Boreopterus is based on holotype JZMP-04-07-3, a nearly complete but crushed skeleton and skull. The skull is 235 millimeters long (9.25 inches), low and elongated with a rounded tip. Its wingspan is estimated to have been around 1.45 meters (4.76 feet). Its teeth, especially the anterior nine pairs, are quite large, forming a mesh of sharp teeth at the front of the mouth; the third and fourth teeth from the front are the largest. There are at least 27 teeth in each side of both the upper and lower jaws, which is a large amount.[3]
Classification
Lü and Ji initially placed Boreopterus in the family Ornithocheiridae when they described it in 2006, a classification which was supported later that year by David Unwin.[4] However, Lü in 2006 published a cladistic analysis showing Boreopterus to be the sister taxon of Feilongus (together forming the new familyBoreopteridae[5]) in a more basal position than Haopterus.[6]
In 2013, a more comprehensive study of pterosaur relationships supported the close relationship of Boreopterus and Feilongus, as well as their relatively basal status among pterodactyloids. Later that year, Andres & Myers found the boreopterids as the sister group of Cycnorhamphus within the archaeopterodactyloid group Gallodactylidae.[7] However, subsequent analysis have found boreopterids to be indeed members of the Ornithocheiroidea, composed of Boreopterus, Zhenyuanopterus and Guidraco, while Feilongus is a relative of Gnathosaurus.[8] In 2018, Nicholas Longrich and colleagues found the family Boreopteridae to only contain Boreopterus and Zhenyuanopterus, while Guidraco was placed in a more derived position within the clade Anhangueria. They also found the family Lonchodectidae as the sister taxon of Boreopteridae.[9]
Pterosaurs like Boreopterus are interpreted by Unwin as soaring animals, like today's albatrosses and frigatebirds.[10] However, it has also been suggested that boreopterids foraged while swimming, trapping small prey with their needle-like teeth,[11] a method similar to that of modern Platanista dolphins.
It has been suggested that the closely related Zhenyuanopterus was merely the adult form of this animal.[11]
^Shun-Xing Jiang; Xiao-Lin Wang; Xi Meng; Xin Cheng (2014). "A new boreopterid pterosaur from the Lower Cretaceous of western Liaoning, China, with a reassessment of the phylogenetic relationships of the Boreopteridae". Journal of Paleontology. 88 (4): 823–828. doi:10.1666/13-068. S2CID128515924.
^Witton, Mark P. (2013). "Boreopteridae". Pterosaurs: Natural History, Evolution, Anatomy. Princeton, NJ: Princeton University Press. pp. 164–169. ISBN978-0691150611.
^Junchang Lü; and Qiang Ji (2005). "A new ornithocheirid from the Early Cretaceous of Liaoning Province, China". Acta Geologica Sinica. 79 (2): 157–163. doi:10.1111/j.1755-6724.2005.tb00877.x. S2CID129084078.
^Andres, B.; Myers, T. S. (2013). "Lone Star Pterosaurs". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 103 (3–4): 383–398. doi:10.1017/S1755691013000303. S2CID84617119.