Systematic Parasitology最新文献

Between 2022 and 2023 ascaridoid nematodes of the genus Hexametra were recovered from two captive central bearded dragons (Pogona vitticeps Ahl) in the Extremadura region of Spain. These nematodes were identified by an integrative approach combining morpho-anatomical and molecular data. We used two rRNA regions (D2-D3 expansion segments of the 28S, and ITS fragments), and the partial region of the cytochrome oxidase I gene (COI mtDNA) sequences. Hexametra angusticaecoides Chabaud & Brygoo, 1960 (Ascarididae) was morphologically characterized and illustrated using light and scanning electron microscopy. Bayesian inference (BI) and Maximum Likelihood (ML) phylogenetic trees for these genetic markers established relationships that highlight the importance of using molecular and phylogenetic data for accurate species identification within the genus Hexametra. Phylogenetic trees indicated that the Spanish isolates of H. angusticaecoides were clustered in a well-supported clade together with other isolates from Central Europe of the same species. Molecular phylogenetic findings also reflect that there was a higher intraspecific variation for ITS genetic markers at the intraspecific level. Phylogenetic results based on 28S rRNA suggest that Ascarididea was divided into three monophyletic major clades. To our knowledge, this is the first report of this species parasitizing bearded dragons, extending the host range of this species. These findings represent the first formal record of H. angusticaecoides in Spain.

Ixodes algericus n. sp. (Acari: Ixodidae) is described based on females, nymphs and larvae ex rodents (Rodentia: Muridae) from Algeria. Females of this new species possess a unique set of morphological characters allowing identification of this species from any other Ixodes Latreille, 1795 species. These characters include the lack of genital apron, length of auriculae, development of syncoxae and length of spurs on coxa I. The nymph and larva of I. algericus n. sp. can be distinguished from the potentially sympatric Ixodes s. str. species by the shape of the scutum, number of alloscutal setae, length of auriculae and shape of the hypostome.

Diplomonorchis micropogoni Nahhas & Cable, 1964 was considered a junior subjective synonym of Diplomonorchis leiostomi Hopkins, 1941 in 1969. Diplomonorchis leiostomi has since been widely reported from the coastal Western Atlantic between Delaware Bay and southern Brazil. Until now, taxonomically verifiable DNA sequence data for D. leiostomi has been available from an individual worm collected from the northern Gulf of Mexico. We generated a partial sequence of the 28S rRNA gene from D. leiostomi from the spot croaker, Leiostomus xanthurus Lacepède (type-host) from Beaufort, North Carolina, USA (type-locality) that differed at 31 of 1,246 bases from the available 28S sequence. This prompted a reevaluation of Diplomonorchis spp. identities from the northern Gulf of Mexico. We found D. leiostomi and D. micropogoni distinguishable by testes shape and size, and to a lesser degree by relative caecal length. Museum specimens of D. leiostomi, identified from the Gulf of Mexico represent a species complex containing D. leiostomi, D. cf. micropogoni and, a new species of Diplomonorchis. The sequences previously identified as D. leiostomi in GenBank (AY222137 & AY222252) are herein identified as D. cf. micropogoni. The new species is described from newly collected material herein. Phylogenetic analysis of 28S rRNA sequences from the species complex plus 46 species from the Monorchioidea Odhner, 1911 indicated all three Diplomonorchis spp. are closely related and form a clade with some species of Lasiotocus Looss, 1907. With the addition of the new species, and acceptance of D. micropogoni, there are currently 14 valid species in Diplomonorchis.

The taxonomic position of the hymenolepidid cestode genera Paraoligorchis Wason et Johnson, 1977 and Sudarikovina Spassky, 1951 from gerbils and ground squirrels from Africa, Southwest Asia and South Asia is clarified based on re-examination of type and voucher materials. The generic diagnosis of Sudarikovina is amended. The main corrections for diagnostic characters at the generic level include: irregularly-spaced transverse anastomoses of ventral osmoregulatory canals; presence of both specimens with dextral genital pores and specimens with sinistral genital pores; vagina clearly covered externally by a dense layer of intensely-stained cells; young uterus reticulate and fully-developed uterus with a labyrinthine structure. The previously proposed generic character of a minimum number of testes per proglottis of species of Sudarikovina is reduced to 3. The genus Paraoligorchis is recognized as a junior synonym of Sudarikovina. For the type species of Paraoligorchis, P. taterae Wason et Johnson, 1977, the replacement name Sudarikovina wasojohni nom. nov. is proposed, thus resolving the secondary homonymy of the transferred species and its senior homonym S. taterae Hunkeler, 1972. The validity of the tribe Sudarikovinini sensu Spassky (1991), to which Paraoligorchis and Sudarikovina had been attributed, cannot be resolved due the lack of molecular data. The cestode specimens from Shaw's jird, Meriones (Pallasiomys) shawi (Duvernoy) from Algeria and Tunisia, initially designated as Hymenolepis sp. by Joyeux (1923) and Hymenolepis procera Janicki, 1904 by Joyeux & Foley (1930), represent undescribed species of Sudarikovina, which are described in this study as Sudarikovina pentatesticulata sp. n. and S. tetratesticulata sp. n., respectively. The main diagnostic characters of the two new species, which distinguish them from their congeners, are the number and the size of the testes.

The Indo-Chinese green peafowl Pavo muticus imperator (Galliformes: Phasianidae) is an endangered bird species. However, our present knowledge of the species composition of nematode parasites of this bird remains limited. In the present study, two nematode parasites Heterakis pedioecetes Mawson, 1956 (Ascaridomorpha: Heterakoidea) and Synhimantus (Dispharynx) nasuta (Rudolphi, 1819) (Spiruromorpha: Acuarioidea) were reported from P. muticus imperator for the first time. The detailed morphology of these two nematode species was further studied using light and scanning electron microscopy, and some previously unreported morphological features were revealed. These supplementary morphological and morphometric data contributed to a more accurate identification of these two common avian nematodes.

Three new species of Jainus Mizelle, Kritzky & Crane, 1968, are described parasitizing the gill filaments of Triportheus angulatus (Spix & Agassiz) (Characiformes: Triportheidae), an omnivorous fish endemic to the Amazon River basin. Jainus iquitensis n. sp. is characterized by the morphology of the vagina, which is bell-shaped, with a canal as a sclerotized tube and the morphology of hook pair VII, which in the new species presents an inflated base, a characteristic not observed in other congeners. Jainus loretoensis n. sp. is unique among Jainus species due to the morphology of its Y-shaped ventral anchors, with an arrow-shaped superficial root and a finger-shaped deep root. Jainus sardinae n. sp. is characterized by presenting a slender, small J-shaped tube with a sigmoid accessory piece and a ventral anchor that is Y-shaped, with inconspicuous finger-shaped deep root and superficial root with rounded ending with a chin-shaped projection. These findings add three new species to the previously reported two Jainus species from Peru.

The familial affiliation of the so-far-monotypic palaeacanthocephalan genus Pseudocavisoma Golvan & Houin, 1964 has solely been based on morphological characteristics, lacking nucleotide sequence data. In this paper, we assess the phylogenetic position of the genus with a dataset consisting of partial sequences of the mitochondrial cytochrome c oxidase subunit I, and the nuclear 18S and 28S rRNA genes for 37 species of palaeacanthocephalans available in public databases along with the ones determined from the new species Pseudocavisoma setoense sp. nov., herein established with specimens collected from the intestine of the pearl-spot chromis Chromis notata (Temminck & Schlegel, 1843) obtained in the Seto Inland Sea, Japan. Our results suggested that Pseudocavisoma should be placed in Micracanthorhynchinidae Yamaguti, 1963, rather than in Cavisomatidae Meyer, 1932 as had been considered by previous authors. Because Micracanthorhynchinidae has been regarded synonymous with Rhadinorhynchidae Lühe, 1912 since 1985, we re-validate the former taxon while providing an amended diagnosis for it. Pseudocavisoma setoense sp. nov. can be distinguished from the sole congener Pseudocavisoma chromitidis (Cable & Quick, 1954) by the distributional pattern and the size of spines on the trunk. We provide a partial morphological redescription of the latter species based on syntypes of Cavisoma chromitidis Cable & Quick, 1954. We also provide an amended diagnosis for Pseudocavisoma to accommodate P. setoense sp. nov.

This study focuses on the opecoelid genus Podocotyle, particularly the species in the northern European seas (White, Barents and Pechora), with additional data from few isolates from the Far East. The research combines molecular analyses (28S, 5.8S+ITS2 rDNA, and cox1 mtDNA) and morphological examinations. Molecular analyses suggested that there are most likely four species of Podocotyle in the northern European seas and three more in the Far East. Morphological redescriptions are provided for three northern European species: P. atomon, P. reflexa, and P. odhneri, with the latter recognized as a valid species. The study also verified the life cycle of P. atomon and identified Lacuna vincta (Littorinidae) as the first intermediate host for P. reflexa. In the Sea of Okhotsk, L. turrita is the first intermediate host for two apparently undescribed Podocotyle species. The results also highlight the morphological variability of P. atomon, emphasizing the need for an integrative approach in the taxonomy and biodiversity studies.

In light of the morphological and molecular data for cyclocoelids observed from the air sacs of Mareca strepera (Linnaeus) (Anatidae, Anseriformes) caught in the southern region of the Russian Far East, we suggest new insights into the systematics of the family Cyclocoelidae. A comparative morphological and phylogenetic analyzes revealed that new cyclocoelids represented the new genus and species Paracyclocoelum lobatum. Based on the 28S rRNA gene fragment we showed the significant genetic divergence of P. lobatum from the type species of the type genus for the family, Cyclocoelum mutabile (Zeder, 1800) Brandes, 1892 and along with the confusing morphological similarity by the prepharyngeal position of the genital pore it most likely indicate homologous development of the reproductive system of Paracyclocoelum and Cyclocoelum. Here, we provide a new dichotomous key for five cyclocoelid genera from the subfamily Cyclocoelinae including Paracyclocoelum n. g. The new genus Paracyclocoelum had sister relationship to the cyclocoelin genus Circumvitellatrema. Based on the polyphyletic interrelationships of Cyclocoelum and Circumvitellatrema the Cyclocoelinae were assigned with the status sensu lato.

The epicaridean isopods previously known to have epicaridium larvae with posterior yolk sacs were species of Pleurocryptella Bonnier, 1900 and a new subfamily, Pleurocryptellinae, was recently erected for this genus. Epicaridium larvae bearing posterior yolk sacs are newly reported from two species of the genus Paragigantione Barnard, 1920 which is transferred from Pseudioninae to Pleurocryptelline on the basis of this and other shared characters of adult males and females with species of Pleurocryptella. Two new species of Paragigantione are described, one from the northeast Atlantic based on type material that was misidentified as belonging to the type species of the genus, P. papillosa Barnard, 1920 and a second from off New Zealand. One specimen of the New Zealand species had a cryptoniscus larva of a new species of hyperparasite of the genus Bourdonia Rybakov, 1990 in the marsupium while another had a species of Duplorbis (Rhizocephala); the former is described based on this material as well as a specimen from a specimen of Pseudione cf. fibriata Richardson, 1910 from New Zealand. Keys to species of Paragigantione for both males and females are provided.