Dinosaurs had at least one thing in common with today’s cats and dogs: fleas.

Ancient fleas that fed on the earliest dinosaurs’ blood were much bigger than today’s fleas. A new species has been discovered that represents the intermediate between the most primitive fleas and those that live today.

Chungkun Shih and Taiping Gao from Beijing’s Captial Normal University reported in the journal Current Biology that a new species of flea, Saurophthyrus exquisitus, had a body and mouth size and shape somewhere in between extinct and extant fleas.

Three S. exquisitus specimens were found in northeastern China that dates back to 125 million years ago. Like the oldest known flea—Pseudopulicidae, who lived 165 million years ago—its body was much bigger than today’s fleas. The new species measures in at about 1 cm, whereas the more ancient Pseudopulicidae was 2 cm and today’s tiny fleas are about .2 cm long. S. exquisitus also had smaller mouthparts –fleas have a long tube protruding from their mouth for sucking blood–than the older flea, yet still larger than that of modern fleas; and lacked the saw-like teeth of primitive fleas.

The oldest fleas fed on what was available to them—the large dinosaurs of the Jurassic period who had tough, thick skin, often with feathers, that wasn’t very sensitive. Fleas in the Jurassic found it useful to have long, piercing mouthparts and sharp teeth. 40 million years later, Saurophthyrus exquisitus found itself faced with early Cretaceous Pterosaurs—prehistoric flying reptiles– with thinner skin that was more sensitive. They had to adapt to smaller sucking tubes and duller teeth that wouldn’t easily alert their victim to a bite. Today’s fleas have followed suit: finding blood meals in mammals with thin, sensitive skin; they evolved to have tiny mouthparts and longer legs for jumping quickly away from a scratching paw or swatting tail.

The study on Saurophthyrus exquisitus was published in Current Biology on June 27, 2013.

The Paleontological Research Institution, Ithaca, New York, is pleased to sponsor Paleontology content for This View of Life. Founded in 1932, PRI has outstanding programs in research, collections, and publications, and is a national leader in development of informal Earth science education resources for educators and the general public.

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Published On: July 3, 2013

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