''Rechnisaurus'' is an extinct
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
dicynodont
Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivorous animals with a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typicall ...
from the
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...
(
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...
)
Yerrapalli Formation
The Yerrapalli Formation is a Triassic rock formation consisting primarily of mudstones that outcrops in the Pranhita–Godavari Basin in southeastern India. The Yerrapalli Formation preserves fossils of freshwater and terrestrial vertebrates ...
of
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. It contains a single species, ''Rechnisaurus cristarhynchus''.
History
''Rechnisaurus'' has had a long history of confusion with the far more widespread dicynodont ''
Kannemeyeria
''Kannemeyeria'' is a genus of dicynodont that lived during the Anisian age of Middle Triassic period in what is now Africa and South America. The generic name is given in honor of Dr. Daniel Rossouw Kannemeyer, the South African fossil collect ...
''. ''Rechnisaurus cristarhynchus'' was originally described as a new genus and species in 1970, on the basis of fossils from India. Later in the 1970s, additional specimens were found in Africa (namely the
Ntawere Formation
The Ntawere Formation is a Middle Triassic (Anisian) geological formation in Zambia, preserving fossils of synapsids, archosaurs, and temnospondyls.
Geology
Several different facies are present in the Ntawere Formation, reconstructing a floodpla ...
of
Zambia
Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most cent ...
and the
Omingonde Formation
The Omingonde Formation is an Early Triassic, Early to Middle Triassic (Anisian to Ladinian) geologic Formation (geology), formation, part of the Karoo Supergroup, in the western Otjozondjupa Region and northeastern Erongo Region of north-central N ...
of
Namibia
Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...
) and referred to the species. These African fossils were noted to be very similar to ''Kannemeyeria'', so ''Rechnisaurus'' was renamed as a species of ''Kannemeyeria'', ''Kannemeyeria cristarhynchus''. However, in 1989 the original Indian fossils were re-compared to ''Kannemeyeria'' and found to be distinct, so ''Rechnisaurus'' was re-established in a more restricted sense including only the Indian fossils.
The African fossils continued to be designated as ''Kannemeyeria cristarhynchus'', but this was later found to be untenable, since that species name was based on ''Rechnisaurus cristarhynchus'', which had been established as a distinct genus. In 2003, the African species of ''Kannemeyeria'' was renamed to ''Kannemeyeria lophorhinus''.
''Rechnisaurus cristarhynchus'' has also been reported from the
Manda Beds
The Manda Formation (also known as the Manda Beds) is a Middle Triassic (Anisian?) or possibly Late Triassic (Carnian?) geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Triassic, including some of the e ...
of
Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...
, though the Tanzanian fossils are in need of re-evaluation and are likely not related to ''Rechnisaurus''. PVL 3963, a partial skull from the
Quebrada de los Fosiles Formation of
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
, was initially referred to ''Rechnisaurus'' and later designated as a new species of ''Kannemeyeria'', under the species name ''Kannemeyeria aganosteus''.
References
The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive
{{Taxonbar, from=Q7302417
Kannemeyeriiformes
Prehistoric synapsids of Asia
Fossil taxa described in 1970
Anomodont genera