Las especies del Género Merluccius en aguas argentinas. Morfología, merística, morfometría, osteología y código de barras genético.
The present study deals with the taxonomic investigation of the species of the Genus Merluccius cited for Argentinean waters: Merluccius hubbsi, Merluccius australis, Merluccius patagonicus and Merluccius tasmanicus. 393 fresh specimens from Argentinean waters were analyzed. Also, type and non-type curated museum specimens were examined from Argentina, Brazil, Uruguay and New Zealand, as well as of other species of Merluccius: M. merluccius, M. bilinearis, M. productus, M. gayi and M. paradoxus, that have been reexamined. Nominal species were analized to corroborate their specific validity by means of the comparative study of morphology, meristic, classic and landmark-based morphometry, both external and internal, and through DNA barcoding molecular tools. Univariate and multivariate analyses were performed to establish the degree of intraand interspecific variation. The usefulness of meristic and morphometric characters in specific differentiation was demonstrated by the analysis of nine of the fourteen species of Merluccius described. Both external and internal morphological characters showed high intraspecific variation. Meristic and morphometric characters of types of M. patagonicus and M. tasmanicus totally overlapped with those of M. hubbsi and M. australis. M. australis showed a greater number of scales along the lateral line, total vertebrae, second dorsal and anal-fin rays than those of M. hubbsi. A trend of having longer snouts and wider heads, in M. australis and bigger eyes and longer ventral fins, in M. hubbsi has been observed. Discriminant characters were found, between M. hubbsi and M. australis, in the internal elements that have been widely used in differentiating Merluccius species (hyomandibular, urohyal and sagitta otolith) and in bones belonging to different body regions (skull, spine and appendicular skeleton). DNA barcoding analyses confirmed the specific validity of M. hubbsi and M. australis, finding no evidence of the existence of other species of Merluccius. We conclude that M. patagonicus and M. tasmanicus are junior synonyms of M. hubbsi and M. australis, respectively, and that only two species of Merluccius occur in Argentinean waters.
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| Format: | Thesis/Dissertation biblioteca |
| Language: | Spanish / Castilian |
| Published: |
Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales
2012
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| Subjects: | Peces marinos, Taxonomía, Morfología animal, Conteos merísticos, Morfometría, Genetics, DNA, ASFA15::M::Marine fish, ASFA15::T::Taxonomy, ASFA15::A::Animal morphology, ASFA15::M::Meristic counts, ASFA15::M::Morphometry, ASFA15::O::Osteology, ASFA15::G::Genetics, ASFA15::D::DNA, |
| Online Access: | http://hdl.handle.net/1834/6807 |
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| Summary: | The present study deals with the taxonomic investigation of the species of the Genus Merluccius cited for Argentinean waters: Merluccius hubbsi, Merluccius australis, Merluccius patagonicus and Merluccius tasmanicus. 393 fresh specimens from Argentinean waters were analyzed. Also, type and non-type curated museum specimens were examined from Argentina, Brazil, Uruguay and New Zealand, as well as of other species of Merluccius: M. merluccius, M. bilinearis, M. productus, M. gayi and M. paradoxus, that have been reexamined. Nominal species were analized to corroborate their specific validity by means of the comparative study of morphology, meristic, classic and landmark-based morphometry, both external and internal, and through DNA barcoding molecular tools. Univariate and multivariate analyses were performed to establish the degree of intraand interspecific variation. The usefulness of meristic and morphometric characters in specific differentiation was demonstrated by the analysis of nine of the fourteen species of Merluccius described. Both external and internal morphological characters showed high intraspecific variation. Meristic and morphometric characters of types of M. patagonicus and M. tasmanicus totally overlapped with those of M. hubbsi and M. australis. M. australis showed a greater number of scales along the lateral line, total vertebrae, second dorsal and anal-fin rays than those of M. hubbsi. A trend of having longer snouts and wider heads, in M. australis and bigger eyes and longer ventral fins, in M. hubbsi has been observed. Discriminant characters were found, between M. hubbsi and M. australis, in the internal elements that have been widely used in differentiating Merluccius species (hyomandibular, urohyal and sagitta otolith) and in bones belonging to different body regions (skull, spine and appendicular skeleton). DNA barcoding analyses confirmed the specific validity of M. hubbsi and M. australis, finding no evidence of the existence of other species of Merluccius. We conclude that M. patagonicus and M. tasmanicus are junior synonyms of M. hubbsi and M. australis, respectively, and that only two species of Merluccius occur in Argentinean waters. |
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