Mummified early Permian reptile reveals ancient amniote breathing apparatus | Nature

## Summary
Article ADS CAS PubMed PubMed Central Google Scholar Brainerd, E. Article ADS CAS PubMed Google Scholar Cieri, R. Article ADS CAS PubMed PubMed Central Google Scholar Sidor C. Article ADS CAS PubMed PubMed Central Google Scholar Scaal, M.

## Article Content
Subjects
Animal physiology
Palaeontology
Abstract
Costal aspiration breathing was an evolutionary innovation that was fundamental to the conquest of the terrestrial realm by amniotes (mammals, reptiles, birds and their common ancestor)
1
,
2
,
3
,
4
,
5
. Extant amniotes use an integrated thoracic skeleton for costal-muscle-generated inhalation and exhalation, differing substantially from their anamniote relatives, which possess more passive cutaneous and buccal pumping forms of ventilation. This difference extends into the Palaeozoic era, but the evolutionary transformation between these modes of breathing is undocumented and largely unclear
6
,
7
,
8
,
9
,
10
in the absence of soft tissue fossils. Here we present the mummified early Permian reptile
Captorhinus
, which includes a covering of three-dimensional skin, native protein remnants and a complete shoulder girdle and ribcage with preserved cartilages. These are the oldest-known preserved cartilages and protein remnants in a terrestrial vertebrate. High-resolution neutron computed tomography and histology data reveal previously undescribed structures, including the cartilaginous sternum, sternal ribs, rib extensions and epicoracoids. Our skeletal reconstruction of this ancient reptile reveals the precise relationships between the ribcage and the shoulder girdle, and their pivotal role in the evolution of terrestrial breathing and locomotor regimes
11
,
12
. This finding substantially changes expectations of soft tissue preservation in deep time to reveal the potential ancestral amniote breathing mechanism and its impact on terrestrial vertebrate evolution.
Access through your institution
Buy or subscribe
This is a preview of subscription content,
access via your institution
Access options
Access through your institution
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
27,99 €
/ 30 days
cancel any time
Learn more
Subscription info for Korean customers
We have a dedicated website for our Korean customers. Please go to
natureasia.com
to subscribe to this journal.
Go to natureasia.com
Buy this article
Purchase on SpringerLink
Instant access to the full article PDF.
39,95 €
Prices may be subject to local taxes which are calculated during checkout
Fig. 1: Mummified
Captorhinus
, ROMVP 88565, showing nCT renderings and skeletal reconstruction in left lateral views.
Fig. 2: Cervical and thoracic regions of
Captorhinus
, ROMVP 88300.
Fig. 3: Histological thin sections through the mummified articulated
Captorhinus
specimen (ROMVP 88565, TS01782 and TS01993).
Fig. 4: SR-µATR-FTIR spectra from various regions of mummified
Captorhinus
ROMVP 88565.
Data availability
nCT scan data for each specimen are available at the open access digital repository Morphobank:
https://www.morphobank.org/permalink/?P6262
(ROMVP 88300),
https://www.morphobank.org/permalink/?P6264
(ROMVP 88564) and
https://www.morphobank.org/permalink/?P6263
(ROMVP 88565).
References
Perry, S. F. & Sander, M. Reconstructing the evolution of the respiratory apparatus in tetrapods.
Resp. Physiol. Neurobiol.
144
, 125–139 (2004).
Article
Google Scholar
Striedter, G. F. & Northcutt, R. G.
Brains Through Time: A Natural History of Vertebrates
(Oxford Academic, 2019)
Buchwitz, M., Jansen, M., Renaudie, J., Marchetti, L. & &Voigt, S. Evolutionary change in locomotion close to the origin of amniotes inferred from trackway data in an ancestral state reconstruction approach.
Front. Ecol. Evol.
9
, 674779 (2021).
Article
Google Scholar
Starck, J. M., Stewart, J. R. & Blackbrun, D. G. Phylogeny and evolutionary history of the amniote egg.
J. Morphol.
282
, 1080–1122 (2021).
Article
PubMed
Google Scholar
Mooney, E. D., Maho, T., Philp, R. P., Bevitt, J. J. & Reisz, R. R. Paleozoic cave system preserves oldest-known evidence of amniote skin.
Curr. Biol.
34
, 417–426 (2024).
Article
CAS
PubMed
Google Scholar
Janis, C. M. & Keller, J. C. Modes of ventilation in early tetrapods: costal aspiration as a key feature of amniotes.
Acta Palaeontol. Pol.
46
, 137–170 (2001).
Google Scholar
Brainerd, E. L. & Owerkowicz, T. Functional morphology and evolution of aspiration breathing in tetrapods.
Resp. Physiol. Neurobiol
154
, 73–88 (2006).
Article
Google Scholar
Vickaryous, M. & Hall, B. K. Homology of the reptile coracoid and a reappraisal of the evolution and development of the amniote pectoral apparatus.
J. Anat.
208
, 263–285 (2006).
Article
PubMed
PubMed Central
Google Scholar
Cieri, R. L., Hatch, S. T., Capano, J. G. & Brainerd, E. L. Locomotor rib kinematics in two species of lizards and a new hypothesis for the evolution of aspiration breathing in amniotes.
Sci. Rep.
10
, 7739 (2020).
Article
ADS
CAS
PubMed
PubMed Central
Google Scholar
Brainerd, E. L. Gradual evolution of costal aspiration breathing in tetrapods.
Anat. Rec.
https://doi.org/10.1002/ar.70017
(2025).
Brainerd, E. L., Ditelberg, J. S. & Bramble, D. M. Lung ventilation in salamanders and the evolu

---

## Expert Analysis

### Merits
- Subjects Animal physiology Palaeontology Abstract Costal aspiration breathing was an evolutionary innovation that was fundamental to the conquest of the terrestrial realm by amniotes (mammals, reptiles, birds and their common ancestor) 1 , 2 , 3 , 4 , 5 .

### Areas for Consideration
- This difference extends into the Palaeozoic era, but the evolutionary transformation between these modes of breathing is undocumented and largely unclear 6 , 7 , 8 , 9 , 10 in the absence of soft tissue fossils.
- Sternal elements of early dinosaurs fill a critical gap in the evolution of the sternum in Avemetatarsalia (Reptilia: Archosauria).

### Implications
- This finding substantially changes expectations of soft tissue preservation in deep time to reveal the potential ancestral amniote breathing mechanism and its impact on terrestrial vertebrate evolution.
- Go to natureasia.com Buy this article Purchase on SpringerLink Instant access to the full article PDF. 39,95 € Prices may be subject to local taxes which are calculated during checkout Fig. 1: Mummified Captorhinus , ROMVP 88565, showing nCT renderings and skeletal reconstruction in left lateral views.
- Evolutionary change in locomotion close to the origin of amniotes inferred from trackway data in an ancestral state reconstruction approach.
- Mooney Authors and Affiliations College of Earth Sciences, International Center of Future Science, Geological Museum and Dinosaur Evolution Research Center, State Key Laboratory of Deep Earth Exploration and Imaging, Bioarchaeology Laboratory, Jilin University, Changchun, China Robert R.

### Expert Commentary
This article covers google, scholar, article topics. Notable strengths include discussion of google. Areas of concern are also raised. Readability: Flesch-Kincaid grade 0.0. Word count: 2266.