Scientists have concluded {that a} newly described dromaeosaurid from Mongolia with its streamlined physique might have been semi-aquatic. The duck-sized theropod, named Natovenator polydontus had a ribcage that angled downwards in the direction of the pelvis, an anatomical trait additionally present in extant diving birds. The researchers, writing within the journal “Communications Biology”, counsel that this dinosaur, a relative of Velociraptor, may probably have been a swimming predator, searching and catching fish.
Natovenator polydontus
The semi-articulated fossil specimen was found in 2008 by a joint Mongolian/Korean area crew. The fabric consisting of considerable postcranial parts and a partial cranium comes from the Barun Goyot Formation at Hermiin Tsav within the southern Mongolian Gobi Desert. Phylogenetic evaluation means that Natovenator polydontus is carefully associated to Halszkaraptor (H. escuilliei) which heralds from southern Mongolia too, however from barely older strata – the Djadochta Formation.
When Halszkaraptor was formally described in 2017, it was proposed that this dromaeosaurid was tailored to a life in water. The invention of Natovenator provides weight to the idea that some dromaeosaurs have been semi-aquatic. The 2 dinosaurs, which have been likely feathered have been positioned in the identical clade – the Halszkaraptorinae.
To learn All the pieces Dinosaur’s weblog submit about Halszkaraptor: The Outstanding and Numerous Maniraptora.
Natovenator A Semi-aquatic Dinosaur?
The dinosaur had an extended, versatile neck and evaluation of the jaws point out that Natovenator had a lot of small tooth, ideally suited for grabbing slippery fish.
The image above exhibits the dorsal vertebrae and ribs of Natovenator in ventral view (a), with (b) a line drawing in left lateral view exhibiting how the ribs are angled downwards in the direction of the rear of the animal. Diving birds and penguins share this anatomical trait (e-i), which is believed to assist these animals to be extra streamlined once they dive and swim. Line drawing (j) exhibits the ribs of the solely terrestrial ostrich while (ok) exhibits the dorsal vertebrae and identified ribs of Shri devi, one other dromaeosaurid from the Barun Goyot Formation which was in all probability solely terrestrial too.
May the form, path and orientation of the ribs be proof to counsel that Natovenator was semi-aquatic?
Swimming Hunter with Many Tooth
The dinosaur’s genus title interprets from the Latin and means “swimming hunter”, while the precise or trivial title refers back to the unusually massive variety of tooth positioned within the jaw. The anatomical place and orientation of the ribs has not been recorded in a non-avian dinosaur earlier than. If Natovenator and the carefully associated Halszkaraptor have been semi-aquatic, then this demonstrates the nice variety throughout the Theropoda. Dinosaurs evolving to use particular niches in historical ecosystems.
A spokesperson from All the pieces Dinosaur commented that this was a exceptional discovery that when once more highlighted the vary of physique plans that dinosaurs advanced to use niches inside ecosystems. As many semi-aquatic animals immediately have dense bones, maybe a examine of the bone density of Natovenator would possibly assist verify that this dinosaur was certainly, at dwelling on the water.
Dromaeosaur Variety
The Dromaeosauridae have been a really profitable group of theropod dinosaurs. Quite a few genera have been described. To achieve an appreciation of various dromaeosaurs, check out the intensive Beasts of the Mesozoic vary of articulated “raptor” figures: Beasts of the Mesozoic Articulated Dinosaur Fashions.
The scientific paper: “A non-avian dinosaur with a streamlined physique displays potential variations for swimming” by Sungjin Lee, Yuong-Nam Lee, Philip J. Currie, Robin Sissons, Jin-Younger Park, Su-Hwan Kim, Rinchen Barsbold and Khishigjav Tsogtbaatar printed in Communications Biology.