Pucadelphys

Pucadelphys
Temporal range: Early Paleocene (Tiupampan)
~66–61.7 Ma
Fossils from Bolivia
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia (?)
Genus: †Pucadelphys
Marshall & De Muizon, 1988
Species:
†P. andinus
Binomial name
†Pucadelphys andinus
Marshall & De Muizon, 1988

Pucadelphys is an extinct genus of non-marsupial metatherian (or possibly crown group Marsupial.). The genus is monotypic and contains the single species P. andinus. Fossils of Pucadelphys have been found in the Santa Lucía Formation in Tiupampa in Bolivia.

Description

Pucadelphys had a thin osseous wall separating the fossa subarcuata and the internal acoustic meatus. Pucadelphys also generally had a short sulcus for the sigmoid sinus located posteriorly to the dorsal edge of the fossa subarcuata, although at least one preserved Pucadelphys petrosal lacks this trait. The sulcus for the superior sinus was very distinct and pronounced in Pucadelphys.

Pucadelphys was small and likely to have eaten insects. It had a long tail, although incomplete on the best preserved fossils. It is possible that the tail was longer than (or at least as long as) its body. 17 vertebrae were preserved, and its estimated that there was 5 to 10 additional vertebrae originally. It is regarded as partially arboreal, and partially terrestrial. It may have been social, as more than 30 specimens have been found together.

Taxonomy

A 2016 phylogenetic analysis recovered Pucadelphys as a member of a metatherian clade including sparassodonts and other South American taxa, but not marsupials (which are instead closer to Cretaceous North American species). The phylogenetic tree from the analysis is shown below.

Marsupialiformes

In 2022, a study, which provided strong evidence that Deltatheridium is the earliest known crown group Marsupial, also provided support for it and Pucadelphys to be positioned as a sister taxa to modern American opossums. This would make Pucadelphys a crown group marsupial.

References

  1. 1 2 Velazco, Paúl M; Buczek, Alexandra J; Hoffman, Eva; Hoffman, Devin K; O'Leary, Maureen A; Novacek, Michael J (30 January 2022). "Combined data analysis of fossil and living mammals: a Paleogene sister taxon of Placentalia and the antiquity of Marsupialia". Cladistics. 38 (3): 359–373. doi:10.1111/cla.12499. PMID 35098586. S2CID 246429311.
  2. ↑ Guillermo W. Rougier, John R. Wible and Michael J. Novacek. First Implications of Deltatheridium specimens for early marsupial history, Nature 396, 459–463 (3 December 1998)
  3. ↑ S. Bi, X. Jin, S. Li and T. Du. 2015. A new Cretaceous metatherian mammal from Henan, China. PeerJ 3:e896
  4. ↑ Guillermo Rougier, New specimen of Deltatheroides cretacicus (Metatheria, Deltatheroida) from the Late Cretaceous of Mongolia, BULLETIN OF CARNEGIE MUSEUM OF NATURAL HISTORY 36(DEC 2004):245–266 · SEPTEMBER 2009
  5. ↑ Guillermo W. Rougier; Brian M. Davis; Michael J. Novacek (2015). "A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia". Cretaceous Research. 52, Part A: 167–177. doi:10.1016/j.cretres.2014.09.009.
  6. ↑ Pucadelphys at Fossilworks.org
  7. ↑ Ladevèze, Sandrine; De Muizon, Christian (14 September 2007). "THE AUDITORY REGION OF EARLY PALEOCENE PUCADELPHYDAE (MAMMALIA, METATHERIA) FROM TIUPAMPA, BOLIVIA, WITH PHYLOGENETIC IMPLICATIONS". Palaeontology. 50 (5): 1123–1153. doi:10.1111/j.1475-4983.2007.00703.x. ISSN 0031-0239. Retrieved 28 October 2026 – via Wiley Online Library.
  8. ↑ "How South America Made the Marsupials". PBS Eons. Archived from the original on 2021-12-21.
  9. ↑ Wilson, G.P.; Ekdale, E.G.; Hoganson, J.W.; Calede, J.J.; Linden, A.V. (2016). "A large carnivorous mammal from the Late Cretaceous and the North American origin of marsupials". Nature Communications. 7 13734. Bibcode:2016NatCo...713734W. doi:10.1038/ncomms13734. PMC 5155139. PMID 27929063.

Further reading