A new species of Supradiscus is described from specimens collected in a tributary of the Lo River, in northern Vietnam. Supradiscus varidiscus differs from its congeners in having fewer lateral-line, circumpeduncular, and predorsal scales, a series of spots on the interradial membranes of the dorsal fin, and a cleft on the central callus pad, forming a split along the midline of the oral disc, extending to the posterior margin of the disc.

This investigation and critical revision of the ichthyofauna of Tajikistan is the result of two nationwide surveys completed by the authors in 2017 and 2019 combined with an analytical examination of previous studies. The ichthyofauna of Tajikistan includes 60 species, of which 44 are native and 15 are nonnative, while one species (Cyprinus carpio) is represented by populations of native and alien origin. Seven species recorded in neighboring countries could potentially be found in Tajikistan, 12 introduced species are nonnaturalized, two were erroneously identified as belonging to the ichthyofauna of Tajikistan, and two are extinct. The current fish fauna is represented by eight orders (Acipenseriformes, Cypriniformes, Cyprinodontiformes, Gobiiformes, Perciformes, Salmoniformes, Siluriformes, and Synbranchiformes) and 18 families (Acipenseridae, Acheilognathidae, Channidae, Cobitidae, Cottidae, Cyprinidae, Esocidae, Gobiidae, Gobionidae, Leuciscidae, Nemacheilidae, Odontobutidae, Percidae, Poeciliidae, Salmonidae, Siluridae, Sisoridae, and Xenocyprididae), of which the largest number of species belong to Leuciscidae (14 species), Nemacheilidae (13 species), and Cyprinidae (9 species). Significant changes in the fish fauna occurred in the 20th century due to anthropogenic factors and climate change. Water diversion for irrigation and construction of canals and reservoirs led to changes in the hydrological regime, which, combined with illegal fishing and overharvesting dramatically affected the abundance of at least eight species and led to the extinction of two, Acipenser nudiventris and Pseudoscaphirhynchus fedtschenkoi. Massive introductions of commercial fish species in the 20th century led to an increase in the alien fauna to 16 species.

A new cricetid rodent genus is described for the Alfaroi Group of Oryzomys sensu lato. The new genus, which includes seven Mesoamerican species of small oryzomyines, is demonstrably monophyletic and easily diagnosed morphologically from its sister taxon, Handleyomys.

Unravelling parallel conceptions of the Ordovician trilobite Flexicalymene senaria (Conrad, 1841) and description of Flexicalymene trentonensis, n. sp.

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Netto-Ferreira, Andre L., Nogueira, Acacio F., Melo, Bruno F., Dutra, Guilherme M. (2024): A New Species of Cyphocharax Fowler (Teleostei: Curimatidae) from the Rio Xingu, Brazil. American Museum Novitates 2024 (4007): 1-20, DOI: 10.1206/4007.1, URL: https://bioone.org/journals/american-museum-novitates/volume-2024/issue-4007/4007.1/A-New-Species-of-Cyphocharax-Fowler-Teleostei--Curimatidae-from/10.1206/4007.1.full

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

The lesser yellow-shouldered bat, Sturnira nana, is a member of the most diverse genus of the New World leaf-nosed bats (Phyllostomidae). This species was considered endemic to Peru until 2009 when researchers captured a series of individuals in the Cordillera del Cóndor of southeastern Ecuador and identified them as S. nana. To assess the taxonomic status of this Ecuadorian population in relation to S. nana from Peru, we analyzed cytochrome b gene sequences and craniodental measurement data. In addition, we used principal component analysis to elucidate differences in climatic niches. Our analyses suggest that populations cur-

We review the systematics of the monotypic alestid genus Petersius and provide a taxonomic redescription of P. conserialis from eastern Tanzania. Morphological investigation includes direct observation and examination of radiographed and µCT-scanned data from type and non-type specimens. We delimit the taxon's geographic distribution along the lowland regions of the Rufiji and Ruvu river basins in Tanzania and provide information on ecology, sexual dimorphism, and ontogenetic variation. Petersius is herein diagnosed by the possession of a unique cuspidation patterning of the inner-row premaxillary dentition and a distinctively shaped anterodorsal margin of the supraoccipital crest. It shares with some species of Phenacogrammus a sigmoid-shaped process on the dorsal margin of the second infraorbital, a feature lacking in other alestid taxa. Additional features of potential utility for ongoing investigation of relationships among alestid genera include the possession of contralateral premaxillae separated by the anteromedial process of the mesethmoid and without interdigitations connecting the medial surfaces of the premaxillae; four, occasionally five or six, small outer-row premaxillary teeth implanted alternately with those of the inner row; a dentary lacking a pair of conical inner-row teeth proximal to the symphysis; a dorsal posttemporal fossa that is smaller than the ventral fossa; a median third posttemporal fossa located entirely within the epioccipital; a truncate dorsomedial cranial fontanel; and a complete circumorbital series forming an uninterrupted ring around the orbit in adult specimens.