Pneumodesmus

Pneumodesmus newmani is a species of millipede that lived during the late Wenlock epoch of the Silurian period around 428 million years ago.^[1][2][3]

Pneumodesmus Temporal range: Wenlock PreꞒ Ꞓ O S D C P T J K Pg N
Reconstruction of Pneumodesmus newmani
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Myriapoda
Class:	Diplopoda
Subclass:	†Archipolypoda
Order:	Incertae sedis
Family:	Incertae sedis
Genus:	Pneumodesmus
Species:	P. newmani
Binomial name
Pneumodesmus newmani Wilson & Anderson, 2004 [1]

Photomicrograph of the type specimen

It is the first myriapod fossil, and the oldest known creature to have lived on land.^[4] The single specimen was discovered in 2004 near Stonehaven, Aberdeenshire.^[2]

Discovery and naming

The fossil of P. newmani was found by Mike Newman. He is a bus driver and amateur palaeontologist from Aberdeen. The fossil was in a layer of sandstone rocks on the foreshore of Cowie, near Stonehaven.^[5] The species was later called "newmani" in honour of its finder. The fossil is kept in National Museum of Scotland, Edinburgh.^[6]

Description

In the photograph above, you can see the back is covered with hard plates, and wispy slender legs. The animal is definitely segmented, and it is like, or related to, millipedes.^[1]

Its cuticle has what look like openings or spiracles. These are part of a gas exchange system that would work in air. So P. newmani is thought to be the earliest documented arthropod with a tracheal system, and the first known oxygen-breathing animal on land.^[4]