Systematic Parasitology最新文献

The study of the monogenean fauna of Brycinus kingsleyae, Brycinus macrolepidotus, Phenacogrammus major and Hepsetus odoe, four characiform fishes consumed in Cameroon allowed to find seven species of Annulotrema Paperna and Thurston, 1969 and provided new information for the diagnosis of these helminths. Concerning the parasites of Brycinus kingsleyae: in Annulotrema combesi Birgi, 1988, the copulatory tube can make two turns of spire contrary to the initial description which indicates a single turn; on the dorsal bar of Anulotrema maillardi Birgi, 1988, a sclerotized structure was observed for the first time; a loop was also noted for the first time on the ventral bar of Annulotrema nyongesnsis Birgi, 1988. For parasites of Phenacogrammus major, the vagina was observed for the first time in Annulotrema gabrioni Birgi, 1988. A membrane extension never reported on the dorsal transverse bar of Annulotrema hepseti Paperna and Thurston, 1969, a parasite of Hepsetus odoe was observed during this study. Principal Component Analysis (PCA) allowed the assignment of a morphogroup to the two recently described species in Brycinus macrolepidotus. Thus, a new morphogroup named Ngombiensis n. gr. was created to classify Annulotrema ngombiensis Ndongo and Tombi, 2023. As for Annulotrema nkengfacki Ndongo and Tombi, 2023, its morphometric characteristics allow it to be associated with the Nyongensis group created by Birgi in 1988.

Descriptions are given for two new diplectanid monogeneans, Cryptoplectanum ishigakiense n. g., n. sp. collected from Malabar grouper Epinephelus malabaricus (Bloch & Schneider) and orange-spotted grouper Epinephelus coioides (Hamilton), and Pseudorhabdosynochus yaito n. sp. from E. malabaricus, both cultured on Ishigaki Island, Okinawa, Japan. Cryptoplectanum n. g. differs from its most similar genus Pseudorhabdosynochus Yamaguti, 1958 by having an unsclerotized vagina and lacking a quadriloculate organ. Cryptoplectanum ishigakiense n. sp. differs from its most similar species Diplectanum maa Justine & Sigura, 2007 by possessing a small, funnel-shaped penis and tegumental scales in posterior body, whereas D. maa has a larger, spoon-shaped penis and lacks tegumental scales. Pseudorhabdosynochus yaito n. sp. is most similar to P. manifestus Justine & Sigura, 2007, but can be differentiated by the shape of the quadriloculate organ; in the new species, all chambers are of equal width and equally sclerotized, while in P. manifestus the chambers became gradually narrower toward the cone and the fourth chamber is more heavily sclerotized than the anterior three. Molecularly, C. ishigakiense n. sp. forms a clade with Diplectanum grouperi Bu, Leong, Wong, Woo & Foo, 1999, both constituting a lineage closely related to the main Pseudorhabdosynochus clades. Both D. maa and D. grouperi possess the penis and vagina characteristic of the newly proposed genus Cryptoplectanum, and thus are assigned to Cryptoplectanum maa n. comb. and C. grouperi n. comb., respectively.

A new nicothoid copepod species Rhizorhina hamatipedicola n. sp. is described, parasitic on the tanaidacean Hamatipeda kohtsukai Kakui & Hiruta (Hamatipedidae) collected at depths of 360-375 m in Sagami Bay, Japan, in the northwestern Pacific. It closely resembles Rhizorhina aesthetes Boxshall & Harrison, 1988 parasitic on an ischnomesid isopod collected at a depth of about 2910 m in the northeastern Atlantic, and Rhizorhina ohtsukai Kakui, 2016 parasitic on the leptocheliid tanaidacean Chondrochelia sublitoralis Sato, Arakawa, & Kakui collected at depths of 151-136 m in the northwestern Pacific. Although there are only minor morphological differences between these Rhizorhina species, their hosts differ at the level of order or family. The known geographical and depth distributions of R. hamatipedicola differ greatly from those of R. aesthetes. A partial nucleotide sequence of the 18S rRNA (18S) gene from R. hamatipedicola was identical to that from R. ohtsukai, but the two species differed by 13.4% and 14.9% p- and K2P distances, respectively, for the cytochrome c oxidase subunit I (COI) gene, which were much greater than intraspecific distances previously reported in Siphonostomatoida. This study suggests that an integrative approach combining morphology, sequences of COI or other genes evolving faster than 18S, and host data is necessary to reliably distinguish among morphologically similar Rhizorhina species.

Telenomus hexodon Debnath & Rajmohana sp. nov. (Hymenoptera: Scelionidae), is described as new to science. The species was reared from eggs of the polyphagous pest Clouded Tiger moth, Creatonotos transiens (Walker) (Lepidoptera: Erebidae). This represents the first record of an insect parasitoid association with C. transiens. Host identity was confirmed through DNA barcoding, while the parasitoid was characterized using an integrative taxonomic approach combining morphological and molecular data. Further, a checklist of Telenomus species reported from India is provided.

A new species of monopisthocotylan parasite has been identified on the body surface of the Antarctic rockcod Notothenia coriiceps Richardson, in the coastal waters surrounding Galindez Island, West Antarctica. The newly described species, Pseudobenedenia galindezensis sp. n., is morphologically distinct from all previously recognized species within the genus Pseudobenedenia as evidenced by a combination of unique morphometric traits. These include the shape and size of opisthaptoral sclerotized elements, the presence of a particularly robust accessory sclerite, and a characteristic ratio between the anterior hamulus and accessory sclerite. These features collectively support its recognition as a separate species. A well-developed orifice of the common genital opening was observed and measured in the newly described species, an anatomical feature not previously documented in Pseudobenedenia. Measurements of the vagina are provided for the first time for all of the described Pseudobenedenia species. The presence or absence of a distinct gap between the testes represents a novel diagnostic character introduced in this description. Additional distinguishing features include the length-to-width ratios of the testes and body, as well as the body length-to-opisthaptor length ratio, all of which further support the species' distinctiveness. Molecular analyses of 18S and 28S nuclear markers were conducted to study the phylogenetic position of this new species within the family Capsalidae. The results indicated consistent genetic divergences, which were accompanied by observed morphological differences, thereby substantiating the classification of the species as new to science. Molecular analysis was conducted to differentiate P. galindezensis sp. n. from the closely related Pseudobenedenia coriicepsi. This new species was found on a fish host that is morphologically distinct from most collected N. coriiceps, characterized by its larger size and reddish color; its identity was confirmed using mitochondrial cox1 sequences. A significant finding of our study is that one nototheniid species can host more than one species of Pseudobenedenia.

Trematodes of the family Accacoeliidae Odhner, 1911 are well known as parasites of sunfishes. Herein, we report the accacoeliid trematode fauna of two sunfish species, Mola mola (Linnaeus) and Masturus lanceolatus (Liénard), in Japanese waters. Between 2023 and 2025, four individuals of each host species were examined, yielding 497 trematodes. These trematodes specimens were assigned to ten accacoeliid species (497 individuals in total) belonging to five genera through morphological and molecular analyses based on partial sequences of the nuclear 28S ribosomal RNA and mitochondrial cytochrome c oxidase subunit I genes. Four of the ten species were identified as new to science: Accacladocoelium latens n. sp., Accacladocoelium mayosenase n. sp., Accacladocoelium mica n. sp., and Rhynchopharynx yarimanbou n. sp. Detailed morphological descriptions were also provided for six known species: Accacladium serpentulum Odhner, 1928; Accacoelium contortum (Rudolphi, 1819); Accacladocoelium nigroflavum (Rudolphi, 1819); Accacladocoelium petasiporum Odhner, 1928; Odhnerium calyptrocotyle (Monticelli, 1893); and Rhynchopharynx paradoxa Odhner, 1928. Furthermore, Accacladocoelium alveolatum Robinson, 1934 was synonymized with Accacladocoelium nigroflavum based on molecular and morphological evidence.

The type species of the trematode genus Skrjabinolecithum, S. spasskii, a parasite of mullets in the Russian Far East and Vietnam, was shown to possess three different variants of rDNA sequences in earlier studies. The goal of the present study is to clarify the taxonomic status of genetically different trematodes, considered S. spasskii, in the Russian Far East and Vietnam by means of new morphological and molecular data. For this study, trematodes of the genus Skrjabinolecithum were collected from mugilid fish from estuaries of rivers of the south of the Russian Far East and the Cat Ba Island, Vietnam. Preliminary species identification and detailed morphometric analysis were carried out using high-resolution light microscopy. Molecular differentiation and phylogenetic analyses were carried out based on nuclear 28S rDNA and mitochondrial cox1 gene sequences. As a result, two morphotypes of S. spasskii were revealed, and two new species, S. kievkaense n. sp. and S. vietnamense n. sp., were validated. These species have no qualitative differences in body form and in organ structure and arrangements but have some differences in metric parameters. The validity of the new species was confirmed by phylogenetic analysis based on the mitochondrial cox1 gene sequence dataset.

Ixodes (Afrixodes) colboi n. sp. (Acari: Ixodidae) is described based on females ex the checkered elephant shrew, Rhynchocyon cirnei Peters (Macroscelidea: Macroscelididae) from Zambia. Females of this new species can be distinguished from other Afrotropical species of the subgenus Afrixodes Morel, 1966 by the development of carinae and scutal punctations, shape of apron and anterior projection of basis capituli, length and development of spurs on palpal segment I, coxae and trochanters, and the size and development of the syncoxae.

Phanerothecium acutum sp. n., the eighth described species of the genus Phanerothecium, is characterized by a unique combination of morphological and molecular traits. Morphologically, it differs from closely related species such as P. spinatus, P. deiropedeum, and P. macrosomum by features of the male copulatory organ (MCO), anchor configuration, and ventral bar structure. Notably, P. acutum sp. n. possesses an MCO armed with delicate spines, robust and truncated anchors with a slight elevation on the shaft, and a ventral bar with expanded extremities. Molecular analyses yielded three new 18S and two partial 28S rDNA sequences. A newly developed primer (DAC18F2) markedly improved PCR success and sequencing quality for 18S amplification. Genetic distance analyses based on 18S support P. acutum sp. n. as a distinct species, with interspecific divergence from most congeners ranging from 1.4-2.0%, and intraspecific variation of 0.0-0.2%. However, its genetic similarity to Phanerothecium sp. KX981456 (0.2-0.9%) highlights the need for additional data to clarify species boundaries. Phylogenetic reconstructions based on 18S and 28S confirmed the monophyly of Phanerothecium, placed within a strongly supported clade alongside viviparous gyrodactylideans, and reaffirmed the validity of the family Oogyrodactylidae. These findings underscore the importance of integrative approaches for resolving taxonomic relationships and suggest that the genus Phanerothecium, particularly among loricariid hosts, harbors greater diversity than currently recognized.