>>Although they may not be as well-known as “exciting” dinosaurs such as the Tyrannosaurus, the duck-billed hadrosaurs were the most common plant-eating dinosaurs at the end of the Mesozoic Era. Now, a newly-classified member of the group appears to be a common ancestor to the various types that came later.<<

https://newatlas.com/new-duck-billed-dinosaur/60591/?utm_source=New+Atlas+Subscribers&utm_campaign=2298277ba7-UA-2235360-4&utm_medium=email&utm_term=0_65b67362bd-2298277ba7-92533145

PermeateFree said:

>>Although they may not be as well-known as “exciting” dinosaurs such as the Tyrannosaurus, the duck-billed hadrosaurs were the most common plant-eating dinosaurs at the end of the Mesozoic Era. Now, a newly-classified member of the group appears to be a common ancestor to the various types that came later.<<

https://newatlas.com/new-duck-billed-dinosaur/60591/?utm_source=New+Atlas+Subscribers&utm_campaign=2298277ba7-UA-2235360-4&utm_medium=email&utm_term=0_65b67362bd-2298277ba7-92533145

Thanks for that.

“where it fed on aquatic vegetation in tidal marshes approximately 80 million years ago.”

I hadn’t realised that hadrosaurs came on the scene that recently. To go from there to the dominant lifeform 14 million years later is quite a step.

“Hadrosaurids were facultative bipeds, with the young of some species walking mostly on two legs and the adults walking mostly on four.”

That’s interesting.

The earliest described full hadrosaur, 1912, is shown below. Isn’t the state of preservation completely amazing for a dinosaur, it would even be considered good for an Egyptian mummy.

The actual definition of what is or isn’t a hadrosaur is not clear. The wikipedia entry on Hadrosauridae has changed the the family tree four times between 1997 and 2016. The wikipedia entry on Hadrosauroidea has been forced to include four totally different and unreconcilable family trees. So expect a lot of changes to the taxonomy in future.

So, where does this new Aquilarhinus palimentus fit in the family tree?

Time to dig out the Jounal of systematic paleontology article “An unusual ‘shovel-billed’ dinosaur with trophic specializations from the early Campanian of Trans-Pecos Texas …”

“Phylogenetic analysis reveals Aquilarhinus to be a non-saurolophid hadrosaurid
allied to Latirhinus from the late Campanian of Mexico, which bears a similar broadly arched nasal. … little is known of the evolution of hadrosaurids during the preceding Santonian through early Campanian. … the new species cannot be included within Kritosaurus.”

“In addition to Aquilarhinus, the taxonomic sample included 63 hadrosauroid taxa (14 outgroup species outside of Hadrosauridae, three non-saurolophid hadrosaurids, 24 saurolophines and 22 lambeosaurines). … Aquilarhinus palimentus appeared at the base of Hadrosauridae, forming a clade with Latirhinus uistslani.”

So, what’s known about Latirhinus?

“Latirhinus is an extinct genus of saurolophine hadrosaurid dinosaur from the Late Cretaceous of Mexico. The type species, Latirhinus uitstlani, was named in 2012 on the basis of a partial skeleton from the Campanian-age Cerro del Pueblo Formation. Lived: 83.5 million years ago – 70.6 million years ago (Campanian)”

The wikipedia article “Timeline of hadrosaur research” is getting very long. It’s an extremely active topic. The following is the entry for the year 2019 alone.
…

Discoveries in Hadosaurs already this year , active research!

2019

Prieto-Márquez and others described the new genus and species Adynomosaurus arcanus.

Zhang and others described the new genus and species Laiyangosaurus youngi.

Tsogtbaatar and others described the new genus and species Gobihadros mongoliensis.

A study on the nature of the fluvial systems of Laramidia during the Late Cretaceous, as indicated by data from vertebrate and invertebrate fossils from the Kaiparowits Formation of southern Utah, and on the behavior of hadrosaurid dinosaurs over these landscapes, will be published by Crystal et al. (2019).

A study on the osteology and phylogenetic relationships of “Tanius laiyangensis” is published by Zhang et al. (2019).

A study on the bone histology of tibiae of Maiasaura peeblesorum, focusing on the composition, frequency and cortical extent of localized vascular changes, is published by Woodward (2019).

Three juvenile specimens of Prosaurolophus maximus, providing new information on the ontogeny of this taxon, are described from the Bearpaw Formation (Alberta, Canada) by Drysdale et al. (2019).

A study on the impact of bone tissue structure, early diagenetic regimes and other taphonomic variables on the preservation potential of soft tissues in vertebrate fossils, as indicated by data from fossils of Edmontosaurus annectens from the Standing Rock Hadrosaur Site (Maastrichtian Hell Creek Formation, South Dakota), is published by Ullmann, Pandya & Nellermoe (2019), who report the first recovery of osteocytes and vessels from a fossil vertebral centrum and ossified tendons.

The first definitive lambeosaurine fossil (an isolated skull bone) is described from the Liscomb Bonebed of the Prince Creek Formation (Alaska, United States) by Takasaki et al. (2019).

Traces preserved on a tail vertebra of a hadrosaurid dinosaur from the Upper Cretaceous Hell Creek Formation (Montana, United States) are described by Peterson & Daus (2019), who interpret their finding as feeding traces produced by a late-stage juvenile Tyrannosaurus rex

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mollwollfumble is glad to see evidence of a T rex feeding on a hadrosaur. It supports mollwollfumble’s aquatic T rex theory, because hadrosaurs didn’t just drink at lakes and rivers, they ate there, too.

mollwollfumble said:

Discoveries in Hadosaurs already this year , active research!

2019

Prieto-Márquez and others described the new genus and species Adynomosaurus arcanus.

Zhang and others described the new genus and species Laiyangosaurus youngi.

Tsogtbaatar and others described the new genus and species Gobihadros mongoliensis.

A study on the nature of the fluvial systems of Laramidia during the Late Cretaceous, as indicated by data from vertebrate and invertebrate fossils from the Kaiparowits Formation of southern Utah, and on the behavior of hadrosaurid dinosaurs over these landscapes, will be published by Crystal et al. (2019).

A study on the osteology and phylogenetic relationships of “Tanius laiyangensis” is published by Zhang et al. (2019).

A study on the bone histology of tibiae of Maiasaura peeblesorum, focusing on the composition, frequency and cortical extent of localized vascular changes, is published by Woodward (2019).

Three juvenile specimens of Prosaurolophus maximus, providing new information on the ontogeny of this taxon, are described from the Bearpaw Formation (Alberta, Canada) by Drysdale et al. (2019).

A study on the impact of bone tissue structure, early diagenetic regimes and other taphonomic variables on the preservation potential of soft tissues in vertebrate fossils, as indicated by data from fossils of Edmontosaurus annectens from the Standing Rock Hadrosaur Site (Maastrichtian Hell Creek Formation, South Dakota), is published by Ullmann, Pandya & Nellermoe (2019), who report the first recovery of osteocytes and vessels from a fossil vertebral centrum and ossified tendons.

The first definitive lambeosaurine fossil (an isolated skull bone) is described from the Liscomb Bonebed of the Prince Creek Formation (Alaska, United States) by Takasaki et al. (2019).

Traces preserved on a tail vertebra of a hadrosaurid dinosaur from the Upper Cretaceous Hell Creek Formation (Montana, United States) are described by Peterson & Daus (2019), who interpret their finding as feeding traces produced by a late-stage juvenile Tyrannosaurus rex

—-

mollwollfumble is glad to see evidence of a T rex feeding on a hadrosaur. It supports mollwollfumble’s aquatic T rex theory, because hadrosaurs didn’t just drink at lakes and rivers, they ate there, too.

Perhaps they were the dinosaur Wildebeest equivalent.