// Workers AI · dad joke modeWhat did Pneumodesmus say? I'm wheezing to meet you.
| Pneumodesmus Temporal range: | |
|---|---|
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| Reconstruction of P. newmani | |
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| Photomicrograph of the type specimen | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Myriapoda |
| Class: | Diplopoda |
| Superorder: | †Archipolypoda |
| Order: | †incertae sedis |
| Family: | †incertae sedis |
| Genus: | †Pneumodesmus Wilson & Anderson, 2004 |
| Species: | †P. newmani |
| Binomial name | |
| †Pneumodesmus newmani Wilson & Anderson, 2004 [1] | |
Pneumodesmus newmani is a species of myriapod that lived in what is now Scotland during the latest Silurian and earliest Devonian period (Priodli–Lochkovian epoch). It is one of the first myriapods, and among the oldest creatures to have lived on land.[2] It was discovered in 2004, and is known from a single specimen from Stonehaven, Aberdeenshire.[3]
Discovery and naming
[edit]The fossil of P. newmani was found by Mike Newman, a bus driver and amateur palaeontologist from Aberdeen, in a layer of sandstone rocks on the foreshore of Cowie, near Stonehaven (Cowie Formation).[4] The species was later given the specific epithet "newmani" in honour of Newman. The holotype is kept in National Museum of Scotland, Edinburgh.[5] The genus name is derived from the Greek πνεῦμα (pneûma), πνεύματος (pneúmatos) "air" or "breath",[1] in reference to the inferred air-breathing habit.[6]
Description
[edit]The single, 1 cm-long fragment of P. newmani depicts small paranota (keels) high on the body, long, slender legs. There are six body segments preserved, and the dorsal portion of each segment is ornamented with a horizontal bar and three rows of roughly hexagonal bosses (bumps).[1] Myriapods are the group that include millipedes and centipedes, and Pneumodesmus newmani would have resembled a millipede in appearance. However it did not belong to the same branch of myriapods as modern millipedes.[1]
Significance
[edit]The fossil is important because its cuticle contains openings which are interpreted as spiracles, part of a gas exchange system that would only work in air. This makes P. newmani the earliest documented arthropod with a tracheal system, and among the first known oxygen-breathing animal on land.[2][7]
Trace fossils of myriapods are known dating back to the late Ordovician[1] (the geologic period preceding the Silurian), but P. newmani may be the earliest body fossil of a myriapod, if it had been dated at 428 million years ago (Silurian, late Wenlock epoch to early Ludlow epoch). However, based on 414 million years ago (Early Devonian (Lochkovian)) estimated from Zircon age estimate,[8] it is not the oldest myriapod, or the oldest of air-breathing terrestrial arthropods, because records from Kerrera (425 millions years ago) and Ludlow (420 millions years ago) are older.[9][5] In spite of the recent competing arguments, the 2023 study suggests that this taxon is still most likely the earliest body fossil of a myriapod, with its age argued as the late Wenlock epoch (around 430 million years ago) based on the dating of the non-marine section with spores and detrital zircons.[10] In 2024, Brookfield and colleagues study doubts this conclusion, because the analysis by Wellman et al. (2023) is not based on an adjacent, structurally separated block with different stratigraphy and sedimentology to the block with fossil site it was discovered; the authors still suggested that millipedes occupied the land during the Wenlock Epoch based on the separate millipede-bearing sediment dated to approximately 427.0 ± 4.5 million years ago.[11] In 2025, Brookfield and colleagues further suggested that the dated section by Wellman et al. (2023) differs from the myriapod-bearing section not only in ages, but in depositional environments and bedrock sources, suggesting that the Pridoli–Lochkovian age estimate is most likely.[12]
During the Silurian, the rocks that would later be part of Scotland were being laid down on the continent of Laurentia, in a tropical part of the Southern Hemisphere.[13]
References
[edit]- 1 2 3 4 5 Heather M. Wilson & Lyall I. Anderson (2004). "Morphology and taxonomy of Paleozoic millipedes (Diplopoda: Chilognatha: Archipolypoda) from Scotland". Journal of Paleontology. 78 (1): 169–184. doi:10.1666/0022-3360(2004)078<0169:MATOPM>2.0.CO;2.
- 1 2 "Fossil millipede found to be oldest land creature". CNN (from Reuters). 27 January 2004.
- ↑ "Fossil find 'oldest land animal'". BBC News. 25 January 2004. Archived from the original on 18 August 2023.
- ↑ "Pneumodesmus newmani Exhibition". Stonehaven Guide. Archived from the original on 24 December 2016. Retrieved 22 October 2013.
- 1 2 Paul Selden & Helen Read (2008). "The oldest land animals: Silurian millipedes from Scotland" (PDF). Bulletin of the British Myriapod & Isopod Group. 23: 36–37. Archived from the original (PDF) on 6 March 2024.
- ↑ Liddell, H.G. & Scott, R. (1940). A Greek-English Lexicon. Revised and augmented throughout by Sir Henry Stuart Jones. With the assistance of Roderick McKenzie. Oxford: Clarendon Press.
- ↑ Rowland Shelley & Paul Marek (1 March 2005). "Millipede Fossils". East Carolina University. Archived from the original on 27 May 2011.
- ↑ Stephanie E. Suarez; Michael E. Brookfield; Elizabeth J. Catlos; Daniel F. Stöckli (2017). "A U-Pb zircon age constraint on the oldest-recorded air-breathing land animal". PLOS ONE. 12 (6) e0179262. Bibcode:2017PLoSO..1279262S. doi:10.1371/journal.pone.0179262. PMC 5489152. PMID 28658320.
- ↑ Brookfield, M. E.; Catlos, E. J.; Suarez, S. E. (3 October 2021). "Myriapod divergence times differ between molecular clock and fossil evidence: U/Pb zircon ages of the earliest fossil millipede-bearing sediments and their significance". Historical Biology. 33 (10): 2014–2018. doi:10.1080/08912963.2020.1762593. ISSN 0891-2963.
- ↑ Wellman, C.H.; Lopes, G.; McKellar, Z.; Hartley, A. (2023). "Age of the basal 'Lower Old Red Sandstone' Stonehaven Group of Scotland: The oldest reported air-breathing land animal is Silurian (late Wenlock) in age". Journal of the Geological Society. The Geological Society of London. doi:10.1144/jgs2023-138. hdl:2164/22754. ISSN 0016-7649.
- ↑ Brookfield, M. E.; Catlos, E. J.; Garza, H. (7 July 2024). "The oldest 'millipede'-plant association? Age, paleoenvironments and sources of the Silurian lake sediments at Kerrera, Argyll and Bute, Scotland". Historical Biology: 1–13. doi:10.1080/08912963.2024.2367554. ISSN 0891-2963.
- ↑ Brookfield, M. E.; Catlos, E. J.; Garza, H. K. (2025). "Reconciling Divergent Ages for the Oldest Recorded Air-Breathing Land Animal, the Millipede, Pneumodesmus newmani Wilson & Anderson, 2004: A Review of the Geology and Ages of the Basal Old Red Sandstone Stonehaven Group (Silurian–Early Devonian), Aberdeenshire, Scotland". Fossil Studies. 3 (2). 6. doi:10.3390/fossils3020006.
- ↑ "Cowie". BBC Scotland. Archived from the original on 29 September 2022. Retrieved 23 March 2024.