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Family Ptilocodiidae Coward, 1909 emend. Ptilocodiidae Coward, 1909: 729; Bouillon et al., 2006: 151���153; Schuchert, 2009: 470���471; Xu et al., 2014: 264���265. Diagnosis. Hydroid. Hydrorhiza stolonal, reticular, or encrusting, covered by naked coenosarc; hydranths sessile, naked and polymorphic; gastrozooid tubular, without tentacles; dactylozooids with 4 or more capitate tentacles, sometimes filiform; gonophores on gonozooids or gastro-gonozooids; developing into fixed sporosacs, eumedusoids or free medusae. Medusa. Mature medusa with more or less bell-shaped umbrella, with or without radial exumbrellar furrows; with marginal nematocyst ring from which usually arise several didermic centripetal nematocyst bands (tracks) or exumbrellar rows of refringent spots; with four marginal tentacles or tentacles absent; four radial canals and circular canal; manubrium with 4 perradial mouth arms ending in nematocyst clusters or 4 simple unbranched perradial oral tentacles arising above mouth rim unarmed terminal nematocyst clusters; gonads four interradial or eight adradial masses on manubrium, or completely perradial gonads; with or without ocelli. Remarks. According to the original report (Du et al., 2012) and by reexamining its shape, position and attachment of oral tentacles, Tregoubovia perradialis Xu, Huang & Du, 2012 is obvious different from other species of Tregoubovia Picard, 1958. In T. perradialis, the oral tentacles are arising above mouth rim with ring nematocysts, while the oral arms of Tregoubovia are extending from the perradial corners of mouth margin, and armed with terminal nematocyst clusters. The position of gonads is on perradial position of manubrium in T. perradialis, and interradial in Tregoubovia. According to these, T. perradialis should be removed from the genus Tregoubovia, and a new genus Tregouboviopsis Guo, Xu & Huang, gen. nov. is proposed to accommodate it. The diagnosis was therefore adapted to fit the new scope of the family. Thus, the family Ptilocodiidae comprises six genera now: Hydrichthella Stechow, 1909, Ptilocodium Coward, 1909, Thecocodium Bouillon, 1967, Hansiella Bouillon, 1980, Tregoubovia Picard, 1958 and Tregouboviopsis Guo, Xu & Huang, gen. nov. For a recent revision of the family Ptilocodiidae see Bouillon et al. (2006), Schuchert (2009), Du et al. (2012) and Xu et al. (2014). From the Chinese waters, two genera, Hydrichthella as hydroid and free eumedusoid, and Tregouboviopsis as medusa, are known. Key to the genera of Ptilocodiidae. 1. Hydroids............................................................................................................................................................................................... 2 Medusae...............................................................................................................................................................................................4 2. Dactylozooids with two types................................................................................................................. Hydrichthella Stechow, 1909 Dactylozooids with one type................................................................................................................................................................ 3 3. Hydrorhiza crust-like, not covered by visible perisarc............................................................................... Ptilocodium Coward, 1909 Hydrorhiza a network of perisarc-protected tube-like stolons................................................................. Thecocodium Bouillon, 1967 4. Without marginal tentacles................................................................................................................................................................... 5 With marginal tentacles........................................................................................................................................................................6 5. Four perradial oral arms, ending swollen with nematocyst clusters; gonads interradial.............................. Tregoubovia Picard, 1958 Four perradial simple oral tentacles, arising above mouth rim, without terminal nematocyst clusters; gonads perradial......................................................................................................................................................... Tregouboviopsis Guo, Xu & Huang, gen. nov. 6. Four interradial gonads........................................................................................................................... Thecocodium Bouillon, 1967 Eight adradial gonads.................................................................................................................................... Hansiella Bouillon, 1980, Published as part of Wang, Lianggen, Du, Feiyan, Xu, Zhenzu, Huang, Jiaqi & Guo, Donghui, 2017, Taxonomical notes on the family Ptilocodiidae (Anthomedusae) from the central and southern of South China Sea, with a new genus and a new species, pp. 236-242 in Zoological Systematics 42 (2) on pages 237-238, DOI: 10.11865/zs.201713, http://zenodo.org/record/4617015, {"references":["Coward, W. E. 1909. On Ptilocodium repens a new gymnoblastic hydroid epizoic on a pennatulid. Verslag van de Gewone Vergaderingen der Wis-En Natuurkundige Afdeeling, 17 (2): 729 - 735.","Bouillon, J., Gravili, C., Pages, F., Gili, J-M., Boero, F. 2006. An introduction to Hydrozoa. Memoires du Museum national d'Histoire Naturelle, 194: 1 - 591.","Schuchert, P. 2009. The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 5. Revue Suisse de Zoologie, 116 (3 - 4): 441 - 507.","Xu, Z. Z., Huang, J. Q., Lin, M., Guo, D. H., Wang, C. G. 2014. The Superclass Hydrozoa of the Phylum Cnidaria in China. China Ocean Press, Beijing. 945 pp.","Du, F. Y., Xu, Z. Z., Huang, J. Q., Guo, D. H. 2012. Studies on the medusae (Cnidaria) from the Beibu Gulf in the northern South China Sea, with description of three new species. Acta Zootaxonomica Sinica, 37 (3): 506 - 519.","Stechow, E. 1909. Beitrae zur Naturgeschichte Ostasiens: Hydroidpolypen der japanischen Ostkuste I Athecata und Plumularidae. A bhandlungen der Mathematisch-Physikalischen K 1 asse der Koniglichen Bayerischen Akademie der Wissenschaften, 1 (6): 1 - 111."]}

Tregouboviopsis perradialis (Xu, Huang & Du, 2012), comb. nov. (Figs 6–12) Tregoubovia perradialis Xu, Huang & Du, 2012 in Du et al., 2012: 507, figs 2–4; Xu et al., 2014: 266–267, figs 127A–C. Material examined. Holotype. 1 male, BG 001, Beibu Gulf, st. S30 (17°30'N, 107°30'E), depth 70m, 6 July 2008, coll. Xin Liang (SFRI). Other material. 1 female, SFI 002, central of South China Sea, st. ZI8 (16°31'N, 113°21'E), depth 1395 m, sampling depth 240–0m, 31 July 2014, coll. Lianggen Wang (SFRI). Diagnosis. Umbrella globular, mesoglea fairly thick; with 16 exumbrellar didermic centripetal tracks; mouth with 4 simple, long oral tentacles, arising above mouth rim, without terminal clusters and with ring nematocysts; 4 gonads very large, long and mass-like, almost covering perradial part along the whole length of manubrium; without marginal bulbs and tentacles. Description. Umbrella 6 mm high, 5.0– 5.5 mm wide, globular, mesoglea fairly thick, marginal portion near as thick as apical portion; without free tentacles; along bell margin a ring of thickened tissue with nematocysts from which originate 16 didermic centripetal tracks (4 perradial, 4 interradial, 8 adradial) running meridionally on the surface of the exumbrella towards aboral pole, reaching maximally to mid umbrella; manubrium large and voluminous, reaching to level of velum, base square to cross-shaped, about 4/5 as long as subumbrella cavity, with 4 interradial subumbrella projections upper the manubrium; mouth quadratic with 4 simple, long oral tentacles, arising above mouth rim, unarmed terminal nematocyst clusters, but with ring nematocysts; four relatively thick radial canals and circular canal wide; mesenteries long, about 1/2 the length of manubrium connected to the radial canals by mesenteries; four gonads very large, long and mass-like, almost covering perradial part along the whole length of manubrium, well separated interradially, female with numerous very large eggs, without isolated pits of adradial series, but male with isolated pits of adradial series; without ocelli; velum wide. Distribution. Central and northern of South China Sea. Remarks. The species is rare as only two specimens were collected so far. The holotype male, collected from the northern South China Sea (Beibu Gulf), has following characters: 16 exumbrella didermic centripetal tracks present; mouth with 4 perradial oral tentacles arising above mouth rim, without terminal clusters and with ring nematocysts; 4 gonads in perradial position of manubrium, each with 2 adradial series of 4–5 isolated pits (male specimen) and no marginal tentacles (Figs 6–7). The female, another specimen collected from the central of South China Sea, has similar structures as the holotype but has 4 large, smooth gonads without isolated pits in longitudinal series (Figs 8–12) (see genus remarks).

Genus Hydrichthella Stechow, 1909 Hydrichthella Stechow, 1909: 31; Hirohito, 1988: 142, 144; Bouillon et al., 2006: 153; Xu et al., 2014: 265. Hydrichthelloides Bouillon, 1978: 55; Bouillon, 1985: 59. Type species: Hydrichthella epigorgia Stechow, 1905. Diagnosis. Hydroid. Colony usually growing on sea fans, hydrorhiza encrusting, covered by naked coenosarc, or consisting of perisarc-covered reticular stolons pending substrate; gastrozooid tubular, without tentacles; hypostome studded by nematocysts; dactylozooids hollow, without mouth, with two types: one with many capitate tentacles and the other filiform, with capitate tip; gonozooids similar to gastrozooids in shape, bearing eumedusoids. Medusa. Reduced to short-living eumedusoids, with 4 radial canals and subumbrellar cavity, with manubrium not eccentric; with 8 non-tentacular bulbs; gonads on manubrium; with or without ocelli. Remarks. The genus Hydrichthella shares with Hydrichthelloides the hydroids colony polymorphic and dactylozooids of two types: one with many capitate tentacles and the other filiform with capitate tips. Type species of both genera show distinct from the structure of hydrorhiza: Hydrichthelloides reticula Bouillon, 1978 consists of perisarc, covered reticular stolons pending substrate; Hydrichthella epigorgia Stechow, 1909 is encrusting, covered by naked coenosarc. The systematic value of this distinguished character is questionable even at the generic level. Hirohito (1988) treated Hydrichthelloides as a synonym of Hydrichthella. The genus Hydrichthella comprised two species: the hydroid H. epigorgia Stechow, 1909 from the East China Sea, Japan, Indonesia, Papua New Guinea and Seychelles Island (Hirohito, 1988; Tang & Gao, 2008; Xu et al., 2014) and H. reticulata (Bouillon, 1978) from Papua New Guinea (Bouillon, 1978). In the present work, a new medusa species, H. ocellata Xu, Huang & Wang, sp. nov., collected from the South China Sea with red ocelli on the 8 non-tentacular bulbs which suggests it should be a new species of the genus., Published as part of Wang, Lianggen, Du, Feiyan, Xu, Zhenzu, Huang, Jiaqi & Guo, Donghui, 2017, Taxonomical notes on the family Ptilocodiidae (Anthomedusae) from the central and southern of South China Sea, with a new genus and a new species, pp. 236-242 in Zoological Systematics 42 (2) on page 238, DOI: 10.11865/zs.201713, http://zenodo.org/record/4617015, {"references":["Stechow, E. 1909. Beitrae zur Naturgeschichte Ostasiens: Hydroidpolypen der japanischen Ostkuste I Athecata und Plumularidae. A bhandlungen der Mathematisch-Physikalischen K 1 asse der Koniglichen Bayerischen Akademie der Wissenschaften, 1 (6): 1 - 111.","Hirohito, E. S. 1988. The hydroids of Sagami Bay. Part 1 Athecata. Biological Laboratory Imperial Household, Tokyo. 179 pp.","Bouillon, J., Gravili, C., Pages, F., Gili, J-M., Boero, F. 2006. An introduction to Hydrozoa. Memoires du Museum national d'Histoire Naturelle, 194: 1 - 591.","Xu, Z. Z., Huang, J. Q., Lin, M., Guo, D. H., Wang, C. G. 2014. The Superclass Hydrozoa of the Phylum Cnidaria in China. China Ocean Press, Beijing. 945 pp.","Bouillon, J. 1978. Sur un nouveau genre et une nouvelle espece de Ptilocodiidae Hydrichthelloides reticulata et la super-famille des Hydractinoidea (Hydroida-Athecata). Steenstrupia, 5 (6): 53 - 67.","Bouillon, J. 1985. Essai de classification des Hydropolypes-Hydromeduses (Hydrozoa-Cnidaria). Indo-Malayan Zoology, 1: 29 - 243."]}

Hydrichthella ocellata Xu, Huang & Wang, sp. nov. (Figs 1���4) Material examined. Holotype SFI 001, southern of South China Sea, st. B4 (10��16'N, 114��13'E), depth 2000 m, sampling depth 20���0 m, 22 May 2014, colls. Shen Chen & Jie Li (SFRI). Diagnosis. Free eumedusoid, umbrella nearly spherical; with short and wide gastric peduncle, with 4 large mass-like gonads, interradial on manubrium; bell margin with 8 non-tentacular bulbs, 4 perradial larger than 4 interradial bulbs, each with a distinct red ocellus at the extreme tip. Description. Medusa reduced to short-living eumedusoid; umbrella up to 1 mm high, nearly as wide as high in preserved specimen; mesoglea about 1/3���1/4 diameter of exumbrella; exumbrella covered with nematocysts, without exumbrellar furrows and didermic centripetal tracks; manubrium hanging from short and wide peduncle, mouth more or less quadratic in shape with simple mouth lips; 4 gonads interradial, extending to adradial on manubrium, smooth without folded; with 4 radial canals and circular canal; umbrella margin with 8 non-tentacular bulbs, 4 perradial larger than 4 interradial bulbs, each with a distinct red ocellus at the extreme tip; velum middle broad. Hydroid. Unknown. Distribution. Southern South China Sea. Etymology. The specific name refers to the Latin ocellata, meaning ocellus. The eumedusoid name refers to the marginal bulbs each with a red ocellus at the extreme tip. Remarks. Although only one specimen was found, its good preservation of morphological characters suggests that a new eumedusoid is present. The eumedusoid of Hydrichthella ocellata Xu, Huang & Wang, sp. nov. is very similar to the eumedusoid of H. epigorgia Stechow, 1909 (redescribed by Hirohito (1988)), by the bearing eumedusoids with four radial canals, 8 marginal bulbs, 4 large, mass-like gonads, interradial positions on manubrium, with velum. But the eumedusoid of H. ocellata Xu, Huang & Wang, sp. nov. is clearly different from H. epigorgia by free swimming eumedusoid with exumbrellar scattered nematocysts, with a short and wide gastric peduncle, 8 marginal bulbs, 4 perradial bulbs larger than 4 interradial bulbs, each with a red ocellus at the extreme tip (Figs 1���4)., Published as part of Wang, Lianggen, Du, Feiyan, Xu, Zhenzu, Huang, Jiaqi & Guo, Donghui, 2017, Taxonomical notes on the family Ptilocodiidae (Anthomedusae) from the central and southern of South China Sea, with a new genus and a new species, pp. 236-242 in Zoological Systematics 42 (2) on pages 238-239, DOI: 10.11865/zs.201713, http://zenodo.org/record/4617015, {"references":["Stechow, E. 1909. Beitrae zur Naturgeschichte Ostasiens: Hydroidpolypen der japanischen Ostkuste I Athecata und Plumularidae. A bhandlungen der Mathematisch-Physikalischen K 1 asse der Koniglichen Bayerischen Akademie der Wissenschaften, 1 (6): 1 - 111.","Hirohito, E. S. 1988. The hydroids of Sagami Bay. Part 1 Athecata. Biological Laboratory Imperial Household, Tokyo. 179 pp."]}

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.

To understand fish species composition,community pattern,dominant species and seasonal variation in the continental shelf of northwestern South China Sea,four otter trawl surveys were conducted in January and August 2006,and April and November 2007,representing winter,summer,spring and autumn,respectively.Sixteen stations were assigned in each otter trawl survey along the coastlines from eastern Leizhou Peninsula to southeastern Hainan Island.Fish collection and data analysis followed the National Marine Survey Standards(GB/T12763.6—2007).Totally 262 fish species,from 102 families and 20 orders,were collected in the four seasonal surveys.The results revealed that the highest species diversity was in winter with 166 species recorded and the lowest was in spring with 135 species recorded;161 and 155 species were recorded in summer and autumn,respectively.The Order Perciformes was the most important fish group in the continental shelf of northwestern South China Sea;the highest species diversity recorded was the Perciformes in all four seasons,and 40 out of 72 species recorded year-round belonged to the Perciformes.Species found in all four seasons contributed to 80.34% of total fish biomass.Ninety-one species found only in a single season contributed to 1.62% of total fish biomass.The spatial pattern of fish communities was analyzed using the hierarchical clustering and non-metric multi-dimensional scaling(NMDS),five fish groups were indentified.The Group Ⅰ,recorded in all four seasons,was located in the coastal waters of western Guangdong Province and consisted of 3 or 4 stations.The scale and the distribution area of the Group Ⅰ were stable among seasons.The Group Ⅱ,recorded in spring,summer and autumn,was located in the coastal waters of southeastern Hainan Island and consisted of 6—9 stations.The scale and the distribution area of the Group Ⅱ had seasonal variation.The Group Ⅲ,recorded in spring,summer and autumn,was located in the deep waters of eastern Hainan Island and consisted of 4 stations.The scale and the distribution area of the Group Ⅲ were stable.The Group Ⅳ as a transitional community,recorded in summer and autumn only,was located in the deep waters of eastern Hainan Island and consisted of 1—3 stations.The scale and the distribution area of the Group Ⅳ were small and changed largely with season.The Group Ⅴ as a mixed community,recorded in winter only,was also located in the deep waters of eastern Hainan Island and consisted of 13 stations.The scale and the distribution area of the Group Ⅴ were the largest among the 5 groups.Based on the analysis of similarities(ANOSIM),the results showed the significant differences(R=0.847-0.939,P 0.001) in fish community pattern for all four seasons.Although the station combinations in each fish community had seasonal variation,the correlation coefficients on the community similarities between spring and summer,between summer and autumn and between autumn and winter were 0.780,0.630 and 0.777,respectively.The variations of fish community pattern are closely related to ocean currents and depth.The brackish fishes distributed in the cold eddy area of eastern Leizhou Peninsula and contributed to the Group Ⅰ.The deep sea fishes along the South China Sea Warm Current in eastern Hainan Island contributed to the Group Ⅲ.In winter with the strongest South China Sea Warm Current recorded in the deep waters of eastern Hainan Island,the area was dominated by fishes from the mixed Group Ⅴ.Because of the upwelling in the coastal waters of southeastern Hainan Island the area was dominated by fishes from the Group Ⅱ.In summer and autumn,the coastal current was strong and mixed with the upwelling in the deep waters of eastern Hainan Island;therefore,the area was dominated by fishes from the transitional Group Ⅳ.This study provides scientific evidences for further sustainable fisheries development and conservation in the continental shelf of northwestern South China Sea.

Bay ecosystem health,recently,has faced a growing interference and disturbance by anthropogenic activities,which has also caused challenges to ecosystem management.Ecosystem health assessment,a new methodology of ecosystem assessment,could obtain the current situation both of ecosystem structure and function and provide a great of necessary information for ecosystem management.An integrated assessment methodology for bay ecosystem health was established based on geographical information system(GIS) technology,which was on basis of a "pressure-structure-response" frame model for marine ecosystem and an ecosystem health assessment indicator system constructed by external pressure,ecosystem structure and response parameters.This paper also presented a case study of Daya bay in spring by employing GIS technology. The results showed that the average ecosystem health integrated index was 0.57 in Daya Bay ecosystem in spring.Detailedly,organic pollutant index ranged from 0.36 to 1,with the average value at 0.87,was at "very good" level of Daya Bay ecosystem.Eutrophic level index value ranged from 0.17 to 1,with the average of 0.77,indicated "better" level of the ecosystem.Furthermore,phytoplankton abundance index was at a "worse" level because of the ranges from 0.33 to 1 and the average of 0.21.Zooplankton biomass index ranged from 0.16 to 1,with the average of 0.88,suggested the ecosystem was at a "very good" level.Zoobenthos biomass index was at "critical state",as the index value ranged from 0 to 1 and the average value at 0.59.Moreover,phytoplankton diversity index was also "critical state" level,as the index ranged from 0.39 to 0.75 and the average of 0.55.Primary productivity index,ranged from 0.21 to 1 and the average of 0.77,illustrated the "better" level of the ecosystem.However,ecological buffer capacity index was at a "worst" level,as the index value ranged from 0 to 0.39 and the average value of 0.06.Resumptively,spatial distribution of the assessed sea area could be divided into three zones according to the grade of integrated assessment index,namely "good health zone","critical health zone" and "bad health zone".The percentages of three zones were 46.56%,47.97% and 5.47%,with the average integrated health index of 0.64,0.54 and 0.35,respectively. In general,the status of the Daya Bay ecosystem health was at a "better" level according to the above indexes.However,the health status of the ecosystem was potential to change to "critical state" by the negative influences by factors including phytoplankton abundance,phytoplankton diversity and buffer capacities of the ecosystem.The "bad health zone" in the Daya Bay ecosystem distributed at or near the area with the intensive anthropogenic activity.Consequently,the special distribution of Daya Bay ecosystem health status was mostly affected by anthropogenic activity around the bay.The established methodology has been ultimately proved to be a valuable quantitative assessment method and to be worth widely popularizing in marine ecology due to the characteristics of wide applicability,high accuracy and good expression.