Zoological Studies最新文献

The occurrence of cyclic morphological alternation in male crayfish of the family Cambaridae following molting is widely acknowledged. However, there remains a contentious issue within the genus Cambaroides: Some previous studies have proposed that male Cambaroides exhibit a pair of noncorneous Form II gonopods during the non-breeding season, while others argue that these species lack Form II in adult males. This study examined the color and shape of the corneous tips on the gonopod to determine its form. Additionally, morphometric methods were utilized to distinguish between Form II adults and juveniles. The results of the study confirm the presence of Form II adults in Cambaroides dauricus and Cambaroides similis. The Form I gonopod is characterized by four golden-colored corneous terminal elements, whereas the Form II gonopod features blunt, non-corneous terminal elements, on which the color is the same as that of the surrounding surface. Furthermore, cyclic dimorphism on the gonopod of C. dauricus was observed seasonally, and distinct morphological differences in the chela were noted between Form I and Form II adults.

Terpios hoshinota Rützler & Muzik, 1993 is a poriferan species that competes with corals and is known as a coral-killing sponge. However, limited information is available on its biology, including morphological traits. This study aims to examine the arrangement and development of spicules in various body parts of the sponge, including settled larvae. Spicules were found to appear on the second day after settlement and were present in all individuals on the fifth day. The spicules in the thread-like tissue of the growth portion were oriented in the direction of growth, with their pointed tips facing forward to support the elongated pioneer tissue. Furthermore, the spicules in the surface layer of the sponge tissue were perpendicular, with outward-facing tips associated with collagens. The study indicates that the spicules of T. hoshinota are arranged to support both encrusting basal tissue and pioneering tissue to colonize corals.

Confined by the Mid-Atlantic Ridge and the European continental shelf, the deep-sea acorn barnacle Bathylasma hirsutum (Hoek, 1883) lives in the northeast Atlantic deep sea, where it has been frequently reported in high current areas. Cemented to a solid substrate during its entire adult life, the species can only disperse by means of planktotrophic nauplius larvae. This study reports on the occurrence, ecology and genetic connectivity of B. hirsutum from four sites within the northeastern Iceland Basin and presents the first record of the species living affiliated with hydrothermal vent field on the Reykjanes Ridge axis. Vent-associated specimens were found to differ extrinsically from their naturally shaded conspecifics by a prominent brown-black shell precipitate. Energy Dispersive Spectroscopy revealed ferromanganese oxides to be the main component of these shell precipitates. Morphometric measurements of shell plates revealed specimens from the vent-associated habitat to be smaller compared to non-venting sites. Molecular species delimitation based on the mitochondrial COI and nuclear EF1 genetic markers aided species identification and revealed a low intraspecific genetic variability. Our findings suggest a pronounced genetic connectivity of B. hirsutum within the studied region and provide a first step towards a biogeographic study. As such, habitats of hydrothermal influence along the Mid-Atlantic Ridge are discussed as possible niches, as are deep-sea basins in the western Atlantic. In light of the reported affiliation with hydrothermal activity, we elaborate on the potential for the sister species Bathylasma corolliforme (Hoek, 1883) and Bathylasma chilense Araya & Newman, 2018 to utilise equivalent habitats in the Antarctic and Pacific Ocean, respectively. Our record of the unacquainted ecological niche occupation for B. hirsutum emphasises the need for further research on bathylasmatid acorn barnacles along the extensive Mid-Atlantic Ridge, where many biological communities remain to be discovered.

Two new amphipod species from Iran, Niphargus sahandensis sp. nov. and Niphargus chaldoranensis sp. nov., are described based on their morphological characteristics and molecular analyses. Bayesian inference analyses of COI and 28s rDNA sequence data provided evidence for the validity of the two species and their placement in the Niphargus genus. N. sahandensis sp. nov. primarily differs from similar species by having more than two hook-like retinacles on the inner surface of pleopods I-III, the presence of two spines at the base of uropod I and rectangular-shaped propodi in both gnathopods. N. chaldoranensis sp. nov. is distinguished by the trapezoidal-shaped propodi in gnathopods I to II, the equal sizes of pereopods V and VI, and the proportional size of periopod VII in relation to the total body (60%). Morphological descriptions with illustrations of the new species, as well as a DNA-based phylogeny generated from analyses of a multigene dataset, are provided to better understand species relationships.

The genus Corticarina in Taiwan was previously known to contain three species, C. bhutanensis Johnson, C. clareae Johnson, and C. minuta (Fabricius). Corticarina bhutanensis Johnson and C. clareae Johnson are known from the Palearctic, and C. minuta (Fabricius) is a cosmopolitan species. In this study, the genus Corticarina in Taiwan is reviewed for the first time, with three species being recognized, including two recorded species, C. bhutanensis Johnson and C. clareae Johnson, and a species new to science, C. tenuis sp. nov. The species Corticarina minuta (Fabricius) that had been recorded previously was not collected from Taiwan in this study. The description, habitus, and male genitalia of three species are provided, and the distributions and genetic distances of three species in Taiwan are discussed.

Our understanding of species distribution and ecology is critical to properly assess their conservation status. Vertigo lilljeborgi, V. genesii, and V. geyeri have the centre of their current distribution in northern Europe, where their occurrence is relatively frequent. However, to the south their occurrence is fragmented and restricted to sites of late glacial/early Holocene origin. In the last ~30 years, there has been an increase in records, connected with the listing of the latter two species in Annex II of the EU Habitats Directive (94/43/EEC). However, there is no comprehensive publication documenting their pan-European distribution. Therefore, we assembled all available data from online databases, books, and scientific literature and combined them with our unpublished records to create distribution maps. The results show a more frequent occurrence in temperate Europe than previously known, especially for V. geyeri. Analyses performed on data from 327 ecologically potentially suitable sites, covering the entire distribution range of the species, have improved our knowledge of their ecology. Vertigo lilljeborgi and especially V. genesii are restricted to areas with lower summer and winter temperatures, and therefore, their further decline is expected in the face of rising temperatures due to climate change. The preference of V. geyeri for higher temperatures, in comparison to the latter two species, may explain its relatively frequent distribution in temperate Europe. Vertigo lilljeborgi favors base-poor sites, while V. genesii and V. geyeri prefer calciumrich sites, with the latter being the most calcicolous. Their need for a stable water regime and lowproductive sites, known from previous studies, was not conspicuous in our results, probably due to the selection of sites well within the species range. Despite the increase in record frequency, these species are still endangered, especially in temperate Europe. Their sites should therefore be strictly protected as sites of high biological diversity and conservation value. Because of their relict nature, these land snails should be considered umbrella species and indicators of well-preserved groundwater-dependent ecosystems in temperate Europe.

A new species of splitfin fish, Synagrops atrumoris sp. nov., from Dongsha Island, Taiwan, South China Sea, is described based on its morphological characteristics, including osteology and otolith morphology, and DNA sequence. Synagrops atrumoris sp. nov. is closely similar to Synagrops japonicus and can be distinguished by its black mouth cavity covering the lower portion of the tongue, posteriorly enlarged and complex basioccipital fossae, and a triangular otolith with a strong postero-dorsal angle, as well as a strong genetic difference. In addition, the taxonomy of the genus Synagrops was revised. Available published data, together with our results, suggest that S. bellus is a synonym of S. japonicus.

Two new pseudoscorpion species, Pseudochthonius aware sp. nov. and Pseudochthonius itakuatiara sp. nov., are herein described. These species exhibit distinct characteristics that differentiate them from other congeneric species, including variations in chelal and cheliceral dentition, coxal chaetotaxy, and measurements. In addition to taxonomic details, we provide ecological observations for each species, identify potential threats, propose avenues for future research, and offer a key for distinguishing the Pseudochthonius species found in Brazil.

Correct identification of species is crucial for invasion ecology and management, particularly in aquatic systems. In this study, specimens of the freshwater shrimp genus Neocaridina from Kyushu and southern Honshuof Japan were identified by using an integrative approach that combined DNA barcoding of mitochondrial cytochrome oxidase subunit I (COI) and morphological examination. Among the eight species detected, two are native, viz. N. denticulata and N. ikiensis. Four are regarded as non-indigenous, viz. N. davidi, N. koreana, N. palmata, N. aff. palmata, which are believed to have been introduced from other East Asian countries either by the aquarium trade or as live fish bait. The remaining two species are likely cryptic native species, which have either been mistaken for known species, e.g., N. aff. denticulata, or species that have not been discovered before, e.g., N. aff. fukiensis. While the four alien species have spread widely in central Honshu, northern Kyushu and Tsushima Island, their impacts on the native species and the overall ecology remain mostly unexplored. Problems associated with using DNA barcoding for species identification are highlighted for further research.

Understanding how climate, ecological and environmental changes, and anthropogenic activities have driven animals' development and predicting their prospective distribution profiles are essential to making a tangible conservation strategy. Macaques (Macaca) distributed in China provide an ideal research model for such an effort. We reconstruct their geographic distribution profiles from the last inter-glaciation (LIG, 120,000-140,000 years BP), the Last Glacial Maximum (LGM, 22,000 years BP), and the present (1970-2000), based on which we deduce their distribution perspective in the 2050s. The results show that their suitable habitats during LIG and LGM were mainly in eastern Southwest, Central, and Coastal China. A noticeable distribution reduction started in LIG and persisted until the present (1970-2000). Their distribution centroid would shift northward to mountainous regions, mainly in Southwest China, where more migration corridors would be available for their prospective development. Also, the results indicate that China's Protected Area currently does not cover more than 94.00% of macaques' potential habitats, which is a dismal situation for their conservation. Finally, this study proclaims that the conservation priority of the macaques in the years to come should focus on Southwest China -their future refuge region.