Zoological Studies最新文献

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 Here we present unpublished "archival" data (1996-1998) from endemic populations of the Colorado chipmunk (Neotamias quadrivittatus) and brushmouse (Peromyscus boylii), which coexist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.

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.

In this study, we present descriptions of two new species of the genus Mesobiotus discovered in the tropical rainforest of Kibale National Park in Uganda, the first new tardigrade species from this location. Our research utilized morphological data obtained with phase-contrast and scanning electron microscopes and DNA sequences of four genetic markers (28S rRNA, 18S rRNA, CO1 and ITS-2). The main character distinguishing the new species, Mesobiotus ugandicus sp. nov., is the presence of egg processes in the shape of wide cones without filaments. The second new species Mesobiotus krystynae sp. nov. is distinguished mainly by having egg processes with long, slender endings with short filaments. However, both new species are properly differentiated from phenotypically similar species of the Mesobiotus harmsworthi morpho-group by morphological and morphometric details of animals and eggs. The genetic data allowed us also to conduct a phylogenetic analysis, which elucidated positions of the new taxa and extended our understanding of the relationships within the genus.

A new ribbon worm, Tetrastemma luteum sp. nov., reported from Japanese waters, is described using morphological and DNA sequence data based on 15 specimens-10 from Oshoro, 2 from Otsuchi, and 3 from Sugashima-all associated with brown algae in the family Sargassaceae. The new species is characterized by its entirely yellowish body; a rounded, notched, and knobbed head that is similarly coloured to (or lighter than) the body; brown-orange, more indented anterior and bright-orange posterior ocelli; a central stylet shorter than the stylet basis; ventrolateral, non-connected anterior cephalic furrows that are not visible in dorsal view; and a posterior cephalic furrow encircling the head. Tetrastemma luteum sp. nov. exhibits variation in the degree of its body colouration, body and head pigmentation patterns, head shape, stylet basis shape, and number of accessory stylets. Additionally, we report a new locality, Oshoro, for Tetrastemma phaeobasisae Kulikova, 1987, based on a single specimen, representing the first record of this species in Japan. This species was previously known to be distributed only in Vostok Bay and Peter the Great Bay, Russia. Its occurrence in Oshoro is confirmed both by morphology and DNA sequence. Furthermore, we tested the phylogenetic positions of T. luteum sp. nov. and T. phaeobasisae within the genus Tetrastemma Ehrenberg, 1828 using newly determined 16S, 18S, and 28S ribosomal RNA, cytochrome c oxidase subunit I, and histone H3 gene sequences. Our phylogenetic analyses confirmed the genus placement of T. luteum sp. nov. being nested within the Asian-Australia Pacific subclade of the genus together with T. phaeobasisae. The new species is a sister taxon to the clade consisting of Tetrastemma pseudocoronatum Chernyshev, 1998 and T. phaeobasisae.

The taxonomy and biogeography of Neocaridina species in Japan remain complex and contested. In a recent commentary, Fuke (2024) criticized the conclusions of Shih et al. (2024), challenging their species delineations and argues that such taxonomy directly conditions interpretations of native versus introduced lineages. As the first two authors of Shih et al. (2024), we agree that accurate identification is essential for conservation of native taxa, but we contend that several of Fuke's inferences reflect misreadings of both morphological and genetic data. In this reply, we address these misinterpretations, clarify our taxonomic conclusions, and reassess phylogenetic and population genetic evidence. Our findings suggest that N. denticulata and N. davidi can be consistently distinguished using integrated molecular and morphological criteria, in contrast to Fuke's claim of conspecificity. We also emphasize the limitations of relying solely on mitochondrial DNA or SNP admixture patterns for species delimitation, particularly in hybridizing lineages. Finally, we advocate for integrative, evidence-based taxonomy as the best approach to resolving species boundaries and supporting conservation of cryptic native species of Neocaridina.

Tachaea chinensis Thielemann, 1910 is a species of ectoparasitic isopod that infests freshwater shrimps and prawns. Individuals are often found attached to the side of their host shrimp's carapace. Despite the limited space for attachment there, records indicate that several isopods can infest a single host shrimp simultaneously. There are limited data, however, on the prevalence of such occurrences and their potential effect on host survival. Here, we report on the occurrence of multiple infestation by T. chinensis on the freshwater shrimp Palaemon paucidens De Haan, 1844 in Izumo, Shimane Prefecture, Japan, during April and May of 2018 and 2019. The prevalence of infested shrimp was higher (80.0-90.2%) at St. 1, a semi-closed spillway that alternates between continuous water flow and isolated stagnancy, than at St. 2 (45.0-55.0%), an open stream with year-round continuous water flow. The number of parasites per host was zero to nine at St.1 and zero to three at St. 2. A significant positive correlation was observed between the prevalence of isopods on shrimp and the mean number of these parasites per host. In a laboratory experiment in which individual shrimp of three size groups were reared for seven days with different numbers of isopods from three matching size groups, the survival rate of hosts was 100% with one T. chinensis, 90-100% with two, 50-80% with four, and 10-40% with eight. These results suggest that the presence of two or more parasites negatively affects the hardiness of the host, increasing shrimp mortality and potentially reducing their density in nature, especially in semi-closed habitats. This has obvious implications for shrimp farms, which should strive to prevent the entry of this isopod into their water systems.

The Taiwan Broad-tailed Swallowtail, Papilio maraho, is an endangered species in Taiwan and has been recognized as sister to continental Papilio elwesi. However, the exact species identification between them has remained contentious because of similar genital morphology and only a few DNA diagnostic sites. Here, we integrate wing morphometrics and next-generation sequencing to reevaluate their identification. Our analyses show that hindwing morphology clearly separates these taxa: Papilio maraho has a broader, shorted hindwing with a much higher proportion of red scaling, whereas Papilio elwesi shows a narrower, elongated hindwing with higher proportion of black scaling. Furthermore, phylogenetic relationships and the haplotype network based on 37 mitochondrial genes separates the two taxa into reciprocally monophyletic clusters, further confirming their genetic distinctiveness. The congruence among morphological and genetic evidences strongly supports that Papilio maraho is an independent lineage. Formal recognition at the species level will facilitate more targeted and effective conservation strategies.