Mayarhynchus karlae n. g., n. sp. (Acanthocephala: Neoechinorhynchidae), a parasite of cichlids (Perciformes: Cichlidae) in southeastern Mexico, with comments on the paraphyly of Neoechynorhynchus Stiles & Hassall, 1905

Abstract

Mayarhynchus n. g. (Acanthocephala: Neoechinorhynchidae) is erected for Mayarhynchus karlae n. g, n. sp. described from the intestine of four species of cichlid fishes distributed from southeastern Mexico. The new genus placed in the family Neoechinorhynchidae (Ward, 1917) Van Cleave, 1928, is readily distinguished from the other 17 genera in the family by having a small proboscis armed with 45-46 relatively weak rooted hooks arranged in nine longitudinal rows of five hooks each. In addition, Mayarhynchus n. g., n. sp. is diagnosed by the presence of a short trunk, body wall with five dorsal and one ventral giant hypodermal nuclei, proboscis receptacle nearly cylindrical with single layered wall, lemnisci broad and flat with large nuclei, testes in tandem, cement gland with eight large nuclei, and eggs elongate to oval. Partial sequences of the cytochrome c oxidase subunit 1 (cox1), internal transcribed spacers (ITS1 + 5.8S + ITS2), and the D2-D3 domains of the large subunit rRNA gene (28S) were obtained for five specimens of the new species and other species belonging to the Neoechinorhynchidae. Phylogenetic analyses confirmed that the new genus belongs to the Neoechynorhynchidae and indicated that the genus Neoechynorhynchus Stiles & Hassall, 1905 is not monophyletic. Comparison between three populations of the new species yielded nine variable sites for cox1, 11 for ITS and four for 28S.

Molecular characterization ofNeoechinorhynchus cylindratusVan Cleave, 1913 (Acanthocephala: Neoechinorhynchidae), a parasite of the largemouth bass (Micropterus salmoides) in northern Mexico

“…Neoechinorhynchus is the most diverse genus within acanthocephalans, with 117 described species distributed worldwide (Amin, 2013; Smales, 2013; Pinacho-Pinacho et al ., 2014). A few species of the genus Neoechinorhynchus have been analysed using molecular data, suggesting that the genus is paraphyletic (Pinacho-Pinacho et al ., 2017), which is consistent with our phylogenetic trees inferred with three molecular markers. Therefore, the genus Neoechinorhynchus requires a taxonomic revision.…”

“…Finally, between N. (N) panucensis and N. (N) emyditoides , genetic divergences were 21% for LSU, 35% for ITS and 27% for cox 1. These high levels of genetic divergence among species are similar to those exhibited within Neoechinorhynchus , ranging between 2.3 and 46.8% for LSU, 4.7 and 61.9% for ITS and 9.7 and 59.2% for cox 1 (Pinacho-Pinacho et al ., 2014, 2015, 2017, 2018).…”

“…Although neoechinorhynchid species are highly diverse in the Americas (Amin, 2013), particularly in North America, a few species of this genus have been typified using molecular data, including Neoechinorhynchus (Neoechinorhynchus) pseudemydis Cable & Hopp, 1954; Neoechinorhynchus (Neoechinorhynchus) crassus Van Cleave, 1919; Neoechinorhynchus (Neoechinorhynchus) saginatus Van Cleave & Bangham, 1949; and Neoechinorhynchus (Neoechinorhynchus) cylindratus Van Cleave, 1913 (Near et al . 1998; García-Varela and Nadler, 2005; Pinacho-Pinacho et al ., 2017).…”

Redescription and molecular analysis of Neoechinorhynchus (Neoechinorhynchus) johnii Yamaguti, 1939 (Acanthocephala, Neoechinorhynchidae) from the Pacific Ocean off Vietnam

“…Regarding the monophyletic and/or paraphyletic assemblage of N. johnii , we found that the sequences were not construed as a monophyletic assemblage in both regions (18S and ITS1-5.8S-ITS2) analyses. The present analyses show that the genus is paraphyletic and our phylogenetic trees corroborate the findings of other researchers [24, 34]. Thus, the genus Neoechinorhynchus requires more investigation as it has rich species diversity and, most likely, does not represent a monophyletic group.…”

“…Phylogenetic analysis demonstrated that N. johnii occupies a separate position in the trees, probably indicating an Asian origin of this species. It has already been described in various studies that the genus Neoechinorhynchus harbors rich species diversity [3, 33, 34], but the lack of molecular data from the Asian region for species of Neoechinorhynchus demonstrates that the sampling of members of the genus, especially in Asia, is still incomplete. Previous molecular studies also reported paraphyly within the Palaeacanthocephala [28, 37], while findings related to monophyly in Eoacanthocephala are yet to be elucidated.…”