Thursday, February 26, 2015

Fossil record has shown that the genus Carcharias and probably species C. taurus Rafinesque, 1810 occupied the western coast of South America during the Miocene and part of the Pliocene. The genus is absent in the area today. It is suggested that its local extinction was the consequence of a drop of global temperatures during the middle Pliocene and Pleistocene and the coeval lowering of sea level that shrinked the area of distribution to the northern areas and provoked the disappearance of suitable environments when the shelf area became extremely reduced. After approximately 3 Ma it would have not been possible for the species to migrate from the north to the region due to the establishment of the Panamanian isthmusBIG SHARKS THAT SWIM BETWEEN THE SOUTH-AMERICAN -AFRICAN RIFT 110 TO 100 MILLION YEARS AGO OR BEFORE THE MESSIAH GROW IN NUMBERS BY ADAPTATIVE RADIATION BEFORE THE BIG METEOR CRUNCH AND SOMEHOW SOMEHERE SURVIVE TILL NOW

OLIGOCENE DROUGHT 

OBIK SEA GO BUST ....

MIOCENE ...CRUSH BETWEEN EUROPE 

AND AFRICA  17 MEGAYEARS AGO

MEDITERRANEAN OR PARATETHYS 

SHARK   EXTINCTION

NOTHING NEW ....IT HAPPENS
Neoselachians sharks are included in the class
Chondrichthyes, a very ancient clade which perhaps
ranges from the Ordovician but certainly from the
Devonian. Sharks, very important fishes in the economy of the sea today, include the most ancient
vertebrate recent genera. A family of relatively large
sharks, Odontaspididae, is known since the Aptian
(early Cretaceous;
Carcharias
striatula

Today it includes the
genera
Odontaspis
Agassiz, 1838 and
Carcharias.
Genus
Carcharias
is monospecific today but it had
several fossil species (Cappetta, 1987). Recent
species
C. taurus
(Rafinesque, 1810) is wide-ranging
in warm-temperate and tropical coastal waters of the
Atlantic Ocean, Mediterranean Sea, and Indo-West
Pacific Ocean but is absent from the Central Pacific and
eastern Pacific oceans However, the fossil record has
shown that the distribution of the genus
Carcharias
and possibly the species
C. taurus
occupied the
western coast of South America during the Miocene
and at least part of the Pliocene. The World Conservation Union considers
C. taurus
as a vulnerable
species today, with its populations seriously depleted
(Compagno, 2001). It is critically endangered in New
South Wales, Australia, after large numbers were
killed in sports and commercial fisheries and by divers
described several cases of extirpation of fishes in the
Atlantic Ocean.  the occurrence of genus
Carcharias in the eastern Pacific is reviewed and a
hypothesis for explaining its local extinction is
proposed