Trigonotarbid arachnids from the Lower Devonian (Siegenian) of Bürdenbach (Lahrbach Valley, Westerwald area, Rhenish Slate Mountains, Germany)

Abstract

An association of trigonotarbid arachnids from Siegenian strata of Bürdenbach in the Westerwald is described. The Bürdenbach trigonotarbids are numerically dominated by a new genus and species, Spinocharinus steinmeyeri n. gen. n. sp., which is characterized by a rounded carapace with a unique pattern of thorn-like tubercles. A comparison with previously described Devonian trigonotarbids suggests that the new taxon is most probably assignable to the family Palaeocharinidae, which is well represented by the genus Palaeocharinus from the Scottish Rhynie cherts. This would constitute the first record of Palaeocharinidae from the Rhenish Devonian and contrasts sharply with previously described Emsian associations from the Rhenish Slate Mountains, which are dominated by archaeomartids. A rare archaeomartid, Archaeomartus cf. levis, occurs in association with the putative palaeocharinids.Keywords Arachnida Á Trigonotarbida Á Spinocharinus Á Devonian Á Westerwald GermanyKurzfassung Eine Assoziation trigonotarbider Spinnentiere aus dem Siegenium von Bürdenbach im Westerwald wird beschrieben. Diese Trigonotarbiden-Assoziation wird zahlenmäßig von einer neuen Art in einer neuen Gattung, Spinocharinus steinmeyeri n. gen. n. sp., dominiert, die durch einen abgerundeten Carapax mit einer einzigartigen Verzierung aus kräftigen, dornenartigen Tuberkeln charakterisiert wird. Ein Vergleich mit bereits bekannten devonischen Trigonotarbiden zeigt große morphologische Ü bereinstimmungen mit der Familie Palaeocharinidae, die insbesondere durch die Gattung Palaeocharinus aus den schottischen Rhynie Cherts gut bekannt ist. Dies würde den ersten Nachweis von Palaeochariniden für das Rheinische Devon darstellen und kontrastiert mit früher bekannt gewordenen Trigonotarbiden-Vergesellschaftungen aus dem Rheinischen Schiefergebirge mit einem Emsium-Alter, die von Archaeomartiden dominiert werden. In Assoziation mit den mutmaßlichen Palaeochariniden tritt der seltene Archaeomartide Archaeomartus cf. levis auf.Schlü sselwörter Arachnida Á Trigonotarbida Á Spinocharinus Á Devon Á Westerwald Deutschland

First Palaeozoic arachnid from Portugal and implications for Carboniferous palaeobiogeography

“…Rhenish Slate Mountains, Germany) (e.g. Poschmann and Dunlop, ). The youngest trigonotarbids (Late Carboniferous) such as Aphantomartus pustulatus and A. areolatus lived in environments which were dominated by fluvial systems (Rössler, ).…”

“…The trigonotarbid arachnids (Trigonotarbida) are among the earliest terrestrial animals and range in age from the Late Silurian to the Early Permian (e.g. Jeram et al ., ; Dunlop, , , , ; Rössler, ; Dunlop et al ., , ; Garwood et al ., ; Selden and Pillola, ; Garwood and Dunlop, ; Poschmann and Dunlop, , ). Trigonotarbids were extinct spider‐like animals that lacked silk‐producing spinnerets, and their bodies were divided into a prosoma (i.e.…”

“…abdomen) a few centimetres in length. They are anatomically characterized by a box-shaped or triangularsubtriangular prosoma and by elliptical (oval) opisthosoma composed of nine visible tergites (segments) divided into median and lateral plates (Petrunkevitch, 1913;Dunlop, 1995Dunlop, , 1996Dunlop, , 1997Dunlop, , 2010Dunlop et al, 2008Dunlop et al, , 2009Garwood et al, 2009;Poschmann and Dunlop, 2011;Dunlop, 2010, 2011). The oldest trigonotarbid arachnids occur in the Late Silurian-Early Devonian strata of Germany and Britain (e.g.…”

“…The oldest trigonotarbid arachnids occur in the Late Silurian-Early Devonian strata of Germany and Britain (e.g. Jeram et al, 1990;Dunlop, 1996Dunlop, , 2010Garwood and Dunlop, 2010;Poschmann and Dunlop, 2011). Several Early Devonian trigonotarbids occur in the Westerwald area of the Rhenish Slate Mountains in Germany (Poschmann and Dunlop, 2011).…”

Trigonotarbus johnsoni Pocock, 1911, revealed by X-ray computed tomography, with a cladistic analysis of the extinct trigonotarbid arachnids

“…Many exceptionally preserved specimens assigned to the early family Palaeocharinidae have been recovered from Devonian localities. Perhaps the most famous of these is the Rhynie Chert in Scotland, dating to ∼411.5 Mya (Pragian; Parry et al ., ), but valuable specimens have also been discovered at Bürdenbach in Germany (Pragian/Emsian; Poschmann & Dunlop, ) and Gilboa in New York (Givetian; Shear et al ., ). Gilboa and Windyfield/Rhynie Chert fossils include both individuals and exuviae, and preserve trigonotarbid morphology in remarkable detail (including internal anatomy), making them excellent tools for research.…”