Recently, a scientific research team from the Ludwig-Maximilians University of Munich (LMU) in Germany discovered a previously unknown fossil of a hemipteran insect in amber produced in the Kachin region of Myanmar. Its front feet had huge "crab claw"-like claw-like structures, which attracted academic attention. Research shows that this "true stink bug" insect that lived in the Cretaceous forest ecosystem about 100 million years ago not only has a weird shape, but also provides rare new evidence for the evolution of arthropods.
According to reports, Myanmar’s Kachin amber is famous for preserving a rich variety of small biological fossils, recording ancient fauna in the offshore forest environment about 100 million years ago. In this study, the LMU team used micro-computed tomography technology to conduct three-dimensional and detailed imaging of a piece of insect-containing amber, and locked in an individual hemipteran insect that had never been described before. Unlike other insects, this insect has evolved "chelae" at the end of its front legs that resemble crab claws. They resemble a pair of giant grippers and are extremely rare among insects.
The researchers pointed out that before, similar chelate-like structures had appeared on the body surface of insects in only three known groups, and the discovery of this fossil means the fourth and independent "chelate" evolutionary event in the history of insect evolution. The team then conducted a quantitative morphological comparative analysis of more than 2,000 chelae and similar grasping structures from living and fossil species. The results showed that the chelae of this fossil insect were significantly different from other insects in morphology, but were closer in shape to the grasping organs of decapod Crustacea (such as crabs, lobsters, shrimps) and some distant crustaceans.
Due to its highly unique morphological characteristics, the research team classified the fossil into a new genus and species, named Carcinonepa libererrantes. The genus name "Carcinonepa" combines the meanings of "crab" (carcino-) and "water bug" (nepa), pointing to the dual characteristics of its front legs being like crab claws and belonging to the water bug group. More topically, the species epithet "libererrantes" is derived from the Latinized form of the name of the popular K-pop group Stray Kids, inspired by the resemblance of the insect's claws to the group's iconic look, and the band is a favorite of Fenja Haug, one of the study's authors.
Judging from the preserved body surface characteristics, scientific researchers classified Carcinonepa libererrantes into the Nepomorpha group in the order Hemiptera. This group is usually associated with aquatic or wetland environments. Except for the peculiar front claws, the fossil is similar in overall size and appearance to living members of the family Gelastocoridae, which are mostly small predatory insects that live on land. Zoologist Carollin Haug, the first author of the paper, speculated that this new species was likely to have been active on the Cretaceous offshore forest floor, using other small insects as its main prey, and using its giant claws on its front legs to capture and control them.
The research team emphasized that Carcinonepa libererrantes not only fills the gap in the evolution of insect chelicerate structures in terms of morphology, but also provides new clues for understanding the relationship between species composition and predation in Cretaceous terrestrial ecosystems. This result has been published in the journal "Insects" in a paper titled "A True Bug with a True but Unique Chela in 100 Million-Year-Old Amber", further demonstrating the unique value of amber fossils in reconstructing ancient biodiversity and evolutionary history.