Pigmentation patterns are useful for species identification of third-stage larvae of gnathiids (Crustacea: Isopoda) parasitising coastal elasmobranchs in southern Japan

Two new temporary ectoparasitic isopods (Cymothoida: Cymothooidea) from Korean waters with a note on geographical distributions of Rocinela Leach, 1818 and Gnathia Leach, 1814

Two new species of temporary ectoparasitic isopods, Rocinela excavata sp. nov. and Gnathia obtusispina sp. nov., are reported from the southern Islands of the Korean Peninsula. Rocinela excavata sp. nov. is distinguishable from its related species by the following characteristics: (1) laterally stepped rostrum; (2) separated eyes; (3) propodal blade having eight robust setae; and (4) merus having four or five blunt robust setae in pereopods 1-3. Gnathia obtusispina sp. nov. differs from its congeners by the combination of the following characteristics: (1) body covered with numerous tubercles and setae, (2) cephalon having tooth-like paraocular ornamentations; and (3) frontal border having two inferior frontolateral processes. These two new species are the 13^th Rocinela species and 19^th Gnathia species in the temperate Northern Pacific region, respectively. Discovery of these new species represents high species diversity of the genera Rocinela Leach, 1818 and Gnathia Leach, 1814 worldwide as well as in the Northern Pacific region. In addition, faunal diversity analysis on the members of both genera revealed that Rocinela species show high-latitude diversity whereas Gnathia species have low-latitude diversity.

First record and molecular characterisation of two Gnathia species (Crustacea, Isopoda, Gnathiidae) from Philippine coral reefs, including a summary of all Central-Indo Pacific Gnathia species

Due to their unusual life cycle that includes parasitic larval and free living adult stages, gnathiid isopods are typically overlooked in biodiversity surveys, even those that focus on parasites. While the Philippines sits within the region of highest marine biodiversity in the world, the coral triangle, no gnathiid species have been identified or described from that region. Here we present the first records of two gnathiid species collected from the Visayas, central Philippines: Gnathia malaysiensis Müller, 1993, previously described from Malaysia, and G. camuripenis Tanaka, 2004, previously described from southern Japan. This paper provides detailed morphological redescriptions, drawings and scanning electron microscope images as well as the first molecular characterisation of both species, Furthermore, a summary of the Central-Indo Pacific Gnathia species is provided.

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Morphological description of two gnathiid species collected from the central Philippines, along with molecular data, are presented.

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Gnathia malaysiensis was previously described from Malaysia and G. camuripenis was previously described from southern Japan.

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Although the Philippines is in the highly biodiverse coral triangle, this is the first gnathiid description from this region.

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The wide geographic range of G. camuripenis suggests dispersal via large, highly mobile fishes, and/or tropical cyclones.

First records of Gnathia Leach, 1814 and Tachaea Schioedte & Meinert, 1879 from South Korea, with descriptions of two new species (Isopoda, Cymothoida, Cymothooidea)

Two new species of cymothoid isopods, Gnathiakoreana sp. n. and Tachaeakoreaensis sp. n., are described from South Korea. The genera Gnathia Leach, 1814 and Tachaea Schioedte & Meinert, 1879 are recorded for the first time in South Korea. Gnathiakoreana sp. n. is distinguished from its congeners by having the smooth dorsal surface of the pereon, the strongly ridged unornamented paraocular ornamentation, the strong bifid mediofrontal process, and the serrated superior frontolateral process. Tachaeakoreaensis sp. n. is distinguished from its congeners by having the expanded propodus with serrated inferior margins in pereopods 1-3, the propodus with serrated inferodistal margins in pereopods 4-7, one seta on the apical lobe of the maxilla, and ten robust setae on the posterior margin of the pleotelson.