Science Advances<\/em><\/a> this week, which studied the organisation of skull bones in over 100 different living and fossil animals in order to understand the evolution of an early tetrapod skull.<\/p>\nJames Rawson, lead author of the publication, said: \u201cTetrapod skulls generally have fewer skull bones than their fish ancestors, but simply counting the number of bones misses some important data.<\/p>\n
\u201cWe used a technique called network analysis, where the arrangement of skull bones is recorded in addition to bone number.\u201d<\/p>\n
Dr Borja Esteve-Altava, an expert in this technique, said: \u201cNetwork analysis provides a sound mathematical framework to quantify anatomical relations among bones: a kind of data often overlooked in most studies on morphological evolution.\u201d<\/p>\n
Because tetrapods were found to have fewer skull bones than fish, it meant the organisation of their skulls were more complex.<\/p>\n
Rawson said: \u201cIt might seem strange, but having fewer bones means each of those bones must connect with more of its neighbours, resulting in a more complex arrangement. Modern frogs and salamanders had the most complex skulls of all the animals we studied.\u201d<\/p>\n
\u201cThe skulls of the earliest tetrapods also became more consolidated into a single unit, whereas their fish ancestors had skulls made of several distinct sections.\u201d<\/p>\n
Looking at different skull structures over time led to the discovery that skull arrangement variety dropped when tetrapods originated.<\/p>\n
Professor Emily Rayfield, senior author of the study, said: \u201cWe were surprised to find these changes to the skull seemed to limit tetrapod evolution, rather than promoting radiation to new habitats on land. We think that the evolution of a neck, extinction events or a bottleneck in skull development may be responsible.\u201d<\/p>\n
Mr Rawson concluded: \u201cWe also see a similar drop in structural variability for the limb bones in early tetrapods, but the drop in the limbs happens 10 million years earlier. It seems that different factors were affecting skull and limb evolution in early tetrapods, and we have so much more to learn about this crucial time in our own evolutionary history.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"
Scientists from the University of Bristol have discovered that early tetrapods had fewer skull bones, which limited their evolution<\/p>\n","protected":false},"author":17,"featured_media":25384,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[24429],"tags":[3475],"acf":[],"yoast_head":"\n
Tetrapods discovery provides exciting insights about evolution<\/title>\n\n\n\n\n\n\n\n\n\n\n\n\n\t\n\t\n\t\n\n\n\n\n\n\t\n\t\n\t\n