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Adynomosaurus

Herbivore·Late Cretaceous·Catalonia, Spain·Quadrupedal with the ability to walk bipedally

Adynomosaurus is a genus of lambeosaurine dinosaur that lived during the Late Cretaceous period in what is now Catalonia, Spain. Discovered in 2012 and named in 2019, it is known from limited fossil material, notably a distinctive, underdeveloped shoulder blade. This feature, contributing to its scientific name meaning "weak shoulder lizard," sets it apart from other hadrosaurs, though its precise evolutionary relationships remain a subject of ongoing research.

Key Facts

  • Adynomosaurus is named for its underdeveloped shoulder blade, a unique trait among hadrosaurs.
  • It lived in a coastal estuary ecosystem with meandering rivers and mud flats.
  • The genus is only known from scant fossil material, making its precise relationships difficult to determine.
  • Adynomosaurus belongs to the lambeosaurine subfamily of hadrosaurs.
  • Its discovery contributes to the incomplete fossil record of European hadrosaurids in the Late Cretaceous.
Adynomosaurus
Scientific Name
Adynomosaurus arcanus
Physical Characteristics
  • Weakly developed shoulder blade with underdeveloped musculature.
  • Long skull with a beak and complex array of teeth.
  • Possessed a cranial crest.
  • Dental anatomy has teeth intermediate to other Spanish hadrosaurs, with tooth crowns roughly three times taller than wide.
  • V-shaped supraacetabular crest of the ilium, extended far back.
  • Iliac process of the ischium with nearly parallel dorsal and ventral margins and a stout, broad articulate facet.
Habitat
Diverse coastal estuary ecosystem with meandering rivers and mud flats.
Dinosaur Group
Ornithischian
Temporal Range
Maastrichtian
Named By
Albert Prieto-Márquez, Víctor Fondevilla, Albert G. Selles, Jonathan R. Wagner and Angel Galobart
Year Named
2019
Related Species

Tsintaosaurus, Pararhabdodon, Arenysaurus, Blasisaurus, Koutalisaurus, Parasaurolophus Cyrtocristatus, Aralosaurus, Canardia, Jaxartosaurus, Nanningosaurus, Ajnabia

Etymology
The generic name is a composite of the Greek words 'adýnamos' (weak), '-mos' (shoulder) and 'sauros' (lizard), referring to the taxon's underdeveloped shoulder blade. The specific name arcanus means "secret" or "occult", referring to the scant hadrosaur fossil record from the region.
Fossil Record Quality
Scant material
Geographic Distribution

Europe

About Adynomosaurus

Adynomosaurus is a genus of lambeosaurine dinosaur that roamed what is now Catalonia, Spain, during the Late Cretaceous period. First discovered in 2012 and formally described in 2019, the species Adynomosaurus arcanus is known from limited fossil remains. Its scientific name, derived from Greek words meaning "weak shoulder lizard," highlights its most distinctive anatomical feature: an underdeveloped shoulder blade that likely supported less musculature than in other hadrosaurs. This peculiar trait, alongside other dental and postcranial features, helps distinguish it, though its exact evolutionary placement among other hadrosaurs remains an area of active study.

Discovery and Naming

The fossil material of Adynomosaurus was unearthed in 2012 at the Costa de les Solanes locality within the Conques Formation, dating to the upper Maastrichtian stage. Excavations conducted in 2012 and 2013 yielded associated but disarticulated remains, including parts of the jaw, vertebrae, shoulder blade, sternum, ribs, pelvis, and hindlimb bones. Initially thought to belong to a new species of Pararhabdodon, the remains were later formally named and described by a team of paleontologists. The scapula, designated as the holotype specimen, was chosen for its diagnostic value. The generic name Adynomosaurus references the weak shoulder, while the specific epithet arcanus refers to the scant nature of hadrosaur fossil evidence in the region.

Description and Paleobiology

While many aspects of Adynomosaurus's anatomy, such as its vertebrae and limb bones, are indistinguishable from other hadrosaurids, its shoulder blade is uniquely underdeveloped. This feature suggests a reduction in arm musculature, potentially impacting its locomotion or limb function. As a hadrosaur, Adynomosaurus was a herbivore, likely possessing the characteristic beak and complex dental batteries for processing plant matter. It was capable of both quadrupedal and bipedal locomotion. Its dental anatomy shows intermediate characteristics compared to other Spanish hadrosaurs, with specific rotations of tooth sockets and a crown height-to-width ratio that differs from its relatives.

Paleoenvironment and Classification

Adynomosaurus inhabited a diverse coastal estuary ecosystem characterized by meandering rivers and mud flats. This environment was part of the Ibero-Armorican island during the Late Cretaceous. Its discovery is significant for understanding the "Maastrichtian Dinosaur Turnover," a period of major faunal change in Late Cretaceous Europe where previously dominant herbivore groups were replaced by different titanosaurs and lambeosaurine hadrosaurs. Adynomosaurus is classified within the subfamily Lambeosaurinae, though its precise phylogenetic relationships are complex and debated, with some studies placing it in groups like Arenysaurini or close to Tsintaosaurus and Pararhabdodon, while others suggest it might fall outside of Lambeosaurinae altogether.

Source: Wikipedia ↗

Frequently Asked Questions

What does the name Adynomosaurus mean?

The scientific name Adynomosaurus is derived from Greek words meaning "weak shoulder lizard." This name refers to the dinosaur's distinctively underdeveloped shoulder blade, which suggests weaker musculature compared to other hadrosaurs.

Where were Adynomosaurus fossils found?

Fossils of Adynomosaurus were discovered in Catalonia, Spain, specifically at the Costa de les Solanes locality of the Conques Formation. This region was part of the Ibero-Armorican island during the Late Cretaceous.

What did Adynomosaurus eat?

As a member of the hadrosaurid family, Adynomosaurus was a herbivore. Hadrosaurs were known for their powerful jaws and complex dental batteries, adapted for grinding plant material.

What period did Adynomosaurus live in?

Adynomosaurus lived during the Late Cretaceous period, specifically within the Maastrichtian age. This places its existence towards the very end of the age of dinosaurs.

What were the distinguishing physical characteristics of Adynomosaurus?

The most notable physical characteristic of Adynomosaurus is its underdeveloped scapula (shoulder blade), which was proportionally shorter and had a significantly narrower blade compared to other hadrosaurs. While otherwise similar to other hadrosaurs, this feature suggests reduced arm musculature.

What is the significance of Adynomosaurus in paleontology?

The discovery of Adynomosaurus adds important information to the incomplete fossil record of hadrosaurid dinosaurs in Late Cretaceous Europe. It helps researchers understand the ecological changes, like the "Maastrichtian Dinosaur Turnover," that were occurring in the region.