Vinay at 22:14, 2 February 2026

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{{Short description|Extinct genus of dinosaurs}}
{{speciesbox
| fossil_range = [[Late Triassic]], {{fossilrange|228}}
| image = Alwalkeria.png
| image_caption = Holotype distal femur (D) and historically referred proximal femur (A–C)
| display_parents = 4
| genus = Alwalkeria
| species = maleriensis
| authority = (Chatterjee, 1987)
| parent_authority=[[Sankar Chatterjee|Chatterjee]] & [[Ben Creisler|Creisler]], 1994
| synonyms =
* ''Walkeria'' {{small|Chatterjee, 1987 ([[Walkeria|preoccupied]])}}
* ''Alickmeron'' {{small|Sen & Ray, 2025}}
}}
'''''Alwalkeria''''' ({{IPAc-en|ˌ|æ|l|w|ɔː|ˈ|k|ɪər|i|ə}}; "for Alick Walker") is a historically problematic [[extinct]] [[genus]] of [[avemetatarsalia]]n known from the [[Late Triassic]] [[Lower Maleri Formation]] of India. The genus contains a [[monotypic taxon|single species]], '''''Alwalkeria maleriensis'''''. It was initially described in 1987 under the genus name {{gloss|''Walkeria''}}, based on a partial skull, several vertebrae, and fragmentary hindlimb bones. As this name is [[preoccupied]], the new genus ''Alwalkeria'' was proposed to replace it. Early research interpreted the material belonging to a 'podokesaurid' ([[coelophysoid]]) theropod, [[herrerasaur]], or ''[[Eoraptor]]''-like [[Basal (phylogenetics)|basal]] eusaurischian dinosaur. Subsequent work recognized the [[Chimera (paleontology)|chimaeric]] status of the fossils referred to this species, as they belong to multiple unrelated taxa. Some of the bones may belong to a dinosaur, and the skull is likely from a [[pseudosuchia]]n. A 2025 study suggested [[lagerpetid]] affinities for the femora, though this was deemed unlikely by a subsequent review, which regarded ''A. maleriensis'' as a member of Pan-Aves (Avemetatarsalia) of [[Incertae sedis|uncertain placement]].

== History and classification ==
In 1987, [[Sankar Chatterjee]] named ''Walkeria maleriensis'' as a new genus and species of [[podokesaurid]] 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 the [[Godavari River|Godavari]] Valley locality from the [[Lower Maleri Formation|Maleri Formation]] of [[Andhra Pradesh]], India. The remains were collected by Chatterjee in 1974 in red [[mudstone]] that was deposited during the [[Carnian]] stage of the [[Triassic]] period, approximately 235 to 228 million years ago. The specimen is housed in the collection of the [[Indian Statistical Institute]], in [[Kolkata]], India.

The generic name, ''Walkeria'', was proposed in honor of British paleontologist [[Alick Walker]]. The specific name, ''maleriensis'', is a reference to the [[Lower Maleri Formation]], in southern India, where its [[fossil]]s were found. Chatterjee described the taxon as a basal theropod.<ref>Chatterjee, S. 1987. A new theropod dinosaur from India with remarks on the Gondwana-Laurasia connection in the Late Cretaceous. In: McKenzie, G.D. (Ed.). ''Gondwana Six: Stratigraphy, Sedimentology, and Paleontology. Geophysical Monograph 41''. Washington, D.C.: American Geophysical Union. Pp. 183–189.</ref> Since the original generic name was found to be [[International Code of Zoological Nomenclature|preoccupied]] by a [[bryozoa]]n, the new replacement generic name ''Alwalkeria'' was created in 1994 by Chatterjee and Ben Creisler.<ref>Chatterjee, S. & Creisler, B.S. 1994. ''Alwalkeria'' (Theropoda) and ''Morturneria'' (Plesiosauria), new names for preoccupied ''Walkeria'' Chatterjee, 1987, and ''Turneria'' Chatterjee and Small, 1989. ''Journal of Vertebrate Paleontology'' 14(1): 142.</ref>

In 1996, Loyal et al. agreed with a theropod identity for the type material.<ref>R. S. Loyal, A. Khosla, and A. Sahni. 1996. Gondwanan dinosaurs of India: affinities and palaeobiogeography. Memoirs of the Queensland Museum 39(3):627-638</ref> Paul (1988) understood ''Alwalkeria'' as a link between herrerasaurids and the genus ''[[Protoavis]]'', and hence assigned it to [[Herrerasauridae]] based on features of the [[femur]].<ref>Paul, 1988. Predatory dinosaurs of the world. Simon and Schuster, New York. A New York Academy of Sciences Book. 464 pp.</ref> However, Langer (2004) and Martínez and Alcober (2009), observed that ''Alwalkeria'' was too primitive to be a [[theropod]] and considered it a basal [[saurischia]]n.<ref name="langer2004">Langer, M.C. 2004. Basal Saurischia. In: Weishampel, D.B., Dodson, P., & Osmolska, H. (Eds.). The Dinosauria (2nd Edition). Berkeley: University of California Press. Pp. 25–46.</ref><ref>R. N. Martínez and O. A. Alcober. 2009. A basal sauropodomorph (Dinosauria: Saurischia) from the Ischigualasto Formation (Triassic, Carnian) and the early evolution of Sauropodomorpha. PLoS ONE 4(2 (e4397)):1-12</ref>

[[File:Alwalkeria maleriensis.jpg|thumb|left|Speculative [[life restoration]] as a dinosaur]]

=== Chimeric identity ===
In 2005, Rauhut and Remes found ''Alwalkeria'' to be a chimera, with the anterior skull referable to a [[Crurotarsi|crurotarsan]], and the vertebrae referable to various other ancient [[reptile]]s including [[Prolacertiformes]]; however, they claimed the [[femur]] and the [[talus bone|astragalus]] were clearly dinosaurian, with the latter possessing saurischian characteristics.<ref>Remes and Rauhut, 2005. The oldest Indian dinosaur ''Alwalkeria maleriensis'' Chatterjee revised: a chimera including remains of a basal saurischian. in Kellner, Henriques and Rodrigues (eds). II Congresso Latino-Americano de Paleontologia de Vertebrados, Boletim de Resumos. Museu Nacional, Rio de Janeiro. 218.</ref> In 2011, Novas and colleagues argued that ''Alwalkeria'' 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.<ref>{{cite journal|author1-link=Fernando Novas |last1=Novas |first1=Fernando E. |last2=Ezcurra |first2=Martín D. |author3-link=Sankar Chatterjee |last3=Chatterjee |first3=Sankar |last4=Kutty |first4=T.S. |year=2011 |title=New dinosaur species from the Upper Triassic Upper Maleri and Lower Dharmaram formations of central India |url=https://www.researchgate.net/publication/231824148 |journal=[[Earth and Environmental Science Transactions of the Royal Society of Edinburgh]] |volume=101 |issue=3–4 |pages=333–349 |doi=10.1017/S1755691011020093}}</ref> In 2016, Lecuona, Ezcurra & Irmis reiterated the chimaeric nature of the ''Alwalkeria'' holotype, noting that the skull material could be referred to the [[Crocodylomorpha]]. They also observed that the distal femur was more consistent with the morphology of [[pseudosuchia]]ns, 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.<ref name="Lecuona2016">{{Cite journal |last1=Lecuona |first1=Agustina |last2=Ezcurra |first2=Martín D. |last3=Irmis |first3=Randall B. |date=2016-10-03 |editor-last=Angielczyk |editor-first=Kenneth |title=Revision of the early crocodylomorph ''Trialestes romeri'' (Archosauria, Suchia) from the lower Upper Triassic Ischigualasto Formation of Argentina: one of the oldest-known crocodylomorphs |journal=Papers in Palaeontology |language=en |volume=2 |issue=4 |pages=585–622 |doi=10.1002/spp2.1056 |bibcode=2016PPal....2..585L |issn=2056-2799|hdl=11336/66393 |hdl-access=free }}</ref>

In 2025, Sen & Ray determined the partial femora belonged to a novel representative of the [[Lagerpetidae]], which they named '''''Alickmeron maleriensis'''''. The authors did not classify the astragalus within the genus ''Alwalkeria'', but rather as indeterminate saurischian comparable in morphology to an unnamed Argentinan [[herrerasaurid]].<ref name="Sen&Ray25">{{Cite journal |last1=Sen |first1=Sulagna |last2=Ray |first2=Sanghamitra |date=2025-09-29 |title=Taxonomic reassessment of archosaurs with dinosaurian affinities from the lower fauna of the Upper Triassic Maleri Formation of India and their significance |journal=[[Journal of Vertebrate Paleontology]] |article-number=e2546434 |language=en |doi=10.1080/02724634.2025.2546434 |issn=0272-4634}}</ref> In 2026, McDavid, Marchant, and Reid stated that ''Alickmeron'' is an objective [[junior synonym]] of ''Alwalkeria'', due to both taxa having the same type species based on the same holotype, ''Walkeria maleriensis'', based on ISI R 306. They agreed with restricting the holotype of ''Alwalkeria'' to ISI R 306b, the distal femur, but suggested that the taxon can only be confidently assigned to Pan-Aves (=[[Avemetatarsalia]]) ''incertae sedis'', not a lagerpetid pterosauromorph as proposed by Sen & Ray (2025). They further regarded the referral of any other material, including the proximal femur, to ''A. maleriensis'' as ambiguous.<ref>{{cite journal|author1=McDavid, S.N.|author2=Marchant, C.J.|author3=Reid, I.J.|date=2026-02-02|title=''Alickmeron'' Sen & Ray, 2025 is an objective junior synonym of ''Alwalkeria'' Chatterjee & Creisler, 1994|journal=[[Journal of Vertebrate Paleontology]]|doi=10.1080/02724634.2025.2604088}}</ref>

==Paleoecology==
The [[Lower Maleri Formation|Maleri Formation]] has been interpreted as being the site of an ancient lake or river. Material of the sauropodomorphs ''[[Jaklapallisaurus]]'' and ''[[Nambalia]]'' and the herrerasaurian ''[[Maleriraptor]]'' have been found in the [[Upper Maleri Formation]], as well as intermediate prosauropod remains.<ref name="Maleriraptor">{{Cite journal |last1=Ezcurra |first1=Martín D. |last2=Garcia |first2=Maurício Silva |last3=Novas |first3=Fernando E. |last4=Müller |first4=Rodrigo Temp |last5=Agnolín |first5=Federico L. |last6=Chatterjee |first6=Sankar |date=2025-05-07 |title=A new herrerasaurian dinosaur from the Upper Triassic Upper Maleri Formation of south-central India |journal=[[Royal Society Open Science]] |language=en |volume=12 |issue=5 |article-number=250081 |doi=10.1098/rsos.250081 |pmid=40370605 |issn=2054-5703 |doi-access=free|pmc=12077243 |bibcode=2025RSOS...1250081E }}</ref>

== References ==
{{Reflist|2}}

=== Bibliography ===

* Norman, D.B. 1990. Problematic Theropods: Coelurosaurs. In: Weishampel, D.B., Dodson, P. & Osmolska, H. (Eds.). ''The Dinosauria'' (1st Edition). Berkeley: University of California Press. Pp. 280–305.

{{Avemetatarsalia}}
{{Taxonbar|from=Q133238}}

[[Category:Saurischia]]
[[Category:Dinosaur genera]]
[[Category:Carnian dinosaurs]]
[[Category:Dinosaurs of India]]
[[Category:Fossil taxa described in 1994]]
[[Category:Taxa named by Sankar Chatterjee]]

Alwalkeria - Revision history

Vinay at 22:14, 2 February 2026