Hallopus
Hallopus Temporal range: Late Jurassic,
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Hallopus victor front and hind limb | |
Scientific classification ![]() | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Family: | †Hallopodidae |
Genus: | †Hallopus Marsh, 1881 |
Type species | |
†Hallopus victor | |
Synonyms | |
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Hallopus was a prehistoric reptile, named in 1877 as a species of Nanosaurus and classified by O. C. Marsh in 1881 from the Late Jurassic Morrison Formation, originally as a dinosaur,[1] though the animal is now thought to be a pseudosuchian more closely related to crocodilians. It was a quite small animal, reaching a length of 1 m (3.3 ft).[2] It was redescribed as a sphenosuchian crocodylomorph.[3] Later, it was speculated to be more derived than Sphenosuchus and near or within the Junggarsuchus + Crocodyliformes node.[4]
Phylogeny[]
A recent phylogenetic analysis[5] recovered Hallopus in a clade with Macelognathus and Almadasuchus, the Hallopodidae (defined as "all taxa more closely related to Hallopus victor than to Protosuchus richardsoni or Dibothrosuchus elaphros). The Hallopodidae was recovered as the nearest sister to the Crocodyliformes and more derived than Junggarsuchus or the "sphenosuchians" whose monophyly was not supported in this analysis.
Similarly, in redescribing Macelognathus from the Morrison Formation, Göhlich et al. (2005)[6] recognized several anatomical similarities between Macelognathus and Hallopus while also noting if the provenance of the latter was correct, they would overlap stratigraphically.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5d/Hallopus_NT.jpg/220px-Hallopus_NT.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/92/Hallopus_skeletal.jpg/220px-Hallopus_skeletal.jpg)
References[]
- ^ O. C. Marsh. 1877. Notice of some new vertebrate fossils. American Journal of Arts and Sciences 14:249-256
- ^ "Better Know a [Crocbeak] – Macelognathus and Hallopus". 27 May 2011.
- ^ A. D. Walker. A Revision of the Jurassic Reptile Hallopus victor (Marsh), with Remarks on the Classification of Crocodiles. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Vol. 257, No. 816 (Feb. 26, 1970), pp. 323-372
- ^ "Re: Hallopus Question". Archived from the original on 2005-04-17.
- ^ Leardi et al. (2017), Detailed anatomy of the braincase of Macelognathus vagans Marsh, 1884 (Archosauria, Crocodylomorpha) using high resolution tomography and new insights on basal crocodylomorph phylogeny. PeerJ 5:e2801; DOI 10.7717/peerj.2801
- ^ Göhlich, U. B., Chiappe, L. M., Clark, J. M. & Sues, H.-D. 2005.The systematic position of the Late Jurassic alleged dinosaur Macelognathus (Crocodylomorpha: Sphenosuchia). Canadian Journal of Earth Sciences — Revue canadienne de sciences de la Terre 42(3):307-321.
- Late Jurassic crocodylomorphs
- Terrestrial crocodylomorphs
- Morrison fauna
- Taxa named by Othniel Charles Marsh
- Fossil taxa described in 1881
- Prehistoric pseudosuchian genera
- Prehistoric archosaur stubs