310-million-year-old fossil of ancient spider species found in Germany

The appearance of the fossil suggested that it belonged to a previously unknown spider species. 

Following the finding, Wolterbeek gave the specimen to fossil arachnid expert Jason Dunlop of the Museum für Naturkunde in Berlin for further examination. 

This nearly complete fossil specimen indicated that it is a member of the Araneae order, which includes eight-legged venomous spiders. 

The fossil showcased a well-preserved spinneret (silk-producing organ), which is one of the distinguishing features of true spiders.

“It has been almost four years since I found an unidentified arachnid fossil in the Westphalian D (Late Carboniferous) of the Piesberg quarry near Osnabrück, Germany,” mentioned Wolterbeek in an online forum. 

Wolterbeek added: “This has been a great experience, as I learned a great deal about arachnids and spiders and spinnerets along the way.”

Reportedly, the finding of this fossilized spider makes it one of just 12 known Carboniferous species. 

The diversity of Carboniferous spider species is noted to be relatively less than that of closely related arachnids such as Phalangiotarbids and Trigonotarbids. 

The results were published in the journal PalZ.

Study abstract:

The first Palaeozoic spider (Arachnida: Araneae) from Germany is described as Arthrolycosa wolterbeeki sp. nov. and comes from the late Carboniferous (Moscovian) strata of Piesberg near Osnabrück in Lower Saxony. Characteristic for the genus, the new fossil reveals a posteriorly tuberculate dorsal opisthosoma, and relatively elongate and setose legs in which the first leg is longer than the second and third legs. Spinnerets are also preserved, confirming its status as a genuine spider rather than being part of an extinct spider-like arachnid lineage. Carboniferous spiders in general are rather rare. While modern spiders are a megadiverse group, the published fossil record suggests they were only moderately diverse in the late Carboniferous compared to other Coal Measures arachnids. Part of the explanation must be that major radiations within Araneae occurred later, probably during the Mesozoic. If the lifestyle of the Carboniferous fossils was similar to that of modern mesothele spiders their rarity as fossils might also relate to them spending much of their lives in burrows, or similar retreats, with limited opportunities for preservation.