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Freshwater mussels of the tribe Gonideini (Bivalvia: Unionidae: Gonideinae) constitute one of the most taxonomically diverse groups and serve as keystone species in riverine and lacustrine ecosystems across East Asia. A new genus and species of Gonideini (Bivalvia: Unionidae) is described from Jiangxi, China, as Pseudopostolata angula gen. et sp. nov. based on an integrative analysis of shell morphology and molecular data. The validity of the new genus and species is supported by distinct conchological features: a short, rounded anterior; a long, wide posterior; a slightly downward-curved dorsal margin; and a distinctly obtuse angle at the center of the posterior margin. The multi-locus (COI + 16S rRNA + 28S rRNA) phylogeny showed that the species formed a monophyletic group in the tribe Gonideini of the subfamily Gonideinae. Pseudopostolata angula gen. et sp. nov. is identified as the sister group to a clade comprising the genera Postolata, Cosmopseudodon, Obovalis, Ptychorhynchus, Parvasolenaia, and Koreosolenaia. We emphasize the significant morphological convergence in freshwater mussels, particularly within Gonideini, highlighting the necessity of an integrated taxonomic approach for accurate generic classification of this group.

The Pearl River Basin, China’s second-largest freshwater basin, hosts a significant diversity of species and a highly endemic freshwater mussel fauna. In this study, a new species from the Liuxi River in Guangzhou, Guangdong, China, Pletholophus guangzhouensis sp. nov., is described based on morphological diagnostic features and molecular phylogenetics. The glochidia shells of the new species are subtriangular, medium-sized, and have a styliform hook on the ventral angle of each valve. Phylogenetic analyses based on the COI and 28S rRNA gene fragments indicated that Pletholophus guangzhouensis sp. nov. is the sister to Pletholophus tenuis + Pletholophus reinianus. The pairwise uncorrected COI p-distance analysis demonstrated genetic distances ranging from 5.27% (between P. guangzhouensis sp. nov. and P. tenuis) to 11.06% (between P. guangzhouensis sp. nov. and P. honglinhensis). Our findings suggest a significant underestimation of the diversity of freshwater mussel species in Guangdong. Further field collections and systematic studies are necessary to fully explore the biodiversity of this region. Furthermore, integrative classification methods and genetic research are essential for informing the development of effective conservation strategies.

Our study contains the first molecular phylogeny of Chinese enids based on the mitochondrial markers cytochrome oxidase c (COI) and 16S rRNA (16S). We have sequenced 19 species belonging to 10 out of the 12 currently accepted genera. A new species, Petraeomastus limenghuai Chen, Dai, Wu & Ouyang, sp. nov., is described from the Lancangjiang River Valley in southwest China based on comparative morphology and molecular phylogeny. The currently accepted classification of Chinese enids relies largely on shell morphology and is deemed to require systematic revision.

A molecular phylogenetic study was conducted on genus Tropidauchenia, based on COI and 16S sequences. A total of six out of 18 species in the genus, as well as three species of Grandinenia and eight species of subfamily Synprosphyminae and Phaedusinae were sequenced. The phylogenetic results supported the monophyly of three Clausiliid subfamilies distributed in East Asia and demonstrated that Tropidauchenia was divided into two clades that corresponded to its two main distribution areas. A new species, Tropidauchenia jiangjilini Z.-G. Chen, Z.-Y. Chen & R.-X. Lin, sp. nov., from Guangdong, southern China, has been identified and described based on morphological comparison and molecular phylogeny. The discovery expanded the distribution range of Tropidauchenia and revealed the potential species diversity of land snails in the karst region of Guangdong.

The genus Pupinidius Möllendorff, 1901 is endemic in China and Nepal and consists of 15 species. China is the distribution centre of it with 12 species being recorded.A new species, Pupinidius pulchellus Chen, Dai, Wu & Ouyang sp. nov. is described from Jiuzhaigou, Sichuan, China. It can be distinguished from congeneric species by the shell with wide and distinct radial stripes; the thin, slightly reflexed and reddish-brown peristome; the unpointed apex; the unfused A-1 and A-2; the sub-globular and well defined bursa copulatrix; the unexpanded diverticle and the presence of epiphallic caecum.

A molecular phylogenetic study was conducted on genus Grandinenia, based on COI and 16S sequences. A total of eight out of 26 species in the genus, as well as three unidentified species were sequenced. Phylogenetic results supported the monophyly of Grandinenia and the validity of all sampled species and subspecies. A new species, Grandinenia jiangjilini Chen, Lin, Wu & Ouyang, sp. nov., from Guangxi, southern China is identified and described, based on morphological comparison and molecular phylogeny. The discovery indicates that the inflated-fusiform shell is not isolated in genus Grandinenia and the species diversity of the genus still remains to be explored.

A new catfish species, Liobagrus chenhaojuni Chen, Guo & Wu, sp. nov., is described from the Tiaoxi River, a tributary of Taihu Lake, located in Zhejiang Province, China. This description is based on morphological characteristics and phylogenetic analysis. This species belongs to a group defined by the presence of a smooth posterior edge of the pectoral-fin spine and can be distinguished from other species in the group by a unique combination of characteristics, including: an upper jaw longer than the lower jaw; maxillary barbels reaching the middle of the pectoral fin; irregular blotches present on the lateral body; a rounded caudal-fin with a length ranging from 16.5% to 19.9% of the standard length; 39 to 41 post-Weberian vertebrae; and 15 to 17 anal-fin rays. The validity of this new species is further supported by the molecular phylogenetic analysis based on Cytb sequences.

The monotypic freshwater mussel genus Diaurora Cockerell, 1903 has long been enigmatic due to its rarity and morphological confusion with Acuticosta. In this study, we comprehensively redescribed Diaurora aurorea (Heude, 1883) through a detailed analysis of shell morphology and molecular phylogenetics of recently collected specimens. Moreover, a new species, Diaurora laeve sp. nov., was identified from the Fuyishui River, a tributary of the Zishui River in Shaoyang County, Shaoyang City, Hunan Province, China. Molecular phylogenetic analyses showed that D. aurorea and D. laeve sp. nov. were reciprocally monophyletic and formed a clade as sister to Schistodesmus. Our study underscores the necessity of further exploring the diversity of freshwater mussels in understudied small tributaries throughout China.

Central China harbors the native dart-sac-bearing camaenids Laeocathaica. The genus is revised and seven new species are proposed based on museum material and newly collected specimens. This work confirmed that most Laeocathaica species have restricted habitats. The comparison of the dart sac apparatus among the dart-sac-bearing camaenid genera indicated the importance of the presence of the proximal accessory sac that might be analogous to the membranous/muscular sac surrounding the proximal dart sac and/or the distal region of the vagina near the atrium, which also plays a significant role in the diagnosis of Laeocathaica species based on its number, symmetry and position on the dart sac. Species with similar shell morphology were studied using geometric morphometric methods to detect variations in shell shape. A molecular phylogenetic analysis based on 16S and ITS2 sequence data of partial Laeocathaica species and many other dart-sac-bearing taxa suggested that Laeocathaica might be monophyletic. Furthermore, the present phylogeny indicated that Stilpnodiscus, Cathaica, Bradybaena, and Pseudobuliminus might be polyphyletic and therefore the taxonomy of dart-sac-bearing camaenids in this region requires a thorough revision. This work reconfirms that the Southern Gansu Plateau is important as a hotspot for malacodiversity conservation on the Chinese mainland.

Effective species conservation necessitates the ability to accurately differentiate among species, a challenge compounded by taxonomic uncertainties in freshwater mussels due to substantial intraspecific variation and pronounced phenotypic plasticity in shell morphology. The taxonomic status and species validity of Scabies longata and S. chinensis, two species endemic in China, have been under continuous debate since establishment. The lack of essential molecular data required for a comprehensive systematic study has resulted in the unresolved taxonomic status of these two species. This study presents molecular data, including COI barcoding, COI + 28S rRNA, and mitogenomic data combined with morphological characteristics to assess the validity of S. longata and S. chinensis. Both morphological and COI barcoding data support the conclusion that S. longata and S. chinensis are junior synonyms of Nodularia douglasiae and N. nuxpersicae respectively. Our findings suggest the absence of Scabies species in China. Mitochondrial phylogenetic analyses were used to further elucidate intrageneric relationships within the genus Nodularia, revealing the following relationships: (N. breviconcha (Nodularia sp. 1 (N. douglasiae (N. nuxpersicae, N. nipponensis)))). We underscore the significance of employing an integrated taxonomic approach for species identification, especially given the considerable morphological disparities between larvae and adult freshwater mussels. Proper morphological identification of adult specimens is essential for extracting meaningful taxonomic characters. Furthermore, our findings suggest a notable resemblance between the freshwater bivalve fauna in southern China and those east of the Mekong River. [ABSTRACT FROM AUTHOR]

In the article, the authors report on the characteristics and features of the torrent catfish specie Liobagrus chengduensis sp. nov that is discovered at the upper Changjiang River basin in southwest China. Also cited are the unique features of the fish including its pectoral-fin spine, anal fin, and rounded caudal fin, as well as the description of 18 Liobagrus species.