title: Molecular identification and first description of the male of Neoechinorhynchus schmidti (Acanthocephala: Neoechinorhynchidae), a parasite of Trachemys scripta (Testudines) in México.
abstract: The morphology of the males of Neoechinorhynchus schmidti (Acanthocephala: Neoechinorhynchidae) is unknown, because this species was described based exclusively on females. However, recently we collected 2 common slider turtles Trachemys scripta in Centla swamps, Tabasco, Mexico, parasitized by 27 specimens of an acanthocephalan whose females were morphologically identical to N. schmidti. The domains D2 and D3 of the large subunit of the nuclear ribosomal RNA (LSU) of 3 males and 2 females of this material were sequenced. The sequences of both sexes were identical, and based on this result, we described for the first time the morphology of the males of N. schmidti. In addition, 6 sequences of a congeneric species, also parasite of turtles (Neoechinorhynchus emyditoides) were generated in the current research. The 11 sequences of these 2 species were aligned with 13 sequences of another 4 species of the same genus, producing a data set of 24 taxa with 674 nucleotides. The genetic divergence between N. schmidti and N. emyditoides was 4% and intraspecific differences ranged from 0.01 to 0.02%. Pairwise differences between either of these species and 4 other congeners parasitic in fresh and brackish water fishes (Neoechinorhynchus golvani, Neoechinorhynchus roseum, Neoechinorhynchus saginatus, and Neoechinorhynchus sp.) varied from 9.5 to 33%. Maximum likelihood and maximum parsimony analyses show that N. schmidti and N. emyditoides are sister taxa. Bootstrap analysis also indicates that the sister relationship is reliably supported.
authors.affiliation: Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, Mexico. garciav@servidor.unam.mx
authors.forename: Martín
authors.initials: M
authors.lastname: García-Varela
authors.forename: Luís
authors.initials: L
authors.lastname: García-Prieto
authors.forename: Rodolfo Pérez
authors.initials: RP
authors.lastname: Rodríguez
mesh_terms: D000049:Acanthocephala / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000648:ultrastructure; D000818:Animals; D018509:DNA, Helminth / Q000032:analysis / Q000096:biosynthesis; D005260:Female; D005393:Fish Diseases / Q000469:parasitology*; D006374:Helminthiasis, Animal / Q000469:parasitology*; D008297:Male; D008800:Mexico; D008855:Microscopy, Electron, Scanning; D010473:Perciformes / Q000469:parasitology*; D010802:Phylogeny; D025341:Principal Component Analysis; D012335:RNA, Ribosomal / Q000032:analysis / Q000096:biosynthesis; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014426:Turtles / Q000469:parasitology*
chemical_list: D018509:DNA, Helminth; D012335:RNA, Ribosomal