Lessemsaurus

{{short description|Sauropodomorph dinosaur genus from Late Triassic Argentina}}

{{speciesbox

| name = Lessemsaurus

| fossil_range = Norian
~{{fossilrange|228|208.5}}

| image = Lessemsaurus Senckenberg.jpg

| image_caption = Reconstructed skeleton

| genus = Lessemsaurus

| parent_authority = Bonaparte 1999

| species = sauropoides

| authority = Bonaparte 1999

}}

Lessemsaurus is an extinct genus of sauropodiform dinosaur belonging to Lessemsauridae.

Naming and description

The type species, L. sauropoides, was formally described by José Fernando Bonaparte in 1999 in honor of Don Lessem, a writer of popular science books. It was found in the Los Colorados Formation of the Ischigualasto-Villa Unión Basin in La Rioja Province, Argentina.Weishampel, David B; et al., 2004. "Dinosaur distribution (Late Triassic, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 527–528. {{ISBN|0-520-24209-2}}.

It was discovered in strata dating to the Norian stage, around 210 million years ago.{{cite journal|url=http://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/2480|title=Evolución de las vértebras presacras en Sauropodomorpha|author=Bonaparte, J. F.|author-link=José Bonaparte|year= 1999|journal=Ameghiniana|volume=36|pages= 115–187}}{{cite journal|author1=Pol, D. |author2=Powell, J. E. |year=2007|url=https://www.researchgate.net/publication/230213248|title= New information on Lessemsaurus sauropoides (Dinosauria: Sauropodomorpha) from the Upper Triassic of Argentina|journal=Special Papers in Palaeontology|volume=77|pages=223–243}} It is estimated to have reached {{convert|10|-|12|m|ft}} long and weighed over {{convert|7|MT|ST}}, possibly up to {{convert|8|-|10|MT|ST}}, in maximum body mass.{{cite journal |author=Diego Pol |author2=Alberto Garrido |author3=Ignacio A. Cerda |year=2011 |title=A New Sauropodomorph Dinosaur from the Early Jurassic of Patagonia and the Origin and Evolution of the Sauropod-type Sacrum |journal=PLOS ONE |volume=6 |issue=1 |pages=e14572 |doi=10.1371/journal.pone.0014572 |pmid=21298087 |pmc=3027623 |bibcode=2011PLoSO...614572P |doi-access=free }}{{cite journal|author1=Foelix, Rainer|author2=Pabst, Ben|author3=Kindlimann, René|year=2011|title=Die Saurier in Frick|journal=Mitteilungen der aargauischen Naturforschenden Gesellschaft|volume=37|url=https://doc.rero.ch/record/232631/files/PAL_E4501.pdf|doi=10.5169/seals-283430}}{{cite journal|author1=Apaldetti, C.|author2=Martínez, R.N.|author3=Cerda, I.A.|author4=Pol, D.|author5=Alcober, O.|year=2018|title=An early trend towards gigantism in Triassic sauropodomorph dinosaurs|journal=Nature Ecology & Evolution|volume=2|issue=8|pages=1227–1232|doi=10.1038/s41559-018-0599-y|pmid=29988169 |bibcode=2018NatEE...2.1227A |hdl=11336/89332 |s2cid=256705065 |hdl-access=free}}{{cite journal | title=A giant dinosaur from the earliest Jurassic of South Africa and the transition to quadrupedality in early sauropodomorphs |last1=McPhee |first1=Blair W. |last2=Benson |first2=Roger B.J. |last3=Botha-Brink |first3=Jennifer |last4=Bordy |first4=Emese M. |last5=Choiniere |first5=Jonah N. |name-list-style=amp | journal=Current Biology | volume=28 | issue=19 | pages=3143–3151.e7 | year=2018 | doi=10.1016/j.cub.2018.07.063| pmid=30270189 |doi-access=free |bibcode=2018CBio...28E3143M |url=https://ora.ox.ac.uk/objects/uuid:70de4052-c736-4737-a4d7-6ef8ab2b21b0/files/m8e3f7c7b635474911e65e3da30edadac }}

Classification

File:Lessemsaurus mount.jpg

A cladogram after Pol, Garrido & Cerda, 2011,{{cite journal |author=Diego Pol |author2=Alberto Garrido |author3=Ignacio A. Cerda |year=2011 |title=A New Sauropodomorph Dinosaur from the Early Jurassic of Patagonia and the Origin and Evolution of the Sauropod-type Sacrum |journal=PLOS ONE |volume=6 |issue=1 |pages=e14572 |doi=10.1371/journal.pone.0014572 |pmid=21298087 |pmc=3027623 |bibcode=2011PLoSO...614572P |doi-access=free }} illustrates a possible placing of Lessemsaurus and Antetonitrus in Sauropodomorpha:

{{clade| style=font-size:85%;line-height:85%;margin:1em auto;

|label1=Sauropodomorpha

|1={{clade

|1=Saturnalia

|2={{clade

|1={{clade

|1=Pantydraco

|2=Thecodontosaurus }}

|2={{clade

|1=Efraasia

|2={{clade

|1=Ruehleia

|2=Plateosaurus

|label3=Massopoda

|3={{clade

|1=Riojasaurus

|2={{clade

|1={{clade

|1=Massospondylus

|2={{clade

|1=Coloradisaurus

|2=Lufengosaurus

|3=Gyposaurus

|4=Yunnanosaurus }} }}

|label2=Anchisauria

|2={{clade

|1=Anchisaurus

|2={{clade

|1=Aardonyx

|2={{clade

|1=Leonerasaurus

|2={{clade

|1=Melanorosaurus

|label2=Sauropoda

|2={{clade

|1={{clade

|1=Antetonitrus

|2=Lessemsaurus }}

|2={{clade

|1=Kotasaurus

|2={{clade

|1=Vulcanodon

|2=Eusauropoda }} }} }} }} }} }} }} }} }} }} }} }} }} }}

In 2018, Apaldetti et al. recovered it as part of a clade they named Lessemsauridae, after Lessemsaurus. Their cladogram is reproduced below:{{Cite journal |last1=Apaldetti |last2=Martínez |first2=Ricardo N. |last3=Cerda |first3=Ignatio A. |last4=Pol |first4=Diego |last5=Alcober |first5=Oscar |year=2018 |title=An early trend towards gigantism in Triassic sauropodomorph dinosaurs |journal=Nature Ecology & Evolution |volume=2 |issue=8 |pages=1227–1232 |doi=10.1038/s41559-018-0599-y|hdl=11336/89332 |pmid=29988169|bibcode=2018NatEE...2.1227A |s2cid=49669597 |hdl-access=free }}

{{Clade |style=font-size:85%; line-height:100%

|label1=Sauropodiformes

|1={{clade

|1=Mussaurus

|2={{clade

|1=Aardonyx

|2=Sefapanosaurus

|3={{clade

|1={{clade

|label1=Melanorosauridae

|1={{clade

|1=Camelotia

|2=Melanorosaurus }} }}

|2={{clade

|label1=Sauropoda

|1={{clade

|label1=Lessemsauridae

|1={{clade

|1=Antetonitrus

|2={{clade

|1=Ingentia

|2=Lessemsaurus }} }} }}

|2={{clade

|1=Blikanasaurus

|2={{clade

|1=Gongxianosaurus

|2={{clade

|1=Pulanesaura

|2=Gravisauria }} }} }} }} }} }} }} }} }}

The following cladogram shows the position of Lessemsaurus outside of Sauropoda, according to Oliver W. M. Rauhut and colleagues, 2020:{{cite journal |last1=Rauhut |first1=O. W. M. |last2=Holwerda |first2=F. M. |last3=Furrer |first3=H. |title=A derived sauropodiform dinosaur and other sauropodomorph material from the Late Triassic of Canton Schaffhausen, Switzerland |journal=Swiss Journal of Geosciences |date=2020 |volume=113 |issue=1 |page=8 |doi=10.1186/s00015-020-00360-8|s2cid=220294939 |doi-access=free |url=https://dspace.library.uu.nl/bitstream/handle/1874/408535/Rauhut2020_Article_ADerivedSauropodiformDinosaurA.pdf?sequence=1&isAllowed=y }}

{{clade| style=font-size:85%;line-height:80%

|label1=Massopoda

|1={{clade

|1=Eucnemesaurus

|2=Riojasaurus 80px

}}

|2={{clade

|1=Sarahsaurus

|2={{clade

|label1=Massospondylidae

|1={{clade

|1=Yunnanosaurus