One of the pleasures of visiting the London Natural History Museum gardens is the opportunity to spot exhibits that many visitors overlook.  For example, tucked away in an area of ferns we spotted a display board highlighting one of the largest invertebrates of all time – Arthropleura.  Several species have been named but the type species is Arthropleura armata.  The display board makes particular reference to A. armata. Fossils of this species seem to be confined to the base of the Westphalian to the top of the Stephanian – western European sub-divisions of the Carboniferous.

The display board at the London Natural History Museum gardens highlighting Arthropleura armata. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Arthropleura armata

The gold-coloured model was probably created prior to the publication of the recent scientific paper that revealed details of the head of this arthropod for the first time.  For example, the antennae were comprised of at least seven segments, and the compound eyes were club-shaped and on stalks.

To read Everything Dinosaur’s earlier blog post about new fossil discoveries providing fresh insight into the head of Arthropleura: Newly Described Fossils from France Reveal the Head of Arthropleura.

The information on the board does not give exact size measurements, these remain controversial.  However, it is stated that it is the largest known land invertebrate. The comment about its great size was partly caused by the higher oxygen levels in the atmosphere is also controversial.  Some palaeontologists who have examined trackways and fragmentary body fossils, suggest a body length in excess of two and half metres.  The size of Arthropleura having been frequently attributed to higher atmospheric oxygen levels during the Carboniferous.

Intriguingly, the dated Arthropleura fossils do not align with the evidence to indicate higher concentrations of oxygen.  For instance, the largest known body fossil dates from an interval where oxygen levels were only about 20% higher than they are today.

Arthropleura may have reached an enormous size due to the large amounts of food (decaying plants and animals) in the equatorial environment or simply because it lacked competition.

Sue from Everything Dinosaur commented:

“We enjoyed visiting the Natural History Museum gardens.  Everyone rushes around and wants to see the Diplodocus statue.  However, for us, the pleasure was in finding those little out of the way, tucked away snippets of information that highlight the rich diversity of the fossil record.”

If you were to find an Arthropleura in the garden, that would be something remarkable.

The Everything Dinosaur website: Prehistoric Animal Models.