Giant Prehistoric Fossilized Fleas Found From Mesozoic Era Of China

We are all familiar with modern day fleas that bite and feed on our pet pooches, but it seems that millions of years ago, dinosaurs faced the same problem, only a much bigger one.

AsianScientist (Mar. 2, 2012) – We are all familiar with modern day fleas that bite and feed on our pet pooches, but it seems that millions of years ago, dinosaurs faced the same problem, only a much bigger one.

In a seminal piece of work, Professor Huang Diying from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, and collaborators from Kansas, United States, and Paris, France, have discovered giant fleas from the Middle Jurassic and Early Cretaceous periods of China.

The work, published online this week in the journal Nature, is the only evidence of prehistoric Mesozoic era fleas in China, aside from another record of the fossil flea Tarwinia from the Late Cretaceous of Australia (ca. 120 million years).

Prior to this finding, records were controversial and lacking, because ectoparasitic insects do not fossilize easily. As a result, definitive fossil evidence of fleas has been largely confined to Cenozoic amber, and they are of modern day fleas.

Modern day fleas – of which exist around 2,500 recent species or subspecies – are ectoparasitic insects which typically feed on the blood of mammals or birds. Some special characteristics include: reduction of wings, laterally-flattened bodies, and their small size of about 1-3 mm long.

Mesozoic fleas, however, are significantly larger; one of the species from Daohougou had females which measured an average of 14 mm long – almost twice as long as males, which measured 8 mm.

Like modern day fleas, their prehistoric counterparts are also wingless insects, but dorso-ventrally flattened, and with antennae that are short and compact with more antennal (16-19 segments) than extant segments (11 segments).

In this study, the fossil fleas had long, piercing siphonate mouthparts; and long legs armed with various comb-like structures called ctenidia.

Their long piercing mouthparts suggest a resemblance to some Mesozoic siphonate mecopteran, which supports the hypothesis that fleas are derived from Mecoptera.

Other ancient fleas such as the Tarwinia also had various ctenidia on legs and numerous posterior-directed setae on the abdomen, which indicate an adaption to hosts with hair or fur, and of small body size.

These comb-like adaptations are believed to have helped the fleas pierce through the fur or feathers – and to the skin – of their feathered dinosaur hosts.

The article can be found at: Huang D et al. (2012) Diverse transitional giant fleas from the Mesozoic era of China.

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Source: Chinese Academy of Sciences; Photo: Huang Diying.
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