Genetic diversity and phylogeography of Corynosoma australe Johnston, 1937 (Acanthocephala: Polymorphidae), an endoparasite of otariids from the Americas in the northern and southern hemispheres
Por:
Garcia-Varela, Martin, Masper, Alice, Crespo, Enrique A., Hernandez-Orts, Jesus S.
Publicada:
1 feb 2021
Resumen:
Adult specimens of Corynosoma australe Johnston, 1937 were recorded from
the intestines of California sea lions, Zalophus californianus (Lesson),
from Baja California Peninsula, Mexico, whereas larval forms were
collected from two fish species on the Argentinian coast. Adult
specimens of C. australe were morphologically characterized by having a
cylindrical proboscis with 18-20 rows of 12-14 hooks per row and a
cylindrical trunk expanded anteriorly into a disk with tiny, triangular
spines spreading almost to three quarters of the hind-trunk in males and
to the posterior body end in females. The aim of this study was to
explore the genetic diversity and systematic position of C. australe
distributed in the Americas. Newly generated sequences of the
mitochondrial cytochrome c oxidase subunit 1 (cox 1) gene were compared
with sequences available from GenBank.
Phylogenetic analyses performed with the cox 1 dataset using maximum
likelihood and Bayesian inference showed that the 11 new sequences of C.
australe recovered from the California sea lion in northern Mexico plus
the six sequences from Argentinian seashores formed a clade with other
sequences of specimens previously identified as C. australe. The
intraspecific genetic divergence among the isolates was very low,
ranging from 1 to 1.7%, and in combination with the phylogenetic trees
confirmed that the isolates belonged to the same species. The cox 1
haplotype network inferred with 27 sequences revealed 18 haplotypes
divided into two clusters clearly separated from each other by 5
substitutions. The first cluster corresponded to specimens from the
Northern Hemisphere (United States of America and Mexico), and the
second corresponded to specimens from the Southern Hemisphere (Argentina
and Brazil). The current evidence suggests that C. australe has an
amphitemperate distribution and is associated mainly with otariids with
secondary and independent colonization events to other mammals and the
Magellanic penguin in the Southern Hemisphere.
Filiaciones:
Garcia-Varela, Martin:
Univ Nacl Autonoma Mexico, Inst Biol, Dept Zool, Ave Univ 3000,Ciudad Univ, Mexico City 04510, DF, Mexico
Masper, Alice:
Ctr Invest Alimentac & Desarrollo, Sanchez Taboada Carret Varadero Nacl,Km 6-6, Heroica Guaymas 85480, Sonora, Mexico
Crespo, Enrique A.:
Ctr Estudio Sistemas Marinos CESIMAR CCT CONICET, Lab Mamiferos Marinos, Blvd Brown 2915, RA-9120 Puerto Madryn, Chubut, Argentina
Univ Nacl Patagonia San Juan Bosco UNPSJB, Blvd Brown 3000, RA-9120 Puerto Madryn, Chubut, Argentina
Hernandez-Orts, Jesus S.:
Czech Acad Sci, Biol Ctr, Inst Parasitol, Branisovska 31, Ceske Budejovice 37005, Czech Republic
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