Temporal range: Campanian–Maastrichtian
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Protostegidae
Genus: Calcarichelys
Zangerl, 1953
Type species
Calcarichelys gemma
Zangerl, 1953

Calcarichelys ('spur turtle' or 'thorn turtle')[1] is an extinct genus of protostegid turtle from the Late Cretaceous of the Selma Formation in Alabama, and possibly from Angola.[2][1][3][4] It contains only one species, C. gemma.[3][5]


The holotype specimen of Calcarichelys is known from Mooreville Chalk, Alabama.[1] More complete specimens are later described from same formation.[3] Another specimen that possibly belongs to Calcarichelys or related species is known from the Maastrichtian of Bentiaba, Angola.[4]


Calcarichelys is a small protostegid, with a carapace length of 25.3 cm (10.0 in).[3] It is considered[by whom?] as closely related to Chelosphargis, as they share some characteristics.[1][3] But unlike Chelosphargis, Calcarichelys is characterized by thorn-like neural plates.[1][3]


  1. ^ a b c d e Zangerl, Rainer; Museum, Chicago Natural History (1953). The vertebrate fauna of the Selma Formation of Alabama. [Chicago, Ill.]: Chicago Natural History Museum.
  2. ^ "". Retrieved 2022-04-22.
  3. ^ a b c d e f Hooks, G. E. (1998-04-10). "Systematic revision of the Protostegidae, with a redescription of Calcarichelys gemma Zangerl, 1953". Journal of Vertebrate Paleontology. 18 (1): 85–98. doi:10.1080/02724634.1998.10011036. ISSN 0272-4634.
  4. ^ a b Mateus, Octávio; Polcyn, Michael; Jacobs, Louis; Araujo, Ricardo; Schulp, A.; Marinheiro, João; Pereira, Bruno; Vineyard, Diana (2012-01-01). "Cretaceous amniotes from Angola: dinosaurs, pterosaurs, mosasaurs, plesiosaurs, and turtles". V Jornadas Internacionales sobre Paleontolog'ia de Dinosaurios y su Entorno.
  5. ^ "Calcarichelys - Encyclopedia of Life". Retrieved 2022-04-22.