Pampadromaeus
| Pampadromaeus | |
|---|---|
| |
| Skeletal reconstruction showing known remains | |
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Family: | †Saturnaliidae |
| Genus: | †Pampadromaeus Cabreiraet al.2011 |
| Species: | †P. barberenai
|
| Binomial name | |
| †Pampadromaeus barberenai Cabreiraet al.2011
| |
Pampadromaeusis anextinctgenusofbasalsauropodomorphdinosaursknown from theLate Triassic(Carnian)Santa Maria Formationof theParaná BasininRio Grande do Sul,southern Brazil.[1]
Discovery
[edit]Pampadromaeusis known only from theholotypespecimenULBRA-PVT016, adisarticulated,partial but well preservedskeletonfrom a single individual which includes most of theskullbones and thelower jaws;dorsal,sacralandcaudal vertebrae;elements of theshoulder girdleand theforelimbs,aniliumand elements of thehindlimbs.It was collected in the upperHyperodapedonbiozone from theAlemoa Memberof theSanta Maria Formation(Rosário do Sul Group) in the "Janner" (also known as "Várzea do Agudo" ) locality,geoparkof Paleorrota, dating to theCarnianfaunal stageof the earlyLate Triassic,about 230–228million years ago.[1]A U-Pb (uraniumdecay) dating found that the Santa Maria Formation dated around 233.23 million years ago, putting it 1.5 million years older than theIschigualasto Formation,and making the two formations approximately equal as the earliest dinosaur localities.[2]
Description
[edit]
Pampadromaeuswas a small bipedal animal. It shows a mosaic of basal and derived traits. It differs from other sauropodomorphs by a combination of characters. Some of these are shared with members of theTheropoda:thepremaxillais pointed downwards forming a subnarial gap with themaxillaand the anterior-most teeth are unserrated; in the location where with theropods thefenestra promaxillarisis positioned, a small depression is present. Basal traits consist of a large skull, a short thighbone, the possession of just two sacral vertebrae and the presence of fifteen teeth in thepterygoid.[1]
There were four teeth in the premaxilla and about twenty in both the maxilla and the lower jaw for a total of eighty-eight. The teeth were large, elongated, lanceolate, slightly recurved, sharply pointed and coarsely serrated. The lower leg was much longer than the thighbone, indicating a cursorial lifestyle.[1]
In 2022, Aureliano and colleagues performed a mirco-computed tomography scan on the postcranial skeletons of some of the earliest saurischian dinosaurs that lived during the lateCarnianincludingGnathovoraxwith sauropodomorphsPampadromaeusandBuriolestes,which showed that the invasive air sac system was absent and that their bones were not pneumatised. These results indicate that pneumatisation in archosaur groups (pterosaurs,theropodsandsauropodomorphs) are not homologous, but are traits that independently evolved at least 3 times.[3]
Etymology
[edit]Pampadromaeuswas first named by Sergio F. Cabreira, Cesar L. Schultz, Jonathas S. Bittencourt, Marina B. Soares, Daniel C. Fortier, Lúcio R. Silva and Max C. Langer in2011and thetype speciesisPampadromaeus barberenai.Thegeneric nameis derived fromQuechuapampa,"plain", in reference to the present landscape of the site, and Greek δρομεύς,dromeus,"runner", referring to the cursorial habits; the Latinised spelling variantdromaeusis used. Thespecific namehonours the BrazilianpaleontologistMário Costa Barberena.[1]
Phylogeny
[edit]Pampadromaeuswas found to be abasalsauropodomorph in four differentcladisticanalyses. The describers emphasized however, that this position was not strongly supported, showing the difficulties of determining the affinities of such early forms with the basalDinosauromorpha,Saurischia,Sauropodomorpha and Theropoda.[1]
References
[edit]
- ^abcdefCabreira et al., 2011
- ^Langer et al., 2018
- ^Aureliano T, Ghilardi AM, Müller RT, Kerber L, Pretto FA, Fernandes MA, Ricardi-Branco F, Wedel MJ (2022)."The absence of an invasive air sac system in the earliest dinosaurs suggests multiple origins of vertebral pneumaticity".Scientific Reports.12(1). 20844.Bibcode:2022NatSR..1220844A.doi:10.1038/s41598-022-25067-8.PMC9734174.PMID36494410.
Bibliography
[edit]- Cabreira, Sérgio F.; Schultz, Cesar L.; Bittencourt, Jonathas S.; Soares, Marina B.; Fortier, Daniel C.; Silva, Lúcio R.; Langer, Max C. (2011),"New stem-sauropodomorph (Dinosauria, Saurischia) from the Triassic of Brazil"(PDF),Naturwissenschaften,98(12): 1035–1040,Bibcode:2011NW.....98.1035C,doi:10.1007/s00114-011-0858-0,PMID22083251,retrieved2019-03-29
- Langer, Max Cardoso; McPhee, Blair Wayne; Marsola, Júlio César de Almeida; Da Silva, Lúcio Roberto; Cabreira, Sérgio Furtado (2019), "Anatomy of the dinosaurPampadromaeus barberenai(Saurischia—Sauropodomorpha) from the Late Triassic Santa Maria Formation of southern Brazil ",PLoS ONE,14(2): 1–64,Bibcode:2019PLoSO..1412543L,doi:10.1371/journal.pone.0212543
- Langer, M.C.; Ramezani, J.; Da Rosa, Á.A.S. (2018),"U-Pb age constraints on dinosaur rise from south Brazil"(PDF),Gondwana Research,53:133–140,Bibcode:2018GondR..57..133L,doi:10.1016/j.gr.2018.01.005,retrieved2019-03-29
