Pterosaurs of the genus Cretornis lived in the late Cretaceous (Turonian) stage of the 92 million-year-old Jizera Formation in the Czech Republic. Cretornis hlavaci is the only species of the genus Cretornis.
Discovery and Naming
Workers in a sandstone quarry in Zářecká Lhota, close to the town of Choceň, found the fossils in 1880 while extracting gravel for a nearby road repair. František Hlaváč, a fossil collector and pharmacist from Choceň, was then informed about the discovery by a specific Mrs. Tomková, a croupier from Choceň. After realizing that this fossil was unique, he collected the remaining fossils and mailed them to Professor Antonín Frič, a naturalist, in Prague. It was recognized as an ancient toothed bird the size of a modern swan by Antonín Frič in 1881, who also named it Cretornis Hlaváči, the type species. The generic name is derived from Greek ὄρvις, ornis, "bird," and Latin creta, "chalk," referring to the Cretaceous. Frič's initial theory was that the fossil bones belonged to an old toothed bird, akin to the species Ichthyornis. The particular name is in Hlaváč's honor. Nowadays, the National Museum in Prague is home to the holotype specimens of this pterosaur. Unconfirmed reports suggest that before and after this discovery, other bones—possibly even pterosaur bones—were discovered in other locations around the quarry; however, they were subsequently said to have vanished. Later on, it was discovered that the discovery was actually a pterosaur. Richard Lydekker misapplied the name in 1888, changing it to Ornithochirus hlavatschi Fritsch 1881. The particular name has to be written since diacritical marks are prohibited in scientific species names. Because of the considerable German cultural influence on Bohemia at the time, Lydekker wrote it as though it and Frič himself were German. In 1905, Frič, a Czech ethnic person, finally utilized the accurate transliteration Ornithocheirus hlavaci. The taxon has generally been regarded as a nomen dubium since 1905. Nevertheless, Russian paleontologist Alexandr Averianov came to the conclusion in 2010 that distinguishing characteristics ought to be feasible. He and Czech paleontologist Boris Ekrt presented a revised description in 2015, coming to the conclusion that Cretornis belonged in its own taxon. The holotype of Cretornis is currently on display as "Object 10" in the collection of the Národní muzeum (National Museum) in Prague. It was discovered in the Turonian-era Mittlere Iserschichten, or what is now known as the Jizera Formation, according to Frič. Without the head, it is only a half skeleton. It has two wing finger phalanges, an ulna, a radius, a wrist, and the whole humerus (upper arm bone).
Description
Averianov approximated the wingspan of C. hlavaci to be 1.5 to 1.6 meters (4.9 to 5.2 ft) based on comparison with its relatives. The length of the humerus is 76 millimeters (3 in). The distal portion of the humerus features a diamond-shaped cross-section, which Averianov (2015) identified as a solitary autapomorphy, unique derived characteristic.
Classification
In the nineteenth century, Cretornis was assigned a species designation inside the Ornithocheirus genus. Coralia-Maria Jianu proposed in 1997 that it was a member of the Pteranodontidae family. Averianov believed it to be a member of the Azhdarchidae in 2010. After doing more thorough analyses of the wing bones, Averianov came to the conclusion in 2015 that they belonged to a non-azhdarchid azhdarchoid, most likely one that shared many characteristics with the Neoazhdarchia group. With a joint surface located more proximally than the tubercle in the distal section of the ulna, it is similar to Montanazhdarcho and likely more evolved than the Thalassodromidae. In contrast to its placement within the Azhdarchoidea, paleontologist Nicholas Longrich and associates discovered Cretornis in the family Nyctosauridae in 2018. This puts it in a more derived position than Alamodactylus and Volgadraco. Below is the cladogram resulting from their analysis:
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Reconstruction of Cretornis by Tawa99.
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