Blasco-Costa, I.; Balbuena, J. A.; Raga, J. A.; Kostadinova, A.; Olson, P. D. (2010). Molecules and morphology reveal cryptic variation among digeneans infecting sympatric mullets in the Mediterranean. Parasitology. 137(02): 287-302.
Blasco-Costa, I.; Balbuena, J. A.; Raga, J. A.; Kostadinova, A.; Olson, P. D.
2010
Molecules and morphology reveal cryptic variation among digeneans infecting sympatric mullets in the Mediterranean
Parasitology
137(02): 287-302
Publication
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We applied a combined molecular and morphological approach to resolve the taxonomic status of Saccocoelium spp.
parasitizing sympatric mullets (Mugilidae) in the Mediterranean. Eight morphotypes of Saccocoelium were distinguished
by means of multivariate statistical analyses: 2 of Saccocoelium obesum ex Liza spp.; 4 of S. tensum ex Liza spp.; and 2
(S. cephali and Saccocoelium sp.) ex Mugil cephalus. Sequences of the 28S and ITS2 rRNA gene regions were obtained for a
total of 21 isolates of these morphotypes. Combining sequence data analysis with a detailed morphological and multivariate
morphometric study of the specimens allowed the demonstration of cryptic diversity thus rejecting the hypothesis of a
single species of Saccocoelium infecting sympatric mullets in the Mediterranean. Comparative sequence analysis revealed 4
unique genotypes, thus corroborating the distinct species status of Saccocoelium obesum, S. tensum and S. cephali and a new
cryptic species ex Liza aurata and L. saliens recognized by its consistent morphological differentiation and genetic divergence.
However, in spite of their sharp morphological difference the 2 morphotypes from M. cephalus showed no
molecular differentiation and 4 morphotypes of S. tensum were genetically identical. This wide intraspecific morphological
variation within S. tensum and S. cephali suggests that delimiting species of Saccocoelium using solely morphological criteria
will be misleading.
