Southeast Asian Species Research Articles

Setting the priority medicinal plants for conservation in Indonesia

Setting priority species for conservation planning in a large and biodiverse country such as Indonesia is crucial. At least 80% of the medicinal plant species in South East Asia can be found in Indonesia, whether they are native or introduced. However, their conservation is currently ineffective due to limited human and financial resources. By examining factors such as species' occurrence status, rarity and part of the plant harvested, the various Indonesian medicinal plant species can be prioritised for conservation planning. In this study, various threatened plant species have been included in the priority list as well as those listed in related legislation. Some 233 species within 161 genera and 71 families are recommended for prioritisation. An inventory of these priority species was produced presenting compiled data including vernacular names, plant habit, harvested plant part, uses, distribution, whether it is conserved ex situ, and their DNA barcoding. Significantly 41.20% of priority species have no information on their current conservation status in either in situ or ex situ national or international genebanks.

Establishment of hematopoietic tissue primary cell cultures from the giant freshwater prawn Macrobrachium rosenbergii.

The giant freshwater prawn Macrobrachium rosenbergii is one of the most important aquaculture species in Southeast Asia. In this study, in vitro culture of its hematopoietic tissue cells was achieved and characterized for use as a tool to study its pathogens that cause major farm losses. By transmission electron microscopy, the ultrastructure of the primary culture cells was similar to that of cells lining intact hematopoietic tissue lobes. Proliferating cell nuclear antigen (PCNA) (a marker for hematopoietic stem cell proliferation) was detected in some of the cultured cells by polymerase chain reaction (PCR) testing and flow cytometry. Using a specific staining method to detect phenoloxidase activity and using PCR to detect expression markers for semigranular and granular hemocytes (e.g., prophenoloxidase activating enzyme and prophenoloxidase) revealed that some of the primary cells were able to differentiate into mature hemocytes within 24h. These results showed that some cells in the cultures were hematopoietic stem cells that could be used to study other interesting research topics (e.g. host pathogen interactions and development of an immortal hematopoietic stem cell line).

On Hydrangea peruviana, an endangered species from Ecuador, and Hydrangea oerstedii, very common in Costa Rica and Panama, and seven threatened Central and South American Hydrangeas, which have been confounded with these.

Hydrangea section Cornidia, currently consisting of 19 accepted taxa, occurs from Mexico to Chile and Argentina, with one species in southeast Asia. Its representatives are root-climbing lianas which may grow up to 60 m high in the tree canopy of temperate to (sub)tropical forests. Our extensive field work throughout its distribution area, study of herbarium specimens and ongoing molecular studies have resulted in the discovery of species new to science, as well as new insights into the circumscription of many taxa. We here present amended descriptions for seven Hydrangea species of Central and South America and discuss the taxonomical situation of two Colombian Hydrangeas, including an identification key, illustrations, and distribution maps. Field work was carried out in Costa Rica, Panama, Ecuador and Peru, including exploration in areas where the genus had not been collected before. These specimens and observations were complemented with the study of specimens of 41 herbaria of North, Central and South America, as well as Europe. Detailed morphological studies of all species were carried out, based on living plants in their natural habitat, as well as on dried specimens from our own collections and all available herbarium material. Type material was studied in detail for all species concerned. Based on an extensive number of morphological characters, combined with distribution patterns, phenological differences and ecological preferences, including molecular data in most cases, Hydrangea peruviana and H. oerstedii are clearly distinct taxa, as well as the other seven species mentioned here, which had been synonymized with either of these two species. The present study results in the recognition of 26 species in section Cornidia and exemplifies the urgent need for profound taxonomic studies in plants, as in many families we do not dispose of well-circumscribed units for conservation to mitigate the already occurring unprecedented loss of biodiversity.

Determination of biosafety of the antibiotic oxytetracycline hydrochloride in Pangasianodon hypophthalmus

Pangasianodon hypophthalmus is one of the most important aquaculture species in Southeast Asia, with a significant contribution to the world fish basket. Like other crops, the striped catfish suffers from bacterial diseases that demand the use of antibiotics. The present study has evaluated the safety of oxytetracycline, one of the approved and commonly used antibiotics, in this species. Juvenile stages of the fish (31.16 ± 1.03 g) were administered with the antibiotic in feed at the dose rate of 80–800 mg kg−1 body weight daily for 30 days, followed by 10 days of withdrawal observation. Fish health was assessed by the study of behaviour and feed intake, haematology, blood biochemistry, and histopathology. Results showed that up to 30 days of antibiotic treatment resulted in no significant toxic effects in terms of behaviour and fish mortality. However, fish suffered from reduced feed intake and hepatotoxicity evidenced by proliferative and degenerative changes of hepatocytes, and increase in AST and ALT enzyme activities, especially in 400–800 mg kg−1 doses which, however, recovered after withdrawal of the drug. Although few fish died from a bacterial infection at the lowest concentration of the drug used, fish were able to mount adaptive physiological responses best at 80 mg kg−1 fish dosage. The study establishes that in-feed administration of the antibiotic oxytetracycline @ 80 mg kg−1 fish biomass is safe for therapeutic use in P. hypophthalmus.

Demographic History and Genomic Response to Environmental Changes in a Rapid Radiation of Wild Rats.

For organisms to survive and prosper in a harsh environment, particularly under rapid climate change, poses tremendous challenges. Recent studies have highlighted the continued loss of megafauna in terrestrial ecosystems and the subsequent surge of small mammals, such as rodents, bats, lagomorphs, and insectivores. However, the ecological partitioning of these animals will likely lead to large variation in their responses to environmental change. In the present study, we investigated the evolutionary history and genetic adaptations of white-bellied rats (Niviventer Marshall, 1976), which are widespread in the natural terrestrial ecosystems in Asia but also known as important zoonotic pathogen vectors and transmitters. The southeastern Qinghai-Tibet Plateau was inferred as the origin center of this genus, with parallel diversification in temperate and tropical niches. Demographic history analyses from mitochondrial and nuclear sequences of Niviventer demonstrated population size increases and range expansion for species in Southeast Asia, and habitat generalists elsewhere. Unexpectedly, population increases were seen in N. eha, which inhabits the highest elevation among Niviventer species. Genome scans of nuclear exons revealed that among the congeneric species, N. eha has the largest number of positively selected genes. Protein functions of these genes are mainly related to olfaction, taste, and tumor suppression. Extensive genetic modification presents a major strategy in response to global changes in these alpine species.

Isolation and Characterization of Fifteen Microsatellite Loci for the Use in Breeding of Gmelina arborea Roxb. (Lamiaceae)

Gmelina arborea (melina) is a valuable tree species throughout tropical areas, and there are extensive commercial plantations of this species in Southeast Asia, West Africa, and Latin America. As part of a research program for the genetic improvement and management of G. arborea at Instituto Tecn´ologico de Costa Rica, we developed, validated, and optimized fifteen microsatellite loci. We used 23 clones belonging to five different companies currently using clonal selection to manage their commercial plantations. Our results showed that all fifteen loci were polymorphic and together had 75 alleles (2-7 alleles/locus). We also found that eleven loci showed lower heterozygosity than expected under Hardy-Weinberg equilibrium (HWE). We calculated the genetic similarity among all clone pairs using the number of shared alleles to examine the potential of these loci for clone discrimination. Overall, pairwise similarity among clones ranged from 0.36 to 0.83, and our findings also showed that clones from the same commercial plantation tended to be more similar to each other than to clones from other plantations. These microsatellite loci will contribute toward the characterization of the genetic diversity, the identification of elite clone lines for timber production, and breeding and adequate management of commercial plantations of G. arborea.

Hypothermal stress-induced salinity-dependent oxidative stress and apoptosis in the livers of euryhaline milkfish, Chanos chanos

Water temperature is one of the key environmental factors affecting the physiological responses of fish, hence it becomes a significant concern for aquaculture fisheries. The euryhaline milkfish, Chanos chanos, one of the major aquaculture species in Southeast Asia, can be cultured in ponds of different salinities ranging from fresh water (FW) to sea water (SW). Being a tropical species, high mortality occurs in cultured milkfish after a cold snap in winter, leading to a huge economic loss. In the present study, we studied salinity effects on mechanisms underlying hypothermal tolerance in milkfish using various molecular and physiological approaches. At low temperatures, FW milkfish were found to have poorer cold-tolerance ability and more oxidative stress than SW milkfish. In addition, milkfish hepatocytes exhibited apoptosis induced via an extrinsic or intrinsic pathway, indicating the source of oxidative stress. This study further revealed that under low-temperature acclimation, more hepatocytes were shrunk and showed positive response to terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining in FW milkfish than in SW milkfish. The caspase-3 activity was up-regulated, which, in turn induced apoptosis via an extrinsic pathway in the hepatocytes of FW milkfish under hypothermal stress. Although the enzymatic antioxidant mechanisms were up-regulated to neutralize oxidative stress, apoptosis was still observed in the hepatocytes of FW milkfish under hypothermal stress. On the other hand, the hepatocytes of SW milkfish under identical hypothermal conditions showed no redox imbalance and apoptotic responses. Overall, this study suggests a hypothermal FW environment induces oxidative stress and apoptosis in hepatocytes and impairs liver functions that may lead to cold intolerance in milkfish.

Taxonomic status of genera Nodularia, Middendorffinaia and Inversiunio (Bivalvia: Unionidae) from South-East Asia: morphometric, genetic and GenBank data

Recent investigations of East Asian freshwater mussel genera Nodularia, Middendorffinaia and Inversiunio confirmed validity of the taxa, while their composition and taxonomic uncertainty concerning classification of these genera within a specific subfamily are still in question. The aim of the present study is to clarify the taxonomy and systematics of Nodularia and Middendorffinaia genera from the Russian Far East and Inversiunio from Japan, using a multiple dataset approach that combines morphology of glochidia, detailed conchological analyses with morphometry of adult and glochidial shells, and a molecular technique involving COI barcoding marker. As a result, three genetically distinct and highly divergent lineages were recognized confirming the existence of three distinct genera. The existence of five Nodularia species in Southeast Asia is shown. One of the sequences is shown to be incorrectly assigned to N. jourdyi, while in fact it also represents N. douglasiae, according to the BIN system. Existence of a single Nodularia species, namely N. douglasiae, and a single Middendorffinaia species, namely M. mongolica, in the Russian Far East is supported. We conclude that so-called comparatory species Nodularia amurensis, N. schrencki, and N. vladivostokensis are junior synonyms of the species Nodularia douglasiae; the comparatory species Middendorffinaia ussuriensis and M. dulkeitiana are junior synonyms of the species Middendorffinaia mongolica. Within Inversiunio specimens from Japan four species were recognized based on types of glochidial microsculpture of shells and genetic data. Gene sequences of Inversiunio verrucosus, endemic to the Seomjingang River basin in South Korea, and I. yanagawensis from Kyushu Island in Japan are very similar and they can be regarded as the same species, with Inversiunio verrucosus as a junior synonym of Inversiunio yanagawensis. Mussels from Honshu Island first referred to I. yanagawensis are shown to be a separate species.

Cytotoxicity of Snake Venoms and Cytotoxins From Two Southeast Asian Cobras (Naja sumatrana, Naja kaouthia): Exploration of Anticancer Potential, Selectivity, and Cell Death Mechanism.

Venoms of cobras (Naja spp.) contain high abundances of cytotoxins, which contribute to tissue necrosis in cobra envenomation. The tissue-necrotizing activity of cobra cytotoxins, nevertheless, indicates anticancer potentials. This study set to explore the anticancer properties of the venoms and cytotoxins from Naja sumatrana (equatorial spitting cobra) and Naja kaouthia (monocled cobra), two highly venomous species in Southeast Asia. The cytotoxicity, selectivity, and cell death mechanisms of their venoms and cytotoxins (NS-CTX from N. sumatrana: NS-CTX; N. kaouthia: NK-CTX) were elucidated in human lung (A549), prostate (PC-3), and breast (MCF-7) cancer cell lines. Cytotoxins were purified through a sequential fractionation approach using cation-exchange chromatography, followed by C18 reverse-phase high-performance liquid chromatography (HPLC) to homogeneity validated with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and identified by liquid chromatography-tandem mass spectrometry (LCMS/MS). The cobra venoms and their respective cytotoxins exhibited concentration-dependent growth inhibitory effects in all cell lines tested, with the cytotoxins being more potent compared to the corresponding whole venoms. NS-CTX and NK-CTX are, respectively, P-type and S-type isoforms of cytotoxin, based on the amino acid sequences as per LCMS/MS analysis. Both cytotoxins exhibited differential cytotoxic effects in the cell lines tested, with NS-CTX (P-type cytotoxin) being significantly more potent in inhibiting the growth of the cancer cells. Both cytotoxins demonstrated promising selectivity only for the A549 lung cancer cell line (selectivity index = 2.17 and 2.26, respectively) but not in prostate (PC-3) and breast (MCF-7) cancer cell lines (selectivity index < 1). Flow cytometry revealed that the A549 lung cancer cells treated with NS-CTX and NK-CTX underwent necrosis predominantly. Meanwhile, the cytotoxins induced mainly caspase-independent late apoptosis in the prostate (PC-3) and breast (MCF-7) cancer cells lines but lacked selectivity. The findings revealed the limitations and challenges that could be faced during the development of new cancer therapy from cobra cytotoxins, notwithstanding their potent anticancer effects. Further studies should aim to overcome these impediments to unleash the anticancer potentials of the cytotoxins.

A new record of the nocturnal orb-weaving spider Poltys illepidus (Araneae: Araneidae) from northern Thailand

The orb-weaving spider Poltys illepidus Koch 1843 is recorded from northern Thailand for the first time. The distribution of the species in Southeast Asia is extended northwest. The morphotype is characterized by an unusual small accessory protuberance on the carapace which is described and illustrated as a median anterior process without apparent function. Keywords: arachnid, biogeography, distribution, morphotype, Southeast Asia

Owston’s civet Chrotogale owstoni: a priority for conservation breeding

Owston’s civet Chrotogale owstoni is categorized as Endangered on The IUCN Red List of Threatened Species. The species is the only member of the genus Chrotogale and is restricted to Vietnam, Lao PDR and southern China. Its restricted distribution, taxonomic status as the sole member of its genus, declining conservation status and the known absence of any effective protection within its range make the Owston’s civet a global priority for carnivore conservation. In April 2019, 57 stakeholders, including civil society organizations, zoos from Europe and the region, representatives of the International Union for Conservation of Nature (IUCN) Species Survival Commission (SSC) and the Vietnamese government, gathered in Hanoi, Vietnam, to identify what priority in situ and ex situ actions are needed to avert the extinction of Owston’s civet. The result was the development of a 10 year conservation strategy for this species, part of which includes establishing a conservation‐breeding programme. Conservation‐breeding programmes for globally threatened species in South East Asia are on the whole failing because of poor planning, conflicting institutional objectives and lack of resources. This short report summarizes some of the outputs from the conservation‐planning workshop, and how zoos and other facilities can support the recovery of Owston’s civet in Indochina.

Wood and Pulping Properties Variation of Acacia crassicarpa A.Cunn. ex Benth. and Sampling Strategies for Accurate Phenotyping

Research Highlights: This study provides a comprehensive set of wood and pulping properties of Acacia crassicarpa A.Cunn. ex Benth. to assess variation and efficient sampling strategies for whole-tree level phenotyping. Background and Objectives: A. crassicarpa is an important tree species in Southeast Asia, with limited knowledge about its wood properties. The objective of this study was to characterize important wood properties and pulping performance of improved germplasm of the species. Furthermore, we investigated within-tree patterns of variation and evaluated the efficiency of phenotyping strategies. Materials and Methods: Second-generation progeny trials were studied, where forty 50-month-old trees were selected for destructive sampling and assessed for wood density, kraft pulp yield, α-cellulose, carbohydrate composition, and lignin content and composition (S/G ratio). We estimated the phenotypic correlations among traits determined within-tree longitudinal variation and its importance for whole-tree level phenotyping. Results: The mean whole-tree disc basic density was 481 kg/m3, and the screened kraft pulp yield was 53.8%. The reliabilities of each sampling position to predict whole-tree properties varied with different traits. For basic density, pulp yield, and glucose content, the ground-level sampling could reliably predict the whole-tree property. With near infrared reflectance spectroscopy predictions as an indirect measurement method for disc basic density, we verified reduced reliability values for breast height sampling but sufficiently correlated to allow accurate ranking and efficient selection of genotypes in a breeding program context. Conclusions: We demonstrated the quality of A. crassicarpa as a wood source for the pulping industry. The wood and pulping traits have high levels of phenotypic variation, and standing tree sampling strategies can be performed for both ranking and high-accuracy phenotyping purposes.

Molecular phylogeny of Asian pipesnakes, genus Cylindrophis Wagler, 1828 (Squamata: Cylindrophiidae), with the description of a new species from Myanmar.

Cylindrophis is a genus of secretive, semi-fossorial, non-venomous snakes comprising 14 species, characterized by a generally cylindrical body, uniform scales (with barely enlarged ventrals), and vestiges of pelvic and limb bones, the latter terminating in a claw lateral to the vent. We reconstructed a concatenated molecular phylogeny of seven taxa of Cylindrophis taxa based on one nuclear (R35) and two mitochondrial (16S, ND2) genes. Analyses recovered the Sri Lankan endemic C. maculatus as sister to all other sampled Cylindrophis. The mainland Southeast Asian species C. burmanus and C. jodiae form successive sister lineages to a monophyletic Wallacean island group containing C. boulengeri, C. isolepis, and C. yamdena. We also describe a new species of Cylindrophis, morphologically similar to C. burmanus, from Kachin State in northern Myanmar. Cylindrophis slowinskii sp. nov. is distinguished from all congeners by the following combination of characters: 19 dorsal scale rows at midbody, 216-220 ventrals, eight subcaudals, a dark venter with > 60 very narrow diffuse pale blotches, and a pale bar running along the posterior border of the prefrontals. In our phylogeny, the new species is strongly supported as the sister species of C. burmanus. It is the 15th currently recognised species in the genus, and the fourth from mainland Southeast Asia.

The synonymy of Parasesarma foresti (Rahayu &amp; Davie, 2002) with P. indiarum (Tweedie, 1940) (Decapoda, Brachyura, Sesarmidae)

Abstract Two Southeast Asian species of Parasesarma De Man, 1895, P. indiarum (Tweedie, 1940) and P. foresti (Rahayu &amp; Davie, 2002), have been reported to be morphologically and genetically very similar. Present comparisons of a range of material show the two species to be identical in male chelar dactylar tuberculation, pleon, and first gonopod characters, all typically used to separate close sibling species in this genus. CO1 genetic distances between the two putative species are also too low to be regarded as interspecific. Parasesarma foresti is thus here regarded as a junior subjective synonym of P. indiarum.

Mucosal responses of brown-marbled grouper Epinephelus fuscoguttatus (Forsskål, 1775) following intraperitoneal infection with Vibrio harveyi.

Groupers are popular aquaculture species in South-East Asia, but their cultivation is affected by infectious disease outbreaks. Mucosa-associated lymphoid tissues provide a first-line defence against pathogens; however, few studies are available relating to cellular or proteomic responses of mucosal immunity in grouper. Skin, gill and intestine were sampled from brown-marbled grouper Epinephelus fuscoguttatus (Forsskål, 1775) at 4 and 96hr post-infection (hpi) and 7days post-infection (dpi) following intraperitoneal infection with Vibrio harveyi, and stained with haematoxylin/eosin and Alcian Blue/periodic acid-Schiff. Skin mucus was analysed by 2D-gel electrophoresis, and proteins modulated by the bacterial infection identified. In the infected fish, significant increases in sacciform cells in skin and increased levels of nucleoside diphosphate kinase in mucus were detected at 4 hpi. At 96 hpi, goblet cells containing acidic mucins significantly increased in the intestine, while those containing mixed mucins increased in skin and gills of infected fish. Proteasome subunit alpha type-I and extracellular Cu/Zn superoxide dismutase levels also increased in mucus. Rodlet and mast cells did not appear to respond to the infection. Mucosal tissues of grouper appeared actively involved in response to Vibrio infection. This information may help future research on improving grouper health, production and vaccine development.

Liothrips species (Thysanoptera, Phlaeothripinae) from leaf-galls on Piper species in Southeast Asia and Australia.

Variation in colour and structure is re-considered amongst 19 species of Liothrips collected from leaf-galls on Piper vines in Asia. Gynaikothrips crassipes Karny, Liothrips aemulans Priesner, and Liothrips baccati Priesner are considered new synonyms of Liothrips chavicae (Zimmermann). Gynaikothrips karnyiBagnall is considered a new synonym of Liothrips mirabilis(Schmutz). Gynaikothrips kuwanai Moulton and Liothrips reynvaanae Priesner are considered new synonyms of Liothrips pallipes (Karny). Doubts are expressed about the significance of several further described species, and an identification key is provided to nine putative species. Despite the number of Liothrips species described from Piper, there is little evidence of thrips radiation on this plant genus, and the two most common species of the genus on Piper are probably not closely related.

Genetic evidence for the recognition of two allopatric species of Asian bronze featherback Notopterus (Teleostei, Osteoglossomorpha, Notopteridae)

The fish genus Notopterus Lacepède, 1800 (Notopteridae) currently includes only one species, the Asian bronze featherback Notopterus notopterus (Pallas, 1769). This common freshwater species is widely distributed in the Oriental region, from the Indus basin in the west, the Mekong basin in the east and Java Island in the south. To examine the phylogeographic structure of N. notopterus across its range, we analysed 74 publicly available cytochrome oxidase I (COI) sequences, 72 of them determined from known-origin specimens, along with four newly-determined sequences from Peninsular Malaysian specimens. We found that N. notopterus is a complex of two allopatric species that diverge from each other by 7.5% mean p-distance. The first species is endemic to South Asia (from Indus basin to Ganga-Brahmaputra system), whereas the distribution of the second species is restricted to Southeast Asia. The exact limit between the distributions of these two species is not known, but it should fall somewhere between the Ganga-Brahmaputra and Salween basins, a region already identified as a major faunal boundary in the Oriental region. The name N. notopterus is retained for the Southeast Asian species, while the name Notopterus synurus (Bloch &amp;amp; Schneider, 1801) should be applied to the South Asian species. A comparative morphological study is needed to reveal the degree of morphological differentiation between the two species.

First record of Acanthosiphonia echinata (Rhodomelaceae, Rhodophyta) in the Mediterranean Sea, molecular and morphological characterization

AbstractIn this study we report the first finding of the red algaAcanthosiphonia echinatain the Mediterranean Sea. Specimens were identified using the DNA barcoding method and, in particular, the plastidialrbcL and the mitochondrial COI-5P markers. This species has been considered to be restricted to the western Atlantic and was reported in blooms from North Carolina to South Carolina. In 2015 the introduction of this species in Southeast Asia (Indonesia) was reported. Probably this taxon was introduced in the Mediterranean Sea from Indonesian populations associated with seaweed farming activities or hull fouling, via the western Atlantic-Mediterranean-Indonesia ship route.

Differential effects of hypothermal stress on lactate metabolism in fresh water- and seawater-acclimated milkfish, Chanos chanos

The milkfish Chanos chanos, an economically important cultured marine species in Southeast Asia, exhibits stenothermal and euryhaline characteristics and huge mortality usually occurs during extreme cold weather in winter. Under conditions beyond optimal temperatures, ectothermic species experience an increase in anaerobic glycolysis. To better understand the hypothermal acclimation response of this tropical species, the lactate metabolic profiles of freshwater (FW)- and seawater (SW)-acclimated milkfish were compared under control (optimal temperature; 28 °C) and hypothermal treatment (18 °C) conditions. In this study, the lactate dehydrogenase (LDH) isoform genes, ldha and ldhb, were identified in milkfish livers and muscles, respectively. The LDH is a bidirectional enzyme that triggered the conversion of pyruvate to lactate via anaerobic glycolysis as LDH exhibits the reductase activity (LDH-R), while via the reverse direction as LDH exhibits the oxidase activity (LDH-O). The hypothermal stress significantly upregulated the LDH-R activity in the muscles and the monocarboxylate transporter activity in both muscles and livers, of SW- and FW-acclimated milkfish. The levels of blood lactate, however, decreased in SW-acclimated milkfish. Under hypothermal stress, anaerobic metabolism increased in the muscles of both FW and SW individuals, whereas the liver of SW-acclimated milkfish showed better acute phase capacity to utilize blood lactate than FW-acclimated milkfish. Taken together, in the present study, the major functions of the bidirectional enzyme LDH were identified according to its LDH-O and LDH-R activities. Furthermore, environmental salinities were found to affect the acute anaerobic metabolic strategies of euryhaline teleosts under hypothermal stress and were correlated with their hypothermal tolerance ability.

Dataset for genome sequencing and de novo assembly of the Vietnamese bighead catfish (Clarias macrocephalus Günther, 1864).

Freshwater catfish of the genus Clarias, known as the airbreathing catfish, are widespread and important for food security through small scale inland fisheries and aquaculture. Limited genomic data are available for this important group of fishes. The bighead catfish (Clarias macrocephalus) is a commercial aquaculture species in southeast Asia used for aquaculture and threatened in its natural environment through habitat destruction, over-exploitation and competition from other introduced species of Clarias. Despite its commercial importance and threats to natural populations, public databases do not include any genomic data for C. macrocephalus. We present the first genomic data for the bighead catfish from Illumina sequencing. A total of 128 Gb of sequence data in paired-end 150 bp reads were assembled de novo, generating a final assembly of 883 Mbp contained in 27,833 scaffolds (N50 length: 80.8 kbp) with BUSCO completeness assessments of 96.3% and 87.6% based on metazoan and Actinopterygii ortholog datasets, respectively. Annotation of the genome predicted 21,124 gene sequences, which were assigned putative functions based on homology to existing protein sequences in public databases. Raw fastq reads and the final version of the genome assembly have been deposited in the NCBI (BioProject: PRJNA604477, WGS: JAAGKR000000000, SRA: SRR11188453). The complete C. macrocephalus mitochondrial genome was also recovered from the same sequence read dataset and is available on NCBI (accession: MT109097), representing the first mitogenome for this species. Lastly, we find an expansion of the mb and ora1 genes thought to be associated with adaptations to air-breathing and a semi-terrestrial life style in this genus of catfish.