BMC Zoology最新文献

Background: Fishes are key components of the megafauna of the deep sea, and evolutionary adaptations to deep-sea life appear to have occurred independently in at least 22 fish orders. In this context, the analysis of even more fish genomes and mitogenomes has fundamental importance, providing a valuable resource for understanding the molecular mechanisms underlying evolutionary adaptation, especially to extreme environments such as the deep sea. Here, we report the first complete mitochondrial genome of Zu cristatus (Bonelli, 1819), providing essential information on its structure and phylogeny.

Results: After sequencing on the Illumina HiSeq 4000 platform, processing, and assembly via MitoFinder software v.1.4.1, a single circular mtDNA molecule of 17,450 bp in length was annotated. A total of 37 genes were identified, including the first D-loop region for this species. The asymmetry for both AT skews and GC skews is negative, and the AT content is 56.4%. We also detected the presence of 15 small, noncoding, intergenic nucleotide (IGN) regions and some rare stop codons in bony fishes. Pairwise distance and phylogenetic analyses against a list of other mitochondrial sequences from 42 bony fishes confirmed the current phylogeny with previously related orders. EasycodeML analysis revealed that only 4 PCGs underwent positive selection. New questions about the phylogeny of Lampriformes emerged from our phylogenetic analyses of Lampriformes COI.

Conclusion: Overall, the findings of this study highlight the need to elucidate the genetic features of bony fishes in relation to their deep-sea adaptation, with a focus on rare and interesting species.

Background: The Middle Miocene fauna of La Venta, Colombia, offers a grand opportunity to understand low-latitude South American ecosystems prior to the late Cenozoic Great American Biotic Interchange (GABI). We present new material of two proterotheriid litopterns, Villarroelia totoyoi and Mesolicaphrium sanalfonense, and a macraucheniid litoptern, Theosodon, from La Venta. During the GABI, North and South American faunas intermixed, after which some lineages proliferated and others died out. We conducted an ecomorphological analysis of 11 North and South American faunas pre-dating and post-dating the GABI by scoring all mid- to large-sized mammalian herbivores on their body size, tooth morphology, and feeding height.

Results: The fossils studied here offer new information on the deciduous dentition of M. sanalfonense and mandible of the La Venta Theosodon. Pre-GABI South American faunas were more ecomorphologically diverse than their North American counterparts. The post-GABI Pleistocene fauna exhibited similar ecomorphological diversity to pre-GABI South American faunas, but modern faunas show this diversity was mostly lost in the end-Pleistocene extinctions.

Conclusions: The new litoptern fossils provide previously unknown information on these species' morphology, but they do not resolve outstanding systematic and phylogenetic questions. Discrepancies in ecomorphological diversity between pre-GABI North and South American faunas is attributable to the presence of small, high-feeding (arboreal) taxa and hypselodont (ever-growing cheek teeth) taxa in South America, which North America lacked. Arboreal herbivores (porcupines and primates) experienced some success in North America after dispersing during the GABI. Although hypselodont xenarthrans were successful in post-GABI North America, the fact that most other hypselodont lineages went extinct during and after the GABI suggests that dental morphology may not fully capture the ecomorphological diversity in diet of North American herbivores. Future studies could examine faunas immediately before and after the GABI to uncover the precise dynamics of the interchange and why certain lineages succeeded while others failed.

In this study, we report the whole mitochondrial genomes of two species, Meghimatium pictum and Succinea arundinetorum, which belong to Stylommatophora, one of the most abundant orders of Gastropoda. The total sizes of M. pictum and S. arundinetorum mitogenomes are 14,352 bp and 15,282 bp, with surprisingly biased proportions of A+T contents of 72.1% and 76.78%, respectively. The protein coding genes (PCGs) in two mitogenomes show negative AT skew values and evolved primarily under purifying selection. Compared with the ancestor of Stylommatophora, the mitochondrial genes of M. pictum exhibited multiple rearrangement events, while the mitochondrial genes of S. arundinetorum showed only minor differences. Moreover, the order of PCGs was conserved, while the tRNA genes showed high frequency of rearrangement among the Stylommatophora species, suggesting that the latter could be one of the major driving forces of mitogenomic evolution in terrestrial Mollusca species. Our research lays a theoretical foundation for investigating the evolution and divergence of mitochondrial genes and provides valuable resources for studying evolutionary genetics in Stylommatophora species.

Big-scale sand smelt (Atherina boyeri) is an euryhaline pelagic schooling fish found throughout the Caspian Sea. A specialized fishery does not target this species, and its body length can reach up to 13 cm. A. boyeri serves as prey for many omnivorous and predatory fish and is one of the primary food sources for the Caspian seal (Pusa caspica). The objective of this study was to determine the size composition of A. boyeri in the diet of P. caspica, a declining species of the Caspian Sea. A coprological method was used, involving the collection of seal feces during spring and autumn haul-outs in the Northern and Middle Caspian, followed by examination of fish otoliths. Before this, otoliths from fish were analyzed to assess morphological diversity and growth patterns in relation to Atherina boyeri. Equations were developed to estimate fish length from otolith length and width. Otoliths from feces were classified into three wear categories: lightly, moderately, and heavily abraded. A comparison of otolith sizes from fish and feces allowed the calculation of wear coefficients based on otolith length for each group, which were incorporated into the reconstruction formula. The reconstructed fish length distribution showed that at the Northern Caspian haul-outs, individuals measuring 60-70 mm predominate, while at the Middle Caspian haul-out, individuals measuring 80-90 mm are most common. Overall, this is the first study to confirm that P. caspica feeds on both juvenile and mature A. boyeri, with lengths ranging from 23.1 to 117.1 mm.

Background: Leptospira are endemic and cause disease among California sea lions (Zalophus californianus), but the epidemiology of Leptospira in Galapagos sea lions (Z. wollebaeki) is almost completely unknown. Understanding the presence and circulation of this zoonotic pathogen is essential not only for the conservation of Galapagos sea lions, but also for assessing potential health risks to humans and other animals within the Galapagos archipelago. This study fills knowledge gaps by investigating Leptospira in this endemic host species to provide valuable insights into the dynamics of the pathogen in an isolated island ecosystem that is completely different from others in which Leptospira have been documented.

Results: In 2016, serological analyses detected 24 positive samples in the "El Malecón" rookery (n = 43) and 18 positive samples in the "Punta Pitt" rookery (n = 33), confirming exposure to pathogenic Leptospira species. In 2017, we identified 15 (n = 29) and 13 (n = 30) positive samples, respectively. Molecular analyses further detected leptospiral DNA in 70.8% (n = 24) of sand with urine samples and 45.8% (n = 24) of kidney samples. Amplicon sequencing of the secY gene fragment yielded 10 consensus sequences, confirming the circulation of Leptospira interrogans among Galapagos sea lions.

Conclusions: Our findings confirm that Galapagos sea lions are exposed to pathogenic Leptospira species and, for the first time, identify L. interrogans as the circulating species over two consecutive years. By expanding sampling across multiple rookeries, we provide a clearer picture of pathogen exposure in this endemic population. These results improve our understanding of Leptospira dynamics in marine mammals on remote islands, where management efforts aim to reduce disease risks from human activity, livestock, and synanthropic species.

The conservation of water is of great importance to terrestrial snails in order to survive in arid environments. However, evaporation of body water does occur, and it is unclear whether snails are able to actively reduce the evaporation or whether increased environmental temperature inevitably leads to increased evaporation. Physically, the quantity of evaporating water is largely determined by the temperature, the relative humidity and the velocity of the surrounding air, as well as the surface area of the evaporating body. Theba pisana, a widespread Mediterranean land snail, is exposed to a wide range of ambient temperatures. For this species the experimentally recorded evaporation rate per mass was tested as a 'response' variable to the 'explanatory' variables temperature, relative humidity and air velocity using multiple regression modelling. The variation in specific evaporation of T. pisana could be explained to 72.8% by these parameters. Threshold temperatures, which depended on the parameters relative humidity, air velocity and body size, were found to induce an active response in the snail that reduced their evaporation rate. A comparative analysis of the specific evaporation rate of different-sized snails shows that, at low temperatures, larger snails have a lower specific evaporation rate than smaller snails. However, above a threshold temperature this trend reversed, depending on air velocity and relative humidity. In general, the evaporation rate is lower at higher relative humidities. In the specified temperature range (23-35 °C) the snails tend to actively reduce the evaporation rate to conserve water rather than increase the evaporation rate to avoid overheating. These findings provide valuable information about the physiological adaptations that support survival in water-limited environments, offering important implications for understanding arid-adapted species such as desert snails.

Understanding the population dynamics and ecology of mammals ensures an effective conservation of wildlife. This study was conducted to examine the population status, structure, feeding ecology and habitat preference of common bushbuck (Tragelaphus scriptus decula) in Simien Mountains National Park, Ethiopia, covering both wet and dry seasons from August 2018 to March 2019. Data on the population structure and feeding ecology of common bushbuck was collected using a total count and focal sampling methods, respectively. Counting was done at three sites which have fourteen blocks. The collected data was analyzed using descriptive statistics and compared with Chi-square, the Kruskal-Wallis test, and Multivariate Analysis of Variance. The total number of common bushbucks in the study area was 99 and 102 during the wet and dry seasons, respectively. There was no significant difference (U = 7413, P < 0.340) in the number of individuals between wet and dry seasons. Of the total individuals observed, 64.5% constituted adults, 25.5% sub-adults and 9.8% unidentified sex. The study documented the consumption of 37 plant species over the study period which herbs comprised the highest proportion (62%), followed by shrubs (16.2%) and trees (13.5%). The most preferred species were Cyanotis barbata (12.29%) and Alchmila pedata (11.64%), whereas Gladiolus abyssinicus (0.14%) and Pterocephalus frutescens (0.2%) were the least consumed, respectively. The common bushbucks consumed mainly youngy leaves and shoots. However, there was a significant difference in plant part consumed by common bushbuck during wet and dry seasons ([Formula: see text]= 1762.3, df = 6, P < 0.05). To ensure the common bushbucks conservation in SMNP, we recommend the long term habitat and population monitoring and integrated research to inform broader ecosystem management and biodiversity protection.

Background: The lacertid genus Mesalina has been the subject of several phylogenetic and biogeographic studies as well as taxonomic revisions within the last decade. The genus is partitioned into seven main clades, some of which represent species complexes of morphologically very similar species. The Mesalina guttulata species complex is one such case. This complex currently comprises four described species that occur through Arabia and northern Africa, however, the presence of a cryptic species in Saudi Arabia, Kuwait, and Jordan was pointed out recently. For this study, we collected new material of the various species of the M. guttulata complex, including the undescribed lineage from across Saudi Arabia. We carried out multilocus phylogenetic analyses using three mitochondrial and three nuclear markers and analysis of morphological data to verify whether the undescribed lineage deserves a species rank.

Results: The results show that the lineage is clearly genetically separated from the other species of the complex and shows morphological differentiation from the other species. Therefore, we describe it herein as a new species, Mesalina cryptica sp. nov.

Conclusions: We contribute to the taxonomy of Arabian lacertid lizards by describing a new species distributed in central Saudi Arabia, with isolated populations occurring in Kuwait and Jordan. Despite its large range, the species is genetically and morphologically homogeneous. The gap in its distribution between the Jordan and Saudi Arabia populations is ascribable to the paucity of sampling along the Saudi/Iraqi border.

Background: Human-primate conflict is a global conservation challenge, particularly in densely populated, low-income countries like Ethiopia. The Omo River Valley forest belt, spanning across the Omo River in Ethiopia to Lake Turkana in Kenya, harbors a diverse array of African primate species. An investigation on non-human primate population density and human primate conflict was carried out from January 2022 to December 2023 in the Tembaro Community Conserved Forest, Omo River basin, South Central Ethiopia. The population density of non-human primates was estimated using distance sampling method, and the intensity of conflict among human-primate was quantified by a questionnaire survey and focus group discussions.

Results: The study revealed some interesting results which include the presence of black colobus monkeys (Colobus satanas) in Ethiopia. The mean density of Anubis baboons (Papio anubis) was 10.06 ± 2.93, grivet monkeys (Chlorocebus aethiops) 17.09 ± 4.53, black colobus monkeys (Colobus satanas) (vulnerable primate species in Africa) was 8.3 ± 1.20, and mantled guerezas (Colobus guereza) was 14.76 ± 3.57 individuals/km². Crop damage and livestock predation were prevalent issues in the present study area. Majority of the local village respondents (51.96%, n = 146) reported that crop damage was the common cause of human-primate conflict, followed by livestock predation and crop damage (33.5%, n = 94). Majority of the conflict was caused by Anubis baboon (Papio anubis) (41%, n = 115), followed by grivet monkeys (Chlorocebus aethiops) (33.1%). The most common cultivated crop by farmers in the study area and the most damaged by the non-human primates was maize (Zea mays) (33.5%, n = 94). The average estimated loss of crops was US$ 6544.50 per year. The average annual loss incurred by each household due to primates predation on their small animals was 94.19 US$. Physical guarding (33%, n = 93) was chosen as the most effective strategy to prevent crop damage and livestock predation.

Conclusion: This study provides valuable insights into primate ecology and the challenges they pose to local communities. The findings reveal varying primate population densities, with Grivet monkeys exhibiting the highest densities. These primate densities contribute significantly to human-wildlife conflict, primarily through crop foraging and livestock predation. While traditional mitigation methods are currently in place, a more sustainable and integrated approach is urgently needed to ensure the harmonious coexistence of primates and local communities. The findings of this study are crucial for developing effective conservation and conflict mitigation strategies that will safeguard the long-term survival of both primates and the livelihoods of local people.

Clinical trial number: Not applicable.