Yongde Cui

Macrozoobenthic community of Poyang Lake, the largest freshwater lake of China, in the Yangtze floodplain

Poyang Lake (Poyang Hu) is located at the junction of the middle and lower reaches of the Yangtze (Changjiang) River, covering an area of 3283 km2. As one of the few lakes that are still freely connected with the river, it plays an important role in the maintenance of the unique biota of the Yangtze floodplain ecosystem. To promote the conservation of Poyang Lake, an investigation of the macrobenthos in the lake itself and adjoining Yangtze mainstream was conducted in 1997–1999. Altogether 58 benthic taxa, including 22 annelids, 8 mollusks, 26 arthropods, and 2 miscellaneous animals, were identified from quantitative samples. The benthic fauna shows a high diversity and a marine affinity. The standing crops of benthos in the lake were much higher than those in the river, being 659 individuals/m2 and 187.3 g/m2 (wet mass) in the main lake, and 549 individuals/m2 and 116.6 g/m2 in the lake outlet, but only 129 individuals/m2 and 0.4 g/m2 in the river. The dominant group in the lake was Mollusca, comprising 63.4% of the total in density and 99.5% in biomass. An analysis of the functional feeding structure indicated that collector-filterers and scrapers were predominant in the lake, up to 42.2% and 24.7% in density and 70.2% and 29.2% in biomass, respectively, while shredders and collector-gatherers were relatively common in the river. The present study was restricted to the northern outlet and the northeast part of Poyang Lake. A scrutiny is required for the remaining areas.

Distributions of two ectosymbionts, branchiobdellidans (Annelida: Clitellata) and scutariellids (Platyhelminthes: "Turbellaria": Temnocephalida), on atyid shrimp (Arthropoda: Crustacea) in southeast China

Distribution of two ecologically similar but usually spatially separate ectosymbionts, branchiobdellidans (Annelida) and scutariellids (Platyhelminthes), on atyid shrimp (Neocaridina spp.) is reported from 18 localities in five Provinces of southeastern China. Prevalence was determined for the branchiobdellidan, Holtodrilus truncatus, found at seven locations, the scutariellid, Scutariella japonica, present at every site, and where cohabitation occurred. Both ectosymbionts showed a microhabitat predilection for the hosts branchial chambers and instances of cohabitation occurred at all seven locations where H. truncatus were collected, although not on every shrimp. On-site observations of live hosts supporting both ectosymbionts showed that neither H. truncatus nor S. japonica reacted aggressively or defensively towards the other when in close proximity. Instances of imported Chinese Neocaridina spp. into central Honshu Island, Japan, almost certainly came from areas in southeast China identified in this study. These imported populations are predicted to spread northwards into the area where endemic Japanese branchiobdellidans occur.

Relationships between testate amoeba communities and water quality in Lake Donghu, a large alkaline lake in Wuhan, China

The middle Yangtze Reach is one of the most developed regions of China. As a result, most lakes in this area have suffered from eutrophication and serious environmental pollution during recent decades. The aquatic biodiversity in the lakes of the area is thus currently under significant threat from continuous human activities. Testate amoebae (TA) are benthic (rarely planktonic) microorganisms characterized by an agglutinated or autogenous shell. Owing to their high abundance, preservation potential in lacustrine sediments, and distinct response to environmental stress, they are increasingly used as indicators for monitoring water quality and reconstructing palaeoenvironmental changes. However this approach has not yet been developed in China. This study presents an initial assessment of benthic TA assemblages in eight lakes of Lake Donghu in the region of Wuhan, China. Testate amoeba community structure was most strongly correlated to water pH. In more alkaline conditions, communities were dominated by Centropyxis aculeata, Difflugia oblonga, Pontigulasia compressa, Pon. elisa and Lesquereusia modesta. These results are consistent with previous studies and show that TA could be useful for reconstructing past water pH fluctuations in China. To achieve this, the next step will be to expand the database and build transfer function models.

Limnodrilus simplex sp. nov. (Oligochaeta: Naididae: Tubificinae) from Changjiang River, China

Limnodrilus simplex sp. nov. (Oligochaeta: Naididae: Tubificinae) is described based on a single specimen from the mainstream of the Changjiang River near Anqing City, Anhui Province, China. The new species is assigned to Limnodrilus by the presence of long vasa deferentia, spindle-shaped atria with long ejaculatory ducts, large prostate glands, and thick cylindrical penial sheaths. It differs from its congeners in having simple-pointed chaetae and cuticularized penial sheaths without hoods. Limnodrilus simplex is closer to L. paramblysetus and L. amblysetus in possessing penial sheaths with relatively low length/maximum width ratio.

Potamothrix scleropenis sp. nov. (Oligochaeta: Tubificidae) from Fuxian Lake, the Deepest Lake in Southwest China

Abstract Potamothrix scleropenis sp. nov. (Tubificidae: Tubificinae) is described from the profundal zone (74 m) of Fuxian Lake, the deepest lake (up to 155 m) on the Yunnan-Guizhou Plateau in China. The new species is assigned to Potamothrix because of its short vasa deferentia and its tubular atria without ejaculatory ducts and prostate glands. It differs from congeners by its cuticularized penis sheaths; bifurcated, strongly curved spermathecal chaetae; bifurcated lower prongs of bifids; and feathered hairs. P. scleropenis appears closely related to P. cekanovskajae Finogenova, 1972 and P. tudoranceai Sporka, 1994, since all the three species have homogeneous atria without prostate glands.

Records of Naididae and Lumbriculidae (Clitellata) from Tibet, China, with description of a new species of Nais

The Tibetan Plateau is considered to have a unique fauna of fish and invertebrates. However, little taxonomic work has been conducted on the aquatic Oligochaeta of Tibet, China. Based on the surveys of rivers and lakes in this region between 2010 and 2011, we recorded 25 species of oligochaetes belonging to 2 families and 15 genera. This paper provides an overview of the species composition of different waterbodies, the description of one new species, Nais longidentata sp. n., and re-descriptions of four previously described species. Hitherto, 30 species of aquatic oligochaetes have been recorded from Tibet. The oligochaete fauna is similar to that of the Holarctic, but has several endemic elements.

Pectinatella magnifica (Leidy, 1851) (Bryozoa, Phylactolaemata), a biofouling bryozoan recently introduced to China

Freshwater biofouling threatens a variety of human activities, from the supply of water and energy to recreation. Several species of freshwater bryozoans are notorious for clogging pipes and filters but have been relatively poorly studied to date. We report, for the first time, a biofouling species of freshwater bryozoan, Pectinatella magnifica (Leidy, 1851), from several freshwater rivers, lakes and ponds in China. A complete description, national distribution and the fouling problems are provided. Exactly how Pectinatella magnifica arrived in China remains unclear, but anthropochory and zoochory are considered to be important dispersal pathways.

Two new species of Potamothrix (Oligochaeta: Tubificinae) from plateau lakes of Yunnan Province, southwest China

Abstract Two new species of Potamothrix (Oligochaeta: Tubificinae), P. rhytipeniatus, new species and P. aductus, new species, are described from Fuxian Lake and Xingyun Lake of Yunnan Province, southwest China. Potamothrix rhytipeniatus differs from congeners by its wrinkled penis surface and vasa deferentia entering the atrium subapically. Potamothrix aductus is distinguishable from all congeners by lacking a spermathecal duct. Hitherto, 31 species of freshwater oligochaetes have been recorded from Yunnan Province, including seven endemic species from plateau lakes.

Three new species of Potamothrix (Oligochaeta, Naididae, Tubificinae) from Fuxian Lake, the deepest lake of Yunnan Province, Southwest China

Abstract Three new species of Potamothrix Vejdovský & Mrázek, 1902 (Oligochaeta: Tubificinae), Potamothrix praeprostatus sp. n., Potamothrix paramoldaviensis sp. n. and Potamothrix parabedoti sp. n., are reported from Fuxian Lake of Yunnan Province, Southwest China. Potamothrix praeprostatusdiffers from its allies by its prostate glands joining atria in its proximal to middle portion, and spermathecal chaetae. Potamothrix paramoldaviensis is distinguishable from its allies by having penial chaeta but no penes, and differs from Potamothrix moldaviensisby its homogenous atrium. Potamothrix parabedoti is distinctive in the position of its reproductive organs, and differs from Potamothrix bedoti by its homogenous atrium. Hitherto, 34 freshwater oligochaete species have been recorded in Yunnan Province, including nine endemic species from the plateau lakes.

Two species of Naididae (Annelida, Clitellata) from southern Tibet, China

Abstract One new species of Naidinae (Oligochaeta, Naididae), Nais badia sp. n. and one new record species from China, Tubifex montanus Kowalewski, 1919 (Tubificinae) are found in southern Tibet. The new species is distinguished from congeners by its large area of reddish brown pigment in the anterior segments I–VIII, serrate hairs, pectinate needles with 1–2 intermediate teeth, ventral chaetae partly with 1–2 fine intermediate teeth and wave-like movements. The new material of the species Tubifex montanus differs slightly from the previous descriptions by its vas deferens entering atrium subapically, wide ental end of penial sheath and smooth hair chaetae.