Open Paleo

Ignavusaurus

Knoll, 2010 ig-NAY-vu-SOR-us

From Latin 'ignavus' meaning 'coward' and Ancient Greek 'sauros' meaning 'lizard', giving 'coward's lizard'; the name refers to the type locality Ha Ralekoala, which literally means 'the place of the father of the coward' in the local language.

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

Ignavusaurus is a genus of basal sauropodomorph dinosaur that lived during the Early Jurassic in what is now Lesotho. Its fossils were found in the Upper Elliot Formation which is probably Hettangian in age (around 200 million years ago). It was described on the basis of a partial, well preserved articulated skeleton. The type species, I. rachelis, was described in 2010 by Spanish paleontologist F. Knoll.

Under dispute

Ignavusaurus rachelis is recovered close to Sarahsaurus; it falls outside Massospondylidae (Apaldetti and colleagues, 2011) or within it (Chapelle and colleagues, 2019) depending on the analysis.

Diagnosis

  1. Transverse width of ventral ramus of postorbital greater than rostrocaudal width at midshaft
  2. Height of postorbital rim of orbit raised so it projects laterally to caudal dorsal process
  3. First dentary tooth adjacent to symphysis with teeth linearly placed within jaws
  4. Serrations along mesial and distal carinae of tooth restricted to apical half of crown
  5. 14 Vertebrae between cervicodorsal transition and primordial sacral vertebrae
  6. Metacarpal V about as wide as long with strongly convex proximal articulation surface

Species

Ignavusaurus rachelis Knoll, 2010

Type species

Named for Spanish paleontologist Raquel López-Antónanzas.

Holotype
BM HR 20 , Statens Naturhistoriske Museum (SNM), Københavns Universitet
Material
Partial, articulated skeleton.
Horizon
upper Elliot Formation, Hettangian–Sinemurian, Early Jurassic , 201.4–192.9 million years ago
Locality
Ha Ralekoala, Qacha's Nek, Lesotho

References

  1. Knoll, F. (2010). A primitive sauropodomorph from the upper Elliot Formation of Lesotho. Geological Magazine 147(6): 814-829. Cambridge University Press (CUP). doi:10.1017/s001675681000018x knoll2010a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b
  3. Apaldetti, C.; Martínez, R. N.; Alcober, O. A.; Pol, D. (2011). A New Basal Sauropodomorph (Dinosauria: Saurischia) from Quebrada del Barro Formation (Marayes-El Carrizal Basin), Northwestern Argentina. PLoS ONE 6(11): e26964. Public Library of Science (PLoS). doi:10.1371/journal.pone.0026964

    Describing analysis of this basal sauropodomorph placed Ignavusaurus close to Sarahsaurus, outside Massospondylidae.

    apaldetti2011a
  4. Chapelle, K. E. J.; Barrett, P. M.; Botha, J.; Choiniere, J. N. (2019). Ngwevu intloko: a new early sauropodomorph dinosaur from the Lower Jurassic Elliot Formation of South Africa and comments on cranial ontogeny in Massospondylus carinatus. PeerJ 7: e7240. PeerJ. doi:10.7717/peerj.7240

    Ngwevu intloko phylogenetic analysis recovered Ignavusaurus within Massospondylidae.

    chapelle2019a