Detecting a complex of cryptic species within Neoechinorhynchus golvani (Acanthocephala: Neoechinorhynchidae) inferred from ITSs and LSU rDNA gene sequences.
Neoechinorhynchus golvani is an intestinal parasite of freshwater and brackish water fishes distributed in Mexico. The genetic variability of 40 samples representing 12 populations from north, south, and central Mexico, and 1 from Costa Rica, was estimated by sequencing 2 nuclear genes (ITS1, 5.8S, ITS2, and LSU rDNA, including the domain D2 + D3). The length of both genes ranged from 700 to 779 base pairs (bp) and from 813 to 821 bp, for ITSs and LSU, respectively. The genetic divergence among populations ranged from 19.5 to 35.3% with ITSs and from 9.28 to 19.58% with LSU. Maximum likelihood and maximum parsimony analyses were performed for each data set and also for 2 combined data sets (ITSs + LSU rDNA with and without outgroups), showing strong similarities among trees, with high bootstrap support in all cases. Genetic divergence, in combination with phylogenetic analyses, suggested that the acanthocephalan N. golvani represents a complex of cryptic species, which is composed of at least 3 lineages. The first lineage, corresponding with N. golvani, shows a wide distribution, including localities from northeastern Mexico, southwards through central and southeastern Mexico, and further down to Costa Rica. This lineage is associated with cichlid fishes in strictly freshwater environments. Lineages 2 and 3 are distributed in brackish water systems along the Gulf of Mexico and Pacific slopes, respectively; both are associated with eleotrid fishes, and apparently represent 2 cryptic species. The diversification of the eleotrid and cichlid lineages seems to be the result of independent host-switching events from the ancestral population.
Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Distrito Federal, México.
Andrés
A
Martínez-Aquino
Miriam E
ME
Reyna-Fabián
Rogelio
R
Rosas-Valdez
Ulises
U
Razo-Mendivil
Gerardo Pérez-Ponce
GP
de León
Martín
M
García-Varela
D000049:Acanthocephala / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics; D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D023681:Cichlids / Q000469:parasitology; D003364:Costa Rica; D018509:DNA, Helminth / Q000737:chemistry; D004275:DNA, Ribosomal / Q000737:chemistry*; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005393:Fish Diseases / Q000469:parasitology*; D005618:Fresh Water; D014644:Genetic Variation; D006374:Helminthiasis, Animal / Q000469:parasitology*; D007422:Intestines / Q000469:parasitology; D016013:Likelihood Functions; D008800:Mexico; D008969:Molecular Sequence Data; D010473:Perciformes / Q000469:parasitology*; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012623:Seawater; D016415:Sequence Alignment / Q000662:veterinary
D018509:DNA, Helminth; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer