Tetrapods areorganismsthat evolved from fish to possess four limbs and digits. These animals include frogs, cats and also humans. After analyzing over 100 skull bones in extinct and non-extinct tetrapods, researchers discovered that tetrapods have fewer skull bones than fish both extinct and living. Anew studyshows that the limited amount of skull bones may have prevented evolution for an incredible number of years.
Researchers from the University of Bristol, Barcelona’s Universitat Pompeu Fabra and University College London analyzed fossilized skulls of animals from the transitional period between aquatic and terrestrial environments. In accordance with anews release, their findings indicate that tetrapods had a far more complex connection between their skull bones than fish.
Although it may seem such as this difference in bone connection would result in evolutionary changes among land animals, these changes actually hindered the evolution of the tetrapod skull.
“Tetrapod skulls generally have fewer skull bones than their fish ancestors, but merely counting the amount of bones misses some important data,” says lead study author James Rawson in a news release. “We used a method called network analysis, where in fact the arrangement of skull bones which bones hook up to which is recorded along with bone number.”
Network analysishelps provide graph and numerical data. This data then helps pinpoint the way the subjects in the info set relate with one another.
“Traditionally, anatomy research has been mostly descriptive or qualitative. Network analysis offers a sound mathematical framework to quantify anatomical relations among bones: some sort of data often overlooked generally in most studies on morphological evolution,” says co-author Borja Esteve-Altava, a specialist in this system, in a news release.
With their surprise, the researchers discovered that the evolution process was slowed with fewer skull bones.
“It could seem strange, but having fewer bones means all of those bones must connect to more of its neighbors, producing a more technical arrangement,” says Rawson in a news release. “Modern frogs and salamanders had probably the most complex skulls of all animals we studied.”
The authors continued to state that early tetrapod skulls consolidated right into a single piece, whereas fish skulls were manufactured from several sections.
In accordance with a news release, researchers also discovered that tetrapods’ origins coincide with a drop in a variety of skull bone arrangements.
“We were surprised to get these changes to the skull appeared to limit tetrapod evolution instead of promoting radiation to new habitats on land. We believe that the evolution of a neck, extinction events or perhaps a bottleneck in skull development could be responsible,” says co-author Emily Rayfield in a news release.
Researchers noticed an identical change in bone variety in tetrapods that occurred much sooner than the skull bones.
“We also visit a similar drop in structural variability for the limb bones in early tetrapods, however the drop in the limbs happens 10 million years earlier. It appears that different facets were affecting skull and limb evolution in early tetrapods, and we’ve a lot more to learn concerning this crucial amount of time in our very own evolutionary history,” says Rawson in a news release.