INVESTIGADORES
LUCIFORA Luis Omar
artículos
Título:
Tooth counts, vicariance, and the distribution of the sand tiger shark, Carcharias taurus
Autor/es:
LUIS O. LUCIFORA; ALBERTO L. CIONE; ROBERTO C. MENNI; ALICIA H. ESCALANTE
Revista:
ECOGRAPHY
Referencias:
Año: 2003 vol. 26 p. 567 - 572
ISSN:
0906-7590
Resumen:
Geographic variation in tooth row counts among sand tiger sharks Carcharias taurus
(Chondrichthyes), from the SW Atlantic, NW Atlantic and the East China Sea is
analyzed in this paper. We found significant differences between sand tigers from the
SW Atlantic (Southern Hemisphere population) and each of the other two (Northern
Hemisphere) regions in the number of upper lateral tooth rows, and between
individuals from the SW Atlantic and the East China Sea in the total number of
upper tooth rows. Sand tiger sharks from the two Northern Hemisphere populations
did not differ in any of the studied variables. Our results agree with comparisons of
vertebral counts between sand tiger sharks from Southern and Northern Hemi-
spheres. Both lines of evidence suggest that Southern and Northern Hemisphere
populations of C. taurus were isolated to a larger extent than populations of the
Northern Hemisphere. The fossil record of the genus Carcharias begins in the Early
Cretaceous and C. taurus is certainly known since the Late Miocene. During the
Miocene, the Tethys Sea separating northern and southern land masses was still
present and it provided a continuous temperate shallow sea that could allow dispersal
of sand tiger sharks along Northern Hemisphere seas. Independent observations on
the distribution and evolutionary history of the genera Myripristis, Neoniphon,
Sargocentron and Aphanius, and genetic studies on the temperate shark genus
Mustelus that indicate a close relationship between the Indo-Pacific M. manazo and
the Mediterranean M. asterias suggest that this hypothesis is plausible and deserves
to be tested.