Triassic Isopoda – Three New Species from Central Europe Shed Light On
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University of Groningen Triassic Isopoda – three new species from Central Europe shed light on the early diversity of the group Schädel, Mario; van Eldijk, Timo; Winkelhorst, Herman; Reumer, Jelle W.F.; Haug, Joachim T. Published in: Bulletin of Geosciences DOI: 10.3140/bull.geosci.1773 IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2020 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Schädel, M., van Eldijk, T., Winkelhorst, H., Reumer, J. W. F., & Haug, J. T. (2020). Triassic Isopoda – three new species from Central Europe shed light on the early diversity of the group. Bulletin of Geosciences, 95(2), 145-166. https://doi.org/10.3140/bull.geosci.1773 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 24-09-2021 Triassic Isopoda – three new species from Central Europe shed light on the early diversity of the group Mario Schädel, TiMo van eldijk, herMan WinkelhorST, jelle W.F. reuMer & joachiM T. haug Despite its vernacular names (e.g. ‘woodlice’) Isopoda is a group with mostly aquatic species, with most species living in marine environments. The fossil record for isopods compared to other groups of Eucrustacea is relatively sparse. This applies even more for the Triassic. While in the Jurassic Isopoda is relatively well represented by fossils, only eight species have previously been described from the Triassic. In this study three new species of Isopoda are described from two field sites in Europe:Obtusotelson summesbergeri sp. nov. and Discosalaputium aschauerorum sp. nov. from Polzberg (Gaming, Lower Austria, Austria) and Gelrincola winterswijkensis sp. nov. from Winterswijk (Gelderland, Netherlands). All three new species are interpreted as representatives of Scutocoxifera (ingroup of Isopoda). The species Gelrincola winterswijkensis sp. nov. is further interpreted to be a representative of Cymothoida (ingroup of Scutocoxifera). Most of the oldest fossils of Isopoda belong to Phreatoicidea, which is supposed to be the sistergroup to all remaining Isopoda. Nowadays, Phreatoicidea is a small relic group, its representatives living in freshwater environments. The new species herein presented contribute to our understanding of the diversity of Isopoda in the Triassic and support the assumption that the transition from a dominance of Phreatoicidea towards the dominance of the remaining lineages of Isopoda happened quite early (likely prior to the Triassic). • Key words: fossil, morphometry, Scutocoxifera, Polzberg, Winterswijk. MARIO SCHÄDEL, TIMO VAN ELDIJK, HERMAN WINKELHORst, JELLE W.F. REUMER & JOACHIM T. HAUG 2020. Triassic Isopoda – three new species from Central Europe shed light on the early diversity of the group. Bulletin of Geosciences 95(2), 145–166 (7 figures, 4 tables, 1 appendix, 3 supplementary files). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received September 28, 2019; accepted in revised form February 26, 2020; published online May 16, 2020; issued May 30, 2020. Mario Schädel, Department of Biology II, Ludwig-Maximilians-Universität Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany; [email protected] • Timo van Eldijk, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands • Herman Winkelhorst, Molenstraat 14, 7122ZW Aalten, The Netherlands • Jelle W.F. Reumer, Stratigraphy and Paleontology, Department of Earth Sciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands • Joachim T. Haug, Department of Biology II, Ludwig-Maximilians-Universität Munich, Großhaderner Str. 2, 82152 Planegg- Martinsried, Germany & GeoBio-Center of the LMU Munich, Richard-Wagner-Str. 10, 80333 Munich, Germany Isopoda is a large ingroup of the crustacean group Peracari- appendages (uropods) is dissimilar to that in many other da, comprising morphologically diverse representatives lineages of Isopoda by being styliform rather than flat. that inhabit a variety of ecosystems such as the deep sea, Extant representatives of Phreatoicidea are only found shores, brackish waterbodies, freshwater and one ingroup in freshwater environments (Wilson & Johnson 1999). even managed to inhabit terrestrial ecosystems (Wägele Phreatoicideans are also interesting, as the oldest fos sils of 1989, Brandt & Poore 2003, Broly et al. 2013). Even though Isopoda supposedly are representatives of this group. the majority of representatives of Isopoda can easily be The fossil record of the group Isopoda in the Palaeozoic recognised by the organisation of the body and the overall (see Tab. 1 for all described Palaeozoic species) can be shape, this does not necessarily apply for all groups. One denoted as rather scarce compared to the record in the of these groups is Phreatoicidea. Phreatoicidea is thought Meso- and Cenozoic. The oldest fossil record of the group to be the sistergroup to all remaining ingroups of Isopoda (Hesslerella shermani Schram, 1970) is from the Middle and is morphologically distinct in some aspects, including Pennsylvanian (Upper Carboniferous, about 300 million the overall shape (Wägele 1989, Brusca & Wilson 1991). years old) of Mazon Creek (Illinois, USA) and is interpreted Phreatoicideans are rather laterally compressed than dorso- as a representative of Phreatoicidea (Schram 1970). ventrally compressed, similar to sideswimmers (Amphipo - Five species have been described from the Middle Per- da; Nicholls 1942). Also the the shape of the posterior most mian of Brazil (Paraná Basin, São Paulo State; Mezzalira & DOI 10.3140/bull.geosci.1773 145 Bulletin of Geosciences • Vol. 95, 2, 2020 Table 1. Palaeozoic species of Isopoda. Species Age Country & reference Hesslerella shermani Schram, 1970 late Carboniferous, Moscovian Illinois, USA (Schram 1970) Sottyella montcellensi Racheboeuf et al., 2009 late Carboniferous, Gzhelian France (Racheboeuf et al. 2009) Pseudopalaega granulifera Mezzalira & Martins-Neto, 1992 early Permian, Artinskian Brazil (Mezzalira & Martins-Neto 1992) Pseudopalaega microcelata Mezzalira & Martins-Neto, 1992 early Permian, Artinskian Brazil (Mezzalira & Martins-Neto 1992) Pseudopalaega iratiensis Martins-Neto, 2001 early Permian, Artinskian Brazil (Martins-Neto 2001) Protourda tupiensis Mezzalira & Martins-Neto, 1992 early Permian, Artinskian Brazil (Mezzalira & Martins-Neto 1992) Protourda circunscriptia Mezzalira & Martins-Neto, 1992 early Permian, Artinskian Brazil (Mezzalira & Martins-Neto 1992) Palaeophreatoicus sojanensis Birstein, 1962 middle Permian Russia (Birstein 1962, Schram 1980) Protamphisopus reichelti Malzahn, 1962 late Permian, Lopingian Germany (Glaessner & Malzahn 1962) Palaeocrangon problematicus (= Prosoponiscus Germany (Schlotheim 1820, Schauroth 1854, late Permian, Lopingian problematicus) (von Schlotheim, 1820) Geinitz 1861) & Great Britain (Kirkby 1857) Martins-Neto 1992, Martins-Neto 2001, Chahud & Petri For the Triassic only eight species of Isopoda and one 2015), which are generally interpreted as representatives not formally described specimen have been reported so far of Scutocoxifera. Scutocoxifera is an ingroup of Isopoda, (Figs 1, 2). Anhelkocephalon handlirschi is deliberately not including Phreatoicidea, which representatives are not included, see discussion below. Records of the group characterised by having scale-like lateral expansions to the Isopoda are missing throughout the Early Triassic (Induan dorsal sclerites of the pereon (postocular segments 7–13) that and Olenekian). are part of the proximal leg element (‘coxal plates’) (Dreyer The earliest Triassic record, so far, is from the early Mid- & Wägele 2002). The remainder of the Palaeozoic fossils dle Triassic of France (‘Grès à Voltzia’ Formation, ‘Volt zien of Isopoda have all been interpreted as representatives of sandstein’, Upper Buntsandstein, Anisian) with Pala ega Phreatoicidea (Glaessner & Malzahn 1962, Schram 1980). pumila Gall & Grauvogel, 1971 (Gall & Grauvogel 1971, A B Figure 1. Maps with the field sites of all published findings of Isopoda from the Triassic. • A – map of Europe. • B – world map. Stars denote field sites corresponding to the herein described fossils. 146 Mario Schädel et al.• Triassic Isopoda – three new species from Central Europe Figure 2. Temporal occurrences of Triassic fossils of Isopoda based on literature information and the new fossil records within this study. Scale in million years. The depicted time-spans (horizontal thick grey lines) do not refer to the longevity of the species, but to the temporal uncertainty of each occurrence. Abbreviations: Ind. – Induan; Jura. – Jurassic; Olen. – Olenekian; Perm. – Permian. Mader 1984, Gall & Grauvogel-Stamm 2005). Pala ega unlikely that