Pneumodesmus newmani

Taxobox | name = "Pneumodesmus newmani"
status = fossil

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image_width = 240px
image_caption = Photomicrograph of the type specimen
fossil_range = Fossil range|428Late Silurian
regnum = Animalia
phylum = Arthropoda
subphylum = Myriapoda
classis = Diplopoda
ordo = Cowiedesmida
familia = Cowiedesmidae
genus = "Pneumodesmus"
species = "P. newmani"
binomial = "Pneumodesmus newmani"
binomial_authority = Wilson & Anderson, 2004 cite journal |quotes=no |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=http://jpaleontol.geoscienceworld.org/cgi/content/abstract/78/1/169 |doi=10.1666/0022-3360(2004)078<0169:MATOPM>2.0.CO;2 |doilabel=10.1666/0022-3360(2004)0780169:MATOPM2.0.CO;2]

"Pneumodesmus newmani" is a species of millipede that lived 428 million years ago [cite news |publisher=BBC News |date=2004-01-25 |url=http://news.bbc.co.uk/2/hi/uk_news/scotland/3427499.stm |title=Fossil find 'oldest land animal'] . It was discovered in 2004, and is known from a single specimen which is held in a museum in Stonehaven, Aberdeenshire, Scotland. It is the oldest known creature to have lived on land." [http://www.cnn.com/2004/TECH/science/01/27/environment.britain.fossil.reut/index Fossil millipede found to be oldest land creature] ", CNN (from Reuters), 27 January 2004]

Discovery

The single, 1 cm-long fragment 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 [cite web |title="Pneumodesmus newmani" Exhibition |url=http://www.britnett-carver.co.uk/stonehaven/prods/21.html |publisher=Stonehaven Guide |accessdate=2007-05-06] . The species was later given the specific epithet "newmani" in honour of Newman. The genus name alluded to the animal being an 'air-breather' as well as taxonomically acknowledging Stonehaven as the birthplace of Robert William Thomson, the inventor of the Pneumatic Tyre!

ignificance

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 arthropod with a tracheal system, and indeed the first oxygen-breathing animal on land cite web |url=http://www.myriapoda.org/diplopoda/millipede_fossils.html |title=Millipede Fossils |publisher=East Carolina University |date=2005-03-01 |author=Rowland Shelley & Paul Marek] .

Ichnofossils of myriapods are known dating back to the late Ordovician, but "P. newmani" is the earliest body fossil of a millipede, and has been dated to 428 mya (late Wenlock epoch to early Ludlow epoch). The earliest centipedes follow some 10 million years later , and the first vertebrate on land, "Tiktaalik", is 50 million years younger than "Pneumodesmus" [cite web |url=http://science_boy.blogspot.com/2006/04/when-animals-first-conquered-land.html |title=When animals first conquered the land |date=2006-04-09 |author=David Winter] . 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 [cite web |url=http://www.bbc.co.uk/scotland/whereilive/coast/stages.shtml?walk=northeast&stage=2 |publisher=BBC Scotland |title=Cowie |accessdate=2007-05-06] .

References