A Great-Appendage Arthropod with a Radial Mouth from the Lower Devonian Hunsrück Slate, Germany

Abstract

Great-appendage arthropods, characterized by a highly modified anterior limb, were previously unknown after the Middle Cambrian. One fossil from the Lower Devonian Hunsrück Slate, Germany, extends the stratigraphic range of these arthropods by approximately 100 million years. Schinderhannes bartelsi shows an unusual combination of anomalocaridid and euarthropod characters, including a highly specialized swimming appendage. A cladistic analysis indicates that the new taxon is basal to crown-group euarthropods and that the great-appendage arthropods are paraphyletic. This new fossil shows that features of the anomalocaridids, including the multisegmented raptorial appendage and circular plated mouth, persisted long after the initial radiation of the euarthropods.

Arthropod eyes: The early Cambrian fossil record and divergent evolution of visual systems

“…Their geological range extends from the lower Cambrian into at least the Lower Devonian, the last known example being Schinderhannes bartelsi from the Hunsrück Slates (Kühl et al, 2009). The emergence of radiodontans preceded arthrodization and the origin of jointed post-protocerebral appendages.…”

The Fezouata fossils of Morocco; an extraordinary record of marine life in the Early Ordovician

“…It is the first anomalocaridid to show definitive evidence of both dorsal and ventral flaps. Anomalocaridids are potentially critical to understanding the origin of the arthropod biramous limb, sitting, as they do, stemward of the euarthropods but above lobopodians (Budd 1996;Zhang & Briggs 2007;Daley et al 2009;Kühl et al 2009;Cong et al 2014;Vinther et al 2014;Ortega-Hernández 2015;Van Roy et al 2015). Prior to the discovery of A. benmoulai, anomalocaridids had been reconstructed with just one row of flaps along each side of the trunk (e.g.…”

“…Represented by just one specimen, Schinderhannes bartelsi (Kühl et al 2009) was described as a euarthropod retaining the raptorial appendages, large eyes and radial mouth characteristic of anomalocaridids. The unusual pair of large swimming appendages behind the head have recently found an analogy in the pair of hypertrophied post-cephalic flaps in the Chengjiang anomalocaridid Lyrarapax unguispinus (Cong et al 2014).…”

Caedichnus, a New Ichnogenus Representing Predatory Attack on the Gastropod Shell Aperture

“…For the peeling scars seen on Paleozoic gastropods, smaller arthropods are among the likely culprits (Schram, 1981;Rolfe and Dzik, 2006;K€ uhl et al, 2009). After the Paleozoic, more familiar groups of crushing predators emerged, particularly the crustaceans that are responsible for much of the apertural lip damage observed in modern systems …”