A new nematode of the family Capillariidae identified in Cairina moschata (Linnaeus) on Marajó Island in the Brazilian Amazon

Abstract

Capillaria Zeder, 1800, parasitizes the organs and tissues of several hosts, including the domestic duck Cairina moschata (Linnaeus). This article describes a new species of Capillaria in domestic ducks identified based on morphological studies and molecular analyses of the ribosomal RNA gene. Thirty-eight specimens of C. moschata from the municipality of Soure, Marajó Island, Pará, Brazil. The organs of the birds' digestive tract were analyzed under a stereomicroscope to confirm the parasitic infection, after which the collected nematodes were identified by light microscopy, scanning electron microscopy, and molecular analysis. Capillariids parasitized the intestine and cecum of the examined birds. These parasites had three bacillary bands and a pair of elongated precloacal papillae on the tail. Phylogenetic analysis indicated that the new species formed a sister clade with Capillaria spinulosa (Linstow, 1890), as described in Indonesia and Japan. Based on morphological distinctions and molecular data, Capillaria cairina n. sp. can be considered a new parasite species of C. moschata in the Brazilian Amazon.

Paracapillaria (Ophidiocapillaria) siamensis sp. nov. (Nematoda: Trichuroidea): a new nematode in Naja kaouthia from Thailand

“…Several characteristics, such as the target organ of infection, type of vulva lips, shape of the proximal spicule and locality, can serve as alternatives for species identification (e.g. Moravec, 2001 ; Timi et al ., 2007 ; Moravec and Justine, 2010 and, 2020 ; Melnychuk et al ., 2020 ; Sakaguchi et al ., 2020 ; Carvalho et al ., 2023 ). Despite the distinctiveness of many species based on those characteristics, a few original papers on Paracapillaria lacked morphological details, resulting in difficulties in the identification of species, particularly Paracapillaria ptyasi found in the southern part of China.…”

“…nov., except for a few measurements i.e. nerve-ring position, stichocytes numbers, anterior part length, female body length and importantly, the spicule shape, a key factor in Paracapillaria 's identification ( sensu Moravec and Justine, 2020 ; Carvalho et al ., 2023 ). The spicule shape was markedly different between these 2 species – round for P. ptyasi and frame-like for P. siamensis sp.…”