Zoological Studies最新文献

In this study, four new species of land hermit crabs (Crustacea: Decapoda: Anomura: Coenobitidae: Coenobita Latreille, 1829) are described from Indonesia. These descriptions are based on evidence from morphological differences as well as mitochondrial 16S rDNA and cytochrome c oxidase subunit I data. Among the new species, Coenobita moluccensis n. sp. (from Aru Island, Maluku), C. patsyae n. sp. (from Central Sulawesi and Southeast Sulawesi), and C. celebensis n. sp. (from Central Sulawesi) form a major clade on the phylogenetic tree, exhibiting similarities in morphology, particularly in the male sexual tubes- a character they share with their closely related counterpart, C. lila Rahayu, Shih & Ng, 2016. Although the four species are similar in overall morphology, they can be distinguished by differences in the left third pereopod, the second article of the antennal peduncles, granulation on the pereopods, as well as their live coloration. Coenobita granularis n. sp., found in Central Sulawesi, shares morphological similarities with the genetically closely related C. pseudorugosus Nakasone, 1988, particularly in the male sexual tubes. However, the two species can be distinguished by differences in the morphology of the male sexual tubes, the presence of tubercles on the left cheliped, the left third pereopod, as well as their live coloration. Additionally, a newly recorded species, C. variabilis McCulloch, 1909, has been confirmed in West Papua. This study brings the total number of Coenobita species known from Indonesia to 13.

Taiwanese Pseudasphondylia species inducing spherical leaf galls on six Neolitsea hosts, viz, N. acuminatissima, N. daibuensis, N. konishii, N. parvigemma, N. sericea and N. variabillima, was regarded as a species allied to Japanese P. neolitseae Yukawa due to similarity of gall structure and host. The Taiwanese species is morphologically different from P. neolitseae in adult palpus segmental number, shapes of pupal antennal horn, pupal prothoracic spiracle, and larval sternal spatula, resulting in its description as a new species to science, Pseudasphondylia hooki sp. n. The species delimitation (Assemble Species by Automatic Partitioning method) supported that P. hooki sp. n. is distinct from P. neolitseae. The sistership of P. hooki sp. n. and P. neolitseae was also supported in the Maximum likelihood tree based on the 1^st codon of COI region. The speciation event of them is assumed to be geographical isolation because the divergence corresponded to the separation of Taiwan and Japan in the Pleistocene. The patterns of ecological features (host species) on the phylogeny revealed that galling on N. sericea is primitive of Neolitsea-associated Pseudasphondylia lineage. Accordingly, the divergence pathway from north to south in Taiwan is suggested by the distributions of primitive (N. sericea) and most derived hosts (N. daibuensis).

Two freshwater tardigrade populations belonging to the genus Dactylobiotus were investigated using phase contrast microscopy, scanning electron microscopy, and molecular markers commonly employed in tardigrade phylogenetic studies (18S rRNA, 28S rRNA, ITS2, and COI). The population from Taiwan, discovered through social media, represents a new species, described here as Dactylobiotus taiwanensis sp. nov. This species is most similar to Dactylobiotus parthenogeneticus but differs in the presence of singular rings of pores surrounding the egg processes and specific morphometric traits. The second population, from Greenland, was provisionally identified as D. cf. octavi, and its morphological discrepancies are discussed in detail. A revision of the type material for Dactylobiotus caldarellai and Dactylobiotus lombardoi raises questions about their validity due to insufficient data. Finally, a phylogenetic analysis incorporating taxa from the family Murrayidae, along with the newly sequenced populations, is presented. An updated dichotomous key for the genus Dactylobiotus is also provided.

This study investigates the trophic cascades and habitat suitability in Udanti Sitanadi Tiger Reserve (USTR), highlighting the roles of apex predators, subordinate predators, and prey species in maintaining ecosystem balance. Using the Trophic Species Distribution Model (Trophic SDM), we explored prey-predator interactions and habitat suitability, revealing that tigers respond to prey depletion by increasingly relying on cattle, while leopards adapt by preying on smaller species. Additionally, climate change projections for 2021-2040 and 2081-2100 under CMIP6 scenarios SSP245 and SSP585 indicate significant regional habitat shifts, necessitating adaptive management strategies. Kulhadighat is projected to face habitat contraction, while Sitanadi may experience habitat expansion. This study emphasizes the need for effective conservation efforts such as habitat restoration, prey augmentation and predator recovery are the most important steps needed to maintain the purpose of a Tiger reserve and conservation potential of Chhattisgarh-Odisha Tiger Conservation Unit (TCU). To achieve these dynamics, focusing on community participation, anti-poaching measures, and scientific recommendations are the most crucial components to focus on. This comprehensive analysis underscores the critical role of targeted conservation activities in prey-depleted landscapes to ensure the long-term survival of tigers and the overall health of forest ecosystems, enhancing biodiversity and mitigating human-wildlife conflicts in USTR.

Twin-tail ornamental goldfish have a bifurcated caudal fin with a morphology that is extremely divergent from the conventional body plan of the vertebrates. Here, we investigate the musculoskeletal histology of this bifurcated caudal fin. From some of the investigated twin-tail goldfish, we found a twin-tail goldfish specific muscle (hereafter referred to as the "medial caudal muscle") between left and right bifurcated caudal fin skeletons. Our immunohistochemical analyses revealed that the medial caudal muscle showed laterally biased distribution patterns of the slow and fast muscle fibers. Similar distribution patterns were also commonly observed in several deep muscles of wild-type goldfish as well as zebrafish, suggesting that these muscle fiber distribution patterns are formed by the same molecular developmental mechanisms even though their morphologies are highly diverged. These findings provide empirical evidence to consider how the histological features of a newly emerged morphology are influenced by selective pressures and pre-existing developmental mechanisms.

Biological specialization plays a central role in species coexistence. While many studies focus on hummingbird pollination, research on the effects of morphological traits of both hummingbirds and plants on the specialization of interaction networks remains scarce. In this study, we aim to address the following questions: i) does the dominance of ornithophilous plant species increase the specialization of hummingbird-plant interaction networks?; ii) do ornithophilous plants exhibit a greater diversity of interactions with hummingbirds compared to non-ornithophilous plants?; iii) do the beak size and body weight of hummingbirds influence the diversity of their interactions? Research was conducted on hummingbird-plant interactions in the Neotropical region. We investigated hummingbird-plant interactions in the Neotropical region by compiling 24 networks from the literature, comprising 1,182 interactions between 34 hummingbird species and 326 plant species. We found no effect of ornithophilous plant dominance on the structure (connectance and modularity) of the networks. However, species-level interactions were influenced by morphological attributes of both plants and hummingbirds. Interaction similarity among plant species was greater for ornithophilous plants than for non- ornithophilous plants. Additionally, beak size positively influenced the degree and specialization of hummingbird interactions. Our findings demonstrate that the morphological characteristics of hummingbird and plant species directly influence the diversity of interactions in Neotropical hummingbird-plant networks and species specialization.

This study aimed to establish reference intervals for red and white blood cell counts, hematocrit levels, mean corpuscular volume, and 25 key plasma biochemistry parameters in captive and wild whale sharks (Rhincodon typus). Blood samples were collected from the caudal vein (CV) and dorsal cutaneous vein (DCV) of 30 wild sharks caught in fixed nets off the Kochi Prefecture coast, Japan, and from 24 captive sharks between 2007-2023. Samples were obtained from restrained captive and wild sharks as well as unrestrained captive sharks trained for husbandry. Comparative analyses considered three factors: captivity status (wild vs. captive sharks under restraint), blood sampling sites (CV vs. DCV under restraint), and handling methods (DCV sampling under restrained vs. unrestrained conditions). Analysis of captivity status revealed significant differences in 12 of 29 parameters, with triglyceride levels significantly lower in wild sharks, possibly indicating nutritional deficiencies due to their prolonged migrations. Comparisons of blood sampling sites revealed significant differences in 11 parameters, including red and white blood cell counts and hematocrit levels, with most CV-derived parameters being higher than those from the DCV. A strong correlation (r > 0.7) was found between the CV and DCV for 19 parameters, indicating predictive values between these vessels. Additionally, the relationship between RBC, Ht, and MCV indicates that the RBC and MCV results may not be entirely reliable and should therefore be interpreted with caution. In the handling method comparison, eight parameters exhibited significant differences; specifically, aspartate aminotransferase, ammonia, and creatine phosphokinase levels were likely influenced by stress effects, including restraint-induced muscle damage. These findings emphasize the importance of unrestrained blood collection, facilitated through husbandry training, for accurate blood parameter evaluations. Integrating statistical results across the three studied factors allowed for the establishment of reference intervals, means, and medians for whale sharks, contributing to health management in captive sharks and conservation in wild populations.

Møller and Erritzøe (2017) reported that birds killed by collisions with vehicles had on average relatively smaller brains than birds killed by other causes, which were not identified. Despite concerns about the method used to assess brain mass, we reanalyzed the published data of Møller and Erritzøe (2017) after excluding extraneous species and confirmed a subtle tendency for birds killed by vehicular collision to have somewhat small brains. Some groups of birds (owls, hawks, garden birds and migratory species) did not reflect the overall result. Surprisingly there was no effect of age or sex, whereas one would expect inexperienced immature birds and females in breeding condition to be vulnerable. Overall, plots of brain mass in birds killed by vehicular collisions and other causes greatly overlap, and in some species, individuals killed by collisions have relatively larger brains. That is, the tendency for birds hit by vehicles to be relatively smaller brained is not universal, nor in any species is there an absolute difference in brain size between the two categories. It is possible that in the short time birds have interacted with moving vehicles that selection has acted on brain size to avoid collisions, although we suggest that slightly larger brains might represent an innate tendency to avoid rapidly approaching objects. An interesting question from their study is what was the cause of mortality in the birds not hit by vehicles. Likely sources of mortality of birds post-nestling stage include depredation (natural and house cats) and collisions with windows and other human structures. In fact, relatively large-brained birds might be more susceptible to collisions with windows or being caught by cats (i.e., the other sources of mortality), for which having a relatively larger brain would not appear to mitigate these sources of mortality.

Temperature is one of the main abiotic factors that influence the growth, reproduction, food availability, distribution, and survival of many species of marine ectotherms. Megastraea undosa and Megathura crenulata are gastropod mollusks with economic, commercial, and biomedical importance that are part of the kelp forest community in the temperate waters of the northern Pacific of Mexico. As knowledge about the thermal biology of these two species is scarce, this study aimed to determine the effect of different acclimation temperatures on the thermal biology and metabolic scope of these two species. 120 M. undosa juveniles were collected from the wild and acclimated to four temperatures (13, 16, 19, and 22°C ± 1°C), while 90 M. crenulata juveniles were cultured in an aquaculture facility (Stellar Biotechnologies, Inc) and acclimated to three temperatures (17, 20, and 23°C ± 1°C). Subsequently, experiments were performed to determine the thermal tolerance, thermal window, thermal safety margin, future thermal safety margin, and thermal metabolic scope of these species. The thermal tolerances of both species were relatively similar (M. undosa juveniles: CT_max = 25.3, 21.0, 25.4 and 27.4°C, CT_min = 6.0, 9.2, 16.3 and 17.3°C; M. crenulata juveniles: CT_max = 27.7, 28.1 and 28.8°C, CT_min = 11.2, 12.1 and 14.7°C). Both species had a small thermal window area (M. undosa: 77.2°C²; M. crenulata: 65.25°C²). The values of the thermal safety margin and the future thermal safety margin of both species were lower during the summer than winter. The optimal temperature proxies of M. undosa and M. crenulata juveniles were 16 and 20°C, respectively. This study shows that the two species of marine gastropods could be moderately affected by ocean warming, being forced to modify their current distribution patterns. The data on thermal limits and optimal temperatures can be used to initiate and maximize the cultivation of both species, which would also help mitigate the impact of overfishing on natural populations.

Terrestrial isopods are important to forest soils, breaking down decaying plant material and aiding in nutrient recycling. Despite their ecological significance, studies on their diversity and dynamics in Neotropical dry forests are limited. This research investigated the seasonality of the alpha and beta diversity of terrestrial isopod assemblages in a protected fragment of Tropical Dry Forest in the Colombian Caribbean. We sampled isopods in 1 m2 units of litter, and recorded soil and litter temperatures, and moisture during twelve field trips conducted between June 2018 and March 2019 in rainy, transition, and dry climatic seasons. A total of 867 individuals belonging to four families, six genera, and eight species were collected. Alpha diversity did not show significant differences across seasons. However, abundance was significantly influenced by seasonality, soil temperature, litter temperature, and soil moisture. Moreover, species richness was affected by soil moisture and litter temperature. Our results highlight pronounced seasonality in the isopod assemblage, characterized by balanced variation in beta diversity, with higher abundance during the transition and rainy seasons. The observed increase in the variables, correlated with higher total beta diversity, underscores their role as drivers of seasonal dynamics in assemblage structure. Soil temperature and moisture significantly influenced balanced variation component of beta diversity. The identified seasonal pattern likely results from the historical adaptive processes of these species to the conditions of the tropical dry forest. Nonetheless, effective conservation strategies are essential to mitigate the impacts of climate change on edaphic arthropod assemblages in this ecosystem.