First decapod crustaceans in aLateDevonian continental ecosystem

Abstract

The origin and early diversification of decapod crustaceans and their expansion from marine to continental environments are key events in arthropod evolution. Rare fossil decapods are known from the Palaeozoic, and the earliest eumalacostracans with undoubted decapod affinities are the Late Devonian Palaeopalaemon and Aciculopoda, found in offshore marine deposits. Here, we describe a new species of the shrimp Tealliocaris found in floodplain and temporary pond deposits from the Famennian (Late Devonian) of Belgium, together with a rare Palaeozoic assemblage of other crustaceans (conchostracans, notostracans and anostracans) and chelicerates (eurypterids). Tealliocaris walloniensis sp. nov. documents the earliest occurrence of continental decapod crustaceans and indicates that decapods have been part of continental ecosystems at least since the Late Devonian.

Fossil Crustaceans as Parasites and Hosts

“…Given the estimated occurrence of calanoid copepods as far back as the Silurian, based on a phylogeny using morphological and molecular evidence (Selden et al, 2010), and the presence of decapods since the Devonian (e.g. Feldmann and Schweitzer, 2010;Gueriau et al, 2014;Jones et al, 2014), Early Jurassic and older occurrences are theoretically possible as the two host groups would have been available. Unfortunately, no rigorous phylogenetic analyses of epicarideans including estimated divergence times are known to us.…”

A crustacean with eumalacostracan affinities from the Early Devonian Hunsrück Slate (SW Germany)

“…The short anterior thoracopods of H. engeli could indicate a closer relationship to decapods where the anterior three thoracopods have become modified to form functional mouthparts (see also discussion in Gueriau et al . ). As it remains difficult to identify the relative lengths of these appendages clearly in our fossil, this also remains a rather unsupported scenario, further complicated by the fact that at least the first thoracopods have become transformed into feeding‐associated appendages in various lineages (e.g.…”

“…Tealliocaris walloniensis Gueriau et al . , has been hypothesized as a representative of Decapoda s . l .…”

The oldest notostracan (Upper Devonian Strud locality, Belgium)

“…Location and partial stratigraphy of the S trud quarry ( U pper F amennian) with major plant, invertebrate and vertebrate bearing strata (modified from Gueriau et al . ).…”