Zoological Studies最新文献

We describe the ostracod Lissostrandesia fonticola gen. et sp. nov. in the subfamily Cypricercinae McKenzie, 1971, collected from six rheocrenic springs in Japan. The populations sampled were separated by up to 1000 km, and some of them by one or two marine straits, which comprise significant barriers for freshwater animals. Lissostrandesia differs from the other 13 cypricercine genera in (1) lacking a groove and inner list on the anterior inner margin of the left valve; (2) having b and d setae on the fifth limb; (3) having d₁ and d₂ setae on the sixth limb; (4) having a stout attachment of the caudal ramus; (5) having a Triebel's loop on the dorsal branch of the attachment; and (6) having a long free ventral branch, its length more than twice its width, and (7) having a free dorsal branch contributing to a tip on Triebel's loop. These differences were enough to warrant establishment of a new tribe, Lissostrandesiini, to accommodate the new genus. We present a key to the genera in Cypricercinae. The maximum p-distance for the mitochondrial cytochrome c oxidase subunit I (COI) gene among six local populations was 0.662%, a low value indicative of conspecificity. In addition, four populations with sample sizes of 13-21 individuals shared two main COI haplotypes, indicating high apparent connectivity. A trend of decreasing genetic diversity from south to north suggests L. fonticola has had a longer history on Honshu Island and dispersed northward from there. Using the 16S rRNA gene as a marker, we detected the endosymbiotic bacterium Cardinium, a group of "reproduction-manipulating" bacteria, in five populations, suggesting that L. fonticola is parthenogenetic. Passive dispersal is the most likely explanation for the broad distribution of this species across strong geographic barriers.

To identify the worldwide genetic structure, gene flow, and diversity of Culex quinquefasciatus, we conducted phylogeographic and population genetics analyses utilizing publicly available mtDNA sequences. Therefore, the aim of this study was to investigate the genetic structure and diversity of natural populations of C. quinquefasciatus worldwide, using available genetic data reflecting its natural distribution. Our study focused on the cytochrome c oxidase subunit I (COI) gene, mirroring the species' distribution pattern. We examined COI gene sequences from C. quinquefasciatus populations across Asia (n = 1,698), America (n = 334), Africa (n = 30), Oceania (n = 21), and Europe (n = 1), identifying 69 haplotypes. Genetic links were observed between Asian populations and those from other continents. Global genetic diversity was 0.531, varying from 0.095 in Oceania to 0.648 in South America. Neutrality tests indicated demographic expansions at the continental level in the Americas, North America, and Asia, as well as in some countries within these regions. In contrast, at both global and continental levels (South America, Oceania, and Africa), and in most countries within these continents, neutral populations were observed. AMOVA revealed genetic structuring among and within countries, with no genetic isolation observed (R ² = 0.03144; p > 0.05). Despite lower genetic diversity, Asian populations facilitated gene flow with other continents, suggesting a possible native origin of the species in Asia. The dispersal of this mosquito to new regions, coupled with its ability to transmit various arboviruses, underscores its significance as a potential public health threat.

The brachyuran crab fauna of subtropical Hong Kong is documented and an updated catalogue presented of all known species. Starting with the milestone studies by William Stimpson in the 1850s, many generations of workers have since added to the knowledge of this fauna. In the previous summary of the fauna by Chia-Jui Shen in 1940, 187 species were reported. Eight decades later, we now report 382 species from 27 superfamilies and 49 families, of which 22 species are new records. The present paper also reviews the history of carcinology in Hong Kong. The taxonomy of each species is treated, and a complete scientific bibliography is presented as far as possible.

Over 110 specimens of xanthid crabs collected from rocky intertidal habitats in Taiwan and its offshore islands over the past 25+ years were examined in the present study. As a result, 24 species were recognized, distributed across seven subfamilies and 16 genera including one new genus record (i.e., Lioxanthodes Calman, 1909) for Taiwan. Of these recognized species, 14 have been previously reported from Taiwan, whereas five are new records for Taiwan, one new to science, and four unnamed species. The five newly recorded species are Chlorodiella barbata (Borradaile, 1900), Etisus frontalis (Dana, 1852), Lioxanthodes alcocki Calman, 1909, and Macromedaeus quinquedentatus (Krauss, 1843), and Pilodius nigrocrinitus Stimpson, 1859. The new species, Cyclodius taiwanensis sp. nov., is herein described.

Echinostylinos comprises 11 species, among which a single, recently reported record for the South Atlantic. Here we propose two further new species from this ocean basin. Echinostylinos iatapiuna sp. nov. (2300‒3200 m depth, São Paulo Ridge) and Echinostylinos abyssalis sp. nov. (4008 m depth, São Paulo Ridge). The latter pushes the genus' known distribution into the abyssal zone for the first time. The morphologic variation observed in the microscleres of Echinostylinos is briefly discussed, motivating our proposal to transfer Echinostylinos glomeris (Topsent, 1904, as Esperiopsis) to Abyssocladia, a stipitate or likely so, which compound with chelae of cleistochelae morphology to point to the latter genus as its best assignment. An identification key for Echinostylinos spp. is offered (now 13). In addition, a new species of Chondrocladia is described, namely Chondrocladia (Chondrocladia) trisigmata sp. nov. (3250-3270 m depth, south of the Vitória-Trindade seamounts' chain). Finally, some biogeographic considerations are made about abyssal sponge records in the South Atlantic.

The symbiotic pinnotherid crab Mesotheres unguifalcula was rediscovered in Acapulco Guerrero, Mexico, and was found infesting the spindle sea snail Leucozonia cerata (Fasciolaridae), a new host record for this crab. A total of 432 snails were collected in 2020, with a prevalence of 77%, well explained by the host width frequency. Monthly prevalence varied from 54% to 90%, and the mean intensity was 1.4 +/- 0.5 crabs per host. The sex ratio of snails was 1:1, and the crab did not prefer to infest males or females. The sex ratio of the crabs was positively skewed towards females. Crabs infested both small and large snails; however, most infested snails ranged between 20 and 40 mm in width. Prevalence increased with the host size: with hosts smaller than 30 mm experiencing an average of 53% infestation, while those from 30 mm to 52 mm averaged 93% infestation. The number of crabs by host varied from 1 to 3; solitary females and males were dominant (51%), followed by heterosexual couples (24%) and other combinations that included homosexual couples and triads, which barely represented 2%. Although there are many heterosexual couples, monogamy is ruled out due to the higher number of solitary males and females and the lower number of heterosexual couples compared to those statistically expected. The available evidence about the life history of Mesotheres unguialcula, like that of other studied species of the subfamily Pinnotherinae sensu stricto, suggests a pure-search polygynandry of sedentary females as its mating system (i.e., larger, solitary, and sedentary females, and smaller males who, in reproductive season, are roaming from one host to another in search of females receptive to copulation).

The Chestnut-capped Blackbird Chrysomus ruficapillus is a neotropical species that nests in wetlands, which are abundant in South America. However, many of these wetlands face threats of disappearance and degradation, with potential consequences for the species inhabiting them. Here, we carried out a detailed study of the breeding biology of this species and examined variables that influence daily nest survival rates (DSR). We described nest site features, nest morphometry, breeding parameters, estimated the growth curves of nestlings, and recorded the causes of nest failure. We evaluated the effects of nest site features, nest morphometry, nest age and timing of breeding season on the DSR of Chestnut-capped Blackbirds. We expected that DSR would increase with greater nests and higher nest concealment at the beginning of the breeding season. Additionally, we predicted that larger nests would have higher nest survival. We studied the breeding performance of 138 nests in a wetland in central Argentina over three consecutive breeding seasons. Nests were placed 80 ± 21.53 cm above the water. The clutch size was 2.75 ± 0.67 eggs (n = 84 nests), and the brood size was 2.28 ± 0.79 nestlings (n = 49 nests). The most frequent cause of nest failures was predation (60%). The daily nest survival rate (DSR) was 0.96, and the cumulative probability of nest survival in a 29-day breeding cycle was 0.31 (n = 85 nests). As expected, we found a positive association between nest height above the water and DSR, suggesting that nests built further away from the water have increased survival rates. However, we found no effects of nest morphometry or the timing of breeding season on DSR. We emphasize the importance of understanding the breeding performance and the influence of nest site features on the survival of species inhabiting wetlands to implement actions to conserve and protect the population.

A taxonomic review on the genus Perinereis (Annelida, Polychaeta, Nereididae) from Taiwan has been conducted by examining over 1000 specimens of the worms in the author's private collection and in the depository of the National Museum of Natural Science. A total of 24 species for this genus has been recognized in the present study. Of these 24 species, 17 are new to science, and they are: Perinereis daxiensis sp. nov., P. fugangensis sp. nov., P. kaomeiensis sp. nov., P. kebalanae sp. nov., P. houbihuensis sp. nov., P. hsinchuensis sp. nov., P. liuqiuensis sp. nov., P. longdongwanensis sp. nov., P. ludaoensis sp. nov., P. pangcahae sp. nov., P. pseudocultrifera sp. nov., P. qiguensis sp. nov., P. taitungensis sp. nov., P. tubicola sp. nov., P. wanlitongensis sp. nov., P. yehliuensis sp. nov., and P. yufuensis sp. nov. The presence of P. cultrifera (Grube, 1840) in Taiwan is confirmed. The remaining six are species previously reported from Taiwan, which are: Perinereis aibuhitensis (Grube, 1878), P. floridana (Ehlers, 1868), P. mictodonta (Marenzeller, 1879), P. nigropunctata (Horst, 1889), P. vancaurica (Ehlers, 1868), and P. wilsoni Glasby & Hsieh, 2006. The generic diagnosis is partially amended to include the presence of neuropodial homogomph spinigers found in the subacicular fascicle of P. longdongwanensis sp. nov. A key to Perinereis species reported from Taiwan is herein provided.

Dung beetles play a vital role in the functioning and sustainability of agroecosystems. The temporal niche partitioning facilitates species coexistence by minimizing interspecific competition. Temporal activity patterns of dung beetles are influenced by various biotic and abiotic factors. Changes in land use by humans may alter activity patterns and spatial distribution. In this study we analyzed a) the seasonal variations in abundance and richness of dung beetle assemblages in two contrasting habitats within a ranch in Uruguay, and their relationship with environmental factors; b) the influence of the habitat on the daily patterns of flight activity of dung beetles, as well as seasonal and daily changes species composition; and c) the seasonal variations of daily activity patterns of the most abundant species. We sampled dung beetles every two weeks for a year with pitfall traps baited with carrion and cow and horse excrements in an open grazed pasture and a Eucalyptus plantation, used as a shelter for livestock. Each 24-hour sampling was divided into 5 intervals: morning, noon, afternoon, evening, and night. The seasonal variations of abundance and species richness of Scarabaeidae in both habitats were similar from midspring to mid-autumn, without activity in the winter season; temperature influenced these patterns. Diurnal dung beetles were more abundant than crepuscular and nocturnal in the open habitat but not clearly in the Eucalyptus plantation. However, the abundance and richness of nocturnal species were similar in both habitats. The daily activity period significantly influenced the segregation of dung beetles in both habitats. Species composition differed markedly between diurnal and crepuscular/nocturnal species without changes across seasons. Scarabaeinae species were mostly diurnal in grassland, while a nocturnal species was predominant in Eucalyptus plantation. Aphodiinae species were mainly active at dusk and night. We concluded that the daily activity of the species depends on the habitat, which should be considered when designing conservation measures for dung beetles in this region.

Fungus-growing termites (FGTs) play ecologically important roles as both decomposers and producers of termite mushrooms. However, they are difficult to research due to a lack of an updated identification key and the inability to locate type specimens. Molecular identification may be helpful, but this requires database information that is lacking for many species found in Thailand. In addition, some researchers use the cytochrome oxidase subunit I (COI) gene as a barcoding gene, but others use cytochrome oxidase subunit II (COII). Thus, we offer detailed descriptions of nine FGT species commonly found in Thailand, together with the DNA sequences of both the COI and COII genes. The descriptions include those of both major and minor soldiers. The DNA sequences of the two genes confirm the morphological identifications. Our data will aid future FGT identification and facilitate research on the biodiversity, conservation, and sustainable use of FGTs and termite mushrooms.