Mesadactylus ( lat. , Literally - “finger from the Mesa ”) - a genus of pterosaurs from the Kimmeridge - Titonian tiers of the upper Jurassic formation Morrison , Colorado , USA . The name of the family was given in 1989 by James Jensen and Kevin Padian. The only species described is Mesadactylus ornithosphyos .
| † Mesadactylus |
| Scientific classification |
|---|
| No rank : | Bilateral symmetrical |
| Infraclass : | Archosauromorphs |
| No rank : | Archosauriformes |
| Treasure : | † Pterosauromorphs |
| Treasure : | † Monofenestrata |
|
| International scientific name |
|---|
Mesadactylus Jensen & Padian, 1989 |
| Single view |
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† Mesadactylus ornithosphyos
Jensen & Padian, 1989 |
Geochronology155.7-145.5 Ma | million years | Period | Era | Aeon |
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| 2,588 | Even | | | Ka | F
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e
R
about
s
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th | | 23.03 | Neogene | | 66.0 | Paleogen | | 145.5 | a piece of chalk | M
e
s
about
s
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th | | 199.6 | Yura | | 251 | Triassic | | 299 | Permian | P
but
l
e
about
s
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th | | 359.2 | Carbon | | 416 | Devonian | | 443.7 | Silur | | 488.3 | Ordovician | | 542 | Cambrian | | 4570 | Precambrian |
◄ Nowadays◄ Cretaceous-Paleogene extinction◄ Triassic extinction◄ Mass Permian Extinction◄ Devonian extinction◄ Ordovician-Silurian extinction◄ Cambrian explosion |
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The holotype is BYU 2024, a complex sacrum of seven sacral vertebrae showing a unique - for the pterosaur - complete fusion of the spinous processes of the sacral vertebrae into a single crest, a trait, as noted in the species epithet characteristic of birds, which prompted Jensen to classify the bone as a bird, Palaeopteryx .
Other taxon-related fossils include bones of the forelimbs, shoulder girdle , vertebrae (including cervical and sacral), and hips [1] . In 2004, additional material was described, including an incomplete skull box [2] . In a 2006 publication, the authors suggested that the larger “contemporary” Kepodactylus may be the same animal, despite slight differences [3] [4] .
Jensen and Padian classified Mesadactylus as a pterodactyloid. In 2007, Christopher Bennett claimed that the holotype and additional material belong to different forms, and that while the latter does belong to some kind of pterodactyloid, the complex sacrum belongs to the representative of the anurognatid family [5] .