Niel L. Bruce

Global diversity of fish parasitic isopod crustaceans of the family Cymothoidae

Graphical abstract

Review of the fish-parasitic genus Ceratothoa Dana, 1852 (Crustacea: Isopoda: Cymothoidae) from Australia, with description of two new species

The genus Ceratothoa Dana, 1852, is revised for Australian waters. Ceratothoa is represented in Australia by nine species, including two new species: Ceratothoa barracuda sp. nov. described from Cairns and Ceratothoa globulus sp. nov. described from Lord Howe Island. Ceratothoa imbricata Fabricius, 1775 is redescribed, with Ceratothoa trillesi (Avdeev, 1979) and Ceratothoa huttoni Filhol, 1885 placed into junior synonymy; the preferred hosts are species of the genus Trachurus (Carangidae). Ceratothoa banksii (Leach, 1818) is validated and brought out of synonymy with Ceratothoa imbricata; host species are from the families Kyphosidae, Scombridae, Latridae, Carangidae, Mugilidae, Salmonidae, Scatophagidae, Pomatomidae and Hemiramphidae. Species excluded from the Australian fauna are Ceratothoa trigonocephala (Leach, 1818) with an unknown host identity and type locality; and Ceratothoa lineata Miers, 1876a, that here is transferred to the genus Mothocya Costa, 1851, with Mothocya ihi Bruce, 1986 placed into junior synonymy. Ceratothoa contracta (Miers, 1880), the New Zealand Ceratothoa novaezelandiae Filhol, 1885 and the East Pacific Ceratothoa gaudichaudii (Milne Edwards, 1840) are regarded here as species inquirenda. A key to the Australian species of Ceratothoa is presented.

Review of the fish-parasitic genus Cymothoa Fabricius, 1793 (Crustacea: Isopoda: Cymothoidae) from Australia

The genus Cymothoa Fabricius, 1793 is revised for Australian waters. Cymothoa hermani Hadfield, Bruce & Smit, 2011, previously known from Tanzania on the host Selar crumenophthalmus (Bloch, 1793) is new to Australian waters. Cymothoa carangi Avdeev, 1979; Cymothoa epimerica Avdeev, 1979; Cymothoa parupenei Avdeev, 1979; Cymothoa propria Avdeev, 1979; Cymothoa rotunda Avdeev, 1979 and Cymothoa pulchrum Lanchester, 1902 are redescribed. Cymothoa curta Schioedte & Meinert, 1884, first described from the host Anableps anableps (Linnaeus, 1758); and Cymothoa plebeia Schioedte & Meinert, 1884, first described from Cape Verde; are redescribed and excluded from the Australian fauna. Cymothoa limbata Schioedte & Meinert, 1884 is placed into junior synonymy with Cymothoa eremita (Brünnich, 1783). A key to the Australian species of Cymothoa is presented.

Review of Mothocya Costa, in Hope, 1851 (Crustacea: Isopoda: Cymothoidae) from Southern Africa, with the Description of a New Species

Three species of Mothocya are reported from the east coast of southern Africa: Mothocya plagulophora (Haller, 1880) from Maputo, Mozambique, from the gills of Hemiramphus far (Forsskål, 1775); Mothocya renardi (Bleeker, 1857) from diverse localities in South Africa and Mozambique, from the hosts Strongylura leiura (Bleeker, 1850) and Tylosurus choram (Rüppell, 1837); and Mothocya affinis sp. nov. from Sodwana Bay, South Africa, from the gills of Hyporamphus affinis (Günther, 1866). Mothocya affinis sp. nov. is characterised by relatively small size (maximum 16 mm); large, wide coxae on pereonite 7 that overlap the pleon; uropods that do not extend past the pleotelson posterior margin; produced anterolateral margins on pereonite 1; and a twisted pleon and pleotelson. Mothocya katoi Nunomura, 1992 and Mothocya toyamaensis Nunomura, 1993 are both transferred to the genus Ceratothoa, with M. katoi being placed into junior synonymy with Ceratothoa guttata (Richardson, 1910). Irona ogcocephalus Avdeev & Avdeev, 1974 and I. callionymus Avdeev & Avdeev, 1974 are both transferred to Elthusa, and Irona trillesi Rokicki, 1986 is synonymised with Mothocya longicopa Bruce, 1986. A key to the south-western Indian Ocean species of Mothocya is given, and a table summarising recent and new nomenclatural acts in the genus is provided.

Cirolana songkhla, a new species of brackish-water cirolanid isopod (Crustacea, Isopoda, Cirolanidae) from the lower Gulf of Thailand

Abstract Cirolana songkhla sp. n. was collected from brackish-water habitats including lagoons and estuaries in the coastal zone of the lower Gulf of Thailand. C. songkhla sp. n. is described and fully illustrated; C. songkhla sp. n. can be recognized by the presence of abundant chromatophores dorsally, lack of ornamentation on the posterior pereonites, pleonites and pleotelson, the number of robust setae on the uropodal and pleotelson margins (uropod exopod lateral margin with 12–14 RS, mesial margin with 5–8 RS; endopod lateral margin with 8–10 RS, mesial margin with 11–13 RS; pleotelson with 12–15 RS) and lack of setae on the endopods of pleopods 3–5. A dichotomous key of brackish Cirolana species in Thailand is given.

A new family Lepidocharontidae with description of Lepidocharon gen. n., from the Great Barrier Reef, Australia, and redefinition of the Microparasellidae (Isopoda, Asellota)

Abstract Lepidocharontidae Galassi & Bruce, fam. n. is erected, containing Lepidocharon Galassi & Bruce, gen. n. and two genera transferred from the family Microparasellidae Karaman, 1934: Microcharon Karaman, 1934 and Janinella Albuquerque, Boulanouar & Coineau, 2014. The genus Angeliera Chappuis & Delamare Deboutteville, 1952 is placed as genus incertae sedis in this family. The Lepidocharontidae is characterised by having rectangular or trapezoidal somites in dorsal view, a single free pleonite, a tendency to reduction of the coxal plates, and the unique uropodal morphology of a large and long uropodal protopod on which the slender uropodal exopod articulates separately and anteriorly to the endopod. Lepidocharon Galassi & Bruce, gen. n. has a 6-segmented antennula, a well-developed antennal scale (rudimentary exopod), long and slender pereiopods 1–7 directed outwards, coxal plates rudimentary, incorporated to the lateral side of the sternites, not discernible in dorsal view, the single pleonite narrower than pereionite 7, scale-like elements bordering the proximal part of male pleopod 1 on posterior side, and stylet-guiding grooves of male pleopod 1 which run parallel to the outer lateral margins of the same pleopod. Lepidocharon priapus Galassi & Bruce, sp. n., type species for the genus, and Lepidocharon lizardensis Galassi & Bruce, sp. n. are described from Lizard Island, northern Great Barrier Reef. The most similar genus is Microcharon, both genera sharing the same general organization of the male pleopods 1 and 2, topology and architecture of the stylet-guiding groove of male pleopod 1, morphology of female operculum, presence of 2 robust claws of different lengths on pereiopodal dactylus 1–7, not sexually dimorphic. Lepidocharon gen. n. differs from Microcharon in the shape of the pereionites, very reduced coxal plates, the presence of imbricate scale-like elements bordering the proximal postero-lateral margins of the male pleopod 1, and the topology of the pereiopods, which are ventro-laterally inserted and directed outwards in Lepidocharon gen. n. and dorso-laterally inserted and directed ventrally in Microcharon. Lepidocharon shares with the genus Janinella the morphology of the tergites and the reduced lacinia mobilis of the left mandible, but differs significantly from Janinella in having a well-developed antennal scale, very reduced coxal plates also in females bearing oostegites, the general morphology and spatial arrangement of the stylet-guiding groove of male pleopod 1 and the possession of a 6-segmented antennula. The family Microparasellidae is redefined as monotypic, the only genus being Microparasellus Karaman, 1933.

A new genus of Stenetriidae Hansen, 1905 (Asellota: Isopoda: Crustacea) from the Great Barrier Reef, Australia and the southwestern Pacific.

Onychatrium gen. nov. is described, with five included species: Onychatrium forceps sp. nov., the type species and Onychatrium torosus sp. nov., both from the Great Barrier Reef; Onychatrium entale (Nordenstam, 1946) comb. nov., from Tapateuen (= Tabiteue Island), Gilbert Islands; Onychatrium thomasi (Bolstad & Kensley, 1999) comb. nov., from Madang, Papua New Guinea; and Onychatrium echiurum (Nobili, 1906) comb. nov., and species inquirenda from the Tumaotu Islands, Eastern French Polynesia. The primary distinguishing characters for Onychatrium gen. nov. are a trapezoid pseudosrostrum, the male pereopod 1 with elongate dactylus (4.7-7.3 as long as proximal width), propodus with strongly produced and acute lobe, carpus with a distally acute, flat, ventrally directed process (except O. torosus sp. nov., which has a short and truncate process) and the merus with a distally directed inferodistal lobe. The genus is known only from the southern Pacific, from the Tuamotus (eastern French Polynesia) to the Great Barrier Reef and northern Papua New Guinea.

Description of four new species of the Cirolana ‘parva group’ (Crustacea: Isopoda: Cirolanidae) from Thailand, with supporting molecular (COI) data

ABSTRACT Four new species of the Cirolana ‘parva group’ from shallow coastal habitats in Thailand are described: Cirolana andamanensis sp. nov. and C. phangnga sp. nov., from the Andaman Sea, and C. siamensis sp. nov. and C. thailandica sp. nov. from the Gulf of Thailand. Molecular (The cytochrome oxidase subunit I gene) analysis incorporating taxa from the Cirolana ‘tuberculate group’ shows a monophyletic clade (Bayesian inference = 1 and maximum likelihood = 100%) within the Cirolana ‘parva group’ with two clades reflecting morphological characters. Cirolana andamanensis sp. nov. with antennula peduncle articles 1 and 2 entirely fused; male pereopod 1 without a setal fringe; uropod peduncle ventrolateral margin with 1 sensory seta. Cirolana phangnga sp. nov., C. siamensis sp. nov. and C. thailandica sp. nov. share the morphological characters of antennula peduncle articles 1 and 2 distinctly articulated; pereopod 1 in male with a setal fringe on the carpus and propodus; uropod peduncle ventrolateral margin with 3 sensory setae. Uncorrected p-distances strongly support the separation of these species, originally based on morphology, and show that the highest value of 32.1% is between C. thailandica sp. nov. and C. andamanensis sp. nov., while the lowest value of 22.5% is between C. phangnga sp. nov. and C. siamensis sp. nov.

A new species of Halacarsantia Wolff, 1989 (Crustacea, Isopoda, Asellota, Santiidae) from Wistari Reef, southern Great Barrier Reef, Australia.

Abstract Halacarsantia acuta sp. n. is described from Wistari Reef, Capricorn Group, southern Great Barrier Reef, the first record of the genus from Australia. The new species differs from its congeners in having antenna flagellum composed of 8 articles; epipod apically acute, without setae, broad maxilliped endite and pereopod 1 basis with a short projection. A key to species of the genus is provided.

Post-mortem human cadaver scavenging by marine crustaceans (Isopoda: Cirolanidae) in tropical waters

Animal feeding, both ante- and post-mortem, in freshwater and marine environments, has become topical recently. This report documents post-mortem scavenging by two identified species of marine crustaceans (Crustacea: Isopoda: Cirolanidae) on a human cadaver from the vicinity of Darwin, Northern Territory, Australia.