The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater taxa) comprise 3154 described marine species in 379 genera in 37 families according to the WoRMS catalogue. The ...history of taxonomic discovery over the last two centuries is reviewed. Although a well defined order with the Peracarida, their relationship to other orders is not yet resolved but systematics of the major subordinal taxa is relatively well understood. Isopods range in size from less than 1 mm to Bathynomus giganteus at 365 mm long. They inhabit all marine habitats down to 7280 m depth but with few doubtful exceptions species have restricted biogeographic and bathymetric ranges. Four feeding categories are recognised as much on the basis of anecdotal evidence as hard data: detritus feeders and browsers, carnivores, parasites, and filter feeders. Notable among these are the Cymothooidea that range from predators and scavengers to external blood-sucking micropredators and parasites. Isopods brood 10-1600 eggs depending on individual species. Strong sexual dimorphism is characteristic of several families, notably in Gnathiidae where sessile males live with a harem of females while juvenile praniza stages are ectoparasites of fish. Protandry is known in Cymothoidae and protogyny in Anthuroidea. Some Paranthuridae are neotenous. About half of all coastal, shelf and upper bathyal species have been recorded in the MEOW temperate realms, 40% in tropical regions and the remainder in polar seas. The greatest concentration of temperate species is in Australasia; more have been recorded from temperate North Pacific than the North Atlantic. Of tropical regions, the Central Indo-Pacific is home to more species any other region. Isopods are decidedly asymmetrical latitudinally with 1.35 times as many species in temperate Southern Hemisphere than the temperate North Atlantic and northern Pacific, and almost four times as many Antarctic as Arctic species. More species are known from the bathyal and abyssal Antarctic than Arctic GOODS provinces, and more from the larger Pacific than Atlantic oceans. Two areas with many species known are the New Zealand-Kermadec and the Northern North Pacific provinces. Deep hard substrates such as found on seamounts and the slopes are underrepresented in samples. This, the documented numbers of undescribed species in recent collections and probable cryptic species suggest a large as yet undocumented fauna, potentially an order of magnitude greater than presently known.
Of the 95 known families of Isopoda only a few are parasitic namely, Bopyridae, Cryptoniscidae, Cymothoidae, Dajidae, Entoniscidae, Gnathiidae and Tridentellidae. Representatives from the family ...Cymothoidae are obligate parasites of both marine and freshwater fishes and there are currently 40 recognised cymothoid genera worldwide. These isopods are large (>6 mm) parasites, thus easy to observe and collect, yet many aspects of their biodiversity and biology are still unknown. They are widely distributed around the world and occur in many different habitats, but mostly in shallow waters in tropical or subtropical areas. A number of adaptations to an obligatory parasitic existence have been observed, such as the body shape, which is influenced by the attachment site on the host. Cymothoids generally have a long, slender body tapering towards the ends and the efficient contour of the body offers minimum resistance to the water flow and can withstand the forces of this particular habitat. Other adaptations to this lifestyle include small sensory antennae and eyes; a very heavily thickened and calcified cuticle for protection; and sharply curved hooks on the ends of the pereopods which allows these parasites to attach to the host. Most cymothoids are highly site and host specific. Some of these parasitic cymothoids have been reported to parasitise the same host fish species for over 100 years, showing this species specificity. The site of attachment on the host (gills, mouth, external surfaces or inside the host flesh) can also be genus or species specific. This paper aims to provide a summary of our current knowledge of cymothoid biodiversity and will highlight their history of discovery, morphology, relationships and classification, taxonomic diversity and ecology.
Cirolana swaraj sp. nov. was collected from brackish-water Neil Lagoon on Havelock Island, South Andaman and is described and illustrated in detail. Cirolana swaraj sp. nov. can be distinguished by: ...frontal lamina 2.2 times as long as greatest width, lateral margins slightly widening to rounded anterior margin; pereonite 1 dorsal anterior mid-region with convex boss covered with fine ridges, pereonites 17 each with a single transverse impressed line, posterior margin with 18, 18, 17 and 12 tubercles on pereonites 47 dorsal posterior margins respectively; pleonites 45 each with prominent median tubercle, 4 and 2 tubercules on each side of pleonites 45; pleotelson dorsal surface with sub-median double row of 5 tubercules, posterior lateral margins straight, posterior margin narrowly rounded with 6 robust setae and plumose marginal setae extending anteriorly to mid-length; uropodal exopod lateral margin with eight robust setae and a continuous row of plumose marginal setae. A key to the marine and estuarine genera of Cirolanidae of the northern Indian Ocean is given.
Cassidinidea andamanensis sp. nov. was collected from intertidal habitats on the coast of South Andaman, Andaman Islands, India and is described and illustrated in detail. Cassidinidea andamanensis ...sp. nov. the second definitive record of the genus from India, is characterized by: smooth body surface, prominently convex epistome anterior margin, pleotelson dorsal smooth surface and the posterior margin is subtruncate and weakly convex with small setae, the appendix masculina posterior margin is narrowly rounded.
Gnorimosphaeroma oregonense
(Dana, 1852) is revised, a male neotype is designated, photographed, and illustrated; the species occurs from Vancouver British Columbia to the central California coast. ...16S-rDNA sequences (~650 bp) for all available ethanol preserved species of
Gnorimosphaeroma
were used to hypothesize their relationships. Our analyses revealed a sister taxon relationship between the fully marine
G. oregonense
and the brackish to freshwater species,
G. noblei
. The oyster associated and introduced
G. rayi
is sister to a previously not recognized or identified, but genetically distinct,
Gnorimosphaeroma
sp. collected at two sites in San Francisco Bay.
Gnorimosphaeroma
sp. is probably also a western Pacific species based on its genetic relationship to
G. rayi
. Photographic comparisons are offered for
G. oregonense
(marine),
G. noblei
(freshwater),
G. rayi
(introduced),
G.
sp. (presumably introduced), and
G. insulare
(San Nicolas Island). Records of the holdings at the Los Angeles County Museum of Natural History are summarized. Without material available north of Vancouver through Alaska, the range of
G. oregonense
could not be genetically verified. This review includes a diagnosis and description of the genus
Gnorimosphaeroma
Menzies, 1954.
Neocirolana taylori sp. nov. is described from Picard Island, Aldabra Atoll, Seychelles, the first record of the genus from the tropical Western Indian Ocean and the eleventh species in the genus. ...The species is characterised by the ovate body shape with a strongly- vaulted dorsum, lack of dorsal nodules and pleotelson carinae, having prominent and strongly-produced coxae on pereonites 5 to 7 and robust pereopods. Neocirolana taylori was collected from the intertidal and shallow subtidal reef crest habitats.
http://www.zoobank.org/urn:lsid:zoobank.org:pub:83825998-C8C9-4CB6-A359-C494ED126BE7
A checklist of parasitic cymothoids from Malaysian waters is presented based on available literature and material collected from 2010 to 2020. Most of the collected specimens were recorded from ...waters of Terengganu, east coast of Peninsular Malaysia (facing the South China Sea), whereas literature records were included from Sarawak, along the Miri coast of northwest Borneo. The checklist comprises 19 species in ten genera, seven of which are new records from Malaysia: Anilocra nemipteri Bruce, 1987; Ceratothoa barracuda Martin, Bruce & Nowak, 2015; Ceratothoa carinata (Bianconi, 1869); Cymothoa epimerica Avdeev, 1979; Elthusa sigani Bruce, 1990; Joryma engraulidis (Barnard, 1936) and Renocila richardsonae Williams & Bunkley-Williams, 1992. Eight new host records are based on collected specimens: Anilocra nemipteri was dorsally attached on Nemipterus nemurus (Bleeker, 1857), Nemipterus nematophorus (Bleeker, 1854), Nemipterus tambuloides (Bleeker, 1853) and Nemipterus thosaporni Russell, 1991 (family Nemipteridae); Ceratothoa carinata was found in the buccal cavity of Decapterus macrosoma Bleeker, 1851 (family Carangidae); Cymothoa eremita (Brunnich, 1783) was attached in the buccal cavity of Nemipterus tambuloides (Bleeker, 1853) and Nemipterus furcosus (Valenciennes, 1830); Elthusa sigani was found attached on the gills of Pterois russelli Bennett, 1831 (family Scorpaenidae), and Renocila richardsonae was attached on the caudal fin of Upeneus japonicus (Houttuyn, 1782) (family Mullidae). All cymothoid species listed here are known to have a Central Indo-Pacific distribution, with some ranging as far as the Western Indian Ocean. A cymothoid-host association is here listed from 28 fish families, with the most commonly reported from Carangidae (pompanos, jack mackerels, runners, scads), Engraulidae (anchovies), and Leiognathidae (ponyfishes, slipmouths). This paper is the first comprehensive review of both verified literature records and deposited specimens. A key for the family of Cymothoidae in Malaysian waters is given.
The genus Lobothorax Bleeker, 1857 is revised with the description of a new species collected from the gempylidaen fish Promethichthys prometheus (Cuvier, 1832) from the southwestern coast of India. ...A revised generic diagnosis is provided based on the redescription of the type species. Lobothorax aurita (Schioedte and Meinert, 1883) is here synonymised with Lobothorax typus Bleeker, 1857 based on the original description. Lobothorax nicosmiti Aneesh, Bruce and Kumar sp. nov. is described from the female stage and it is characterized by: pereonite 1 anterolateral expansion not extending to the anterior margin of cephalon; coarsely pitted pereonites dorsal surfaces; pereonites without dorsal median longitudinal ridges; anteriorly truncate cephalon; pleotelson about 0.6 times as long as wide, posterior margin weakly emarginate, broadly sub-truncate, lateral margins convex; maxilliped palp article 3 with three RS; pereopods basis much wider with prominent carina. A key to the species of Lobothorax Bleeker, 1857 is presented.
Bathynomus jamesi Kou, Chen and Li, 2017 from Zhengbin fishing port in Keelung, Taiwan, was identified by the shape of the distolateral corner of the uropodal endopod, the shape of the clypeus, and ...the nucleotide sequences of the COI (cytochrome c oxidase subunit 1) and 16S rRNA genes. Only two species of Bathynomus have previously been recorded from Taiwan, B. doederleini Ortmann, 1894 and B. decemspinosus Shih, 1972. Bathynomus kensleyi, previously known from the South China Sea as well as the south-east Swain Reefs, Coral Sea, was primarily differentiated by the elongate and upturned pleotelson spines, but that character is now shown to also occur in mature Bathynomus jamesi. Two specimens from the Gulf of Mexico (obtained from the Enoshima Aquarium in Japan) were compared to species of Bathynomus from the western North Atlantic. Sequence data showed that one of two samples was not B. giganteus Milne-Edwards, 1879, as had been assumed, and it did not match any other species of Bathynomus. That specimen was collected off the Yucatán Peninsula and is morphologically distinct from both B. giganteus (in the relative length of the antennal flagellum and the length:width ratio of the pleotelson) and B. maxeyorum Shipley, Brooks, and Bruce in Shipley et al., 2016 (the number of pleotelson spines is seven and the distolateral corner is produced on the uropodal exopod). Therefore, it is here described as B. yucatanensis sp. nov. Bathynomus is currently a very minor fisheries resource in Taiwan and Japan, but this find demonstrates the continuing importance of the fishing industry to marine biological exploration.
http://www.zoobank.org/urn:lsid:zoobank.org:pub:399605D3-356E-402D-9ED1-E36A649A3F1B
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