New species and records of Colurella (Rotifera: Lepadellidae) from South China, with a key to Chinese Colurella.

A new species of the rotifer genus Colurella (Rotifera, Monogononta, Lepadellidae), C. ovalis sp. nov., is described from four sites (an artificial pond site, a mangrove swamp site, a tidal creek site on Qi'ao Island and an estuarine river site in Macao) in the Pearl River Estuary, South China. The ovate lorica of the new species is similar to C. sanoamuangae Chittapun, Pholpunthin Segers, 1999, but can easily be distinguished by asymmetric posterior lorica ends and a less elongate lorica. The eurythermal and euryhaline animal could be observed perennially in the mangrove swamp site, occasionally with high abundances.Besides, two species of uncertain taxonomic status, two new records of Colurella species for China and a key to Chinese Colurella species are also presented. [Species Zoobank url: urn:lsid:zoobank.org:act:A725658A-5364-45EC-8B5C-485B23252710].

Rotifers from China (Western Guangdong Province), with description of Lecane zhanjiangensis sp. nov. (Rotifera: Monogononta: Lecanidae).

Littoral rotifers were collected in three prefectural cities of the little studied Western Guangdong Province (Yangjiang, Maoming and Zhanjiang) in April 2017 and in July 2018. Fifty-six monogonont taxa, including two subspecies/variations, were found. Lecane zhanjiangensis sp. nov., a new brackish-water species from the littoral zone of Shimenhe River Estuary in Zhanjiang, is described. It is characterized by large semicircular projections antero-laterally on the dorsal plate, each equipped with three to five minute spines, and a pair of large acutely pointed projections antero-laterally on the ventral head aperture margin. In addition, three new rotifer records for China, viz. Brachionus cf. caudatus var. indica Novotná-Dvoráková, 1963, Ptygura libera Myers, 1934 and P. thalenoiensis Meksuwan, Pholpunthin Segers, 2011 are also presented. [Species zoobank registraion: http://zoobank.org/urn:lsid:zoobank.org:act:E91C0C2A-8656-4999-B71C-00F39456F7A0].

Influence of Hydrological Heterogeneity on Rotifer Community Structure in Three Different Water Bodies in Shantou Area, Guangdong (China).

Rotifers, small but essential invertebrates in aquatic ecosystems, are sensitive to environmental changes and are proposed to be indicators of trophic state. However, the effects of hydrological heterogeneity on the rotifer community and the ability of rotifer indices to reflect trophic state across different water bodies are still unclear. Here, we investigated rotifer community structure in different seasons in the three types of water bodies: Han river downstream (HD), Reservoir (RE) and Tidal creek (TC) in Shantou City, Guangdong, China. Our findings revealed that rotifer community structure differes significantly among the three water bodies, resulting from a dominance of Keratella cochlearis, Anuraeopsis fissa and Polyarthra vulgaris, who largely accounted for the differences in water bodies. Chlorophyll-a and transparency were the main environmental drivers in RE rotifer communities, while total nitrogen, total phosphorus and salinity were the main factors in HD and TC communities. Rotifer abundance and the rotifer trophic state index decreased in the order: RE > HD > TC. However, both the Sladecek's B/T quotient and the Keratella- index decreased in the order: HD > RE > TC, which was in accordance with the Carlson's trophic index. We conclude that it is efficient to use rotifer composition in water quality assessments when comparing different water bodies. Alpha diversity of rotifers was the highest in HD, which is consistent with the intermediate disturbance hypothesis. Hydrological heterogeneity is the micro-factor that regulates rotifer community structures in the Shantou area.

Period of public commentary begins on the revised proposal of species-group level names, and on the proposal of genus-group level names of the Candidate Part of List of Available Names (LAN) in the phylum Rotifera.

Following ICZN (1999) Article 79 Chapter 17 http://www.nhm.ac.uk/hosted-sites/iczn/code/), we, with the full support of the international community of rotifer researchers as expressed during subsequent international Rotifera symposia, developed a Candidate Part of the List of Available Names for species and genera of Rotifera from the start of zoological nomenclature to the year 2000.

Community patterns of the small riverine benthos within and between two contrasting glacier catchments.

Ongoing glacial retreat is expected to lead to numerous changes in glacier-fed rivers. This study documents the development of community composition of the hitherto widely neglected micro- and meiobenthos (MMB: bacteria, fungi, algae, protists, and meiofauna) in glacier rivers in response to the distinct habitat conditions driven by different stages of (de)glacierization. Our model is based on the glacier catchments of the Möll River (MC) and Kleinelendbach stream (KC), in the Austrian Alps, with 60% and 25% glacierization and glacier retreats of 403 and 26 m, respectively, since 1998. Analyses of overall catchment diversity and resemblance patterns showed that neither intense glacierization nor rapid deglacierization were predominant MMB determinants. This was ascribed to the specific environmental conditions at the MC, where the rapidly retreating Pasterze glacier has formed a harsh unstable proglacial, but also a benign floodplain area, with the former suppressing and the latter supporting the structural development of the MMB. Comparisons of similarly aged riverine habitats of the MC proglacial and the KC main channel further evidenced developmental suppression of the MMB (64 taxa) by the rapidly retreating MC glacier, unlike the moderate glacial retreat in the KC (130 taxa). Habitat conditions interacting with melt periods explained the differences in MMB resemblance patterns, which themselves differentially reflected the spatiotemporal habitat settings imposed by the different glacier activities. The varying glacial influences were represented by a glaciality index (GIm) based on water temperature, electrical conductivity, and stream bed stability. The taxonomic richness of nematodes, rotifers, algae, and diatoms was distinctly related to this index, as were most MMB abundances. However, the strongest relationships to the GIm were those of nematode abundances and maturity. Our observations highlight the intense response of the MMB to ongoing glacier retreat and the utility of a simple index to reveal such patterns.

Hang on or run? Copepod mating versus predation risk in contrasting environments.

Mating durations of copepods were found to differ significantly between fishless high-altitude waters and lowland lakes containing fish. In lowland species the whole mating process was completed within a few minutes, but it averaged over an hour in high-altitude species. Alpine copepods showed a prolonged post-copulatory association between mates, during which the male clasped the female for an extended period after spermatophore transfer, while in lowland species males abandoned their partner immediately after copulation. Prolonged associations also occurred after transfer of spermatophores to heterospecific females with shorter conspecific mating duration, suggesting that male interests largely dictate the time spent in tandem. The differences observed may be adaptations to environments with different predation pressure, as pairs in tandem are more conspicuous and less reactive than single animals. We argue that differences in mating behavior and mating duration evolved under sexual versus natural selection, reflecting trade-offs between enhancement of fertilization success and reduction of vulnerability to visual predation. In fishless mountain lakes with high intrasexual competition, guarding males can reduce the risk of spermatophore displacement or the risk that the female will accept sperm from rival males without increased risk of being eaten, thereby maximizing paternity. Populations from fishless alpine lakes further differed from lowland species by exhibiting higher female/male size dimorphism and more intense pigmentation. While these traits vary between populations according to predation pressure, mating duration appears to be more species-specific.