In Depth
Limnofregata is a genus of bird that many have commented on about its similarity to modern frigatebirds (genus Fregata), however there are a number of differences. First and foremost is the obvious fact that Limnofregata lived inland around freshwater, whereas modern frigatebirds live by the sea. There, frigatebirds rely upon soaring as a main method of flight, but Limnofregata would not have been able to do this, and probably relied upon a greater amount of flapping to stay aloft. This also means that there probably was no difference in wing size between males and females, like what we see in frigatebirds so that males and females can coexist albeit in difference zones of the coastline. Modern frigate birds are also known for having a brightly coloured throat pouch that can be inflated and used in display. However the neck vertebrae of Limnofregata differ to those of frigatebirds, and offer no indication that Limnofregata also had a throat pouch.
A further area of difference between Limnofregata and frigatebirds is that the bill of Limnofregata is in proportion notably shorter than that seen in frigatebirds, and also lacked the hook tip. Despite this Limnofregata is thought to have been a piscivorous bird focusing its attentions upon eating the smaller fish that are known from the Green River Formation such as Diplomystus and Knightia. Overall, despite some superficial similarities to frigatebirds, Limnofregata is thought to have lived more like a gull.
Further Reading
- A Lower Eocene frigatebird from the Green River Formation of Wyoming (Pelecaniformes: Fregatidae). - Smithsonian Contributions to Paleobiology 35:1-33. - S. L. Olson - 1977. - A new species of Limnofregata (Pelecaniformes: Fregatidae) from the Early Eocene Wasatch Formation of Wyoming: implications for palaeoecology and palaeobiology. - Palaeontology: 1–11. - Thomas A. Stidham - 2014.
