Open Paleo

Megapnosaurus

Ivie et al., 2001 meg-AP-no-SAWR-us

big dead lizard

201.4–192.9 million years ago Hettangian–Sinemurian, Early Jurassic
Early Jurassic stages

Megapnosaurus is an extinct genus of coelophysid theropod dinosaur that lived approximately 188 million years ago during the early part of the Jurassic Period in what is now Africa. The species was a small to medium-sized, lightly built, ground-dwelling, bipedal carnivore, that could grow up to 2.2 m (7.2 ft) long and weigh up to 13 kg (29 lb).

Diagnosis

  1. Extensive fusion in the tarsal region, with the astragalocalcaneum fused to the tibia and bearing an atypical ascending process
  2. Distal tarsals fused to the metatarsals, except for a free distal tarsal 4
  3. Fibula free but closely apposed to the tibia and astragalocalcaneum; calcaneum lacking a tuber
  4. Long metatarsals (metatarsal III about 60% of femoral length); pes functionally tridactyl (digits II–IV), with digit I highly reduced and digit V a splint-like metatarsal
  5. Manus large and functionally tridactyl (digits I–III) with recurved raptorial claws; manual digit IV reduced to a metacarpal and a single vestigial phalanx
  6. Femur with a sharply inturned head and a distinct neck
  7. Dolichoiliac pelvis, the iliac blade flared posteriorly into a wide, shallow shelf

Species

Megapnosaurus rhodesiensis (Raath, 1969)

Type species

First named as Syntarsus rhodesiensis

Named for Rhodesia (former name of Zimbabwe), where the holotype was found.

Holotype
QG 1 , Natural History Museum of Zimbabwe
Material
Articulated postcranial skeleton lacking the skull and cervical vertebrae.
Horizon
upper Forest Sandstone Formation, Hettangian–Sinemurian, Early Jurassic , 201.4–192.9 million years ago
Locality
Southcote Farm, Matabeleland North, Zimbabwe

Synonyms

  • Syntarsus rhodesiensis preoccupied

    Original combination Syntarsus rhodesiensis (Raath, 1969); the genus name Syntarsus was preoccupied by a beetle (Syntarsus Fairmaire, 1869), and Ivie, Ślipiński and Węgrzynowicz (2001) provided the replacement name Megapnosaurus.

References

  1. Raath, M. A. (1969). A new coelurosaurian dinosaur from the Forest Sandstone of Rhodesia. Arnoldia Rhodesia 4(28): 1-25.

    Original description as Syntarsus rhodesiensis, based on the holotype postcranial skeleton (QG 1) from the Forest Sandstone of Zimbabwe; source of the diagnosis.

    raath1969a
  2. Ivie, M. A.; Slipinski, S. A.; Wegrzynowicz, P. (2001). Generic homonyms in the Colydiinae (Coleoptera: Zopheridae). Insecta Mundi 15(1): 63-64.

    Coins Megapnosaurus as a replacement name for Syntarsus Raath, 1969, preoccupied by the beetle genus Syntarsus Fairmaire, 1869.

    ivie2001a
  3. Irmis, R. B. (2004). First report of Megapnosaurus (Theropoda: Coelophysoidea) from China. PaleoBios 24(3): 11-18.

    First report of the genus from the Lower Lufeng Formation of China.

    irmis2004a
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026c