Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.

The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the...

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Main Authors: Denver W Fowler, Holly N Woodward, Elizabeth A Freedman, Peter L Larson, John R Horner
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2011-01-01
Series:PLoS ONE
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21738646/?tool=EBI
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author Denver W Fowler
Holly N Woodward
Elizabeth A Freedman
Peter L Larson
John R Horner
author_facet Denver W Fowler
Holly N Woodward
Elizabeth A Freedman
Peter L Larson
John R Horner
author_sort Denver W Fowler
collection DOAJ
description The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.
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spelling doaj.art-6efcc6dbda514d50980b4e62094f95e42022-12-21T22:43:33ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-0166e2137610.1371/journal.pone.0021376Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.Denver W FowlerHolly N WoodwardElizabeth A FreedmanPeter L LarsonJohn R HornerThe carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21738646/?tool=EBI
spellingShingle Denver W Fowler
Holly N Woodward
Elizabeth A Freedman
Peter L Larson
John R Horner
Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.
PLoS ONE
title Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.
title_full Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.
title_fullStr Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.
title_full_unstemmed Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.
title_short Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.
title_sort reanalysis of raptorex kriegsteini a juvenile tyrannosaurid dinosaur from mongolia
url https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21738646/?tool=EBI
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