Zoological Studies最新文献

Three new species of freshwater atyid shrimp, namely Caridina chui sp. nov., C. bauhinia sp. nov. and C. argilla sp. nov., are described from Hong Kong, southern China using an integrative taxonomic approach. All three species belong to the C. serrata species group and differ from the other members in characteristics of the rostrum, pereiopods, and male first and second pleopods. Phylogenetic analyses based on mitochondrial COI and 16S rRNA sequences show that the C. serrata species group is polyphyletic and comprises at least four lineages. The validity of the C. serrata species group is discussed and more detailed diagnosis of the species group is proposed. The C. serrata species group sensu stricto is restricted to the nominal lineage containing C. serrata and closely related species, distinguished from other species of the C. serrata species group mainly by having relatively stout carpus of first pereiopod, stout appendix masculina of male second pleopod, and large number of spiniform setae on the uropodal diaeresis.

Two new species of the labeonin cyprinid genus Hongshuia, H. boulobos and H. wangi, are here described from tributaries of the Pearl River Basin, Southwest China. Both share with H. brevibarba the presence of a lower lip with a sector-shaped median lobe (the maximum width positioned at anterior potion of median lobe), distinguishing them from H. microstomata and H. megalophthalmus, which have a roughly rounded median lobe. Hongshuia wangi is distinct from H. brevibarba and H. boulobos in having wider median lobe of lower lip (width 47.8-57.6% of head width vs. 40.5-43.4% in H. brevibarba and 38.5-44.0% in H. boulobos). Hongshuia boulobos further differs from all other congeners in having a lower lip with larger lateral lobes (width more vs. less than one-third of the median lobe width). The study also considers H. paoli as a junior synonym of H. megalophthalmus based on morphological and molecular evidence.

Previous studies have shown that culturing corals under controlled blue light can increase calcification rate and stimulate the production of pigments while reducing the photosynthetic capacity of the corals' symbiotic algae. Additionally, feeding coral can accelerate growth and enhance their resistance to environmental changes. However, most studies have left their combined effects on coral physiology largely unexplored. Here we investigate the effects of two blue light intensities and two feeding concentrations on coral growth rates and color expression during cultivation. We cultured Stylophora pistillata and Pocillopora damicornis under different blue light intensities and fed varying concentrations of enriched brine shrimp (Artemia) twice a week. Both species maintained high survival (100%) and photosynthetic efficiency (Fv/ Fm > 0.6). S. pistillata exhibited the highest growth under high-light and high-feeding conditions, while P. damicornis showed no significant growth differences among treatments. However, both species displayed reduced color scores under high-light conditions, as indicated by elevated red-green-blue values. Together, these findings highlight coral species-specific responses to blue light intensity with feeding interactions and demonstrate that manipulating environmental regimes can optimize coral cultivation. This approach supports high-density ex-situ cultivation, advancing both reef restoration and production of corals for ornamental aquariums.

Trophic interactions between fish and their resources depends on resource availability and interspecific competition. To understand dry-season trophic profiles of a speciose Characiformes assemblage, we performed stomach content analysis to describe diet and determine levels of niche partitioning and morphological adaptations among eight Characiformes species in the dry season in Mata de Itamacaoca, Chapadinha Municipality, State of Maranhão, northeastern Brazil. Insectivory dominated most diets, with Astyanax cf. bimaculatus and Characidium cf. bimaculatum exhibiting the broadest niches. Specialization occurred in Curimatopsis cf. cryptica (85.07% plant material), and there was significant dietary segregation, with indicator species analysis linking Astyanax cf. bimaculatus to piscivory and Knodus guajajara to vermivory. Pianka's index revealed a wide gradient of trophic niche overlap, with the highest overlap observed between Hyphessobrycon piorskii and Knodus guajajara (0.95), and between Holopristis cf. ocellifera and Nannostomus beckfordi (0.96). Morphological PCA associated traits with feeding strategies, including caudal fin length (Astyanax cf. bimaculatus), body depth (Curimatopsis cf. cryptica), and oral gape width (Bario oligolepis). Mixed models confirmed insects and plant material, with a marginally significant effect, as key drivers of dietary variation. Therefore, the assemblage shows high niche overlap combined with diverse trophic profiles. The results demonstrate how dry-season resource scarcity promotes trophic divergence via morphological specialization, with generalists (Astyanax cf. bimaculatus) coexisting with specialists through niche partitioning, which is critical for conservation in this threatened urban-protected area.

There is wide-spread agreement that effective management and conservation of assemblages of cooccurring species necessitates baseline studies of spatiotemporal and climatological dynamics underlying community relationships. Such studies are particularly relevant to residual populations of relic species scattered throughout mountainous regions of the North American Southwest. Yet few investigations have examined effects of environmental covariates on disjunct populations of syntopic species in semi-arid woodland or montane forest landscapes. Here we present unpublished "archival" data (1996-1998) from endemic populations of the Colorado chipmunk (Neotamias quadrivittatus) and brushmouse (Peromyscus boylii), which coexist within mature multi-age stands of pinyon-juniper woodland. We evaluated variance in the spatiotemporal regimes of these two species in response to: 1) seasonal area climate, 2) microhabitat use; 3) reproductive output; and 4) estimates of population density. Results of our analysis showed that theoretical density plots and spatial structure of live-trap quadrat data were non-normally distributed for both species. Microhabitat use in each taxon was primarily associated with limestone escarpmentcliff edges and rock outcrops, particularly in chipmunks. Density estimates closely mimicked variance in seasonal climate but with some differences between species. Redundancy analysis showed that drivers of spatiotemporal patterns in these small mammals was predominantly due to seasonal variance in temperature, solar radiation, and humidity during summer, spring, and early fall. Because conservation of mature stands of pinyon-juniper woodlands and relic montane forest represent critical challenges for contemporary and future management of endemic species in these refugial ecosystems, our archival ecological data may facilitate understanding of the dynamics of ecosystem function, uncover legacy effect, and provide a reference for crafting contemporary management and future conservation goals, particularly in the era of rapid climate.

The present study reviews the parasite fauna of fishes in the Aral Sea, before, during and after the recent regression and salinization crisis. The native fish fauna was much depleted compared to the nearby Caspian Sea, comprising only 20 spp., all having a freshwater origin. The parasite fauna was similarly poorer, both in total species number and when considering parasites infesting individual species. Some fish species and parasites were introduced during the 20^th century. Species introduction of fish and progressive salinization in the latter half of the 20^th century interacted in various ways, occasionally favouring the spread of parasites. During the salinization parasites with endoparasitic lifecycles endured longer than many ectoparasites, the latter being constantly exposed to the salty water. But all parasites eventually suffered when the salinity tolerance of their free-swimming larvae was exceeded. Predation on zooplankton by introduced fish also temporarily impacted the free larvae of crustacean parasites, causing a decline. Alternatively, introduced fish that were prey to larger species could act to transmit parasites. All the parasites in the southern Large Aral Sea ultimately disappeared, either because their hosts were gone or because of an inability to endure high salinity. Many of the original fish species have now naturally repopulated the reconstituted Small Aral Sea, forming the basis of a renewed commercial fishery. As a result, some parts of the original parasite fauna have also reappeared together with some newly introduced species. The present study highlights the complex, sometimes unexpected, manner in which hosts and parasites can interact during a progressive ecological crisis. We emphasize that they must be an integral part of any sustainable ecological management of lakes and reservoirs. In the framework of revived fisheries and emerging aquaculture, we suggest a system for sound monitoring and control of fish parasites in the Aral Sea system.

In this contribution, we describe two new species of the burrowing crayfish genus Parastacus Huxley, 1879 from swamp forest fragments in the municipalities of Igrejinha and Bom Princípio, both in the Guaíba hydrographic region of the state of Rio Grande do Sul, southern Brazil. We provided a detailed morphological description and evaluated their conservation status according to the IUCN Red List Criteria. Parastacus paulae sp. nov. is distinguishable from the burrowing species of Rio Grande do Sul state in having a short triangular rostrum, prominent postorbital carinae, cervical groove strongly V-shaped, short pleon and subtrectangular telson with very small lateral spines. Parastacus mingusi sp. nov. is distinguishable from the burrowing species of Rio Grande do Sul state in having a short triangular rostrum with a concave dorsal surface, prominent postorbital carinae, globose chelipeds, short pleon and areola narrow. The extent of occurrence of P. paulae sp. nov. and P. mingusi sp. nov. were estimated at 576 km² and 662 km², respectively. The main threats identified were continued decline in the habitat quality, resulting from deforestation, habitat fragmentation, agriculture, urbanization and pollution. We suggest that both be categorized as Endangered.

Salmo sengulae sp. nov. is described from the Berdan (a drainage of Mediterranean Sea) and İvriz (a drainage of Konya closed basin) streams. It is distinguished from Salmo species in adjacent water by having 8-10 parr marks on flank; no red spots on flank in specimens larger than about 180 mm SL, if the red spot present in specimens larger than 180 mm SL, they are almost covered with black dots; number of black spots increasing with size, while number of red spots decreasing with size; a longer maxilla in males; a shorter predorsal length; fewer scale rows between dorsal-fin origin and lateral line; more scale rows between anal-fin origin and lateral line; and 16-19 gill rakers on first gill arch. Salmo sengulae sp. nov. was also compared the two closed species (Salmo chilo and Salmo kottelati) by using PCA analysis. The results of the PCA confirmed that Salmo sengulae sp. nov. differs from the other two species (S. chilo and S. kottelati). Salmo sengulae sp. nov. shares the same mtDNA Cyt b (991 bp) haplotype with S. chilo and S. kottelati. Additionally, genome-wide SNP data confirmed the separation of S. sengulae from those of Mediterranean trouts of Türkiye.

Multi-functional free water surface constructed wetlands (FSWs) operate as interconnected wastewater treatment ponds characterized by gradients of bio-physicochemical variables, they are also important to support biodiversity through provision of habitats and food resources. Yet, the ecological responses of aquatic macroinvertebrate community structure to environmental conditions associated with wastewater treatment processes in subtropical FSWs remain unclear. Macroinvertebrate biodiversity, water chemistry and environmental characteristics of three successive treatment ponds in two FSWs, i.e., DN and HS2, in northern Taiwan during dry and wet seasons were investigated to determine the most important environmental gradients and their spatial and temporal influence on macroinvertebrate community structure. Most water chemistry parameters varied significantly among sites and seasons. However, macroinvertebrate community composition was similar between the two study FSWs and it was dominated by tolerant taxa including Oligochaeta, Hirudinea, Diptera, Gastropoda, and Ostracoda of which their relative abundance reached ~99%, with Oligochaeta being the most abundant taxon. Taxon richness and total abundance of macroinvertebrates exhibited significant increase across the treatment ponds in DN and HS2, whereas diversity indices (exp H' and 1/D) did not differ among ponds. Seasonal differences were generally weak, although Diptera, Gastropoda, and Hirudinea were 3-10 times more abundant in wet season. Multivariate analysis indicated that nitrification (decreasing NH₄-N and increasing NO₃-N levels) and decreasing TP concentration represented the primary environmental gradients across treatment ponds in the study FSWs and they were the main drivers shaping macroinvertebrate community structure, as identified by the BVSTEP algorithm. The consistent increases in taxon richness and abundance of macroinvertebrates along the wastewater treatment gradients, highlighted their value as simple and direct bioindicators of environmental changes, in particular nutrient availability, in subtropical FSWs. Moreover, our findings provide sustainable management strategies through introducing controlled environmental disturbances, such as seasonal hydrological changes in water levels and retention time, could help reduce wetland terrestrialization, enhance macroinvertebrate biodiversity, and prevent dominance of highly tolerant taxa in FSWs.

The origin of biota and dispersal routes in eastern Taiwan have long intrigued scientists. The Loxoblemmus appendicularis complex (LAC) is a group of common crickets that inhabit grasslands and woodlands in the low hills of Taiwan. Because of their limited flight capability, the genetic diversification of LAC crickets may have been affected by geographic isolation imposed by mountains and rivers, as well as by historical Pleistocene climatic fluctuations. In this study, we conducted phylogeographic analyses of Southeastern LAC crickets to investigate their patterns of differentiation, possible refugia, and dispersal routes. Results from mitochondrial 16S rRNA gene and amplified fragment length polymorphism (AFLP) suggest that LAC crickets likely dispersed to southeastern Taiwan through low hills and lower mountains in southern Taiwan approximately 0.21 million years ago (Mya) during the middle Pleistocene, highlighting the isolating effects of the Central Mountain Range. Two subsequent northward dispersals, originating from a southern population and crossing major rivers, were estimated to have occurred around 0.12-0.14 Mya. These findings indicate that major rivers did not consistently impede the dispersal of Southeastern LAC lineage. These populations may have experienced recent expansion following isolation in refugia during the late Pleistocene. Genetic homogeneity and higher genetic diversity suggests the existence of three potential refugia for the Southeastern LAC. Moreover, STRUCTURE analysis based on AFLP data revealed varying levels of genetic admixture between two genetic clusters, suggesting recent divergence or possible gene flow between northern and southern populations. Overall, this study demonstrates how geographic barriers, such as mountains and rivers, and Pleistocene glaciations have shaped the current phylogeographic patterns and genetic diversification of LAC crickets in southeastern Taiwan.