Taxonomia de helmintos parasitos de aves do Estado de Minas Gerais, Brasil: novos registros por abordagem morfológica e molecular

Abstract

Birds represent the group of vertebrates with the greatest diversity of helminths. In Brazil, although more than 800 species of these organisms have been reported in the most varied types of birds, the real diversity, hosts and distribution of these parasites are far from being completely known. Aiming to contribute to filling these gaps, the present study aimed to perform the taxonomic identification of helminths found in bird samples from the state of Minas Gerais. For this, previously collected samples and new samples from necropsied hosts between 2009 and 2022 were considered. The helminthological material obtained was processed by conventional techniques for each zoological group and subjected to morphological and morphometric characterization under a light microscope, followed by identification with the aid of taxonomic keys and descriptive articles. Additionally, genetic sequences were generated for some of the species and used in phylogenetic analyses. Helminths recovered from 18 bird specimens belonging to 11 species were examined in this study, and 10 families and 18 helminth species were identified. Among the representatives of the class Cestoda, Valipora campylancristrota (Wedl, 1855) is recorded for the first time in birds in Brazil and in a new definitive host, the ardeid Nycticorax nycticorax (Linnaeus, 1758) (savacu). In addition, Paradilepis caballeroi Rysavy & Macko, 1973, found in Nannopterum brasilianus (Gmelin, 1789) (cormorant), and Drepanidotaenia sp. in Butorides striata (Linnaeus, 1758) (socozinho) are recorded for the first time in Minas Gerais. Among members of the class Trematoda, molecular data obtained from Austrodiplostomum compactum (Lutz, 1928) of N. brasilianus support the synonym of A. ostrowskiae Dronen, 2009. Likewise, molecular data obtained from Platynossomum illiciens (Braun, 1901) first recorded in Falco sparverius (quiriquiri) add evidence for the occurrence in birds and mammals and provide additional support for synonymies. Tanaisia valida Freitas, 1951 obtained from Chrysomus ruficapillus (garibaldi) is recorded for the first time in Minas Gerais. Hysteromorpha sp. nov. was also found in N. brasilianus and the molecular data obtained support previous studies that reveal that this is a species yet to be formally described, distinct from Hysteromorpha triloba (Rudolphi, 1819) until then considered as the species present in South America. Drepanocephalus spathans Dietz, 1909 of N. brasilianus is reported for the first time in Minas Gerais. The analysis of specimens obtained from N. brasilianus led to the reestablishment of Ribeiroia insignis Travassos, 1939 as the species found in South America. The study of a species found in Megaceryle torquata (Linnaeus, 1766) (kingfisher) allowed the identification of Pulchrosoma reticulata (Wright, 1879), a species currently included in the family Echinostomatidae Looss 1899, but molecular analyses revealed that this genus should be transferred to the family Echinochasmidae Odhner, 1910. Brachylecithum rarum (Travassos, 1917) was recorded for the first time in Minas Gerais and in a new definitive host, Tachyphonus coronatus (Vieillot, 1822) (black tanager). Eight species of helminths of the phylum Nematoda were identified. Synhimantus (Dispharynx) nasuta (Rudolphi, 1819), Synhimantus (Dispharynx) resticula Canavan, 1929, Cyrnea piayae Sandground, 1929 and Subulura halli Barreto, 1918 are recorded for the first time in the migratory bird Coccyzus americanus (Linnaeus, 1758) (red- winged ground-eating dove). Although it is difficult to determine the precise geographic origin of the parasites, S. halli is reported for the first time in the Americas and S. (D.) resticula in South America. In addition to these, Diplotriaena delirae Pinto & Noronha, 1970 is reported for the first time in Columbina talpacoti (Temminck, 1809) (purple ground-eating dove). Finally, Microtetrameres spiralis (Seurat, 1915) is recorded in Bubulcus ibis (Linnaeus, 1758) (cattle egret), expanding its geographic range. Most of the characterized helminths are recorded for the first time in the state of Minas Gerais, which contributes to the advancement of knowledge on the diversity of helminth parasites of birds in the country.