Dineobellator

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Dineobellator
Temporal range:
Ma
↓
Skeleton reconstruction, featuring the known elements in white
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: †Dromaeosauridae
Clade: †Eudromaeosauria
Genus: †Dineobellator
Jasinski et al. 2020
Type species
†Dineobellator notohesperus
Jasinski et al. 2020

Dineobellator (meaning

theropod dinosaur that lived in North America during the Late Cretaceous period 68 million years ago.[1] The remains have been found in the Maastrichtian stage of the Naashoibito Member at the Ojo Alamo Formation, New Mexico.[2]

Discovery and naming

Diagnostic bones

The holotype remains are designated SMP VP-2430 and were first recovered in 2008 from the Ojo Alamo Formation by Robert M. Sullivan, Steven E. Jasinski and James Nikas. Sullivan and Jasinski collected additional material in 2009. In 2011, the find was reported in the scientific literature.[3] Further excavations were performed by Jasinski in 2015 and 2016.[2]

The remains were realized as belonging to a new taxon, which was only named and described in 2020, by Jasinski, Sullivan and

Diné, the Navajo word used for the people of the Navajo Nation, and bellator, the Latin word for warrior. The specific name is derived from the Greek noto~ (νότος) for southern or south, and hesperis (Ἑσπερίς), meaning western, together "southwest", in reference to the American Southwest.[2]

Description

Life restoration by Nobu Tamura

Dineobellator was a dromaeosaur similar in size to Velociraptor and Saurornitholestes. Unique features of the skeleton suggest greater hand and feet flexion than normal for dromaeosaurs, a tighter grip strength in the manual unguals, and greater movement at the tail base. These may aid in agility and predation. Additionally, the presence of quill knobs on the ulna suggest it was feathered, as assumed for all dromaeosaurids.[2]

Classification

Phylogenetic analysis places Dineobellator in the Velociraptorinae. Its presence, along with that of Acheroraptor and Dakotaraptor, suggests dromaeosaurs were still diversifying by the end of the Cretaceous. The appearance of a second North American velociraptorine suggests the vicariance of these taxa in North America after a Campanian-Maastrichtian dispersal event. Below is the phylogenetic tree found by the authors:[2]

Eudromaeosauria

However, two years later, Jasinski et al. 2022 re-examined the holotype, and found Dineobellator to be a member of Eudromaeosauria, but not within Velociraptorinae, Saurornitholestinae and Dromaeosaurinae.[4]

Dromaeosauridae

Paleobiology

One of the claws on the right hand of the type specimen of Dineobellator bears a gouge, the size of which is consistent with the claws of a similarly-sized theropod, possibly another Dineobellator. No evidence of healing is present, suggesting that the injury occurred close to the time of death. A broken and re-healed rib was also documented in the specimen.[2]

Palaeoenvironment

Restoration of Dineobellator in its ecosystem

Dineobellator is part of the

top predators of the formation's ecosystem were the azhdarchid pterosaur Quetzalcoatlus and Tyrannosaurus. The presence of a dromaeosaur suggests that the dromaeosaurs were active predators that had discrete ecological niches even in the presence of large tyrannosaurs. Other theropods Dineobellator co-existed with were the caenagnathid Ojoraptorsaurus, ornithomimids, and troodontids, as well as Richardoestesia of uncertain affinity. Meanwhile, there are at least eight remains of mammals from the formation, such as Alphadon, Essonodon, Mesodma, and Meniscoessus, while there are five (possibly seven) types of turtle remains (Aspideretoides, Compsemys, Hoplochelys, Neurankylus, Plastomenus, and possibly Adocus and Basilemys), and four remains of fish (including Myledaphus, Squatirhina, and possibly Lepisosteus) all of which could be inferred to be common prey items for Dineobellator.[3][2]

References

  1. ^ Gramling, Carolyn (26 March 2020). "Fossils of a new dromaeosaur date to the end of the Age of Dinosaurs". Science News.
  2. ^
    PMID 32218481. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
    .
  3. ^
    S2CID 210927955
    .
  4. S2CID 253382718
    .

External links
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