where did the loggerhead sea turtle originate from
Although evidence is lacking, modern sea turtles probably descended from a single common ancestor during the Cretaceous period.
Loggerhead sea turtle
Although evidence is lacking, modern sea turtles probably descended from a single common ancestor during the Cretaceous period. 
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Loggerhead sea turtle [SEP] Evolutionary history
Although evidence is lacking, modern sea turtles probably descended from a single common ancestor during the Cretaceous period. Like all other sea turtles except the leatherback, loggerheads are members of the ancient family Cheloniidae, and appeared about 40 million years ago. Of the six species of living Cheloniidae, loggerheads are more closely related to the Kemp's ridley sea turtle, olive ridley sea turtle, and the hawksbill turtle than they are to the flatback turtle and the green turtle. Around three million years ago, during the Pliocene epoch, Central America emerged from the sea, effectively cutting off currents between the Atlantic and Indo-Pacific Oceans.