Morphological and molecular characterization of Brevimulticaecum sinensis sp. nov. (Nematoda: Ascaridoidea) from Alligator sinensis (Crocodilian: Alligatoridae).

Brevimulticaecum sinensis sp. nov. is a novel species belonging to the genus Brevimulticaecum (Nematoda: Heterocheilidae). It was detected in the stomach of a carcass of a Chinese alligator (Alligator sinensis Fauvel, 1879; Crocodilian: Alligatoridae) at the National Nature Reserve of China Alligator, Anhui Province, China. This study investigated the morphological and molecular characteristics of the isolated B. sinensis sp. nov. Herein, light and scanning electron microscopy, DNA sequencing, and histological analyses were performed for B. sinensis sp. nov. Notably, microscopy revealed novel taxonomic features of B. sinensis sp. nov. Additionally, the sequences of the internal transcribed spacer (ITS), cytochrome oxidase I (COI), and small subunit DNA (18S) segments of B. sinensis sp. nov. were 892, 655, and 885 bp, respectively. To the best of our knowledge, this is the first study providing molecular data showing the affiliation of this Brevimulticaecum species with the family Heterocheilidae. The histological analysis revealed the pathology of B. sinensis sp. nov. infection in A. sinensis. Overall, the findings of this study provide novel geographic and infection records of B. sinensis sp. nov., with it being added to nematode species that infect crocodiles.