Temporal range: Late Silurian
|Photomicrograph of the type specimen|
Wilson & Anderson, 2004 
Pneumodesmus newmani is a species of millipede that lived , in the Late Silurian. It is the first myriapod, and the oldest known creature to have lived on land. It was discovered in 2004, and is known from a single specimen from Stonehaven, Aberdeenshire, Scotland.
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. The species was later given the specific epithet "newmani" in honour of Newman. The holotype is kept in National Museum of Scotland, Edinburgh. The genus name derives from the Greek pneumato ("air" or "breath") and desmus ("band", a common millipede root word) in reference to the inferred air-breathing habit.
The fossil of P. newmani depicts small paranota (keels) high on the body, long, slender legs. The dorsal portion of each body segment is ornamented with a horizontal bar and three rows of roughly hexagonal bosses (bumps).
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 indeed the first known oxygen-breathing animal on land.
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 (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. 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.
- 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.
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- "Cowie". BBC Scotland. Retrieved May 6, 2007.