Open Paleo

Alpkarakush

Rauhut et al., 2024 Alf-kara-kush

Named for Alpkarakush, a mythical powerful bird from the Kyrgyz Epic of Manas. The species name honors the Kyrgyz Republic where the specimen was discovered.

165.3–161.5 million years ago Callovian, Middle Jurassic
Middle Jurassic stages

Alpkarakush is an extinct genus of metriacanthosaurid theropod dinosaurs from the Jurassic Balabansai Formation of Kyrgyzstan. The genus contains a single species, A. kyrgyzicus, known from a partial skeleton.

Under dispute

Alpkarakush kyrgyzicus is consistently recovered as a metriacanthosaurid, but its position within the family is unstable: the describing analysis placed it as the sister taxon of Metriacanthosaurinae under implied weighting and within a Metriacanthosaurinae polytomy under equal weights (Rauhut and colleagues, 2024). It is placed conservatively at Metriacanthosauridae incertae sedis pending resolution of whether it belongs to Metriacanthosaurinae.

Diagnosis

  1. Posterior dorsal vertebrae with a channel leading from the centroprezygodiapophyseal fossa posteromedially into pneumatic chambers in the neural arch
  2. Manual phalanx II-1 with a ventral sulcus proximally almost completely enclosed by medial and lateral ventral flanges
  3. Dorsal margin of the ilium slopes steeply posteroventrally
  4. Narrow and deep intercondylar groove on the anterior side of the distal femur
  5. Robust and well-developed medial epicondylar crest on distal femur, considerably offset proximally from the distal end

Species

Alpkarakush kyrgyzicus Rauhut et al., 2024

Type species

References the Kyrgyz Republic, the country where the fossil material was discovered.

Holotype
IGB 2-1, IGB 2-2, IGB 2-9, IGB 2-10, IGB 2-11, IGB 2-12, IGB 2-13, IGB 2-14, IGB 2-15, IGB 2-16, IGB 2-17, IGB 2-18, IGB 2-19, IGB 2-20, IGB 2-21, IGB 2-22, IGB 2-24, IGB 2-25, IGB 2-26, IGB 2-27, IGB 2-28, IGB 2-29, IGB 2-30, IGB 2-31, IGB 2-32, IGB 2-33, IGB 2-34, IGB 2-35, IGB 2-36, IGB 2-37, IGB 2-38, IGB 2-39, IGB 2-40, IGB 2-41, IGB 2-42, IGB 2-43, IGB 2-44, IGB 2-45, IGB 2-46, IGB 2-47 , Institute of Geology, Kyrgyz National Academy of Sciences
Material
Partial skeleton: both postorbitals, left quadratojugal, dorsal and sacral vertebrae, ribs, a manual phalanx and ungual, partial pelvis, and hindlimb bones (femora, tibiae, fibula, tarsals, metatarsals II–III, pedal phalanges)
Horizon
upper Balabansai Formation, Callovian, Middle Jurassic , 165.3–161.5 million years ago
Locality
FTU-1, Uurusai Valley, Jalal-Abad, Kyrgyzstan

References

  1. Rauhut, O. W. M.; Bakirov, A. A.; Wings, O.; Fernandes, A. E.; Hübner, T. R. (2024). A new theropod dinosaur from the Callovian Balabansai Formation of Kyrgyzstan. Zoological Journal of the Linnean Society 201(4). Oxford University Press (OUP). doi:10.1093/zoolinnean/zlae090 rauhut2024a