The giant dinosaurs that roamed the world some 150 million years ago shared the planet with equally daunting parasites: blood-gobbling fleas that were up two centimetres (almost an inch) long.The ancient fleas measured just over 20mmm (0.82 inches) long for females, and nearly 15mm (0.6 inches) in males, compared to a maximum of 5mm (0.2 inch) for today's fleas.
The dino-era fleas were wingless and, unlike their counterparts today, could not jump and had comparatively small mouths, says the study.
But for all that, they were supremely adapted to their environmental niche.
They had claws which enabled them to grip onto hairy or feathered reptilians, whose hide was then pierced with a long, serrated "siphon" to suck out a blood meal.
The fleas were so successful that when the dinosaurs were wiped out some 65 million years ago -- an extinction linked to a collision with Earth by a space rock -- they smoothly moved onto mammals and birds, sizing down in the process.
The study, led by Andre Nel of France's National Museum of Natural History in Paris, appears on Wednesday in the British journal Nature.