[D] Arcusaurus pereirabdalorum [Su] [sG] [T]
Describer
Yates, Bonnan & Neveling 2011
Time
Jurassic Late Hettangian Sinemurian
Classification
Saurischia Sauropodomorpha
Diet
Herbivore
Fossilsite
Elliot Formation [Upper], Spion Kop Heelbo site, Senekal District, Orange Free State, South Africa, Africa
Info
Skull
Abstract: A new basal sauropodomorph dinosaur, Arcusaurus pereirabdalorum, sp. nov., is named and described on the basis of a partial, disarticulated but associated skull and dispersed cranial and postcranial elements from at least two individuals. Arcusaurus is part of a distinctive local fauna from the upper Elliot Formation (Lower Jurassic) in the Senekal District, Free State, South Africa.
It can be diagnosed by various details of the premaxilla, nasal, and dentary in the skull and the shape of the distal caudal vertebrae. The taxon displays an unusual mix of characteristics. It lacks several synapomorphies of Plateosauria (Plateosaurus + Massospondylus and all descendants of their most recent common ancestor) but does display other derived characteristics that are otherwise known only from less inclusive clades within Plateosauria. In a cladistic analysis a position outside Plateosauria as the sister group of the clade of Efraasia + more-derived sauropodomorphs is supported; however, this position was not found to be a significantly better explanation of the data as a relatively derived position within Plateosauria.
If the basal position for Arcusaurus is accepted, then a divergence from other sauropodomorphs in the middle Norian and a ghost lineage up to 35 Ma is implied. No other non-plateosaurian sauropodomorphs are known from the Jurassic, making Arcusaurus a potentially relictual taxon in the Early Jurassic.
Etymology: The generic name is derived from Latin arcus, \\\\\\\"rainbow\\\\\\\", a reference to the Rainbow Nation. The specific name honours Lucille Pereira and Fernando Abdala who discovered the fossils
Holotype: BP/1/6235, consists of a partial skull. Some limb bones and vertebrae are included in the material. Both specimens collected in March 2006 represented juvenile individuals. From detailed features the describers concluded these were not the young of either Aardonyx or Massospondylus.
Yates, Bonnan & Neveling 2011
Time
Jurassic Late Hettangian Sinemurian
Classification
Saurischia Sauropodomorpha
Diet
Herbivore
Fossilsite
Elliot Formation [Upper], Spion Kop Heelbo site, Senekal District, Orange Free State, South Africa, Africa
Info
Skull
Abstract: A new basal sauropodomorph dinosaur, Arcusaurus pereirabdalorum, sp. nov., is named and described on the basis of a partial, disarticulated but associated skull and dispersed cranial and postcranial elements from at least two individuals. Arcusaurus is part of a distinctive local fauna from the upper Elliot Formation (Lower Jurassic) in the Senekal District, Free State, South Africa.
It can be diagnosed by various details of the premaxilla, nasal, and dentary in the skull and the shape of the distal caudal vertebrae. The taxon displays an unusual mix of characteristics. It lacks several synapomorphies of Plateosauria (Plateosaurus + Massospondylus and all descendants of their most recent common ancestor) but does display other derived characteristics that are otherwise known only from less inclusive clades within Plateosauria. In a cladistic analysis a position outside Plateosauria as the sister group of the clade of Efraasia + more-derived sauropodomorphs is supported; however, this position was not found to be a significantly better explanation of the data as a relatively derived position within Plateosauria.
If the basal position for Arcusaurus is accepted, then a divergence from other sauropodomorphs in the middle Norian and a ghost lineage up to 35 Ma is implied. No other non-plateosaurian sauropodomorphs are known from the Jurassic, making Arcusaurus a potentially relictual taxon in the Early Jurassic.
Etymology: The generic name is derived from Latin arcus, \\\\\\\"rainbow\\\\\\\", a reference to the Rainbow Nation. The specific name honours Lucille Pereira and Fernando Abdala who discovered the fossils
Holotype: BP/1/6235, consists of a partial skull. Some limb bones and vertebrae are included in the material. Both specimens collected in March 2006 represented juvenile individuals. From detailed features the describers concluded these were not the young of either Aardonyx or Massospondylus.