Rare insect fossil reveals secrets of evolution

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Vladimir Matveev, 08.02.2011 8:31

Researchers recently discovered the ancestor of a group of large, carnivorous, 100-million-year-old cricket-like insects that are still alive and live today in areas of south Asia, northern Indochina and Africa. A new species found in a limestone fossil bed in northwestern Brazil corrects the misclassification of another fossil of this type and shows that the genus underwent very little evolutionary change since the Early Cretaceous Period, the time of the dinosaurs, before the breakup of the largest continent in ancient times, Gondwana. This information is described in a research paper published in the open access journal ZooKeys.

"The Schizodactylidae or club-footed crickets are an unusual group of large, terrifyingly predatory insects and are directly related to the true crickets, great green grasshoppers, and Orthoptera grasshoppers," explained University of Illinois entomologist Sam Heads, lead author of the Natural History of Illinois Study. "They got their common name from their large, paddle-shaped protrusions on their feet, which served them as support for their large bodies as they moved among their sandy inhabitants, searching for prey."

Although the fossil clearly differs from the club-footed crickets of the modern species, the general characteristics of the insects do not differ much, according to the head of the study, pointing to the fact that the genus has been in an "evolutionary stasis" for at least the last 100 million years.

Other studies have determined that the area where the fossil was found was likely dominated by a dry or semi-dry monsoon climate during the Early Cretaceous Period, " indicating that the environment of preference for insects of the Schizodactylus species changed slightly after more than 100 million years."

Original (in English): Sciencedaily.com Translated by M. Gonchar

A source: http://globalscience.ru/article/read/19120/

Comments

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15.02.2011 20:54, Zlopastnyi Brandashmyg

I reread the article. A representative of the modern genus Schizodactylus is described from the Lower Cretaceous deposits of South America. Previously, the beast was identified incorrectly. Schizodactylids (or schizodactylins) themselves are large creatures (Google them-there are plenty of photos of them on the web), specialized predators adapted to living in the sand. The group includes 2 modern genera, nominative, inhabiting the Middle East, Turkey, up to Northern India and ...? The second genus is known from South Africa. It is now clear that in the past the band's distribution was much wider, including the New World. Given the modern Capa beast, it doesn't look incredible. The second part of the paper is devoted to discussing the phylogenetic position of schizodactilids. Since I am not an expert on Ensifera, I will not discuss specific classification options. It may be noted that we see an example of a widespread situation: difficulties with the classification of very specialized forms. On the one hand, the animal is archaic (there is no particular doubt about this), but the strongest specialization makes it difficult to assess phylogenetic relationships. IMHO, this is exactly the situation when formally the cladistic analysis is "lame" - there is a very high risk that the signs of a life form (in this case, with a high probability of homoplasia) will "over-vote" the signs that carry phylogenetic information. Hence , it seems to me, the discrepancy in hypotheses about the systematic position of the group.

PS. I understand where the "club-footed crickets" came from! In the original, they are "splay-footed crickets", and the first meaning in the lingua for" splay " is oblique. True, the second value is advanced, but why read any further?

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