Open Paleo

Harenadraco

Lee et al., 2023 huh-RAY-nuh-DRAH-ko

Sand dragon; from Latin harena (sand) and draco (dragon), referring to the sandy desert environment of the Baruungoyot Formation

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Harenadraco is an extinct genus of troodontid theropod dinosaurs from the Late Cretaceous Baruungoyot Formation of Mongolia. The genus contains a single species, H. prima, known from a fragmentary skeleton. Harenadraco represents the first troodontid known from the Baruungoyot Formation. Since members of this family are also known from the Nemegt and Djadokhta Formations, the discovery of Harenadraco indicates that troodontids were important faunal components of every formation within the Nemegt Basin.

Under dispute

Harenadraco is a fragmentary troodontid (mostly hind-limb material) recovered in an unstable position by its describers (Lee and colleagues, 2023): under implied weighting it groups with Early Cretaceous Chinese troodontids, but under equal weighting it is pruned as unstable. It is placed at Troodontidae incertae sedis.

Diagnosis

  1. Tall S-shaped medial margin of medial condyle of astragalocalcaneum in anterior view (autapomorphy)
  2. Poorly developed flexor sulcus on distal articular end of metatarsal II, lacking collateral ligament fossae (autapomorphy)
  3. Metatarsal III excluded from proximal end of metatarsus in dorsal view
  4. Metatarsal IV only slightly more robust than metatarsal II at proximal end in ventral view
  5. Pronounced ventral protrusion near proximal end of metatarsal IV
  6. Extremely narrow proximal shaft of metatarsal IV (autapomorphy)
  7. Greatly elongated flexor tubercle of pedal phalanx II-3 reaching preceding phalanx shaft in articulation (autapomorphy)
  8. Distal articular surface of pedal phalanx III-3 not ginglymoid (autapomorphy)
  9. Tarsometatarsus length to width ratio ~22:1, extremely slender among theropods

Species

Harenadraco prima Lee et al., 2023

Type species

From Latin 'prima' meaning 'first', referencing that Harenadraco is the first troodontid known from the Baruungoyot Formation.

Holotype
MPC-D 110/119 , Paleontological Center, Mongolian Academy of Sciences
Material
Partial postcranial skeleton: right ilium fragments, incomplete left hind limb (proximal femur, distal tibiotarsus, metatarsals II-IV, pedal phalanges), distal right femur, unidentified bone fragments.
Horizon
Baruungoyot Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Hermiin Tsav, Ömnögovi, Mongolia

References

  1. Lee, S.; Lee, Y. N.; Park, J. Y.; Kim, S. H.; Badamkhatan, Z.; Idersaikhan, D.; Tsogtbaatar, K. (2023). The first troodontid (Dinosauria: Theropoda) from the Upper Cretaceous Baruungoyot Formation of Mongolia. Journal of Vertebrate Paleontology 43(6). Informa UK Limited. doi:10.1080/02724634.2024.2364746 lee2023a