Ectoparasite crustaceans of ten fish species from the upper Araguari River in northern Brazil.

Fish parasites are an important part of aquatic biodiversity and knowing these species and their interactions with their hosts helps in monitoring the aquatic biota. The present study investigated the ectoparasite crustacean fauna of ten fish species from the upper Araguari River, in the state of Amapá, northern Brazil. A total of 508 fish were collected and analyzed from July to November 2014, of which 82.6% (109) were parasitized by one or more crustacean ectoparasite species. In the ten host fish species, a total of 308 ectoparasite specimens were collected, from 12 taxa, such as Argulus multicolor Stekhoven, 1937, Argulus spinulosus Silva, 1980, Argulus sp.1, Argulus sp.2, Argulus sp.3, Dipteropeltis sp., Dipteropeltis hirundo Calman, 1912, Dolops bidentata Bouvier, 1899, Dolops striata Bouvier, 1899 (Argulidae), Braga fluviatilis Richardson, 1911, Braga amapaensis Thatcher, 1996 (Cymothoidae) and Excorallana berbicensis Boone, 1918 (Corallanidae). Higher levels of prevalence and abundance were recorded for Hoplias aimara (Valenciennes, 1847) and Tometes trilobatus Valenciennes, 1850, respectively. These ectoparasites were found in the fins, integument, mouth, and anus of the host fish. Argulus sp.2 and D. bidentata were the most abundant parasites (65.1%), and had the highest species richness. This study registered 36 novel host-parasite interactions, and thus represents a new record for all host species here examined.

Hooked on you: shape of attachment structures in cymothoid isopods reflects parasitic strategy.

BACKGROUND: Parasite attachment structures are critical traits that influence effective host exploitation and survival. Morphology of attachment structures can reinforce host specificity and niche specialisation, or even enable host switching. Therefore, it is important to understand the determinants of variation in attachment structures. Cymothoid isopods are striking ectoparasites of fishes that include the infamous 'tongue-biters.' They are known to parasitise hosts in one of four qualitatively distinct anatomical regions. Here, we quantify variation in cymothoid attachment structures - hook-like appendages called dactyli - and test whether differences in dactylus shape are correlated with parasite mode (where they attach), allometry, or both, using multivariate ordinary least squares regression. We also assess the influence of shared ancestry on shape using a molecular phylogeny to weight our models using phylogenetic generalised least squares regression. RESULTS: We find clear differences in shape between externally-attaching and internally-attaching cymothoids but also between anterior and posterior dactyli across various species with the same attachment mode. Allometric effects are significant for anterior but not posterior dactyli. Mouth-attaching species show greater shape variability than gill- and mouth-attaching species. We find no evidence that there are clade-specific patterns of association between parasite mode and dactylus shape. CONCLUSIONS: Parasite mode appears to be the main driver of attachment morphology. This likely reflects several components of parasite ecology including feeding and functional demands of attachment in different microhabitats. Geometric morphometric approaches to the quantification of shape variation of simple structures is an effective tool that provides new insights into the evolvability of parasite attachment.

Differences in the ectoparasite fauna between micromammals captured in natural and adjacent residential areas are better explained by sex and season than by type of habitat.

We compared the ectoparasite fauna in 608 micromammals (chiefly 472 wood mice Apodemus sylvaticus, 63 Algerian mice Mus spretus, and 51 greater white-toothed shrews Crocidura russula) captured in natural and adjacent residential areas in spring and autumn during three consecutive years in four areas in periurban Barcelona (NE Spain). We found little support for an association of urbanization with differences in infestation by ectoparasites. Prevalence of Rhipicephalus sp. tick in wood mice and shrews was significantly higher in residential than in natural habitats, and the opposite was found for the flea Ctenophtalmus andorrensis catalanensis in shrews. Marked differences in the prevalence of the flea Leptopsylla taschenbergi amitina in wood mice between seasons were observed in natural but not in residential habitats, probably due to enhanced flea survival probabilities in the latter. However, as a rule, males were more frequently and heavily infested than females, and the prevalence was higher in autumn than in spring. Our results suggest that the ectoparasite fauna of periurban micromammals is shaped more by other factors than by habitat modification. People living in residential areas are at risk of contact with the arthropods borne by non-commensal micromammals and the pathogens transmitted by them.

A scanning electron microscopy study of Argulus vittatus (Rafinesque-Schmaltz, 1814) (Crustacea: Branchiura) from Algerian coast.

A study of the Algerian Branchiura, Argulus vittatus (Rafinesque-Schmaltz, 1814) was conducted using the scanning electron microscopy (SEM). New morphological features are reported for the first time (mouth con, first maxilla, second maxilla, structures and ornamentation of thoracic segments, structure of semen papillae, etc.). The morphology of small and large female specimens was compared. Two new hosts, Pagellus erythrinus L. and Sparus aurata L., are reported for this species. Until now, six host species were reported for A. vittatus, and stenoxenic specificity for Sparid fishes was observed for Algerian specimens. The biogeographical distribution of this species seems to be restricted to the eastern coast of Algeria. Additional information about the host specificity, ecology, and life cycle of this parasitic species were given.

Additional morphological information on Dipteropeltis hirundo Calman, 1912, and a description of Dipteropeltis campanaformis n. sp. (Crustacea: Branchiura) from two characiform benthopelagic fish hosts from two Northern rivers of the Brazilian Amazon.

Dipteropeltis is a monotypic genus of the Branchiura and endemic to South America. Twelve specimens of Dipteropeltis sp. and micrographs of a thirteenth specimen were obtained from four institutions. Measurements and light micrographs were taken of all the specimens. The specimens were compared to all known descriptions of D. hirundo and sorted into two groups, those that conformed to the description of D. hirundo; and those that differed morphologically. Two specimens, one from each group¸ were stained with lignin pink and subsequently prepared for Scanning Electron Microscopy. The differences observed in the specimens indicated that a new species exists. Thus, Dipteropeltis campanaformis n. sp. is described from seven specimens collected from two characiform benthopelagic fish species and compared to D. hirundo. Dipteropeltis campanaformis n. sp. differs from D. hirundo in the head shape, the length and shape of the carapace lobes, the membrane composition of the maxillules, the shape of the maxillae, the shape of the mouth, and the shape of the natatory lobes.

Two New Genera and Species of the Parasitic Copepod Family Chondracanthidae Milne Edwards, 1840 (Copepoda: Cyclopoida) from Deep-Sea Fishes Off Suruga Bay, Japan.

PURPOSE: The present paper describes two new genera and species of the parasitic copepod family Chondracanthidae Milne Edwards, 1840 based on specimens collected from two species of deep-sea fishes at a depth of 212 m off Suruga Bay, Japan. Avatar nishidai gen. et sp. nov. is described from the host fish Chaunax abei Le Danois, 1978 (Chaunacidae). Kokeshioides surugaensis gen. et sp. nov. is described from the host fish Setarches longimanus (Alcock, 1894) (Setarchidae). METHODS: Fresh specimens of chondracanthids were collected from the buccal cavity of two species of deep-sea fishes (fish hosts were frozen), Chaunax abei Le Danois, 1978 (Lophiiformes: Chaunacidae) and Setarches longimanus (Alcock, 1894) (Perciformes: Setarchidae), caught at a depth of 212 m in Suruga Bay, Japan (34° 37'48.87″ N, 138° 43'2.958″ E). Both the species are described and illustrated based on ovigerous females. RESULTS: The genus Avatar gen. nov. can readily be distinguished from all other chondracanthid genera by the following combination of features: cephalothorax slightly wider than long with anterior pair of large and posterior pair of small lateral lobes, and two pairs of ventro-lateral processes; the very posteriormost part of the first pedigerous somite contributes to the neck; cylindrical trunk with two pairs of blunt proximal fusiform processes; antennule with small knob terminally; antenna bearing distal endopodal segment; labrum protruding ventrally; two pairs of biramous legs each with 2-segmented rami. Kokeshioides gen. nov. has the following combinations of features that distinguish it from other chondracanthid genera: body flattened, without lateral processes; cephalothorax much wider than long, with paired anterolateral and posterolateral lobes, folded ventrally; the very posteriormost part of the first pedigerous somite contributes to the neck; mandible elongate; legs unique, heavily sclerotized, represented by two pairs of acutely pointed processes. CONCLUSION: With the addition of two new genera presently reported, the family Chondracanthidae currently includes 52 valid genera. Among the described genera Avatar gen. nov. seems to be very primitive, while Kokeshioides gen. nov. is highly advanced. The deduced evolutionary history of chondracanthid genera is also discussed.

Parasites of wild rabbits (Oryctolagus cuniculus) from an urban area in Germany, in relation to worldwide results.

The European rabbit (Oryctolagus cuniculus) belongs to the most invasive and successful mammalian species, which is distributed nearly worldwide. In Europe, they inhabit broad parts of the mainland and subsequently reached several European islands via anthropogenic diversion. Rabbits can also serve as hosts for numerous parasite species. The parasite and pathogen fauna of O. cuniculus have been well documented in various European countries, although studies in Germany are scarce. Until now, a comprehensive survey combining recent international studies over parasite fauna of wild rabbits had not been conducted. We examined 50 wild rabbits from an urban area near Aachen (Germany) to identify their metazoan parasite fauna, and then compared our findings to previous international investigations. A total of nine parasite species were isolated consisting of four endoparasite species (Cittotaenia denticulata, Graphidium strigosum, Passalurus ambiguus, and Trichostrongylus retortaeformis) and five ectoparasite species (Cheyletiella parasitivorax, Ixodes ricinus, Leporacarus gibbus, Haemodipsus ventricosus, and Spilopsyllus cuniculi). Among the ectoparasites were two verifiable human pathogenic species and two potentially pathogenic species. In comparison to previous studies, a high number of similarities in composition of helminth species fauna were revealed. Furthermore, our results showed partial agreement with international surveys in prevalence and mean intensity of the parasites C. denticulata, G. strigosum, P. ambiguus, and T. retortaeformis.

Ciliate ectoparasites (Ciliophora: Trichodinidae/Chilodonellidae) on gills of Carassius auratus from the Yangtze River, China, with the description of Trichodina luzhoues sp. n.

Three species of the genus Trichodina Ehrenberg, 1838 and one species of the genus Chilodonella Strand, 1926 were collected from gills of Carassius auratus. They are Trichodina luzhoues sp. n., Trichodina mutabilis Kazubski and Migala, 1968, Trichodina reticulata Hirschman and Partsch, 1955, and Chilodonella hexasticha Kiernik, 1909. T. luzhoues sp. n. is a medium-sized trichodinid, and its denticles are very distinctive: the blade is narrow rhombus shaped, the section connecting the blade and central part is long and very thin; the section connecting the central part and ray is short and very thick. Ch. hexasticha is a new record in China.

Biodiversity and prevalence of parasites of domestic pigeons (Columba livia domestica) in a selected semiarid zone of South Khorasan, Iran.

Five species of nematodes and cestodes were collected from alimentary canals of pigeons: the nematodes were two species: Ascaridia colombae (16.66%) and Hadjelia truncata (1.96%), while the cestodes were Cotugnia digonopora (13.79%), Raillietina magninumida (18.62%) and Raillietina achinobothridia (32.35%); fecal examination revealed: Eimeria spp. (40.19%) and Cryptosporidium oocysts (2.94%); and blood smears showed: Haemoproteus cloumbae (47/05%); in mouth, throat and larynx: Trichomonans gallinae (57.84%); four species of ectoparasites were collected from feathers and subcutaneous nodules as follows: feathers: Pseudolynchia canariensis (63.72%), Columbicola columbae (79.41%), Menopen gallinea (44.11%); subcutaneous nodules: Laminosioptes cysticola (1.96%). From the parasitic fauna identified in this study, it is imperative to institute an integrated parasitic control through constant changing of litter, regular use of antihelminthics, anticoccidials and dusting of birds with pesticides.

Parabrachiella jarai sp. nov. (Crustacea: Copepoda: Siphonostomatoida) parasitic on Sillago sihama (Actinopterygii: Perciformes: Sillaginidae).

The presently reported study provides a detailed morphological description of the female and the male of a new species of the genus Parabrachiella-Parabrachiella jarai sp. nov. The parasites were sampled from marine fish, silver sillago, Sillago sihama (Perciformes: Sillaginidae), captured in Malaysia in 1994 and Hong Kong in 1995. The new species bears some resemblance to Parabrachiella lata (Song et Chen, 1976) but differs from it in details of second antenna, mandible, and maxilliped. The genus Parabrachiella currently covers 67 species including those recently transferred from Neobrachiella Kabata, 1979. An amended generic diagnosis is proposed for Parabrachiella and Thysanote. Some members of Parabrachiella are herewith transferred to Thysanote and some Thysanote are now placed in Parabrachiella.

Ectoparasites (sucking lice, fleas and ticks) of small mammals in southeastern Kenya.

During 1998-2000, at least 14 species (n = 309) of small mammals were live-trapped and examined for ectoparasites in moist forests of the Taita and Shimba Hills and drier savannah habitats of Nguruman, southeastern Kenya. Ectoparasites were recorded from 11 species of mammals. Five species of sucking lice [Hoplopleura inexpectans Johnson, H. intermedia Kellogg & Ferris, Polyplax reclinata (Nitzsch), P. waterstoni Bedford and Schizophthirus graphiuri Ferris], six species of fleas (Ctenophthalmus leptodactylous Hubbard, Dinopsyllus grypurus Jordan & Rothschild, D. lypusus Jordan & Rothschild, Hypsophthalmus campestris Jordan & Rothschild, Listropsylla basilewskyi Smit and Xiphiopsylla lippa Jordan) and at least six species of ticks (Amblyomma sp., Haemaphysalis sp., Ixodes sp., I. alluaudi Neumann, I. cumulatimpunctatus Schulze, I. muniensis Arthur & Burrow and Rhipicephalus sp.) were recorded from these hosts. Four of the five species of sucking lice were host specific whereas P. reclinata was recorded from two different species of white-toothed shrews, Crocidura spp. Although fleas and ticks were less host specific, C. leptodactylous, D. grypurus and I. cumulatimpunctatus were only recorded from the murid rodent Praomys delectorum (Thomas), Amblyomma sp. was only recorded from the nesomyid rodent Beamys hindei Thomas, Rhipicephalus sp. was only recorded from the murid Lemniscomys striatus (L.) and I. muniensis was only recorded from the dormouse Graphiurus microtis (Noack). More species of ectoparasites and significantly greater infestation prevalences were recorded from small mammals in moist habitats compared with those from the savannah habitat. At least one of the fleas recorded, D. lypusus, is a known vector of Yersinia pestis Lehmann & Neumann, the causative agent of plague, which is present in the region.

The chiggerflea Hectopsylla pulex (Siphonaptera: Tungidae) as an ectoparasite of free-tailed bats (Chiroptera: Molossidae).

In the present study, we investigated the prevalence and intensity of Hectopsylla pulex infection in Molossus rufus and Molossus molossus, the parasite's choice of attachment site, and whether this host-parasite system varies with host size. Twenty-four bats were captured by hand from the roof of a house in Southeastern Brazil. M. rufus exhibited a prevalence of 71.4% and the mean intensity averaged 5 ectoparasites per bat. M. molossus exhibited a prevalence of 90%, and the average mean intensity was 2.11 ectoparasites. The attachment sites were: ear, tragus, shoulder blade and tibia, anus, wing, axilla, mouth and dactylopatagium. A positive correlation was observed between the bats' weight and the number of fleas.

A New Species of Neoalbionella (Copepoda: Siphonostomatoida: Lernaeopodidae) From Skin of the Gulper Shark, Centrophorus granulosus (Squaliformes: Centrophoridae) In the Northern Gulf of Mexico.

Using light and scanning electron microscopy of male and female copepods, we herein describe a new species of Neoalbionella Özdikmen, 2008 (Copepoda: Lernaeopodidae), Neoalbionella benzipirata n. sp., infecting the skin of the gulper shark, Centrophorus granulosus (Bloch and Schneider, 1801), in the northern Gulf of Mexico. Females of the new species were assigned to Neoalbionella by having 3 setae on the maxillule lateral palp (vs. 2 setae in Lernaeopoda Nordmann, 1832) and a single accessory denticle on the maxilliped subchela claw (vs. ≥2 denticles in Lernaeopoda). Females of the new species resemble those of Neoalbionella longicaudata ( Hansen, 1923 ) Özdikmen, 2008 but can be differentiated from them and those of all congeners by having a unique configuration of 16 dorsocephalic sensilla; an antennule terminal segment having 6 apical setae comprising tubercles 1 and 3, digitiform seta 4, 2 subequal setae of complex 5, and flagelliform seta 6; an antenna exopod with a thickened dorsal ridge, smooth (convex) outer surface with 2 short papillae, and rugose (concave) inner surface plus a terminal endopodal segment having a large dorsal hook, medial spine, bifid distal tubercle, and spinulose ventral process; a mandible having the formula P1, S1, P1, S1, P1, S1, B5; and a single pair of anterolateral spines on the mouth cone labium. Males attached to the posteroventral surface of the females' genital trunk were assigned to Neoalbionella by having tapered (not inflated) caudal rami directed posteroventrally. They were differentiated from previously reported congeneric males by having an antennule with the same number and configuration of apical setae as the female; an antenna with a spatulate exopod having minute spinules along its apex plus a terminal endopodal segment with components the same as the female; a mandible with formula P2, S1, P1, S1, B5; a labium with 1 pair of anterolateral spines like the female; and a conspicuous mediative process with bifid tip. Detail of the dorsocephalic shield (in females) and mouth cone labium (in both sexes) previously had not been used to diagnose Neoalbionella spp. We also dissected voucher specimens of " Neoalbionella longicaudata" (collected from gulper sharks in the western Pacific Ocean off Japan by Shiino in 1956), which we morphologically diagnosed as an innominate species, Neoalbionella sp. This is the first report of a species of Neoalbionella from the Gulf of Mexico and the second species of Neoalbionella reported from C. granulosus, a deepwater shark seldom encountered and surveyed for parasitology.

A new gnathiid (Crustacea: Isopoda) parasitizing two species of requiem sharks from Lizard Island, Great Barrier Reef, Australia.

Third-stage juveniles (praniza 3) of Gnathia grandilaris n. sp. were collected from the gill filaments and septa of 5 requiem sharks, including a white tip reef shark, Triaenodon obesus, and 4 grey reef sharks, Carcharhinus amblyrhynchos, at Lizard Island, Great Barrier Reef, Australia, in March 2002. Some juvenile gnathiids were then maintained in fresh sea water until they molted to adults. Adult males appeared 19 days following detachment of juveniles from host fishes, but no juveniles molted successfully into females. The current description is based, therefore, on bright field and scanning electron microscopy observations of adult males and third-stage juveniles. Unique features of the male include the triangular-shaped inferior medio-frontal process, 2 areolae on the dorsal surface of the pylopod, and a slender pleotelson (twice as long as wide) with lateral concavities. The third-stage juvenile has distinctive white pigmentation on the black pereon when alive, while the mandible has 9 triangular backwardly directed teeth. This species has the largest male and third-stage juvenile of any Gnathia spp. from Australia and of any gnathiid isopods associated with elasmobranchs.

A new species of Ergasilus (Copepoda:Cyclopoida:Ergasilidae) from coastal fishes of the Mexican Pacific.

A new species of the cyclopoid copepod genus Ergasilus von Nordmann, 1832 is described based on adult female specimens removed from the gills of the yellow snapper Lutjanus argentiventris (Peters) and the yellowfin snook Centropomus robalito Jordan et Gilbert from a Pacific coastal system of Mexico. The new species Ergasilus davidi sp. n. has a combination of characters that includes a two-segmented first leg endopod, a three-segmented fourth leg endopod, and the presence of a single seta on the first antennular segment. These characters are shared with 14 other congeners known mainly from Brazil and North America. It differs from these other species in the armature and ornamentation of legs 1 and 4, the shape of the body, and the structure and ornamentation of the antennae. Additional characters include a maxillar basis armed with blunt teeth, distally bent maxillular setae, and naked margins of first exopodal segments of legs 2-4. Previous regional records of Ergasilus sp. from both fish species are probably assignable to E. davidi. The prevalence and intensity of infection was estimated for both teleost species and agrees to previous data. Based on other records of the genus from several other teleost species in the surveyed area and adjacent zones of the Eastern Pacific, it is presumed that the new species could have a wider range of hosts. The new species represents the first Ergasilus described from Mexican waters of the Pacific. Overall, the genus remains poorly known in Central America and Mexico.

Redescription of the Siamese shield leech Placobdelloides siamensis with new host species and geographic range.

The Siamese shield leech Placobdelloides siamensis (Oka, 1917) Sawyer, 1986 (Euhirudinea: Glossiphoniidae) was collected from five new host species, Southeastern Asian Box Turtle (Cuora amboinensis), Yellow-headed Temple Turtle (Heosemys annandalii), Malayan Snail-eating Turtle (Malayemys macrocephala), Mekong Snail-eating Turtle (M. subtrijuga), and Khorat Snail-eating Turtle (M. khoratensis) and was found for the first time in Udon Thani, Thailand. Examination of live leeches provided, for the first time, data on coloration and the combination of parental care behavior, both carrying cocoons and attaching cocoons to the substrate. This species was separated from its congeners based on the following characters: one pair of eyes; spines at proboscis subterminal; mouth terminal on oral sucker; absent plaque in neck region; gonopores located in furrow and separated by two annuli; distinctly triannulated mid-body segments; crop with seven pairs and branched caeca; caudal sucker slightly over half of maximum body width; and strongly dorsal papillae. Phylogenetic relationships based on the COI and ND1 genes were clarified and demonstrated that the species is distinct from others. The original description was amended and the taxonomic history is discussed.

Scanning electron microscopy study of Strabax monstrosus von Nordmann, 1864 (Copepoda: Chondracanthidae) from Tunisian waters and histopathological study of its effects on host.

Strabax monstrosus von Nordmann, 1864 (Copepoda: Chondracanthidae) is an ectoparasite and it was recently recorded from small red scorpionfish, Scorpaena notata Rafinesque, and red scorpionfish, Scorpaena scrofa L., collected from Tunisian coastal waters. Copepod females were found deeply embedded in the branchial cavity reaching the cardiac region with their mouth-parts. Observations of females and males using scanning electron microscopy showed a number of morphological features that have been previously overlooked or incompletely presented. In this study, we report for the first time the fine structures of appendages, mouthparts, external genital organs (nuptial organs), and other structures of male and female Strabax monstrosus. Histopathological study showed lesions in the cardiac region of the host fish which is the target site of the parasite. The presently reported finding is the first record of Strabax monstrosus from Scorpaena notata and Scorpaena scrofa collected from Tunisian waters.

A new family of poecilostomatoid copepods (Umazuracolidae) based on specimens parasitic on the black scraper (Thamnaconus modestus) in Japan.

Umazuracola elongatus n. gen., n. sp., is described based on specimens collected from the body surface of the black scraper, Thamnaconus modestus (Günther), taken from the Seto Inland Sea in western Japan. The new species belongs to a new family of the copepod order Poecilostomatoida. It is characterised by the reduction of the maxilliped and leg 1 in females and modification in both sexes of legs 2, 3, and 4 into robust attachment organs, with heavy, denticulate outer spines. Although the antenna, mandible, maxillule, and maxilla of U. elongatus resemble those of species of the "bomolochiform complex", a cladistic analysis revealed that phylogenetically this species is embedded in a different clade containing the polychaete-parasitizing families Entobiidae Ho, 1984 and Nereicolidae Claus, 1875.

A Natural Cattle Immune Response Against Horn Fly (Diptera: Muscidae) Salivary Antigens May Regulate Parasite Blood Intake.

The horn fly, Haematobia irritans (L.), is a blood-sucking ectoparasite that is responsible for sizeable economic losses in livestock. The salivary gland products facilitate blood intake. Taking advantage of the identification of novel H. irritans salivary antigens (Hematobin, HTB and Irritans 5, IT5), we investigated the parasite loads, H. irritans blood intake, and antibody response of naturally infected bovines during the fly season. Fly loads and fly hemoglobin content fluctuated during the trial. Each time horn fly loads exceeded 200 flies per cattle, a reduction in horn fly blood intake was observed three weeks later. All of the cattle elicited an antibody response against HTB and IT5 that declined once the fly season was over. Cattle anti-IT5 titers were positively correlated with parasite loads and negatively correlated with fly blood intake. These results suggest that the natural changes in the H. irritans blood intake observed in this study were associated with a natural host response against horn fly salivary antigens.

A review of the Taeniacanthus balistae species group (Crustacea: Copepoda: Taeniacanthidae), with descriptions of two new species.

The Taeniacanthus balistae species group is characterized by two displaced elements on an outwardly curved and elongated terminal exopodal segment of leg 4. Members of this group parasitize tetraodontiform fishes. The group is reviewed herein based on both new material collected from tetraodontiform fishes and re-examination of voucher specimens housed at the Smithsonian Institution, U.S.A. Five species are considered valid in this group, including two new species described here, Taeniacanthus dojirii sp. nov. from diodontid hosts collected from the Indo-West Pacific and Taeniacanthus ryukyuensis sp. nov. from balistid hosts collected from the Ryukyu Islands, Japan. Taeniacanthus dojirii sp. nov. differs from other members of the group by having in the female stout spines on the terminal endopodal segment of legs 2 to 4 and on the exopod of leg 5, as well as highly reduced setae on the last two exopodal segments of leg 4. Taeniacanthus ryukyuensis sp. nov. differs from other members of the group by having in the female 16-18 incomplete rows of spinules on the anal somite, minute teeth on the straight terminal claw of the maxilliped and well-developed spinulated flanges on the rami of legs 2 to 4. Supplemental morphological observations, as well as new host and locality records for Taenicanthus balistae (Claus, 1864) and Taeniacanthus similis Dojiri & Cressey, 1987, are also provided.