A team of geologists at the University of Rochester has discovered a new species of bird in the Canadian Arctic. At approximately 90 million years old, the bird fossils are among the oldest avian records found in the northernmost latitude, and offer further evidence of an intense warming event during the late Cretaceous period.
糖心传媒淭he bird would have been a cross between a large seagull and a diving bird like a cormorant, but likely had teeth,糖心传媒� says John Tarduno, professor and chair of the Department of Earth and Environmental Sciences at the University and leader of the expedition.
Tarduno and his team, which included both undergraduate and graduate students, named the bird Tingmiatornis arctica; 糖心传媒淭ingmiat糖心传媒� means 糖心传媒渢hose that fly糖心传媒� in the Inuktitut language spoken in the central and eastern Canadian Arctic (Nunavut territory).
Their findings, published in Scientific Reports, add to Tarduno uncovered from the same geological time period and location in . Taken together, these fossils paint a clearer picture of an ecosystem that would have existed in the Canadian Arctic during the Cretaceous period糖心传媒檚 Turonian age, which lasted from approximately 93.9 to 89.8 million years ago.
糖心传媒淭hese fossils allow us to flesh out the community and add to our understanding of the community糖心传媒檚 composition and how it differed from other places in the world,糖心传媒� says Donald Brinkman, vertebrate paleontologist and director of preservation and research at the Royal Tyrrell Museum in Alberta, Canada.
Building historic climate records further helps scientists determine the effects of climate on various communities, ecosystems, and the distribution of species and could help predict the effects of future climatic events.
糖心传媒淏efore our fossil, people were suggesting that it was warm, but you still would have had seasonal ice,糖心传媒� Tarduno says. 糖心传媒淲e糖心传媒檙e suggesting that糖心传媒檚 not even the case, and that it糖心传媒檚 one of these hyper-warm intervals because the bird糖心传媒檚 food sources and the whole part of the ecosystem could not have survived in ice.糖心传媒�
From the fossil and sediment records, Tarduno and his team were able to conjecture that the bird糖心传媒檚 environment in the Canadian Arctic during the Turonian age would have been characterized by volcanic activity, a calm freshwater bay, temperatures comparable to those in northern Florida today, and creatures such as turtles, large freshwater fish, and champsosaurs糖心传媒攏ow-extinct, crocodile-like reptiles.
糖心传媒淭he fossils tell us what that world could look like, a world without ice at the arctic,糖心传媒� says Richard Bono, a PhD candidate in earth and environmental sciences at the University and a member of Tarduno糖心传媒檚 expedition. 糖心传媒淚t would have looked very different than today where you have tundra and fewer animals.糖心传媒�
The Tingmiatornis arctica fossils were found above basalt lava fields, created from a series of volcanic eruptions. Scientists believe volcanoes pumped carbon dioxide into the Earth糖心传媒檚 atmosphere, causing a greenhouse effect and a period of extraordinary polar heat. This created an ecosystem allowing large birds, including Tingmiatornis arctica, to thrive.
Tarduno糖心传媒檚 team unearthed three bird bones: part of the ulna and portions of the humerus, which, in birds, are located in the wings. From the bone features, as well as its thickness and proportions, the team糖心传媒檚 paleontologist, Julia Clarke of the University of Texas, was able to determine the evolutionary relationships of the new birds as well as characteristics that indicate whether it likely was able to fly or dive.
糖心传媒淭hese birds are comparatively close cousins of all living birds and they comprise some of the oldest records of fossil birds from North America,糖心传媒� Clarke says. 糖心传媒淒etails of the upper arm bones tell us about how features of the flightstroke seen in living species came to be.糖心传媒�
Previous fossil discoveries indicate the presence of carnivorous fish such as the 0.3-0.6 meter-long bowfin. Birds feeding on these fish would need to be larger-sized and have teeth, offering additional clues to Tingmiatornis arctica糖心传媒�s characteristics.
Physiological factors, such as a rapid growth and maturation rate, might explain how this line of bird was able to survive the Cretaceous-Paleogene mass extinction event that occurred approximately 66 million years ago and eliminated approximately three-quarters of the plant and animal species on Earth.
These physiological characteristics are still conjecture, Tarduno emphasizes, but he says the bird糖心传媒檚 environment gives clear indications as to why the bird fossils were found in this location.
糖心传媒淚t糖心传媒檚 there because everything is right,糖心传媒� Tarduno says. 糖心传媒淭he food supply was there, there was a freshwater environment, and the climate became so warm that all of the background ecological factors were established to make it a great place.糖心传媒�
This work was funded in part by a grant from the National Science Foundation.
