''Volkheimeria'' is an extinct genus of
sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...
dinosaurs
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
that lived in what is now Argentina during the Early Jurassic, 178–179 million years ago. Its type and only species is ''Volkheimeria chubutensis''.
Discovery and naming
The only known specimen of ''Volkheimeria'' was discovered at the site of Cerro Cóndor Sur, roughly a kilometer west of the village of
Cerro Cóndor
Cerro Cóndor is a village and municipality in Chubut Province in southern Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina cov ...
in
Chubut Province, Argentina.
In
1979
Events
January
* January 1
** United Nations Secretary-General Kurt Waldheim heralds the start of the ''International Year of the Child''. Many musicians donate to the ''Music for UNICEF Concert'' fund, among them ABBA, who write the song ...
,
José Bonaparte described it as representing a new genus and species, ''Volkheimeria chubutensis'', alongside two other species discovered in the same strata, ''
Piatnitzkysaurus floresi
''Piatnitzkysaurus'' ( meaning "Piatnitzky's lizard") is a genus of megalosauroid theropod dinosaur that lived approximately 179 to 177 million years ago during the lower part of the Jurassic Period in what is now Argentina. ''Piatnitzkysaurus'' ...
'' and ''
Patagosaurus fariasi
''Patagosaurus'' (meaning "Patagonia lizard") is an extinct genus of eusauropod dinosaur from the Middle-Late Toarcian of Patagonia, Argentina. It was first found in deposits of the Cañadón Asfalto Formation, which date to around 179 to 177&nb ...
''.
The genus name ''Volkheimeria'' honors the Argentinean paleontologist Wolfgang Volkheimer.
Fossil record
Only a single specimen of ''Volkheimeria chubutensis'' is known: the
holotype PVL 4077, a partial skeleton from the
Cañadón Asfalto Formation
The Cañadón Asfalto Formation is a Lower Jurassic to Late Jurassic geologic formation, from the Jurassic period of the Mesozoic Era. Its age is controversial, uranium-lead dating of the volcanic tuff beds having given various different ages. A ...
of
Argentina. This specimen consists of a partial cervical vertebra, two complete and two partial dorsal vertebrae, part of the sacrum, several incomplete caudal vertebrae, partial ilia, a pubis, an ischium, a femur, and a tibia.
The specimen was not fully grown, but had probably reached sexual maturity.
An isolated tooth found in the Cañadón Asfalto Formation, MPEF-PV 10860, may belong to ''Volkheimeria'', though this cannot be proven without more complete specimens.
Classification
''Volkheimeria'' was originally identified as a primitive sauropod, distinguishable from ''Patagosaurus''. Some phylogenetic analyses of the taxon have recovered it as a
eusauropod,
vulcanodontid, or primitive sauropod, though its position is variable due to its incomplete nature. The phylogenetic analysis of Pol and colleagues in 2022 recovered ''Volkheimeria'' as a non-eusauropod based on primitive features of the vertebrae, though alternative placements were identified as closer to either ''
Amygdalodon'' or ''
Archaeodontosaurus
''Archaeodontosaurus'' ("ancient-toothed lizard") is a genus of sauropod dinosaur from the Middle Jurassic. Its fossils were found in the Isalo III Formation of Madagascar. The type species, ''Archaeodontosaurus descouensi'', was described in ...
'', as shown below.
Classification history
Bonaparte initially regarded ''Volkheimeria'' as a primitive member of
Cetiosauridae
Cetiosauridae is a family of sauropod dinosaurs which was first proposed by Richard Lydekker in 1888. While traditionally a wastebasket taxon containing various unrelated species, some recent studies have found that it may represent a natural c ...
.
He considered both it and ''Lapparentosaurus'' to represent an early stage in cetiosaurid evolution, more advanced than ''
Vulcanodon'' but more primitive than ''Patagosaurus'' and ''
Cetiosaurus''.
In 1990, John S. McIntosh included both ''Volkheimeria'' and ''Lapparentosaurus'' in
Brachiosauridae,
albeit without providing anatomical evidence for classifying ''Volkheimeria'' as such.
In 2004, Upchurch et al. regarded the affinities of ''Volkheimeria'' as uncertain, due to the lack of a
phylogenetic analysis including the taxon.
In 2011, Pol et al. included both ''Volkheimeria'' and ''Lapparentosaurus'' in a phylogenetic analysis, and recovered them as basal eusauropods, more derived than ''Shunosaurus'' but more basal than ''Barapasaurus'', with ''Volkheimeria'' more basal than ''Lapparentosaurus''.
In 2017, Cerda et al. found ''Volkheimeria'' to be a non-eusauropod sauropod closely related to ''
Tazoudasaurus''.
In 2018, Holwerda and Pol found ''Volkheimeria'' to be a non-eusauropod sauropod, as the sister taxon of ''
Spinophorosaurus
''Spinophorosaurus'' is a genus of sauropod dinosaur that lived in what is now Niger during the Middle Jurassic period. The first two specimens were excavated in the 2000s by German and Spanish teams under difficult conditions. The skeletons w ...
''.
Evolution
''Volkheimeria'' lived during the
Toarcian age of the Early Jurassic, 178-179 million years ago.
The beginning of the Toarcian was a time of significant faunal turnover for sauropodomorphs, as all sauropodomorph lineages except for sauropods died out and eusauropods, which became the dominant sauropod group in the Middle Jurassic, began to diversify.
''Volkheimeria'' was not a member of the eusauropod radiation, and was probably a representative of a lineage that diverged from other sauropods in the earliest Jurassic or even the Triassic.
Paleoecology
The ecosystem represented by the Cañadón Asfalto Formation included at least four sauropods other than ''Volkheimeria chubutensis'', all of them eusauropods: ''
Bagualia alba'',
''Patagosaurus fariasi'', an unnamed basal eusauropod,
and a possible
neosauropod.
References
Dinosaur genera
Middle Jurassic dinosaurs of South America
Jurassic Argentina
Fossils of Argentina
Cañadón Asfalto Formation
Fossil taxa described in 1979
Taxa named by José Bonaparte
{{sauropodomorph-stub