| Alwalkeria | |
|---|---|
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Genus: | †Alwalkeria Chatterjee &Creisler, 1994 |
| Species: | †A. maleriensis |
| Binomial name | |
| †Alwalkeria maleriensis (Chatterjee, 1987) | |
| Synonyms | |
| |
Alwalkeria (/ˌælwɔːˈkɪəriə/; "for Alick Walker") is adubiousgenus ofbasalsaurischian dinosaur from theLate TriassicLower Maleri Formation of India.
In 1987,Sankar Chatterjee namedWalkeria maleriensis as a new genus and species ofpodokesaurid theropod dinosaurs based on specimen ISI R 306, which includes a partial skull, around 28 vertebrae, a proximal left femur, a distal right femur, and an astragalus (ankle bone). The specimen was recovered in theGodavari Valley locality from theMaleri Formation ofAndhra Pradesh, India. The remains were collected by Chatterjee in 1974 in redmudstone that was deposited during theCarnian stage of theTriassic period, approximately 235 to 228 million years ago. The specimen is housed in the collection of theIndian Statistical Institute, inKolkata, India.
The generic name,Walkeria, was proposed in honor of British paleontologistAlick Walker. The specific name,maleriensis, is a reference to theLower Maleri Formation, in southern India, where itsfossils were found. Chatterjee described the taxon as a basal theropod.[1] Since the original generic name was found to bepreoccupied by abryozoan, the new replacement generic nameAlwalkeria was created in 1994 by Chatterjee and Ben Creisler.[2]
In 1996, Loyal et al. agreed with a theropod identity for the type material.[3] Paul (1988) understoodAlwalkeria as a link between herrerasaurids and the genusProtoavis, and hence assigned it toHerrerasauridae based on features of thefemur.[4] However, Langer (2004) and Martínez and Alcober (2009), observed thatAlwalkeria was too primitive to be atheropod and considered it a basalsaurischian.[5][6]
In 2005, Rauhut and Remes foundAlwalkeria to be a chimera, with the anterior skull referable to acrurotarsan, and the vertebrae referable to various other ancientreptiles includingProlacertiformes; however, they claimed thefemur and theastragalus were clearly dinosaurian, with the latter possessing saurischian characteristics.[7] In 2011, Novas and colleagues argued thatAlwalkeria remains valid on the basis of an unusual morphology of its femur and an astragalus with a conservative morphology more similar to that of basal dinosaurs.[8] In 2016, Lecuona, Ezcurra & Irmis reiterated the chimaeric nature of theAlwalkeria holotype, noting that the skull material could be referred to theCrocodylomorpha. They also observed that the distal femur was more consistent with the morphology ofpseudosuchians, leading them to identify this bone fragment as an indeterminate representative of that clade. The vertebrae lack anatomical features allowing for a precise identification, dinosaur, pseudosuchian, or otherwise.[9]
In 2025, Sen & Ray determined the partial femora belonged to a novel representative of theLagerpetidae, which they namedAlickmeron maleriensis. The authors did not classify the astagalus within the genusAlwalkeria, but rather as indeterminate saurischian comparable in morphology to an unnamed Argentinanherrerasaurid.[10]
TheMaleri Formation has been interpreted as being the site of an ancient lake or river. Material of the sauropodomorphsJaklapallisaurus andNambalia and the herrerasaurianMaleriraptor have been found in theUpper Maleri Formation, as well as intermediate prosauropod remains.[11]
