiella shenzhenensis Xu, Guo & Wang , sp. nov. ( Figs 2 , 9 )

Material examined. Holotype (AOB-HL311), one specimen collected from Dapeng Bay , northern of the South China Sea, station V 4 (22°35 ˊ N, 114°19 ˊ E), depth 13.5m, 26 August 2018, coll. Zike Zhao, Guanjie Min and Shihao Deng.

Diagnosis. The species is different from others by following: medusa without apical projection; subumbrella cavity without apical interradial conical projection; manubrium very long, pyramidal with a broad, quadrat base; with 4 unbranched oral tentacles; gonads completely surrounding manubrium; 4 perradial marginal bulbs, near spherical, all of the same size and structure, without developed tentacles.

Description. Umbrella 1.2 mm in height, 1.0 mm in width, bell-shaped, jelly thicker at apex, but thinner toward bell margin, without apical projection; manubrium very long, pyramidal, with a broad, quadrat base, about 3/4 height of bell cavity; mouth simple, circular, with 4 simple, unbranched oral tentacles, inserted distinctly above mouth rim and armed with cnidocyst cluster; gonads completely surrounding manubrium; with 4 radial canals and circular canal; 4 perradial marginal bulbs, near spherical, all of same size and structure, without developed tentacles; without ocelli; velum moderately broad.

Distribution. Dapeng Bay of Shenzhen, northern of the South China Sea.

Etymology. The specific name is from its type locality, Shenzhen (northern of the South China Sea).

Remarks. This species is placed under the genus Paranubiella Xu, Huang & Lin, 2018 of Bougainvilliidae Lütken, 1850 by having simple unbranched oral tentacles, and 4 marginal bulbs without single tentacle.

Before this work, only two species were reported under the genus Paranubiella ( Guo et al., 2018) . The new species can be easily distinguished from the other two by: 1) manubrium very long, pyramidal, with a broad, quadrat base, about 3/4 height of bell cavity; 2) gonads completely surrounding manubrium; 3) umbrella without apical projection.

Key to the known species of genus Paranubiella .

1. Four perradial marginal bulbs, differing in size and structure; with 12 unbranched oral tentacles; gonads on perradial region of manubrium .................................................................................................................................. P. atentaculata (Xu & Huang, 2004) Four perradial marginal bulbs, all of same size and structure; with 4 unbranched oral tentacles......................................................... 2

2. Bell with apical projection; manubrium very short, spherical, with 4 large, ovaliform gonads on interradial region of manubrium..... ............................................................................................................................................ P. nanhaiensis Xu, Huang & Guo, 2018 Bell without apical projection; manubrium very long, pyramidal, with a broad, quadrat base; gonads completely surrounding manubrium ..................................................................................................................... P. shenzhenensis Xu, Guo & Wang , sp. nov.

Figures

Figures 1–6. Hydroidomedusa spp. 1. Nubiella terminaliknoba Xu, Huang & Guo, sp. nov., lateral view. 2. Paranubiella shenzhenensis Xu, Guo & Wang, sp. nov., lateral view. 3. Eucodonium crassonemalis Xu, Guo & Lin, sp. nov., lateral view. 4. Proboscidactyla trifurcata Xu, Huang & Guo, sp. nov., lateral view. 5. Euphysora knides Huang, 1999, lateral view. 6. Monocanna ovale (Mayer, 1900) comb. nov., oral view. Scale bars: 1=0.2mm; 2–3, 5–6=0.5mm; 4=1.0mm.

Figures 7–11. Hydroidomedusa spp., line drawing. 7. Nubiella terminaliknoba Xu, Huang & Guo, sp. nov., lateral view. 8. Ditto, enlargement of marginal tentacle. 9. Paranubiella shenzhenensis Xu, Guo & Wang, sp. nov., lateral view. 10. Eucodonium crassonemalis Xu, Guo & Lin, sp. nov., lateral view. 11. Proboscidactyla trifurcata Xu, Huang & Guo, sp. nov., lateral view. Scale bars: 7=0.2mm; 9–10=0.5mm; 11=1.0mm.