Open Paleo

Amargastegos

Ulansky, 2014 ah-MAR-guh-STEG-os Nomen dubium

From 'Amarga' (the Argentine La Amarga Formation that yielded the type material) and Greek 'stegos' (roof, in reference to stegosaurs); intended sense 'La Amarga roof'.

125.8–121.4 million years ago Barremian, Early Cretaceous
Early Cretaceous stages

Amargastegos is a nomen dubium genus of stegosaurian dinosaur informally proposed by Ulansky (2014) for the partial skeleton MACN N-43 from the Barremian La Amarga Formation of Neuquén Province, Argentina. The same material had previously been formally described by Pereda-Suberbiola and colleagues (2013) as Stegosauria indet.; they noted differences from other stegosaurs suggesting a distinct taxon but judged it too incomplete to name a new genus and species. Galton and Carpenter (2016) treated Amargastegos brevicollus as a nomen dubium: Ulansky gave no description of differentiating characters (ICZN Article 13), Dinologia does not meet the ICZN requirements for a valid publication, and the material lacks autapomorphies. They confirmed Stegosauria indet. as the correct identification of the type material.

Species

Amargastegos brevicollus Ulansky, 2014 Nomen dubium

Type species

From Latin 'brevis' (short) and 'collum' (neck); meaning 'short-necked', in reference to the proportionally short cervical centra of the type material.

Holotype
MACN N-43 , Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’
Material
Anterior right supraorbital, two cervical vertebrae, isolated cervical prezygapophysis, partial rib shaft, anterior caudal centrum, cervical plate, and a probable additional osteoderm.
Horizon
Puesto Antigual Member, La Amarga Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
La Amarga Creek, Neuquén, Argentina

References

  1. Pereda-Suberbiola, X.; Galton, P. M.; Mallison, H.; Novas, F. (2013). A plated dinosaur (Ornithischia, Stegosauria) from the Early Cretaceous of Argentina, South America: an evaluation. Alcheringa: An Australasian Journal of Palaeontology. doi:10.1080/03115518.2012.702531

    Formal redescription of MACN N-43 as Stegosauria gen. et sp. indet., predating Ulansky (2014)'s informal naming; material is stegosaurian but too incomplete to diagnose a new taxon.

    pereda-suberbiola2013a
  2. Ulansky, R. E. (2014). Evolution of the stegosaurs (Dinosauria; Ornithischia). Dinologia.

    In Russian. Informal DINOLOGIA monograph proposing Amargastegos brevicollus for MACN N-43; declared a nomen dubium by Galton and Carpenter (2016).

    ulansky2014b
  3. Galton, P. M.; Carpenter, K. (2016). The plated dinosaur Stegosaurus longispinus Gilmore, 1914 (Dinosauria: Ornithischia; Upper Jurassic, western USA), type species of Alcovasaurus n. gen. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 279(2): 185-208. Schweizerbart. doi:10.1127/njgpa/2016/0551

    Treats Amargastegos brevicollus as a nomen dubium (no diagnosis under ICZN Art. 13, Dinologia not a valid publication, no autapomorphies); confirms MACN N-43 as Stegosauria indet.

    galton2016a