Cytochrome C Oxidase Subunit I Research Articles

A new species of the pill millipede genus Rhopalomeris Verhoeff, 1906 (Diplopoda, Glomerida, Glomeridae) from Myanmar, and notes on Rhopalomeriscarnifex (Pocock, 1889).

The taxonomy of the pill millipede genus Rhopalomeris Verhoeff, 1906, which is restricted to Indochina and currently comprises six described species, is refined and updated. An integrative taxonomic approach was employed that combines morphological examination with DNA barcoding using the cytochrome c oxidase subunit I (COI) gene for species identification and delineation. The first objective was to confirm the identity of Rhopalomeriscarnifex (Pocock, 1889), a charismatic species known as the "candy pill millipede" due to its vivid coloration, based on specimens collected near the type locality in Myanmar. The second objective was to describe a new species, Rhopalomerisnigroflava Likhitrakarn, sp. nov., discovered in Linno Gu, Kayin State, Myanmar. This new species is distinguished by its small body size (5.1-9.7 mm long) and yellow body with contrasting brown to blackish markings on certain terga. In addition, the position of the telopod syncoxital lobe relative to the lateral syncoxite horns separates it from other Rhopalomeris species. The interspecific divergence between R.nigroflava Likhitrakarn, sp. nov. and other congeners ranges from 10.85% to 16.13%, based on uncorrected COI p-distances, while the intraspecific divergence was 0%-7.44%. A distribution map of and a revised identification key to all known species of Rhopalomeris are also provided.

Nasopharyngeal Botflies Oestrus ovis and Cephenemyia stimulator in Roe Deer (Capreolus capreolus) from Northern Spain.

Two of 19 roe deer (Capreolus capreolus) in northern Spain were infested with Cephenemyia stimulator and one individual with Oestrus ovis. Three larvae of O. ovis were recovered from the nasopharynx of an adult female deer examined in February 2017, during the hunting season in the province of Burgos. The larvae were identified by morphology, and DNA sequencing from cytochrome oxidase subunit I and 28S rDNA confirmed the identification of both species of larvae. The possibility of O. ovis parasitizing roe deer should be considered in the diagnosis of nasal bots in cervids.

Genetic diversity and species prevalence revealed by Mitochondrial COI- DNA sequence of thrips population in cotton

Aim: To elucidate the population genetic diversity and species prevalence of thrips on cotton. Methodology: Thrips species were identified utilizing both mitochondrial cytochrome oxidase subunit I (COI) sequence analysis and morphology-based keys. Results: Thrips palmi Karny, Thrips hawaiiensis (Morgan), Ayyaria chaetophora Karny, Scirtothrips dorsalis Hood and Rhipiphorothrips cruentatus Hood identified from collected samples. The distribution analysis revealed that T. palmi stands out as the most abundant and prevalent species, constituting a substantial majority (74%) and occupying a pervasive presence across most cotton-growing locations. The phylogenetic analysis, relying on COI sequences, clearly categorized these five species into four distinct major clades. T. hawaiiensis and R. cruentatus were placed within the first clade, while the second clade featured Scirtothrips dorsalis. The third clade comprised the abundant T. palmi, and the fourth clade accommodated A. chaetophora. Interpretation: The study highlighted genetic diversity of five species of thrips, accentuating the emergence of T. palmi as a dominant pest in cotton, an observation not previously reported. Key words: Cotton thrips, Genetic diversity, MtCOI, Phylogenetic analysis, Species prevalence

A new species of the thorid shrimp genus Lebbeus White, 1847 (Decapoda: Caridea) from the Amami Rift hydrothermal vent field in the Ryukyu region, Japan

A new species of the thorid shrimp genus Lebbeus White, 1847, is described and illustrated on the basis of two specimens collected from the recently discovered Amami Rift hot vent field in the Ryukyu region in southwestern Japan, at a depth of 628 m. Lebbeus parvirostris sp. nov. is morphologically similar to L. microceros (Krøyer, 1841), L. mundus Jensen, 2006, L. saldanhae (Barnard, 1947), L. schrencki (Bražnikov, 1907), L. spongiaris Komai, 2001, and L. tosaensis Hanamura & Abe, 2003, but differs from all of them in the lack of a pterygostomial tooth on the carapace in the female. Other diagnostic characters useful in differentiating the new species from the aforementioned close relatives are also discussed. Genetic analyses using sequences of two mitochondrial markers, including cytochrome c oxidase subunit I (COI) and 16S rRNA, are also presented to provide preliminary support for the status of the new species. Lebbeus parvirostris sp. nov. is the second representative of Lebbeus known from active hydrothermal vents in the Ryukyu region.

Characterizing spatial patterns among freshwater fishes and shrimps of the Poso River (Sulawesi, Indonesia) using DNA barcoding

Fish biodiversity assessments are vital for understanding threats and aquatic ecosystem health. In the Poso River, Central Sulawesi, changes in biodiversity are influenced by habitat alteration, non-native species, and overfishing. This study evaluates fish and crustacean biodiversity in the Poso River system to address these challenges for improving fisheries management, conservation, and fish passage integration into hydropower development. The present biodiversity study utilized a comprehensive methodology that encompassed both traditional taxonomic approaches and DNA barcoding, specifically targeting the mitochondrial cytochrome c oxidase subunit-1 (COI) gene for accurate species identification and spatial boundary validation. The survey was conducted in the upstream, hydropower area and downstream areas of the river. We found 27 species of fish in the Poso River, including both native (e.g., Anguilla celebesensis, Oryzias nebulosus, Rhyacichthys aspro) and non-native species (e.g., Melanochromis auratus, Amphilophus trimaculatus, Oreochromis niloticus). Two International Union for Conservation of Nature (IUCN) red listed endangered species were also observed (e.g., Adrianichthys poptae and Mugilogobius sarasinorum). DNA barcoding was performed to examine species spatial boundaries. The fish population in the Poso River was dominated by non-native species, accounting for 85.70% of the total population. The upstream reaches had the highest fish abundance and diversity, while the downstream reaches had the lowest. There was, however, no significant difference in species richness and diversity across different locations and seasons. The dominance of non-native species in the Poso River necessitates the improvement of existing fishways within the hydropower dams potentially through the development of selective technology that can block the distribution of these non-native species. This research highlights the critical issue of non-native species proliferation and the potential threat they pose to native fish populations, providing valuable insights for conservation and management efforts in Indonesia and similar ecosystems worldwide.

Morphometric trait normalization, cluster analysis and molecular phylogenetic analysis in delimiting sympatric Neolissochilus hexastichus and N. hexagonolepis in Umngi River, Meghalaya (India)

Aim: To assess the ability of an integrative approach comprising multivariate morphometric data analysis and mitochondrial cytochrome oxidase subunit I (CO I) sequence divergence analysis in delimiting sympatric Neolissochilus hexastichus (McClleland, 1839) and N. hexagonolepis (McClleland, 1839) mahseer populations in River Umngi, Meghalaya. Methodology: Authoritative descriptions of mahseers were referred during the sampling of 40 individuals from River Umngi, Meghalaya. Multivariate morphometric data were normalized with respect to standard length. The normalization procedure maintained the particular shape factor for each sample. Normalised data were subjected to hierarchical clustering on principal components Analysis (HCPC) for grouping samples according to morphometric features. Genetic affinities based on CO I sequence divergence were assessed by Bayesian Inference (BI) and Automatic Barcode Gap Discovery (ABGD) protocols. Results: The normalization protocols removed the variations in traits due to body size effects and facilitated the identification of allometric traits. HCPC analysis revealed morphometric features that had a significant impact on clustering. Nine N. hexagonolepis and 13 N. hexastichus individuals were identified by integrative morphological and molecular phylogenetic approach. The remaining 18 individuals had incongruence in their memberships in the morphometric and phylogenetic clusters. Interpretation: The integrative approach, apart from delineating N. hexagonolepis and N. hexastichus congeners, highlighted the need to include nuclear genetic markers in future studies for confirming the presence of natural hybrids in sympatric populations of Neolissochilus mahseers. Key words: Cluster, Morphometric, Neolissochilus, Normalization, Phylogenetics

Mitochondrial evidence on the phylogenetic position of the Southeast Asian catfish genus Encheloclarias Myers, 1937 (Actinopterygii: Siluriformes: Clariidae): Evolutionary and conservation implications

The phylogenetic position of the Southeast Asian catfish genus Encheloclarias Myers, 1937 within the family Clariidae is inferred herein using three mitochondrial nucleotide markers: cytochrome b, cytochrome oxidase subunit I, and 16S rRNA genes. We found that Encheloclarias is neither exclusively related to the African taxa having extended neural spines posterior to the dorsal fin (Encheloclarias shares with some of these taxa the presence of an adipose fin, as opposed to absent in all other clariid taxa) nor to the Asian species of the genus Clarias Scopoli, 1777. Encheloclarias is hypothesized to be the sister group of all other clariids, except Horaglanis Menon, 1951. The inferred position of Encheloclarias confirms that the adipose fin in this genus has an evolutionary origin independent to that of the adipose fin found in some African clariids. Encheloclarias is not only ecologically remarkable, being adapted to acidic peat swamps in Southeast Asia, but it is also an ancient lineage sheltering in these habitats. However, the precise timing of the colonization of peat swamps by Encheloclarias remains to be investigated. The phylogenetic position of Encheloclarias further underscores the importance of studying and protecting the remaining peat swamp habitats in Southeast Asia and their distinctive aquatic fauna.

Megaselia scalaris and Senotainia tricuspis Infesting Apis mellifera: Detection by Quantitative PCR, Genotyping, and Involvement in the Transmission of Microbial Pathogens.

The Megaselia scalaris and Senotainia tricuspis parasitoid flies of the honeybee Apis mellifera were found to infest apiaries of different European and Mediterranean countries but their prevalence and impact on apiary health are little known. Therefore, in this study, quantitative PCR (qPCR)-based methods were developed for their rapid detection directly in hive matrices. The newly developed qPCR assays were targeted at the mitochondrial cytochrome oxidase subunit I (COI) gene for the M. scalaris and the cytochrome B (cytB) gene for the S. tricuspis. The tests were preliminarily applied to 64 samples of adult honeybees and hive debris collected in the Abruzzo and Molise regions, Central Italy, and the Republic of Kosovo showing that both flies occur in the two countries and more frequently in Italy. The positive apiaries in Italy were re-sampled by capturing viable forager bees and isolating emerging flies to carry out the genotyping and analyses aimed at defining if these flies can transmit honeybee pathogens. Genotyping based on the COI and cytB gene sequencing for M. scalaris and S. tricuspis, respectively, identified one S. tricuspis genotype and diverse genotypes of M. scalaris highly similar to those from distant countries. Some fly isolates harbored the DNA or RNA of honeybee microbial pathogens Paenibacillus larvae, deformed wing viruses A and B (DWVA and B), black queen cell virus (BQCV), chronic paralysis virus (CBPV), and Nosema ceranae. The results indicated that these parasites should be efficiently controlled in apiaries by using rapid detection methods to facilitate the large screening studies and early detection.

Integrative morphological, cytogenetic and molecular characterization of the Andean climbing catfish Astroblepus mindoensis (Regan, 1916) (Siluriformes:Astroblepidae).

Astroblepus species, commonly known as Andean climbing catfish, exhibit a unique challenge in species delimitation, leading to ongoing taxonomic debates. Here we report data on Astroblepus mindoensis, a vulnerable species endemic to Ecuador, obtained by an integrative approach that includes cytogenetic analysis, molecular identification of the specimens, and recording of morphological and morphometric characters useful for species diagnosis. Thus, this study aimed to associate the karyotype data of the specimens analyzed with morphological and molecular characters, improving and expanding the existing taxonomic information, thus contributing to the systematics of the species. Our morphology results, unlike Regan's original description, which is brief and ambiguous, provide a more detailed morphometric and meristic description. Molecular phylogenetic reconstruction and genetic distance based on a fragment of the cytochrome c oxidase subunit I (COI) showed that our samples constitute a well-supported and monophyletic clade within the A. grixalvii species complex. The cytogenetic analysis identified distinct chromosomal markers, including a single cluster of major ribosomal genes (on chromosome pair 3) and of minor ribosomal genes (on chromosome pair 12) with their localization differing from those reported in other Astroblepus species analyzed. Additionally, the presence of a heteromorphic chromosome pair in males suggests the presence of an XX/XY sex-determination system that has not been identified in other congeneric species. Further investigation is necessary to determine if these chromosomes are associated with the accumulation of repeated sequences, as typically occurs with sex chromosomes, and to assess their presence in other species of the genus.

Morphological and molecular identification of freshwater eutardigrade Dactylobiotus parthenogeneticus (Bertolani, 1982) in the Greater Zab River of Kurdistan Region - Iraq.

Dactylobiotus parthenogeneticus is one of the widespread species of tardigrade all over the world. Tardigrades of this species were collected from the Greater Zab River in Erbil City-Iraq by filtering water of the river through a plankton net with a mesh of 45 µm pore. The samples were mounted on a slide with a cover slip and examined under the microscope to determine morphological characteristics and measurements. Based on these characters the species identified to be D. parthenogeneticus. To support this diagnosis, DNA barcoding techniques were applied to do molecular analysis and sequencing on the cytochrome oxidase subunit I (COI) gene. The sequence was subjected to the GenBank database of NCBI and recorded with the accession number PP140905. The result of the sequencing and molecular analysis of the cytochrome oxidase subunit I (COI) gene confirmed to be the same species diagnosed by relying upon morphological characters. This study represents one of the pioneer researches and documents on tardigrades and found D. parthenogeneticus for the first time in the Greater Zab River in Kurdistan, North of Iraq. Tardigrades play a magnificent role in different trophic levels and can be utilized as an indicator of ecosystem health.

Hidden species diversity in the Enteromius Cope, 1867 (Teleostei: Cyprinidae) from the Aruwimi basin (Middle Congo) in the Okapi Wildlife Reserve (Democratic Republic of the Congo).

Two new African minnow species, Enteromius cerinus sp. nov. and Enteromius ruforum sp. nov., are described for science from the Angadiko River, a left-bank sub-affluent of first order of the Nepoko River, draining the north-eastern part of the Okapi Wildlife Reserve (OWR). Both new species belong to the group of Enteromius for which the last unbranched dorsal-fin ray is flexible and underrated. Within this morphological group, both are most similar to Enteromius kamolondoensis, especially in life colour pattern characteristics. However, Enteromius cerinus sp. nov. differs from E. kamolondoensis by its low number of circumpeduncular scales, 10-11 (vs. 12), low maximum body depth, 22.8%-25.7% standard length (Ls) (vs. 26.1%-30.0%), and long anterior and posterior barbel lengths, 32.6%-35.3% head length (LH) (vs. 23.6%-27.2%) and 41.6%-43.9% LH (vs. 30.3%-34.9%), respectively. Further, E. ruforum sp. nov. is also easily distinguished from E. kamolondoensis by its high maximum body depth, 30.6%-33.3% Ls (vs. 26.1%-30.0%), and small, isometric, eye diameter, 26.2%-28.0% LH (vs. 29.1%-31.9%). A barcoding study (mtDNA, cytochrome oxidase subunit I [COI]) revealed that specimens of both new species form lineages well differentiated from those of other available species. As such, (i) E. cerinus sp. nov. diverges from E. kamolondoensis by a K2P genetic distance (GD) of 10.3% and (ii) E. ruforum sp. nov. by a K2P GD of 11.2%. To the present day, the fish fauna of the left-bank sub-affluents of the Nepoko River, in general, remains poorly known or undocumented. Unfortunately, at the same time, multiple anthropogenic impacts are affecting this fauna, such as (i) the destruction of habitats along the river banks for agriculture and fishing and (ii) the use of illegal fishing practices, such as fishing with plant-based ichthyotoxins during ecopage, which is combined with dam building. As a result of the demographic growth, this ecopage results in overfishing and thus is threatening both new species in particular, but all other co-occurring fish species as well. Both new species, E. cerinus sp. nov. and E. ruforum sp. nov., should thus be considered Vulnerable (VU) according to IUCN criterion D2. It is therefore hoped that their discovery highlights the urgent need for a better protection and further in situ exploration of the reserve's freshwater (fish) biodiversity, in general, and that of those small sub-affluents, in particular.

Phylogeography of the Sinica Group of Macaques in the Himalayas: Taxonomic and Evolutionary Implications.

Owing to the taxonomic incongruence between the morphological features and genetic relationships of the sinica group of macaques (genus Macaca), the taxonomy of this macaque group has remained inconclusive. We aimed to resolve the taxonomic quandary and improve our understanding of the historical biogeography of the group by including macaque DNA samples from previously unsampled areas in the Himalayas. We sequenced and analyzed three mitochondrial DNA loci [cytochrome b (CYTB), cytochrome oxidase subunit 1 (COI) and D-loop; 2898 bp] for sequence polymorphism, phylogenetics, species delimitation, and ancestral area reconstruction. We confirmed the occurrence of Arunachal macaque (Macaca munzala) on the southern slopes of the Eastern Himalayas in the Xizang Zizhiqu (Tibet Autonomous Region) of China. The results revealed that the sinica group of macaques is a parapatric species group composed of seven distinct species. Phylogenetic and species delimitation analyses revealed that the two previously considered subspecies of Assamese macaques (the eastern subspecies M. assamensis assamensis and the western subspecies M. a. pelops) are two distinct species. The eastern Assamese macaque is a sister species to the Tibetan macaque, whereas the western Assamese macaque and Arunachal macaque are the closest genetic sister species. The sinica group of macaques underwent five vicariance and seven dispersal radiations in the past, which mainly coincided with the Quaternary climatic oscillations between the late Pliocene and the late Pleistocene. By integrating our phylogenetic and ancestral area reconstruction results with findings from previous paleontological and molecular studies, we propose a robust hypothesis about the phylogeography of the sinica group of macaques.

DNA Barcoding using Cytochrome C Oxidase Subunit I (COI) Reveals Wildlife Consumption of Malayan Tapir (Tapirus indicus) and Dusky Leaf Monkey (Trachypithecus obscurus) by the Senoi (Semoq Beri) Tribe in Peninsular Malaysia

Abstract Malaysia, a culturally diverse nation, encompasses various ethnicities, including the Orang Asli, the region’s aboriginal people. Among the Orang Asli tribes in Peninsular Malaysia, the Senoi constitute the largest demographic, followed by the Proto-Malay and Negrito groups, each comprising six distinct subtribes. Traditional methods, such as surveys and interviews, have been instrumental in understanding wildlife consumption practices among indigenous communities like the Senoi. However, they may not always provide accurate and comprehensive data. The adoption of molecular techniques, such as DNA barcoding, presents a promising avenue for enhancing the accuracy and reliability of wildlife consumption studies. This study investigates wildlife consumption practices among the Senoi tribe, particularly the Semoq Beri subgroup in Maran, Pahang, using DNA barcoding that focuses on the Cytochrome C Oxidase Subunit I (COI) gene. Following the collection of biological samples with consent from Semoq Beri villagers, DNA extraction and PCR amplification were performed using established protocols. Subsequently, phylogenetic analysis was conducted to identify wildlife species consumed by the tribe. From the DNA barcoding analysis, two wildlife species were successfully detected: including the Malayan Tapir (Tapirus indicus) and the dusky leaf monkey (Trachypithecus obscurus), commonly consumed by the Semoq Beri tribe. Despite their status conservation, the findings suggest that the Semoq Beri tribe’s hunting practices are relatively sustainable, as they hunt only for subsistence purposes and in small quantities. The study emphasizes the significance of incorporating molecular techniques alongside conventional methods to accurately assess wildlife consumption patterns among indigenous communities. The findings highlight the necessity of collaborative approaches involving indigenous peoples, government agencies, and conservation organizations to preserve traditional knowledge, safeguard wildlife resources, and promote the sustainable coexistence of indigenous communities and biodiversity.

DNA barcoding and cryptic diversity in fishes from the Ili River Valley in China, Xinjiang.

The Ili River Valley, located in the northwest of China, serves as a vital repository for fish genetic resources. Its extensive water network and diverse climate have given rise to a unique fish composition and endemic species. In this study, we collected the cytochrome c oxidase subunit I (COI) sequences from 660 fish specimens in the Ili River Valley. The effectiveness of DNA barcoding in identifying fish species in the area was assessed by examining genetic distances, constructing phylogenetic trees, and performing ABGD (Automatic Barcode Gap Discovery) analyses, among other methods. In total, 20 species were identified, including one unidentified species (Silurus sp.). Except for Silurus asotus and Hypophthalmichthys molitrix (only one sample), the maximum intraspecific genetic distance among the remaining species was smaller than the minimum interspecific distance, which proves that the species exhibit obvious barcode gaps. In the Neighbor-Joining trees, 20 species formed separate monophyletic branches. According to ABGD analysis, 660 sequences were categorized into 19 Operational Taxonomic Units, with Silurus sp. and S. asotus grouped into a single OTU. The Silurus in this study exhibits shared haplotypes and significant genetic divergence, suggesting the potential presence of cryptic species. Furthermore, the nucleotide diversity across all species fell below the threshold level, indicating that the local fish population is gradually declining. In conclusion, this study has demonstrated the effectiveness of DNA barcoding in identifying fish species in the Ili River Valley, providing valuable data to support the conservation of local fish resources.

Two Palaearctic species of Orthonevra (Diptera: Syrphidae) under the name O. brevicornis

During studying European material of Orthonevra Macquart, 1829 the presence of two widespread species so far interpreted as Orthonevra brevicornis (Loew, 1843) has been discovered. One species occurs from Central Europe into Transcaucasia and agrees with the taxon O. brevicornis of Loew (1843). The second species, O. atlantica Żóralski & Van de Meutter sp. nov., has its main distribution range in the Atlantic parts of Europe and is described here. We provide a redescription of O. brevicornis and designate a neotype from the type locality (Poland, Posen [= Poznań] vicinity). The most important characters for distinguishing males of these two closely related species are in the structures of the terminalia. A diagnosis and identification key to European black-legged Orthonevra species is given as well as new sequences of the cytochrome c oxidase subunit I (COI) of mitochondrial DNA (mtDNA), also known as DNA barcodes, for most of the species of this group. Some new information and changes to the known ranges of Orthonevra species are provided as a result of this revisionary work: O. frontalis (Loew, 1843) is removed from the list of species occurring in Poland; O. gemmula Violovitsh, 1979 is confirmed from Hungary; O. incisa (Loew, 1843) is confirmed from its locus typicus (Poland, Posen vicinity); and O. montana Vujić, 1999 is reported from Poland and Austria for the first time and confirmed for Germany. An explanation for some previous records published as O. plumbago (Loew, 1840) is also given.

Anthropogenic activities along the Lake Nyasa catchments alter the habitat and genetic diversity of a Lake Salmon, Opsaridium microlepis

The Lake Salmon, Opsaridium microlepis is an economically important fish along the Lake Nyasa. However, the species is under threat of extinction due to anthropogenic activities such as agriculture, mining, urbanization, and deforestation. Consequently, the fish species is currently regarded as a threatened species, and the International Union for Conservation of Nature (IUCN) has red-listed the species due to an apparent decline in abundance. The current study assesses the potential impact of human activities on the genetic diversity of O. microlepis using partial mitochondrial cytochrome oxidase subunit I (COI) sequences and microsatellite loci. The results indicate that genetic diversity is lower in the areas affected by human activities compared to relatively pristine areas. The results from this study may suggest that human activities taking place in the catchments are likely to contribute to the alteration of the genetic diversity of O. microlepis species. Thus, immediate measure is required to control anthropogenic activities in the areas to protect the species and other aquatic organisms from possible threats of extinction.

Combating Illegal Trade of Monitor Lizards (Varanus spp) in Malaysia through DNA Barcoding Applications

Abstract Varanids, known as monitor lizards are traded as pet animal commodities and demand for skin trade especially in Southeast Asian countries. Given the significant demand in the international trade, accurate species identification is imperative for Varanids particularly endangered species to prevent misidentification and fraud in marketplaces as Varanids species exhibit morphological similarities. Therefore, advanced molecular technique is vital to facilitate accurate species identification especially for closely related species. Besides, few research have used cytochrome oxidase subunit I (COI) to track the genetic and phylogenetic analysis of Varanids. In this study, the COI mitochondrial DNA region was tested as a molecular marker for species identification of Malaysia monitor lizards using the DNA barcode. Two species were successfully identified from eight samples from Pantai Penyabong, Mersing, Johor which are V. salvator and V. nebulosus based on phylogenetic analysis (Neighbor-Joining, Maximum Parsimony and Bayesian Tree). This study showed that by using their relative genetic divergence and evolutionary links, DNA barcodes can aid in the species identification through molecular technique. Short sequences can be used to identify closely related species, and the possibility of species misidentification among the study’s samples should be taken into account. DNA barcoding techniques should be widely practised especially in wildlife forensics to facilitate precise wildlife identification and improve the efficiencies in combatting illegal wildlife trade in Malaysia.

Combined effects of thermal environment and gene regulation on metabolic enzyme activities of major metabolic tissues in a winter-breeding amphibian

Variations in thermal environments can provoke diverse physiological responses in amphibians. Despite extensive studies on the thermal sensitivity of amphibian metabolic physiology, including enzyme activity at different temperatures, the rationale for selecting specific metabolic enzymes and their relationship with gene expression remains unclear. Cytochrome c oxidase (CCO), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) are key metabolic enzymes within the primary metabolic regulatory tissues of animals. Through a comparative analysis of the effects of two different thermal conditions (12 and 18 °C) on the activities and mRNA expression levels of these enzymes within the kidney and liver tissues of a winter-breeding amphibian (Leptobrachium liui), with the field group during the breeding season as the control, we provide insights into the interplay between temperature and gene expression. The mRNA levels of CCO subunits 1 (cox1), 2 (cox2), and 3 (cox3), and LDH subunit A (ldha) were significantly higher in the kidney than in the liver of all individuals. High-temperature acclimation resulted in significantly decreased expression levels of cox1-3, ldha, and SDH complex flavoprotein subunit A (sdha) in the kidney. In the liver, the expression levels of sdha and ldha significantly reduced under high-temperature treatment, whereas cox3 expression increased. SDH and LDH activities displayed tissue-specific variations, while no significant differences in CCO activity were observed between tissues. CCO, SDH, and LDH activities in both liver and kidney tissues significantly declined after high-temperature acclimation, but simultaneously increased with up-regulated gene expression, indicating that the thermal environment and corresponding gene expression combined affect the activities of these metabolic enzymes. In conclusion, the thermal environment is a key factor affecting the physiological and biochemical responses of L. liui. Prolonged exposure to high temperatures during the breeding season could inhibit the activity of primary metabolic enzymes in the winter-breeding amphibian.

Northward migration past the nearctic biogeographical divide; neotropical Gyrodactylus spp. infecting Astyanax have crossed the Trans-Mexican Volcanic Belt

The neotropical fish genus Astyanax (Characidae) and its associated helminths migrated northward from South America following the Great American Biotic Interchange (GABI): ca. 150 Astyanax spp. are found throughout South and Central America, up to the Mexico-USA border. Most characids are distributed south of the Trans-Mexican Volcanic Belt (TMVB), which bisects the country and represents a major transition zone between the neotropical and nearctic realms. Here, we characterize parasites of the monogenean genus Gyrodactylus infecting Astyanax spp. in Mexico: Astyanax aeneus south of the TMBV, Astyanax mexicanus north of it. Based on morphological, phylogenetic (internal transcribed spacer (ITS) and cytochrome oxidase subunit II (cox 2)) and statistical analyses of morphometric data, we confirmed the validity of Gyrodactylus pakan and Gyrodactylus teken, and erected two new species, Gyrodactylus aphaa n. sp. and Gyrodactylus ricardoi n. sp. These four gyrodactylids are part of a complex of morphologically cryptic species, which are phylogenetically closely related to each other, and sister species to Gyrodactylus carolinae and Gyrodactylus heteracanthus, parasites of characins in Brazil. Four gyrodactylid lineages (G. pakan, G. ricardoi n. sp., G. teken, Gyrodactylus sp. A) are distributed north of the TMVB; G. pakan is also widely distributed south of the TMVB, together with G. aphaa n. sp. Based on the ITS phylogeny, Brazilian parasites form a sister clade to all Mexican gyrodactylids, whose derived clades are distributed in progressively more northerly latitudes in Mexico – the three most-derived species north of the TMVB. This would suggest that gyrodactylid species diverged gradually, presumably as their characid fish hosts colonized and adapted to new environments north of the TMVB.

A NEW SPECIES OF ACANTHOBOTHRIUM (CESTODA: ONCHOPROTEOCEPHALIDEA), PARASITE OF THE GIANT ELECTRIC RAY NARCINE ENTEMEDOR JORDAN AND STARKS, 1895 (BATOIDEA: TORPEDINIFORMES) FROM MEXICO.

Spiral valves from specimens of the giant electric ray Narcine entemedor Jordan & Starks, 1895 were examined in search of tapeworms at 2 localities of the Mexican tropical Pacific Ocean. Acanthobothrium oceguerai n. sp. is described herein based on material from Ventanilla, Oaxaca and from Acapulco Bay, Guerrero. The new species is a category 6 species, distinguished by being apolytic, retaining proglottids on the strobila until they are gravid, having strobila of 166-322 proglottids, having a small scolex and very long bothridia relative to the scolex, and having abaxial prongs that are short and thin in comparison to the axial prongs, which are longer and more robust. Acanthobothrium oceguerai n. sp. can be differentiated from other members of category 6 by the hooks, which are shorter, more robust, and smaller than those of the other members of this category. The phylogenetic analysis based on the 28S rRNA locus placed Acanthobothrium oceguerai n. sp. as sister to an unidentified species of larval Acanthobothrium from Philadelphia, Pennsylvania. In addition, sequences of the mitochondrial cytochrome oxidase subunit I gene and nuclear 18S rDNA were generated to provide support for future taxon sampling. Acanthobothrium oceguerai n. sp. is the fifth species of cestode reported from N. entemedor in the tropical eastern Pacific.