Researchers have discovered a never-before-seen species of dinosaur that may have lived in underground caves. The new find shows the versatility of these extinct reptiles in exploiting ecological niches and adapting to their environment, scientists say.
In a new study published Tuesday (July 9) in the journal The anatomical archiveScientists described a series of fossils from the Mussentuchit Member of the Cedar Mountain Formation in eastern Utah that were recovered from the region starting in 2013.
Two of the complete specimens were discovered together, prompting the authors to name the species Fona herzogae. The name refers to the creation mythology of the Chamorro people of the Mariana Islands, in which the goddess Fo’na mourns the death of her brother and eventually creates humanity. One of the authors traces its origins to the region and wanted to honor its heritage.
The extraordinarily complete preservation of several specimens suggests they may have died in caves. Other specimens included in the study were isolated bones. Usually the remains of fossilized animals decay over time as they are exposed to the elements and scavengers, but in this case these dinosaurs appear to be almost intact, suggesting they may have been crushed underground rather than dying in an exposed area.
Aspects of their bone structure also suggest that these animals had a burrowing lifestyle. The specimens had fused pelvic bones, which may have provided stability when the dinosaurs used their hind legs to dig their homes in the muddy floodplains they probably inhabited 99 million years ago, during the Cretaceous period (145 to 66 million years ago). And their large hind feet may also have helped them scrape away heavy clay substrates, according to the study.
The scientists compared these dog-sized dinosaurs to modern-day burrow-digging mammals such as kangaroo rats (genus Dipodomys) and springhares (Pedetes capensis), which have powerful hind legs and shortened forelegs. Like these rodents, F. herzogae probably walked on its hind legs and was a herbivore – its teeth were designed to chew plant material. Burrows provided protection from predators, especially for the even smaller juveniles.
F. herzogae shares some of these characteristics Oryctodromeuswhich were also found in locations that suggest that the individuals were buried in collapsed caves. Article from 2007 described the discovery of an adult animal and its young in a burrow that was petrified.
F. herzogae is probably a relative of Oryctodromeuswhich was created around the same time.
However, the researchers of the new study found that F. herzogaeThe ossified tail tendons suggest that the species does not dig, as a stiff tail does not necessarily contribute to this behavior. However, they suggested that F. herzogae did not necessarily inhabit self-built caves. It could also have lived in caves dug by crocodiles or other animals.
