Indo-Australian Region Research Articles

New record of the giant freshwater whipray from the Lesser Sunda region, Indonesia

Context The taxonomic nomenclature of species can change with the discovery of a distinct species. Such nomenclatural changes occurred for the giant freshwater whipray with the discovery of a similar species in the Indo-Australian region in 2008. Aims This paper reports a finding of the giant freshwater whipray in the Lesser Sunda region as the first confirmed record from the area. Methods The specimen was identified as the giant freshwater whipray based on its morphological features. Morphometric measurements were taken directly in the field and also based on the scale provided in the photographs. Key results The female specimen was recorded from the Alas Strait, West Nusa Tenggara Province, Indonesia on 20 July 2020. It was identified as Urogymnus cf. dalyensis due to its similar morphological characteristics with U. dalyensis from northern Australia but it had a shorter preoral snout and greater distance between the left and right fifth gill slits. Conclusions The occurrence of this species in the Lesser Sunda region may confuse U. dalyensis with the close relative from south-east Asia, U. polylepis. Implications This record may provide a link between the two species, either as a population structure of the same species or showing a clear separation between the two as distinct species.

Taxonomic study on selected species of stingless bees (Hymenoptera: Apidae: Meliponini) in Sulawesi Island, Indonesia

Abstract. Trianto M, Arisuryanti T, Purwanto H, Ubaidillah R. 2024. Taxonomic study on selected species of stingless bees (Hymenoptera: Apidae: Meliponini) in Sulawesi Island, Indonesia. Biodiversitas 25: 2290-2306. Stingless bees are strong candidates as alternative crop pollinators. They are found throughout the tropics, with the exception of the Pacific islands. There are three tropical regions in the world, namely the tropical Americas (Neotropic), Sub-Saharan Africa (Afrotropic), and Indoaustralian (Austroasiatic) region. In this research, we explored the morphological and morphometric characteristics of stingless bees in Sulawesi Island, Indonesia. The genera and species identification of stingless bees were based on morphological characters and coloration, such as the structure and color of the antenna, head, thorax, wing, leg and abdomen. Morphological and morphometric identification of 10 species of stingless bees consisting of five genera, namely the genera Heterotrigona, Homotrigona, Lepidotrigona, Tetragonula, and Wallacetrigona. The genus Tetragonula consists of six small species (<4 mm), namely T. biroi, T. clypearis, T. fuscobalteata, T. laeviceps, T. pagdeni, and T. sapiens. The genera Heterotrigona, Homotrigona, Lepidotrigona, and Wallacetrigona are a group of large stingless bees (>4 mm), each consisting of one species, namely H. itama, H. canifrons, L. terminata, and W. incisa. H. itama and H. canifrons are new records on Sulawesi Island. These species are found in Lore Lindu National Park (TNLL). Until 2023, these species were only found in Java, Kalimantan and Sumatra. This research can be used as a guide in the identification and validation of stingless bee species on Sulawesi Island.

A new species of Zaglyptogastra Ashmead (Hymenoptera: Braconidae: Braconinae) from Thailand

Zaglyptogastra Ashmead, 1900 was erected for a large, distinctive Braconinae wasp, Z. abbotti, collected in Lower Siam (Thailand) (Ashmead 1900). Although nine species are known from the Indo-Australian region, only three are recorded from mainland Indochina: Z. abbotti Ashmead, 1990 (Thailand), Z. vitalisi (Turner, 1919) (Thailand, Laos) and Z. vietnamica Long & Mai, 2015 (Vietnam) (El-Heneidy & Quicke, 1991; Long & Mai, 2015). In 2021, two further Asia species, Z. exilis Li, van Achterberg & Chen, 2021 and Z. tricolor Li, van Achterberg & Chen, 2021 were described from China (Li et al. 2021).

Four new species of Physaraia (Hymenoptera: Braconidae: Braconinae) from Thailand

Four new species of the genus Physaraia Shenefelt, 1978 (Hymenoptera: Braconidae) from Thailand are described and illustrated based on female specimens collected from the Malaise traps and aerial net, increasing the total number of Physaraia species of Indo-Australian region to six species; P. nanensis Chansri, Quicke Butcher, sp. nov., P. panhai Chansri, Quicke Butcher, sp. nov., P. sakaeratensis Chansri, Quicke Butcher, sp. nov., P. sinensis Quicke et al., 1997, P. sumatrana, Enderlein, 1905 and P. tigeri Chansri, Quicke Butcher, sp. nov. A checklist to the species known of Physaraia with their distribution and dichotomous key to accommodate the new species are provided.

Microbial communities associated with mounds of the Orange-footed scrubfowl Megapodius reinwardt.

Megapodius reinwardt, the orange-footed scrubfowl, belongs to a small family of birds that inhabits the Indo-Australian region. Megapodes are unique in incubating their eggs in mounds using heat from microbial decomposition of organic materials and solar radiation. Little is known about the microorganisms involved in the decomposition of organic matter in mounds. To determine the source of microbes in the mounds, we used 16S and 18S rRNA gene sequencing to characterize the microbial communities of mound soil, adjacent soil and scrubfowl faeces. We found that the microbial communities of scrubfowl faeces were substantially different from those of the mounds and surrounding soils, suggesting that scrubfowls probably do not use their faeces to inoculate their mounds although a few microbial sequence variants were present in both faeces and mound samples. Further, the mound microbial community structure was significantly different to the adjacent soils. For example, mounds had a high relative abundance of sequence variants belonging to Thermomonosporaceae, a thermophilic soil bacteria family able to degrade cellulose from plant residues. It is not clear whether members of Thermomonosporaceae disproportionately contribute to the generation of heat in the mound, or whether they simply thrive in the warm mound environment created by the metabolic activity of the mound microbial community. The lack of clarity in the literature between designations of heat-producing (thermogenic) and heat-thriving (thermophilic) microbes poses a challenge to understanding the role of specific bacteria and fungi in incubation.

Delimiting cryptic species within the brown-banded bamboo shark, Chiloscyllium punctatum in the Indo-Australian region with mitochondrial DNA and genome-wide SNP approaches

BackgroundDelimiting cryptic species in elasmobranchs is a major challenge in modern taxonomy due the lack of available phenotypic features. Employing stand-alone genetics in splitting a cryptic species may prove problematic for further studies and for implementing conservation management. In this study, we examined mitochondrial DNA and genome-wide nuclear single nucleotide polymorphisms (SNPs) in the brown-banded bambooshark, Chiloscyllium punctatum to evaluate potential cryptic species and the species-population boundary in the group.ResultsBoth mtDNA and SNP analyses showed potential delimitation within C. punctatum from the Indo-Australian region and consisted of four operational taxonomic units (OTUs), i.e. those from Indo-Malay region, the west coast of Sumatra, Lesser Sunda region, and the Australian region. Each OTU can be interpreted differently depending on available supporting information, either based on biological, ecological or geographical data. We found that SNP data provided more robust results than mtDNA data in determining the boundary between population and cryptic species.ConclusionTo split a cryptic species complex and erect new species based purely on the results of genetic analyses is not recommended. The designation of new species needs supportive diagnostic morphological characters that allow for species recognition, as an inability to recognise individuals in the field creates difficulties for future research, management for conservation and fisheries purposes. Moreover, we recommend that future studies use a comprehensive sampling regime that encompasses the full range of a species complex. This approach would increase the likelihood of identification of operational taxonomic units rather than resulting in an incorrect designation of new species.

Update on Phytochemical and Biological Studies on Rocaglate Derivatives from Aglaia Species

With about 120 species, Aglaia is one of the largest genera of the plant family Meliaceae (the mahogany plants). It is native to the tropical rainforests of the Indo-Australian region, ranging from India and Sri Lanka eastward to Polynesia and Micronesia. Various Aglaia species have been investigated since the 1960s for their phytochemical constituents and biological properties, with the cyclopenta[b]benzofurans (rocaglates or flavaglines) being of particular interest. Phytochemists, medicinal chemists, and biologists have conducted extensive research in establishing these secondary metabolites as potential lead compounds with antineoplastic and antiviral effects, among others. The varied biological properties of rocaglates can be attributed to their unusual structures and their ability to act as inhibitors of the eukaryotic translation initiation factor 4A (eIF4A), affecting protein translation. The present review provides an update on the recently reported phytochemical constituents of Aglaia species, focusing on rocaglate derivatives. Furthermore, laboratory work performed on investigating the biological activities of these chemical constituents is also covered.

Stingless bee honey, a novel source of trehalulose: a biologically active disaccharide with health benefits

Stingless bee (Meliponini) honey has long been considered a high-value functional food, but the perceived therapeutic value has lacked attribution to specific bioactive components. Examination of honey from five different stingless bee species across Neotropical and Indo-Australian regions has enabled for the first time the identification of the unusual disaccharide trehalulose as a major component representing between 13 and 44 g per 100 g of each of these honeys. Trehalulose is an isomer of sucrose with an unusual α-(1 → 1) glucose-fructose glycosidic linkage and known acariogenic and low glycemic index properties. NMR and UPLC-MS/MS analysis unambiguously confirmed the identity of trehalulose isolated from stingless bee honeys sourced across three continents, from Tetragonula carbonaria and Tetragonula hockingsi species in Australia, from Geniotrigona thoracica and Heterotrigona itama in Malaysia and from Tetragonisca angustula in Brazil. The previously unrecognised abundance of trehalulose in stingless bee honeys is concrete evidence that supports some of the reported health attributes of this product. This is the first identification of trehalulose as a major component within a food commodity. This study allows the exploration of the expanded use of stingless bee honey in foods and identifies a bioactive marker for authentication of this honey in associated food standards.

Chemical Cues Induced from Fly-Oviposition Mediate the Host-Seeking Behaviour of Fopius arisanus (Hymenoptera: Braconidae), an Effective Egg Parasitoid of Bactrocera dorsalis (Diptera: Tephritidae), within a Tritrophic Context.

Fopius arisanus is a solitary endoparasitoid that parasitizes a variety of tephritid species. Native to the Indo-Australian region, it is currently exploited worldwide as a biological control agent due to its exceptional efficiency in reducing pest populations. The efficiency of any biological control program is affected by the host location ability of the parasitoids. The present study used a Y-tube olfactometer to test the behavioural responses of female F. arisanus to four fruit species which had undergone different types of damages: undamaged, damaged through Bactrocera dorsalis ovipositioning (i.e., infested), or different levels of mechanical damage. Our results suggest that F. arisanus females were significantly attracted to mangoes and pears (vs. purified air), regardless of their condition; however, whilst infested mangoes did not attract more female parasitoids compared to healthy or mechanically damaged fruits, infested pears attracted significantly more. For citrus fruits and peaches, oviposition damage caused them to be more attractive to parasitoid females. In terms of the longevity of the effects, infested mango fruits remained attractive for up to 5 days after infestation, whereas for infested peaches, pears, and citrus fruits, the attractiveness tended to decrease as time passed. Regarding mechanical damage, mango fruits that had undergone any intensity of damage were equally attractive to parasitoid females; however, peach and citrus fruits with high levels of mechanical damage were more attractive, and pears were found to be most attractive with slight mechanical damage. Additional to the above, we also tested the effect of insecticides on behavioural responses using mangoes. We found that the treatment of infested fruits with lambda-cyhalothrin and cypermethrin remained attractive to F. arisanus females, albeit to different extents, which is in contrast to spinosad, cyantraniliprole, and acetamiprid. Finally, we suggest that the host-searching behaviour of F. arisanus females is mainly mediated by oviposition-induced volatiles, either emitted from the fruit or left by the fruit fly.

Maritime trap-jaw ants (Hymenoptera, Formicidae, Ponerinae) of the Indo-Australian region - redescription of Odontomachus malignus Smith and description of a related new species from Singapore, including first descriptions of males.

The maritime trap-jaw ant Odontomachus malignus Smith, 1859 is thought to be widespread throughout islands in the Indo-Pacific and parts of the Oriental realm. Because of its unique nesting preference for harsh littoral habitat and distinct morphology, O. malignus has usually been assumed to consist of only one species. We, however, describe a new species similar to O. malignus found in the mangroves of Singapore, Southeast Asia – Odontomachus litoralissp. nov. We find strong evidence of both species existing in (near) sympatry, and also distinct morphological differences between O. malignus and the new species. Additional complementary DNA evidence in the form of COI barcodes (313 bp) supporting putative species identification and delimitation is provided. Defining morphological characteristics for the O. malignus species group (nested within the larger O. infandus clade) are given in detail for the first time. The worker and queen castes of the new species are described; a redescription of the worker caste of O. malignus, based on specimens from Singapore and the Philippines in addition to the holotype, is also given. The males of both species are also described for the first time, including male genitalia. A preliminary key to most known species of the O. infandus group based on the worker caste is provided.

Purification and characterization of proteins in multifloral honey from kelulut bee (stingless bee)

The kelulut bee (Meliponini) is a subfamily of stingless bees that produce honey. A total of 89 species out of a total of 500 species of kelulut bees are known to originate from the Indo-Australian region. Kelulut bees do not have quality standards so they still refer to the Codex and EU Directive which basically only applied for Apis honey. The Codex and EU Directive are formed by several psychochemical parameters, one of it is diastase activity. Diastase activity in kelulut honey is known not to meet existing standards or even undetectable. Therefore, this study aimed to explore proteins inside kelulut honey and investigate the possibility of using a specific protein as a biomarker to differentiate honey produced by kelulut bee from other honey. This research can also be considered as an initial step to optimize the exploration of protein in kelulut honey. This research is divided into two sections which are the preliminary research and the research expansion. From preliminary section, glucose dehydrogenase enzyme (GDH) was found to be present inside Tetragonula spp honey. A further examination of GDH enzyme was made in four kelulut bee honeys namely Tetragonula leaviceps, T. biroi, Heterotrigona itama, and Geniotrigona thoracica. The preliminary research has five stages that are exactly the as expansion research section except it didn't include GDH activity measurement. The research includes seven main stages. First honeys were dialyzed to remove the sugar content followed by centrifugation. The samples were then purified using liquid chromatography with anion exchanger column. The molecular weight of proteins was analysed by SDS-PAGE method. The GDH activity was measured using spectrophotometer followed by qualitative analysis using LC-MS/MS. The peptide sequences resulted from LC-MS/MS were then matched with Uniprot to identify the unknow protein. The results showed that only T. biroi and T. laeviceps had GDH enzyme activity of 0,1891 U/mL and 0,1652–1,579 U/mL, respectively. Bands from both species were also qualitatively identified as GDH. With these results, it can be concluded that the GDH enzyme cannot be used as a biomarker to distinguish the kelulut honey.

Extending the Australasian endemicity: first report of Neapterolelaps Girault and Thaumasura Westwood (Hymenoptera: Pteromalidae) from the Oriental Region with the description of new species from Southern Western Ghats, India

ABSTRACT Two rare genera of Pteromalidae viz., Neapterolelaps Girault and Thaumasura Westwood are reported for the first time from the Oriental Region. Distribution of both the genera is currently confined to Australasian Region with majority of species reported from the Australian continent and surrounding island groups in the Indo-Australian region. Here we report the range extension of both the genera in the Oriental region with the description and illustrations of new species Neapterolelaps paraeneiceps Sureshan and Binoy sp. nov. and Thaumasura indica Sureshan and Binoy sp. nov. from Southern Western Ghats, India. Affinities of the new species with closely related conspecifics are discussed and a partial key of Neapterolelaps is provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:5BDBD180-3ADE-4E03-B56E-CC4A92928EEF http://www.zoobank.org/urn:lsid:zoobank.org:act:2BAC50DB-04DB-466E-B479-66C843D45F58

A new species of the genus Toccolosida Walker, 1863 from India(Lepidoptera: Pyralidae: Pyralinae).

The genus Toccolosida Walker, 1863 is a member of the Pyralini tribe of the subfamily Pyralinae in the family Pyralidae. It was described as a monotypic genus for Toccolosida rubriceps Walker, 1863 from Sikkim. Snellen (1890, 1892) described two additional species of Toccolosida, T. pallifrons Snellen, 1890 from Sikkim and T. bilinealis Snellen, 1892 from Indonesia and Java. Hampson (1896) erected a new genus Proteinia Hampson, 1896 for T. pallifrons. In 1899, Snellen described another species, T. subolivalis Snellen, 1899 from Indonesia, Sumatra and Padang. Robinson et al. (1994) included two species, T. rubriceps and T. bilinealis, in their account on South East Asian moths and stated that Toccolosida contains 8+ [described as well as undescribed] species from the Indo-Australian region and 6+ species from South East Asia. However, at present the valid Toccolosida species are only three: T. rubriceps, T. bilinealis and T. subolivalis, whereas pallifrons is currently placed in Proteinia (Nuss et al. 2003-2019; pers. comm. Dr. Richard Mally, University Museum of Bergen, Natural History Collections, Bergen, Norway).

<p><strong>Checklist of Indian Lebiinae Bonelli, 1810 (Coleoptera: Carabidae)</strong></p>

Distribution patterns and literature details of 263 Lebiinae species reported from India are provided. List includes 14 species missed out by Andrewes (1930a) and the 98 species described thereafter. Distribution patterns revealed among the 263 species, 104 species are exclusively Oriental species and 35 species are exclusively Palaearctic species. Among the 263 Indian speceis, 130 species are exclusively Indian species with reports only from the Indian subcontinent and one species with report only from Andaman & Nicobar Islands. Of the 130 Indian species, 89 species are recorded from the Oriental, 27 species from the Palaearctic and 14 species recorded from both Oriental and Palaearctic regions in India. Among the 129 Indian subcontinent species, 45 species are endemics to the three global hotspots of the biodiversity in India with 31 species endemic to the Western Ghats and Sri Lanka hotspot of biodiversity; six species endemic to the Eastern Himalayas hotspot of biodiversity; eight species endemic to the Indo-Burma hotspot of biodiversity; four species recorded only from Chota Nagpur plateu and 27 species recorded only from Indian Himalayas. Four species (Microlestes parvati, Singilis indicus, S. squalidus and Lebia cardoni) recorded only from Chota Nagpur plateu and the 31 endemic species from the Western Gahts and Sri Lanka are of special interest for their Gondwana relationships. 133 species have wider geographic distribution pattern with 15 species having distribution in Oriental and Indian regions; 8 species having distribution in Palaeractic and Indian regions; 10 species having distribution in Oriental and Indo-Australian regions; 48 species with distribution in Oriental and Palaearctic regions; 29 species with distribution in Oriental, Indo-Australian and Palaearctic regions; 2 species with distribution in Oriental, Australian and Palaearctic regions; 6 species with distribution in Oriental, Palaearctic and Afrotropical regions; 9 species with distribution in Oriental, Indo-Australian, Australian and Palaearctic regions; and 6 species with random distributions in different regions. Distribution records indicate that the arrival/origin of 228 species- 137 species with wider geographic distribution outside India and the 91 species with Indian distribution and not endemics to the Western Ghats and the Chotanagpur Plateau- is likely to have occurred after the joining of Indian subcontinent with Asian continent and during the subsequent faunal exchange between the newly formed Indian subcontinent and the surrounding regions (Indo-Burma and Indo-China on the north east front; Mediterranean and Ethiopian regions on the north-western front; Central Asian elements on the northern front). These 228 species represent the younger Indian Lebiinae species compared to the 35 species representing the older/ancient species with Gondwana land origin. Key words: Carabidae, Lebiinae, Perigonini, Pentagonicini, Odacanthini, Cyclosomini, Lebiini, India

Venom gland transcriptomics and microRNA profiling of juvenile and adult yellow-bellied sea snake, Hydrophis platurus, from Playa del Coco (Guanacaste, Costa Rica)

With an extensive range in tropical and subtropical waters of Indo-Australian region and the Pacific coast of the American continent, the yellow-bellied sea snake, Hydrophis platurus, is the most broadly distributed snake species on our planet. We report a comparative analysis of the mRNA and microRNA transcriptional profiles of the venom glands of Costa Rican juvenile and adult yellow-bellied sea snakes, and correlate these datasets with the previously reported venom proteome gathered from an adult specimen of the same population of Playa del Coco. The transcriptomic profiles are qualitatively and quantitatively remarkably similar across both age classes, being overwhelmingly (>99%) dominated by only three toxin classes, three-finger toxins (3FTx, 88%), phospholipases A2 (PLA2, 10–11%), and cysteine-rich secretory proteins (CRISP, 1%). The only appreciable difference between the transcriptomes of juvenile and adult Costa Rican yellow-bellied sea snake lies in the relative abundance of short and long neurotoxic 3FTxs. Comparison of venom gland transcriptome and venom proteome datasets suggest that the venom arsenal of adult H. platurus from Playa del Coco (CR) is subjected to post-transcriptional modulation, involving repression of the translation of pelamitoxin a-encoding mRNAs and enhancement of the translational activity of PLA2 and CRISP mRNAs.

Redescription of Chimaera ogilbyi (Chimaeriformes; Chimaeridae) from the Indo-Australian region.

An integrated taxonomic approach, combining both morphological and molecular data, was adopted to investigate the Hydrolagus lemures-ogilbyi group in the Indo-Australian region. Single mitochondrial markers (CO1 and NADH2) provided evidence supporting the separation of four distinct species in this group. However, detailed morphological data collected from specimens from across their range failed to find any consistent differences, and many features previously considered to be diagnostic were found to be variable. Nuclear DNA data also failed to support the differences found with the single mitochondrial markers and, together with the morphological data, supported the hypothesis that only a single species in this group is present in the Indo-Australian region. In addition, the results failed to support the current generic placement of this group in Hydrolagus, suggesting they belong to the genus Chimaera with doubt over the validity of Hydrolagus as a valid genus. The oldest available name for this group is Chimaera ogilbyi and a redescription is provided. This species occurs throughout Australia, eastern Indonesia (Java, Bali, and Lombok) and northern Papua New Guinea.

POLA KEPENULISAN DAN KOLABORASI PENELITIAN PADA JURNAL TREUBIA

Studies on the pattern of authorship and the level of research collaboration have been done by many scientific journals, but the study on the journal Treubia has never been done.The Journal Treubia is an english language journal of the Indo-Australian animal taxonomy. Established in 1919 by the director of Plantetuin Lands (now botanical garden) named Dr. M. Treub, for the first time this journal discussed only on plant pests. Now, Treubia is an English-language scietific journal focus on biosystematic, ecological, and conservation aspects of terrestrial and aquatic fauna in the Indo-Australian region. This aim of this study is to determine the pattern of the authorship and the level of collaborative research in the journal Treubia during period 2006-2016. The method used in this study is descriptive by using the data from journal article of Treubia, Research Center for Biology-Indonesian Institute of Sciences. Collection and processing data were conducted in March 2017. The results show that during the period 2006-2016, journal Treubia produced 50 articles. The most authors are male with 91 (71.1%) of the 128 authors. Furthermore, by country, Indonesia is the biggest contributor with 86 authors (67.19%) and the lowest is Australia, Singapore, and Vietnam each of them with 1 author (0.78%). The document type most highly cited is the journals which has been cited in 1,307 papers, and then newsletter and map which have been cited in 1 paper. The author's collaboration rate is 0.7 with the author's index per article is 2.56. Both of numeral rate and index are the positive criterion for assessing the higher quality of published papers.

A new species of Palaeugoa Durante, 2012 from Sierra Leone (Lepidoptera, Erebidae, Arctiinae).

The Asura / Miltochrista generic complex (family Erebidae, subfamily Arctiinae, tribe Lithosiini) is one of the largest and taxonomically most difficult Lithosiini groups widely distributed in Afrotropical, Palaearctic, Oriental, and Indo-Australian regions. In Africa, the generic complex is represented by the genera Tumicla Wallengren, 1863 (= Asuroides Durante, 2008, syn. rev.), Afrasura Durante, 2009, Parafrasura Durante, 2012 and Palaeugoa Durante, 2012. The genus Palaeugoa was erected as monobasic for Xanthetis spurrelli Hampson, 1914 described from Ghana (Durante 2012). During the studies of West African Lithosiini materials deposited in the collection of the African Natural History Research Trust, I found a second, yet undescribed species of Palaeugoa collected in Sierra Leone. The description of the new species is given below.

Ten New Subspecies of the Genus Eurema (Lepidoptera, Pieridae) from the Indo-Australian Region

Ten New Subspecies of the Genus Eurema (Lepidoptera, Pieridae) from the Indo-Australian Region

Prosorhynchus Odhner, 1905 (Digenea: Bucephalidae) from the orange-spotted grouper Epinephelus coioides (Hamilton, 1822) (Epinephelidae), including Prosorhynchus tonkinensis n. sp., from the Gulf of Tonkin, Vietnam

A total of 169 specimens of the orange-spotted grouper Epinephelus coioides (Hamilton) were collected from fishermen and marine fish farms in the Gulf of Tonkin, Vietnam. Five different species of Prosorhynchus Odhner, 1905 were recorded, including P. tonkinensis n. sp. The new species differs from all other Prosorhynchus species in the presence of an indented posterior extremity. It can be distinguished from the most closely related P. atlanticus Manter, 1940 and P. crucibulum Rudolphi, 1819 by the extension of the uterus always to the level of the ovary, the width and premouth distance in the former, and the arched vitellarium and smaller egg size in the latter, and a different host and geographical region. Prosorhynchus sp. A (not fully identified in this study) has been earlier reported from E. coioides from New Caledonia (see Prosorhynchus sp. B of Bray and Justine, 2013), P. luzonicus Velasquez, 1959 is reported throughout South-East Asia, and Prosorhynchus sp. B (no further identification possible based on a single specimen in this study) and P. maternus Bray & Justine, 2006 are reported for the first time from Vietnam. The present study demonstrates a close relationship of the Prosorhynchus species composition in Vietnam with the Indo-Australian region, warranting further comparative studies among the different epinephelids.