richardoestesia temporal range

[Greyideas]

Richardoestesia is a weird dinosaur, it seems to have a temporal range stretching from the Late Jurassic to the very end of the Cretaceous. Although commonly accepted fossils range between the Campanian and Maastrichtian range, the Jurassic and early Cretaceous fossils are often included. My suspicion is that it is a wastebasket taxa, any thoughts to its taxonomic and temporal problems? 

[Troodon]

The genus Richardoestesia contains only two valid species R. gilmorei and R. isosceles and both are from the late Cretaceous.  Have not heard of any earlier species.  A recent discovery, partial jaw,  have some paleontologists suggesting that R. Isosceles might be pterosaur but additional discoveries are needed to support that theory.

 

On the Jurassic side what I have seen is that paleontologist like Malafaia or Hendrickx simply refer to isolated teeth morph types has having affinities or are similar to Richardoestesia but fall short claiming it's one.  A common comparison across all families when describing theropod teeth.   Need to see early Cretaceous claims or other Jurassic ones.

 

[Greyideas]

So its form genus?

[Troodon]

It's a valid genus but not sure I understand your question

[Greyideas]

A form taxa is a taxa that is based on a few morphological traits, but that may not reflect its real biological nature https://www.jstor.org/stable/1304949?seq=1  

[DD1991]

On 12/19/2019 at 7:38 PM, Greyideas said:

Richardoestesia is a weird dinosaur, it seems to have a temporal range stretching from the Late Jurassic to the very end of the Cretaceous. Although commonly accepted fossils range between the Campanian and Maastrichtian range, the Jurassic and early Cretaceous fossils are often included. My suspicion is that it is a wastebasket taxa, any thoughts to its taxonomic and temporal problems? 

Richardoestesia is currently restricted to the type species R. gilmorei, the second nominal species R. isosceles being recently designated a nomen dubium by Averianov and Sues (2019). Sues and Averianov (2013) and Averianov and Sues (2019) also view the little-known taxon Asiamericana asiatica from the Turonian-age Bissekty Formation of Uzbekistan to Richardoestesia, but I've taken this referral with a grain of salt because the holotype teeth alone are insufficient to place this genus as a synonym of Richardoestesia (never mind that the late Lev Nessov initially classified Asiamericana as a spinosaur but later changed his mind and assigned this taxon to the fish family Saurodontidae.

 

A list of theropod teeth from the Bathonian to Maastrichtian referred to Richardoestesia is available at the Theropod Database, but those teeth have never been given binomials and are most certainly not Richardoestesia in a strict sense, and sooner or later someone could describe a new taxon with Richardoestesia teeth from pre-Campanian deposits that suggests that pre-Campanian Richardoestesia-like teeth belong to either distinct dromaeosaurs or non-dromaeosaur coelurosaurs.

 

Sues H.D. and Averianov, A. 2013. Enigmatic teeth of small theropod dinosaurs from the Upper Cretaceous (Cenomanian–Turonian) of Uzbekistan. Canadian Journal of Earth Sciences 50: 306-314

 

Alexander Averianov & Hans-Dieter Sues. 2019. Morphometric analysis of the teeth and taxonomy of the enigmatic theropod Richardoestesia from the Upper Cretaceous of Uzbekistan. Journal of Vertebrate Paleontology: e1614941

[Greyideas]

1 hour ago, DD1991 said:

Richardoestesia is currently restricted to the type species R. gilmorei, the second nominal species R. isosceles being recently designated a nomen dubium by Averianov and Sues (2019). Sues and Averianov (2013) and Averianov and Sues (2019) also view the little-known taxon Asiamericana asiatica from the Turonian-age Bissekty Formation of Uzbekistan to Richardoestesia, but I've taken this referral with a grain of salt because the holotype teeth alone are insufficient to place this genus as a synonym of Richardoestesia (never mind that the late Lev Nessov initially classified Asiamericana as a spinosaur but later changed his mind and assigned this taxon to the fish family Saurodontidae.

 

A list of theropod teeth from the Bathonian to Maastrichtian referred to Richardoestesia is available at the Theropod Database, but those teeth have never been given binomials and are most certainly not Richardoestesia in a strict sense, and sooner or later someone could describe a new taxon with Richardoestesia teeth from pre-Campanian deposits that suggests that pre-Campanian Richardoestesia-like teeth belong to either distinct dromaeosaurs or non-dromaeosaur coelurosaurs.

 

Sues H.D. and Averianov, A. 2013. Enigmatic teeth of small theropod dinosaurs from the Upper Cretaceous (Cenomanian–Turonian) of Uzbekistan. Canadian Journal of Earth Sciences 50: 306-314

 

Alexander Averianov & Hans-Dieter Sues. 2019. Morphometric analysis of the teeth and taxonomy of the enigmatic theropod Richardoestesia from the Upper Cretaceous of Uzbekistan. Journal of Vertebrate Paleontology: e1614941

Thanks