By Scott Reid  Etymology: Near-Coast Bird First Described By: Wetmore, 1930 Classification: Dinosa…

By Scott Reid  Etymology: Near-Coast Bird First Described By: Wetmore, 1930 Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostaylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Neornithes, Neognathae, Neoaves, Aequorlitornithes, Charadriiformes, Glareolidae Status: Extinct Time and Place: Between 24.8 and 20.4 million years ago, from the Chattian of the Oligocene through the Aquitanian of the Miocene  Paractiornis is known from the Basal Member of the Marsland Formation in Nebraska  Physical Description: Paractiornis was a smaller bird, no bigger than 20 centimeters in length. Not much is known of this animal, mostly just parts of the legs; but those legs were quite slender compared to other wading birds of the time. Interestingly, it seems to have been similar to the living Pratincoles, which are short-legged insect eating birds. Since Paractiornis is only known from leg bones, it’s possible that it didn’t look particularly like its modern relatives, but like the shorebirds that they evolved from. Or, since it didn’t live near the coast, it was more of a transitional dinosaur, getting used to more mainland habitats rather than aquatic ones. Diet: It seems likely, based on its relatives and habitat, that Paractiornis was an insectivore. Behavior: As a land-going insectivore, Paractiornis would have wandered about its environment in the grass and the mud, searching for insects wherever it could. Upon finding an insect, it would dig into the soil and grab it; if the insect was on the surface, it would rapidly reach out and grab it quickly with its beak. It would behave, in a lot of ways, similar to a plover – just on land! It probably would have been somewhat nocturnal, spending most of its time hunting at night. Given its rarity, Paractiornis would not have been very social, essentially only meeting to mate and rear young.  By José Carlos Cortés  Ecosystem: Paractiornis lived in one of the early grassland ecosystems, and exploited it extensively with the same adaptations for coastal feeding found in its close relatives. Here there were a wide variety of mammals – rodents, horses, ruminants, dogs, bear-dogs, and many others. There were also turtles, though most reptiles present were birds. There was a bird of prey, Promilio, that probably fed upon Paractiornis; a grouse, Palaealectoris, the crake Ortalis, and multiple probable hawks; filling out this ecosystem with a variety of interesting, if modern-esque, dinosaurs. Other: Paractiornis is notable for being an extinct form of the Partincoles, which are a very weird modern group of shorebirds that aren’t actually shorebirds. Since it resembles shorebirds a little bit, but is definitely within the Partincole group, it showcases how the evolution of these land-foraging birds occurred from such an unorthodox origin group as the waders and gulls. That being said, Paractiornis has not been studied extensively, and further fossils of it have not been recorded. ~ By Meig Dickson Sources under the Cut  Carroll, R. L. 1988. Vertebrate Paleontology and Evolution 1-698 Chandler, R. M. 1998. Additions and Comments on the Fossil Birds of Agate Fossil Beds National Monument, Sioux County, Nebraska. National Park Service Paleontological Research: 1 – 3. Lambrecht, K. 1933. Handbuch der Palaeornithologie. 1-1024 Mayr, G. 2017. Avian Evolution: The Fossil Record of Birds and its Paleobiological Significance. Topics in Paleobiology, Wiley Blackwell. West Sussex. Olson, S. L., D. W. Steadman. 1979. The fossil record of the Glareolidae and Haematopodidae (Aves: Charadriiformes). Proc. Biol. Soc. Wash. 91 (4): 972 – 981. Piersma, Theunis (2008), “Family Glareolidae (Coursers and Pratincoles)”, in del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi (eds.), Handbook of the Birds of the World. Volume 3, Hoatzins to Auks, Barcelona: Lynx Edicions, pp. 364–375 Wetmore, A. 1930. Two fossil birds from the Miocene of Nebraska. Condor 32 (3): 152 – 154.





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