Fossilized Newborn Insects Preserved in Amber Provide First Fossil Evidence of Egg Bursters

Researchers often have speculations about certain practices that ancient species followed. No matter how many solid findings support their assertion without physical evidence, there is always some doubt. In 2018, an assertion by experts regarding the process of hatching by ancient insects was proven true after a finding in Central Lebanon. The discovery was explained in detail in a study published in the journal Palaeontology. 

Archaeologists in their analysis of a 130 million-year-old Lebanese amber in Sarhmoul, found fossilized newborns, egg shells, and egg bursters. The newborn larvae from the Early Cretaceous period were determined to be green lacewings. The most noteworthy finding was the egg bursters, the tiny structures the hatchlings utilized to scratch the eggs. "The structures that make hatching possible tend to disappear quickly once egg-laying animals hatch, so obtaining fossil evidence of them is truly exceptional," study author Dr. Michael Engel added, stated Fox News. 

Experts named the species of these fossilized newborns as Tragichrysa ovoruptora. The name means ‘egg breaking’ and ‘tragic green lacewing’ which aligns with the fact that multiple specimens appeared to have been entombed in the resin, stated the University of Oxford. The remains detected in Sarhmoul were the first time physical evidence of egg bursters had been observed in the fossil record of egg-laying animals. Researchers assume that the larvae were possibly trapped by resins when they were still attached to the eggs from which they had emerged. This has been pointed out as the reason behind the assemblage in the resin.

The egg bursters are present with the hatchlings and as the newborns come out of the egg, are used by them to break through. "Egg-laying animals such as many arthropods and vertebrates use egg bursters to break the egg surface during hatching; a famous example is the ‘egg tooth’ on the beak of newborn chicks," explained Dr. Ricardo Pérez-de la Fuente, a researcher at Oxford University Museum of Natural History and lead author of the work. "Egg bursters are diverse in shape and location. Modern green lacewing hatchlings split the egg with a 'mask' bearing a jagged blade. Once used, this 'mask' is shed and left attached to the empty eggshell, which is exactly what we found in the amber together with the newborns."

Researchers noted that the larvae observed in the amber were significantly different from their modern-day successors. However, the eggshell and egg bursters were very similar to those found with present specimens of green lacewings. The egg burster in the resin was noted to be 0.14 mm in length and exhibiting a short triangular blade at its anterior portion. This implied that despite other features changing because of adaptation, the practice of hatching remained the same across several periods. Researchers believe this showcases the endurance of a sophisticated mechanism that fits into all the environmental changes.

Despite the discovery, some experts believe it is not correct to assume that there was no change in the hatching practice during evolution based on just one example. "There are known instances in modern insects where closely related groups, even down to the species level, show different means of hatching that can entail the loss of egg bursters,"  Dr Enrique Peñalver of the Spanish Geological Survey (IGME; Geomining Museum) and co-author of the work said. “So, the long-term stability of a hatching mechanism in a given animal lineage cannot be taken for granted."