Systematic Parasitology最新文献

During parasitological surveys of marine fishes and zooplankton in localities of the Northwestern Pacific coast of Mexico, 28 Gafftopsail pompano (Trachinotus rhodopus Gill) and 50 mysid crustaceans (Metamysidopsis frankfiersi Hendrickx & Hernández-Payán) we identified to be infected with adults and cystacanths, respectively of an acanthocephalan morphologically corresponding to the genus Rhadinorhynchus Lühe, 1911. DNA sequences of the small (SSU) and large (LSU) subunits of ribosomal DNA, and cytochrome c oxidase subunit 1 (cox 1) from mitochondrial DNA were obtained. Phylogenetic analyses revealed that the newly sequenced individuals in a clade with Rhadinorhynchus sp. from carangids in other localities of the Pacific coast of Mexico; together, all these individuals formed an independent lineage that is recognized herein as a new species, Rhadinorhynchus trachinoti n. sp. The new species is morphologically distinguished from the other 38 congeners by having a long and cylindrical proboscis armed with 12 longitudinal rows bearing 16-18 hooks each. The ecological information gathered from the parasites, together with genetic evidence, confirms that the Gafftopsail pompano is the definitive host of R. trachinoti n. sp., while mysid crustaceans serve as the intermediate host. Current records also indicate that R. trachinoti n. sp. is distributed along the Pacific coast of Mexico, from Mazatlán, Sinaloa in the north to Puerto Angel, Oaxaca in the south. This distribution aligns with the Mexican Coastal Current, which extends from the Gulf of Tehuantepec in Oaxaca to the entrance of the Gulf of California and southern Baja California.

Forty-two species of myxozoans, including 31 species of Myxobolus Bütschli, 1882, have been described from centrarchid fishes. One species, the green sunfish (Lepomis cyanellus), has been reported to host at least three species of Myxobolus. Between March 2023 and June 2024, 42 L. cyanellus were collected from watersheds in Montgomery and Polk counties, Arkansas, and their gills, gallbladders, urinary bladders, fins, integument, other major organs, and musculature were examined for myxozoans. Two (5%) L. cyanellus from Polk County were found to harbor a new species of Myxobolus infecting the gill lamellae. A qualitative and quantitative morphological description was based on formalin-fixed preserved plasmodia and myxospores. Plasmodia of Myxobolus polkensis n. sp. are 133 µm long × 123 µm wide, and myxospores are 19.8 µm long × 6.5 µm wide, with two narrowly pyriform unequal polar capsules, one usually longer (9.2 µm) than the other (8.5 µm). Molecular data consisted of a 2,025 base pair sequence of the partial small subunit rRNA gene (SSU). Variably sized, polysporic plasmodia were randomly distributed throughout the gill lamellae in intralamellar locations. Large plasmodia displaced adjacent lamellae inducing mild epithelial proliferation but minimal inflammatory changes. Phylogenetic analysis revealed that M. polkensis n. sp. is a member of a clade of myxozoan species that predominately infect centrarchids from North America. This is the fourth report of a Myxobolus from L. cyanellus but the first report of a species infecting the gill lamellae. This article was registered in the Official Register of Zoological Nomenclature (ZooBank) as urn:lsid:zoobank.org:pub:E9BA08E0-0A7E-487B-80AE-C5C723DBB661.

Cruzia Travassos, 1917 is a diverse genus of nematode parasites in amphibians, reptiles, and mammals. During a parasitological survey, specimens of Cruzia were found in the intestine of the lizards Ameiva ameiva (Linnaeus) and Teius teyou (Daudin) (Squamata: Teiidae) at the Chaco region, Formosa province, Argentina. A comparative analysis revealed that these nematodes represent a new species, named as Cruzia toba n. sp. The new species can be distinguished from the congeners based on the combination of the following features: presence 12-14 teeth per row in the pharynx, equatorial vulva in females, and number and arrangement of caudal papillae in males (11 pairs: 3 precloacal, 3 paracloacal, 5 postcloacal; plus a precloacal minute unpaired papilla). Cruzia toba n. sp. is closely related to C. lauroi Vieira, Gonçalves, Lima, Sousa, and Muniz-Pereira, 2020 a likewise parasite of lizards, regarding the length of spicules and the presence of an unpaired papilla in males, but differs from it in the position of the vulva, the size of the gubernaculum and in the number and arrangement of caudal papillae. This is the first report of a representative of Kathlaniidae parasitizing A. ameiva and T. teyou, and the first Cruzia infecting lizards from Argentina. The morphological affinities among species of Cruzia are mostly random, not allowing a morphological grouping of these parasites in relation to their host taxa, or geographic origin. Thus, the speciation process in Cruzia most likely occurred via host capture.

There are more than 200 species of Macronyssidae parasitizing reptiles, birds, and mammals worldwide. While most species are found on wild animals, show some degree of geographic, and host group specificity, Ophionyssus natricis thrives on captive snakes and lizards and as a result of the pet trade, has a cosmopolitan distribution. In this study, we are providing new host records for this species for the state of São Paulo, as well as SEM images and the first partial sequences of Brazilian specimens.

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.