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    Item type:Publication,
    Two new species of Aricidea (Aricidea) (Annelida: Paraonidae) from the Andaman coast and the Gulf of Thailand
    (2026-07-03)
    Plathong, Jintana
    ;
    Plathong, Sakanan
    ;
    ;
    Ranauro, Natalia
    ;
    Hernández-Alcantara, Pablo
    Two new species of Paraonidae, Aricidea (Aricidea) pacharaphoni sp. nov., and A. (A.) sathingpra sp. nov., are described from the Southwestern Pacific. Aricidea (A.) pacharaphoni sp. nov., collected in the Andaman Coast and the Gulf of Thailand, is clearly distinguished from other species of Aricidea (Aricidea) by having an elongate, faintly annulated median antenna extending to chaetigers 3–7; chaetiger 3 with distinctive globose notopodial postchaetal lobes with long digitiform terminal tips; two types of branchiae, strap-like and foliaceous; and two types of modified neurochaetae, pseudocompound and stout acicular. Aricidea (A.) sathingpra sp. nov., was collected in the Gulf of Thailand and belongs to the articulated antenna group, being separated from all other species of this subgenus by having a triarticulated antenna; pair of distinctive round furrow protuberances on the prostomium; and 6–7 pairs of wide foliaceous branchiae. We suggested that the modification and shape of the notopodial postchaetal lobes in chaetiger 3 are an important morphological character to differentiate the species of this subgenus. Molecular phylogenetic and genetic distance analyses, based on cytochrome oxidase subunit I (COI) gene sequences support the recognition of Aricidea (A.) pacharaphoni sp. nov., as a distinct species. A taxonomic key for all world species of Aricidea (Aricidea) is included.
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    Item type:Publication,
    Resolving Species Identification and Distribution Patterns of Neotrygon spp. in Thai Waters: Inefficiency of Morphometric Analysis and the Power of COI Gene Barcoding and Phylogenetics
    (2025-01-01)
    Panithanarak, Thadsin
    ;
    Karuwanjaroen, Ratima
    ;
    Utama, Chanapa
    ;
    Laongmanee, Penchan
    ;
    Meejan, Titirat
    Three species of maskrays in the genus Neotrygon have previously been reported in Thai waters. However, the high morphological similarity among species within the blue-spotted maskray complex (Neotrygon spp.) makes accurate identification challenging. This study aimed to confirm species identification in Neotrygon spp. using morphometric and genetic data and to further examine their phylogenetic relationships in Thai waters by analyzing mitochondrial COI (cytochrome c oxidase subunit I) sequences. Multivariate analysis (PCA) of 37 morphometric characters from 55 specimens proved insufficient for species-level discrimination. However, molecular phylogenetic analysis of 14 unique COI sequences from Thai waters, combined with 61 reference sequences from previously documented related species and closely related species, identified two monophyletic clades. These clades corresponded to two species: N. varidens, found exclusively in the Gulf of Thailand, and N. malaccensis, recorded for the first time in Thailand, occurring in both the Gulf of Thailand and the Andaman Sea. This DNA-based identification provides clear evidence for species boundaries within Thai Neotrygon species and highlights the importance of molecular tools for distinguishing morphologically similar marine species in the Indo-Pacific region.
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    Item type:Publication,
    Four new species of Fauveliopsidae (Annelida, Sedentaria) from the Gulf of Thailand
    (2026-01-01)
    Plathong, Jintana
    ;
    Plathong, Sakanan
    ;
    ;
    Salazar-Vallejo, Sergio I.
    Four new species of Fauveliopsidae, Fauveliopsis pladang sp. nov., Laubieriopsis tantawan sp. nov., Riseriopsis chaba sp. nov., and R. plahmuk sp. nov., are described from the Gulf of Thailand from sediments at 50–80 m water depth. Fauveliopsis pladang sp. nov., can be distinguished from other species by having 41 chaetigers; anterior parapodia with two acicula chaetae per bundle; in median and posterior segments 1 aciculum and 1 capillary per bundle. Laubieriopsis tantawan sp. nov., differs from all other species in the genus by having 27–43 chaetigers, body annulate; 2 acicula per bundle in anterior parapodia; in median and posterior parapodia with 1 aciculum and 1 capillary per bundle. Riseriopsis chaba sp. nov., can be distinguished from other species by having 34 chaetigers; anterior parapodia with 2 acicula per bundle; median and posterior notopodia with one aciculum and one capillary per bundle; median neuropodia with 1 aciculum and 2 capillaries per bundle; posterior neuropodia with 1–2 acicula and 1 capillary per bundle. Riseriopsis plahmuk sp. nov., can be distinguished from other species by having 2–4 acicula per bundle along anterior segments; median segments with 1–2 acicula and 1–2 capillaries per bundle; and posterior parapodia with 1–6 acicula and 1–5 capillaries per bundle. Genetic data, sequencing of the cytochrome oxidase subunit I (COI) of L. tantawan sp. nov., and R. plahmuk sp. nov., are reported. Update keys for identifying species of Fauveliopsis, Laubieriopsis and Riseriopsis are also provided.