Professor Jingmai O'Connor has led a group of paleontologists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Science, together with researchers from the Shandong Tianyu Museum of Nature, have discovered a new specimen of the volant dromaeosaurid Microraptor zhaoianus with the remains of a nearly complete lizard preserved in its stomach. The findings of the team were published in Current Biology.
Unlike any previously known from the Cretaceous, the lizard represents a new species Indfrasaurus Wangi. The lizard was named after Prof. WANG Yuan from IVPP, who is also director of the Paleozoological Museum of China. Prof WANG is an expert on the paleoherpetofauna of China and has been in charge of several exhibitions of Chinese fossils.
The name Indrasaurus was inspired by a Vedic legend in which the god Indra was swallowed by a dragon during a great battle (the dragon here referring to Microraptor).
Dr. DONG Liping, a former student of Prof. WANG's, ran the most extensive phylogenetic analysis of Cretaceous lizards ever conducted and showed that all known Cretaceous species were more closely related to each other than to any modern lineage. The new lizard had teeth unlike any other previously known from the Jehol Biota, thus expanding the diversity of this clade and possibly suggesting a unique diet for this new species.
As the fourth documented occurrence of a Microraptor preserving stomach contents, this dinosaur is now known to have fed on mammals, birds, fish, and lizards, supporting the interpretation that it was an opportunistic predator. Nearly completed and articulated the lizard shows that it was swallowed whole and head first, meaning that Microraptor fed like living predatory birds and lizards.
While the Jurassic troodontid Anchiornis has been recently demonstrated to have egested pellets similar to extant carnivorous birds, most famously documented in owls, this ability was apparently absent in Microraptor, further adding to the evidence that the evolutionary transition from dinosaur to bird was characterized by extreme homoplasy, that is, numerous traits evolved multiple times independently in closely related groups.
For more than 20 years, direct evidence of trophic interactions in the Jehol Biota has slowly accumulated. Now, there are 20 predator-prey relationships documented through direct proof of stomach contents.
The researchers of this new study used these relationships to reconstruct the first Jehol food web. Although certainly preliminary, this food web indicates that fish formed the most critical food source for secondary and tertiary consumers. The researchers can use this food web in the future to better understand the Jehol ecosystem.
