{{Short description|Genus of millipedes}} {{Use dmy dates|date=April 2022}} {{Speciesbox | fossil_range = {{Fossil range|428|414|Wenlock/Lochkovian}} | image = Pneumodesmus newmani - MUSE.JPG | image_caption = Reconstruction of ''P. newmani'' | image2 = Pneumodesmus_newmani.jpg | image2_caption = Photomicrograph of the type specimen | display_parents = 4 | genus = Pneumodesmus | parent_authority = Wilson & Anderson, 2004 | species = newmani | authority = Wilson & Anderson, 2004 <ref name="Wilson">{{cite journal |journal=Journal of Paleontology |year=2004 |volume=78 |issue=1 |pages=169–184 |title=Morphology and taxonomy of Paleozoic millipedes (Diplopoda: Chilognatha: Archipolypoda) from Scotland |author=Heather M. Wilson & Lyall I. Anderson |url=https://www.researchgate.net/publication/250070300 |doi=10.1666/0022-3360(2004)078<0169:MATOPM>2.0.CO;2}}</ref> }}
'''''Pneumodesmus newmani''''' is a species of myriapod. It is originally considered that it lived during the late Wenlock epoch of the Silurian period around {{Ma|428}}.<ref name="Wilson"/><ref name="BBC">{{cite news |publisher=BBC News |date=January 25, 2004 |url=https://news.bbc.co.uk/2/hi/uk_news/scotland/3427499.stm |title=Fossil find 'oldest land animal' |archive-url=https://web.archive.org/web/20230818174604/http://news.bbc.co.uk/2/hi/uk_news/scotland/3427499.stm |archive-date=2023-08-18 |url-status=live}}</ref><ref name=wellman23/> However, a 2017 study dates its occurrence based on zircon data analysis as the Early Devonian (Lochkovian).<ref name="Suarez2017">{{Cite journal|author1=Stephanie E. Suarez |author2=Michael E. Brookfield |author3=Elizabeth J. Catlos |author4=Daniel F. Stöckli |year=2017 |title=A U-Pb zircon age constraint on the oldest-recorded air-breathing land animal |journal=PLOS ONE |volume=12 |issue=6 |article-number=e0179262 |doi=10.1371/journal.pone.0179262 |pmc=5489152 |pmid=28658320 |bibcode=2017PLoSO..1279262S |doi-access=free }}</ref> Although the 2023 study confirmed the age identification of the 2004 study through palynological, palaeobotanical and zircon analyses incorporating newly discovered additional data,<ref name=wellman23>{{cite journal|first1=C.H.|last1=Wellman|first2=G.|last2=Lopes|first3=Z.|last3=McKellar|first4=A.|last4=Hartley|year=2023|title=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=Journal of the Geological Society|publisher=The Geological Society of London|doi=10.1144/jgs2023-138|issn=0016-7649|doi-access=free|hdl=2164/22754|hdl-access=free}}</ref> this is based on adjacent structurally separated block with different stratigraphy and sedimentology to the block with fossil site it was discovered, and it is confirmed as unsustainable.<ref name=":0">{{Cite journal |last=Brookfield |first=M. E. |last2=Catlos |first2=E. J. |last3=Garza |first3=H. |date=2024-07-07 |title=The oldest 'millipede'-plant association? Age, paleoenvironments and sources of the Silurian lake sediments at Kerrera, Argyll and Bute, Scotland |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2367554 |journal=Historical Biology |language=en |pages=1–13 |doi=10.1080/08912963.2024.2367554 |issn=0891-2963|url-access=subscription }}</ref> It is one of the first myriapods, and among the oldest creatures to have lived on land.<ref name="CNN">{{cite news |url=http://edition.cnn.com/2004/TECH/science/01/27/environment.britain.fossil.reut/index.html |title=Fossil millipede found to be oldest land creature |publisher=CNN (from Reuters) |date=January 27, 2004}}</ref> It was discovered in 2004, and is known from a single specimen from Stonehaven, Aberdeenshire, Scotland.<ref name="BBC"/>
==Discovery and naming== 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).<ref>{{cite web |title=''Pneumodesmus newmani'' Exhibition |url=http://www.stonehavenguide.net/prods/fossil-over-420-million-years-old.html |publisher=Stonehaven Guide |access-date=Oct 22, 2013 |archive-url=https://web.archive.org/web/20161224094410/http://www.stonehavenguide.net/prods/fossil-over-420-million-years-old.html |archive-date=December 24, 2016 }}</ref> The species was later given the specific epithet "''newmani''" in honour of Newman. The holotype is kept in National Museum of Scotland, Edinburgh.<ref name="SeldenRead2008">{{cite journal |url=http://www.paulselden.net/uploads/7/5/3/2/7532217/seldenread2008.pdf |journal=Bulletin of the British Myriapod & Isopod Group |volume=23 |year=2008 |title=The oldest land animals: Silurian millipedes from Scotland |author=Paul Selden & Helen Read |pages=36–37 |archive-url=https://web.archive.org/web/20240306033234/http://www.paulselden.net/uploads/7/5/3/2/7532217/seldenread2008.pdf |archive-date=2024-03-06 }}</ref> The genus name is said to be derived from the Greek ''pneumato'', meaning "air" or "breath",<ref name="Wilson" /> in reference to the inferred air-breathing habit.<ref name="Wilson" /> The proper word in ancient Greek for "air" or "breath" is however ''pneuma'' (πνεῦμα).<ref>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.</ref>
== Description == 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).<ref name="Wilson" /> 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.<ref name="Wilson" />
==Significance== 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.<ref name="CNN"/><ref name="myriapoda">{{cite web |url=http://www.myriapoda.org/diplopoda/millipede_fossils.html |title=Millipede Fossils |publisher=East Carolina University |date=March 1, 2005 |author=Rowland Shelley & Paul Marek |archive-url=https://web.archive.org/web/20110527071726/http://www.myriapoda.org/diplopoda/millipede_fossils.html |archive-date=May 27, 2011 |url-status=usurped}}</ref>
Trace fossils of myriapods are known dating back to the late Ordovician<ref name="Wilson"/> (the geologic period preceding the Silurian), but ''P. newmani'' may be the earliest body fossil of a myriapod, if it had been dated at {{Ma|428}} (Silurian, late Wenlock epoch to early Ludlow epoch). However, based on {{Ma|414}} (Early Devonian (Lochkovian)) estimated from Zircon age estimate,<ref name="Suarez2017" /> 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.<ref>{{Cite journal |last=Brookfield |first=M. E. |last2=Catlos |first2=E. J. |last3=Suarez |first3=S. E. |date=2021-10-03 |title=Myriapod divergence times differ between molecular clock and fossil evidence: U/Pb zircon ages of the earliest fossil millipede-bearing sediments and their significance |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2020.1762593 |journal=Historical Biology |language=en |volume=33 |issue=10 |pages=2014–2018 |doi=10.1080/08912963.2020.1762593 |issn=0891-2963|url-access=subscription }}</ref><ref name="SeldenRead2008" /> 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 reconfirmed as the late Wenlock epoch (around {{Ma|430}}) through various analyses.<ref name=wellman23/> A 2024 study doubts that conclusion, because this analysis is not based on fossil-bearing sediment itself.<ref name=":0" />
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.<ref>{{cite web |url=https://www.bbc.co.uk/scotland/whereilive/coast/stages.shtml?walk=northeast&stage=2 |publisher=BBC Scotland |title=Cowie |access-date=2024-03-23 |archive-url=https://web.archive.org/web/20220929120239/https://www.bbc.co.uk/scotland/whereilive/coast/stages.shtml?walk=northeast&stage=2 |archive-date=2022-09-29 |url-status=live}}</ref>
==References== {{Reflist|32em}}
{{Taxonbar|from1=Q24521381|from2=Q14302552}}
Category:Silurian myriapods Category:Prehistoric myriapod genera †Pneumodesmus Category:Paleozoic arthropods of Europe Category:Fossil taxa described in 2004 Category:Fossils of Scotland Category:Stonehaven Category:History of Aberdeenshire Category:Collection of National Museums Scotland