Paleontologists in China have unearthed and examined the superbly preserved fossilized remains of two lamprey species from the Jurassic Yanliao Biota. Their findings shed new light on the evolution of the feeding apparatus, the life cycle, and the historic biogeography of lampreys.
Lampreys, one of two living lineages of jawless vertebrates, have great weight in the study of vertebrate evolution.
They are characterized by their peculiar feeding behavior of eating blood or cutting off tissues from the hosts or prey to which they firmly attach via their toothed oral sucker.
In such a way, lampreys play a significant role in the aquatic ecosystem and, in some cases, where they are non-native, even bring tremendous loss to the fishery economy.
These jawless fishes have been in existence for approximately 360 million years but left an extremely patchy fossil record in the post-Carboniferous period, with only two species known from the Cretaceous period.
The two new lamprey species, Yanliaomyzon occisor and Yanliaomyzon ingensdentes, lived during the Jurassic period, between 163 and 158.5 million years ago, and were part of the Yanliao Biota.
Yanliaomyzon occisor was around 64 cm (25 inches) long, making it the largest fossil lamprey ever found.
These fossil lampreys were exquisitely preserved with a complete suite of feeding structures, including the well-developed movable biting plates on the tongue-like piston.
The specimens of Yanliaomyzon occisor were found in the Tiaojishan Formation in China’s Liaoning Province and in the corresponding layers of Nanshimen Village in Hebei Province. The specimens of Yanliaomyzon ingensdentes came from the Daohugou beds in Liaoning Province.
Both Yanliaomyzon occisor and Yanliaomyzon ingensdentes astonishingly resemble the pouched lamprey (Geotria australis), a large flesh eater that can even destroy the skull of teleost fish and now confined to the southern hemisphere.
Dr. Feixiang Wu, a paleontologist with the Institute…
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