The genetic structure and demographic history of marine organisms are influenced by biological and ecological features, oceanic currents, and the paleo-geological effects of sea-level fluctuations. In this study, we used mitochondrial COI + 16S gene analysis to investigate the phylogeographic pattern and demography of Monodonta labio and M. confusa in Taiwan, the Ryukyu Islands, Japan, mainland China, and Korea. Our genetic analysis identified two major lineages that were not evident from the distribution patterns of different populations. The Taiwan Strait, which acted as a land bridge during Pleistocene glaciations, and the lack of strong dispersal barriers to gene flow between ocean basins after glaciations shaped the phylogeographic pattern. The genetic differentiation in the Ryukyu Islands was influenced by the specialist-generalist variation hypothesis and the Kuroshio Current. Bayesian skyline plot analyses suggested that the effective population size of M. labio and M. confusa rapidly increased approximately 0.1 and 0.075 million years ago, respectively. Our approximate Bayesian computation analysis suggested that all M. labio and M. confusa populations experienced a decline in population size following a recent population expansion and constant size, respectively. Our study provides a baseline for future investigations of the biogeographical patterns of marine gastropods in the Northwest Pacific and offers valuable insights for the management, sustainable resource utilization, and conservation of this species.

Even though spring ecosystems are ecologically unique and socio-culturally important worldwide, they hardly attract research attention. The aims of this study were to evaluate the environmental status of water quality, and to inventory the species diversity of aquatic animals in 65 springs in Taiwan from 2012 to 2017, of which seven springs were unable to be sampled due the fact that they were dried or sealed up. The environmental status of 58 springs with complete water quality data was assessed by the River Pollution Index (RPI). Based on the RPI, the water quality of these 58 sampled springs was mainly non-/mildly polluted (26 springs, 44.8%) and lightly polluted (23 spring, 39.6%), and nine (15.5%) springs were moderately polluted. However, when applied to springs, the RPI may intensify the pollution rankings because dissolved oxygen is an assessing factor, and hypoxia may naturally be observed in the springs. To avoid this concern, we suggest choosing the concentration of coliform instead of dissolved oxygen content in the RPI when it is applied to springs. During the 6 years of the study period, we collected 48 fish species in 44 springs, 24 gastropoda and bivalve species in 46 springs, 16 shrimp species in 34 springs, and 14 crab species in 18 springs. Within the species collected, 31 fish, 20 gastropoda and bivalves, 12 shrimps, and 14 crabs are native species of Taiwan. They totaled 27.2 to 35% of the known aquatic native species of the island. Thus, springs in Taiwan may be considered to be a conservation hotspot of aquatic animals. Other than native species, exotic aquatic animals also represent threats, as seventeen fishes (35.4%), four gastropoda and bivalves (16.6%), and two shrimps (12.5%) were found in the springs of Taiwan. The springs in Taiwan show diverse and vital ecosystem services, such as delivering social, cultural, and economic value, conserving native and endangered freshwater animals, developing new academic theories, and supplying habitat refugees from climate change. Unfortunately, springs in Taiwan currently are also threatened by multiple anthropogenic disturbances, such as the overconsumption of groundwater by land development and urbanization, deterioration of water quality by agricultural, domestic, and industrial pollution, and inappropriate tourism and management tactics. To restore and sustain the springs in Taiwan, effective strategies and practical measures are urgently required to minimize human-caused threats and revitalize social awareness of springs.

A new species of land-locked freshwater shrimp, Neocaridinafonticulatasp. n. (Atyidae), is described from Kenting, Hengchun Peninsula, Pingtung County, southern Taiwan. This new species can be distinguished from its congeners by rostrum structure, pereiopods, and male first and second pleopods. The molecular evidence of mitochondrial cytochrome oxidase subunit I (COI) also supports the establishment of a new species. This is the third endemic species of Neocaridina known from Taiwan.

A new Macropodus species was collected from the river basins of southeastern China. The new species Macropodus minnanensis, from Fujian Province, China can be well distinguished from congeners by the following combination of features: (1) dorsal fin with 13 spines and 7 soft rays; (2) anal fin with 20 spines and modally 10 soft rays; (3) vertical insertion of dorsal fin origin at second to third soft rays of anal fin; (4) longitudinal scale rows in midline modally 28; (5) transverse scale rows 14; (6) vertebrae 27 and (7) specific coloration: body with posteriorly black margin on scale pockets; eye greyish; a large opecular, deep black ocellus spot in male. The brief discussions of its related species are also provided.