A new genus of eurypterid (Chelicerata, Eurypterida) from the Upper Devonian salt deposits of Belarus

Abstract

We describe a new stylonurid eurypterid from the evaporitic potassium-salt deposits of the Upper Devonian (Famennian) Soligorsk Formation in the Pripyat Trough of Belarus. All specimens are assigned to Soligorskopterus tchepeliensis new genus new species, which represents the first formally described eurypterid species from Belarus. The occurrence of well-preserved eurypterids in these unusual evaporite deposits is most likely due to transport from freshwater stream habitats into a hypersaline setting following death. Soligorskopterus tchepeliensis n. gen. n. sp. appears to be intermediate between the traditionally considered parastylonurids and stylonurids and thus extends our understanding of stylonurid evolution in the mid-Paleozoic. Soligorskopterus n. gen. extends the occurrence of Famennian eurypterids into eastern Laurussia and the Stylonuridae into the Upper Devonian, and this taxon could be part of a global eurypterid habitat shift that took place in the Late Devonian.UUID: http://zoobank.org/466b0195-6199-495b-9270-6f032e2d7493

Stylonurine eurypterids from the Strud locality (Upper Devonian, Belgium): new insights into the ecology of freshwater sea scorpions

“…The occurrence of eurypterids in an Upper Devonian non-marine setting at Strud corroborates previous observations that eurypterids underwent a marine to freshwater transition during the Devonian (Lamsdell & Braddy, 2010;Lamsdell & Selden, 2017), with all Famennian eurypterids either known from fluvial settings (Hall, 1884;Ehlers, 1935) or from near-shore lagoons and deltas alongside plant material indicating the eurypterid material was swept in from continental settings (Lamsdell et al 2009;Plax et al 2018). This transition occurs independently in several eurypterid groups (Lamsdell & Braddy 2010;Lamsdell & Selden, 2017), as well as in the other aquatic chelicerate groups Xiphosura (Lamsdell, 2016) and Chasmataspidida (Lamsdell & Briggs, 2017), suggesting that some external (potentially environmental) factor drove a concerted shift to non-marine habitats .…”

Discerning the Diets of Sweep-Feeding Eurypterids Through Analyses of Mesh-Modified Appendage Armature

“…The Stylonuridae consist of five genera: Stylonurus, Pagea, Ctenopterus, Lauriepterus (Lamsdell et al, 2010a), and Soligorskopterus (Plax et al, 2018). Their appendages are generally very long; however, the anterior prosomal appendages have not been preserved in Stylonurus specimens (Woodward, 1872).…”

“…Soligorskopterus (Figure 8) occurs in the Upper Devonian and had robust prosomal appendages that increased in length posteriorly. Appendages II-IV were spiniferous Ctenopterus-type, bearing multiple rows of small spines approximately equal in length on the distal podomeres, while appendages V and VI were nonspiniferous Parastyonurustype (Plax et al, 2018).…”

“…Soligorskopterus is associated with hypersaline deposits of Belarus. Although Soligorskopterus likely did not take up permanent residence in hypersaline water bodies (Plax et al, 2018), its closely spaced appendage armature compared to most other eurypterids may have been an adaptation for feeding on the smaller organisms that may have been abundant in saline water bodies.…”

“…(Right) A disarticulated spiniferous appendage (BKM 942) of the sweep-feeding stylonurid Soligorskopterus tchepeliensis (BKM 1052, inset) (fromPlax et al, 2018).…”