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Redescription of the cheloniellid euarthropod Triopus draboviensis from the Upper Ordovician of Bohemia, with comments on the affinities of Parioscorpio venator

Published online by Cambridge University Press:  13 June 2022

Peter Van Roy Open the ORCID record for Peter Van Roy [Opens in a new window] ,
Štěpán Rak ,
Petr Budil Open the ORCID record for Petr Budil [Opens in a new window]  and
Oldřich Fatka Open the ORCID record for Oldřich Fatka [Opens in a new window]
Peter Van Roy*
Affiliation:
Department of Geology, Ghent University, Krijgslaan 281/S8, B-9000 Ghent, Belgium
Štěpán Rak
Affiliation:
K Berounce 252/3, 153 00 Prague 5 – Radotín, Czech Republic
Petr Budil
Affiliation:
Czech Geological Survey, Klárov 3, 118 21 Prague 1, Czech Republic
Oldřich Fatka
Affiliation:
Institute of Geology and Palaeontology, Charles University, Albertov 6, 128 43 Prague 2, Prague, Czech Republic
*
Author for correspondence: Peter Van Roy, Email: peter.vanroy@ugent.be
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Abstract

Cheloniellida is a rare but significant clade of artiopod euarthropods, and a major component of Vicissicaudata alongside aglaspidids. The first cheloniellid to be described was Triopus draboviensis, based on a single specimen from the Upper Ordovician Letná Formation in Bohemia. Because this specimen was believed to be missing its anterior, Triopus draboviensis has been the subject of considerable speculation regarding its affinities, with several authors combining various isolated cephalic shields with its trunk. Notwithstanding, Triopus draboviensis has eluded detailed restudy in the 150 years since its first description. Here we provide a redescription of the holotype and hitherto only known specimen of Triopus draboviensis, and describe a recently discovered second partial specimen as Triopus sp. It is shown that the holotype of Triopus draboviensis preserves the complete cephalic shield, while the trunk reveals a likely articulating device, which may represent an apomorphy for Cheloniellida. Further information on the trunk morphology provided by the new specimen has allowed a complete reconstruction of the dorsal exoskeleton of Triopus. An assessment is made of fossils previously suggested to represent the cephalic shield of Triopus draboviensis; while it is shown that none of those fossils can be attributed to Triopus, it is reaffirmed that Drabovaspis complexa likely does belong to Cheloniellida, making Drabovaspis the third cheloniellid genus known from the Letná Formation, after Triopus and Duslia. A revised diagnosis for Cheloniellida is provided, and the recently described problematic euarthropod Parioscorpio venator from the Silurian of Wisconsin is firmly rejected from this clade.

Keywords

ArtiopodaCzech RepublicDrabovaspisLetná FormationVicissicaudataZonoscutumZonozoe
Type
Original Article
Information
Geological Magazine , Volume 159 , Issue 9 , September 2022 , pp. 1471 - 1489
Copyright
© The Author(s), 2022. Published by Cambridge University Press

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References

Alessandrello, A and Bracchi, G (2006) Late Ordovician arachnomorph arthropods from the Anti-Atlas (Morocco). Atti della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano 147, 305–15.Google Scholar
Anderson, EP, Schiffbauer, JD, Jacquet, SM, Lamsdell, JC, Kluessendorf, J and Mikulic, DG (2021) Stranger than a scorpion: a reassessment of Parioscorpio venator, a problematic arthropod from the Llandoverian Waukesha Lagerstätte. Palaeontology 64, 429–74.CrossRefGoogle Scholar
Barrande, J (1846) Notice préliminaire sur le système silurien et les trilobites de Bohème. Leipzig: C. L. Hirschfeld, 97 pp.Google Scholar
Barrande, J (1852) Système silurien du centre de la Bohème: 1ère partie, Crustacés: Trilobites. Prague, Paris: Author, 935 pp.Google Scholar
Barrande, J (1872) Système silurien du centre de la Bohème. 1ère partie. Recherches paléontologiques. Supplément au Volume 1. Trilobites, crustacés divers et poissons. Paris, Prague: Author, 613 pp.Google Scholar
Bartels, C and Brassel, G (1990) Fossilien im Hunsrückschiefer. Dokumente des Meereslebens im Devon. Museum Idar-Oberstein Band 7. Idar-Oberstein: Museum Idar-Oberstein, 232pp.Google Scholar
Bartels, C, Briggs, DEG and Brassel, G (1998) The Fossils of the Hunsrück Slate: Marine Life in the Devonian. Cambridge: Cambridge University Press, 309 pp.Google Scholar
Beecher, CE (1901) Discovery of eurypterid remains in the Cambrian of Missouri. American Journal of Science 12, 364–6.CrossRefGoogle Scholar
Bengtson, S (2000) Teasing fossils out of shales with cameras and computers. Palaeontologia Electronica 3, 4.Google Scholar
Bergström, J (1968) Eolimulus, a Lower Cambrian xiphosurid from Sweden. Geologiska Föreningens i Stockholm Förhandlingar 90, 489–503.CrossRefGoogle Scholar
Bergström, J (1975) Functional morphology and evolution of xiphosurids. In Evolution of the Trilobita, Trilobitoidea and Merostomata. Fossils & Strata 4 (ed. Martinsson, A), pp. 291–305. Oslo: Universitetsforlaget.Google Scholar
Bergström, J (1980) Morphology and systematics of early arthropods. In Arthropoden Phylogenie. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg (NF) 23 (ed. Kraus, O), pp. 7–42. Hamburg: Verlag Paul Parey.Google Scholar
Bergström, J and Hou, XG (2003) Arthropod origins. Bulletin of Geosciences 78, 323–34.Google Scholar
Beyrich, E (1846) Untersuchungen über Trilobiten. Zweite Stück als Fortsetzung zu der Abhandlung “Ueber einiger böhmische Trilobiten”. Berlin: G. Reimer, 37 pp.Google Scholar
Boudreaux, HB (1979) Arthropod Phylogeny with Special Reference to Insects. New York: Wiley, 320 pp.Google Scholar
Braddy, SJ and Dunlop, JA (2021) A sting in the tale of Parioscorpio venator from the Silurian of Wisconsin: is it a cheloniellid arthropod? Lethaia 54, 603–9.Google Scholar
Briggs, DEG and Collins, D (1988) A Middle Cambrian chelicerate from Mount Stephen, British Columbia. Palaeontology 31, 779–98.Google Scholar
Briggs, DEG, Siveter, DJ, Sutton, MD, Garwood, RJ and Legg, DA (2012) Silurian horseshoe crab illuminates the evolution of arthropod limbs. Proceedings of the National Academy of Sciences 109, 15702–5.CrossRefGoogle ScholarPubMed
Broili, F (1932) Ein neuer Crustacee aus dem rheinischen Unterdevon. Sitzungsberichte der Bayerischen Akademie der Wissenschaften, mathematisch-naturwissenschafliche Abteilung 1932, 27–38.Google Scholar
Broili, F (1933) Ein zweites Exemplar von Cheloniellon . Sitzungsberichte der Bayerischen Akademie der Wissenschaften, mathematisch-naturwissenschafliche Abteilung 1933, 11–32.Google Scholar
Bruton, D L (1981) The arthropod Sidneyia inexpectans, Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London, B 295, 619–53.Google Scholar
Caster, KE and Macke, WB (1952) An aglaspid merostome from the Upper Ordovician of Ohio. Journal of Paleontology 26, 753–7.Google Scholar
Chlupáč, I (1963) Report on the merostomes from the Ordovician of Central Bohemia. Věstník Ústředního ústavu geologického 38, 399–402.Google Scholar
Chlupáč, I (1965) Xiphosuran merostomes from the Bohemian Ordovician. Sborník geologických věd, Paleontologie 5, 7–38.Google Scholar
Chlupáč, I (1970) Phyllocarid crustaceans from the Bohemian Ordovician. Sborník geologickych Věd, Paleontologie 12, 41–77.Google Scholar
Chlupáč, I (1988) The enigmatic arthropod Duslia from the Ordovician of Czechoslovakia. Palaeontology 31, 611–20.Google Scholar
Chlupáč, I (1999a) Some problematical arthropods from the Upper Ordovician Letná Formation of Bohemia. Journal of the Czech Geological Society 44, 79–92.Google Scholar
Chlupáč, I (1999b) Unusual arthropods from the Bohemian Ordovician: a review. Acta Universitatis Carolinae – Geologica 43, 393–6.Google Scholar
Cotton, TJ and Braddy, SJ (2004) The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh, Earth Sciences 94, 169–93.CrossRefGoogle Scholar
Crabb, P (2001) The use of polarised light in photography of macrofossils. Palaeontology 44, 659–64.CrossRefGoogle Scholar
Drage, HB, Laibl, L and Budil, P (2018) Postembryonic development of Dalmanitina, and the evolution of facial suture fusion in Phacopina. Paleobiology 44, 638–59.CrossRefGoogle Scholar
Dunlop, JA (2002) Arthropods from the Lower Devonian Severnaya Zemlya Formation of October Revolution Island (Russia). Geodiversitas 24, 349–79.Google Scholar
Dunlop, JA and Selden, PA (1997) The early history and phylogeny of the chelicerates. In Arthropod Relationships. The Systematics Association Special Volume Series 55 (eds Fortey, RA and Thomas, RH), pp. 221–35. London: Chapman & Hall.Google Scholar
Ebbestad, JOR and Budd, GE (2003) Burlingiid trilobites from Norway, with a discussion of their affinities and relationships. Palaeontology 45, 1171–95.CrossRefGoogle Scholar
Edgecombe, GD, García-Bellido, DC and Paterson, JR (2011) A new leanchoiliid megacheiran arthropod from the lower Cambrian Emu Bay Shale, South Australia. Acta Palaeontologica Polonica 56, 385–400.CrossRefGoogle Scholar
Edgecombe, GD, Paterson, JR and García-Bellido, DC (2017) A new aglaspidid-like euarthropod from the lower Cambrian Emu Bay Shale of South Australia. Geological Magazine 154, 87–95.CrossRefGoogle Scholar
Fatka, O, Lerosey-Aubril, R, Budil, P and Rak, Š (2013) Fossilised guts in trilobites from the Upper Ordovician Letná Formation (Prague Basin, Czech Republic). Bulletin of Geosciences 88, 95–104.Google Scholar
Fritsch, A (1908) Über eine Echinodermenlarve aus dem Untersilur Böhmens. Zoologischer Anzeiger 33, 797–8.Google Scholar
Havlíček, V (1998) Ordovician. In Palaeozoic of the Barrandian (Cambrian to Devonian) (eds Chlupáč, I, Havlíček, V, Kříž, J, Kukal, Z and Štorch, P), pp. 39–79. Prague: Czech Geological Survey.Google Scholar
Havlíček, V and Vaněk, J (1966) The biostratigraphy of the Ordovician of Bohemia. Sborník geologických věd, Paleontologie 8, 7–69.Google Scholar
Hou, X-g and Bergström, J (1997) Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils & Strata 45, 1–116.Google Scholar
Jago, JB, García-Bellido, DC and Gehling, J (2016) An Early Cambrian chelicerate from the Emu Bay Shale, South Australia. Palaeontology 59, 549–62.CrossRefGoogle Scholar
Jahn, JJ (1893) Duslia, eine neue Chitonidengattung aus dem böhmischen Untersilur, nebst einige Bemerkungen über die Gattung Triopus Barr. Sitzungsberichte der kaiserlichen Akademie der Wissenschaften Wien, mathematisch-naturwissenschaftliche Classe 102, 591–603.Google Scholar
Kettner, R and Prantl, F (1948) Nové rozdělení a návrh jednotného značení vrstev středočeského ordoviku [A new division of the Ordovician strata in Central Bohemia and proposal of a uniform terminology]. Věstník Státního geologického ústavu 23, 49–68.Google Scholar
Kříž, J and Steinová, M (2009) Uppermost Ordovician bivalves from the Prague Basin (Hirnantian, Perunica, Bohemia). Bulletin of Geosciences 84, 409–36.CrossRefGoogle Scholar
Kühl, G, Bartels, C, Briggs, DEG and Rust, J (2011) Fossilien im Hunsrück-Schiefer: Einzigartige Funde aus einer einzigartigen Region. Wiebelsheim: Quelle & Meyer Verlag, 120 pp.Google Scholar
Kühl, G, Bartels, C, Briggs, DEG and Rust, J (2012) Visions of a Vanished World: The Extraordinary Fossils of the Hunsrück Slate. New Haven, Connecticut, and London: Yale University Press, 128 pp.Google Scholar
Kukal, Z (1958) Petrografický výzkum vrstev letenských barrandienského ordoviku [A lithological investigation of the Letná beds of the Ordovician of the Barrandian]. Sborník Ústředního ústavu geologického, Oddíl geologický 24, 7–111.Google Scholar
Kukal, Z (1998) Sediments of the Barrandian Palaeozoic. In Palaeozoic of the Barrandian (Cambrian to Devonian) (eds Chlupáč, I, Havlíček, V, Kříž, J, Kukal, Z and Štorch, P), pp. 136–48. Prague: Czech Geological Survey.Google Scholar
Lamsdell, JC (2020) The phylogeny and systematics of Xiphosura. PeerJ 8, e10431.CrossRefGoogle ScholarPubMed
Lankester, ER (1904) The structure and classification of the Arthropoda. Quarterly Journal of Microscopical Science 47, 523–82.Google Scholar
Lee, C-F, Satô, M, Shepard, WD and Jäch, MA (2007) Phylogeny of Psephenidae (Coleoptera: Byrrhoidea) based on larval, pupal and adult characters. Systematic Entomology 32, 502–38.CrossRefGoogle Scholar
Lefebvre, B, Van Roy, P, Zamora, S, Gutiérrez-Marco, JC and Nohejlová, M (2022) The Late Ordovician Tafilalt Biota, Anti-Atlas, Morocco: a high-latitude perspective on the GOBE. In The great Ordovician Biodiversification Event: Insights from the Tafilalt Biota, Morocco. Geological Society of London, Special Publication, vol. 485 (eds AW Hunter, JJ Álvaro, B Lefebvre, P Van Roy and S Zamora), pp. 5–35. London: Geological Society of London.Google Scholar
Legg, DA (2014) Sanctacaris uncata: the oldest chelicerate (Arthropoda). Naturwissenschaften 101, 1065–73.CrossRefGoogle Scholar
Legg, DA and Pates, S (2017) A restudy of Utahcaris orion (Euarthropoda) from the Spence Shale (Middle Cambrian, Utah, USA). Geological Magazine 154, 181–6.CrossRefGoogle Scholar
Legg, DA, Sutton, MD and Edgecombe, GD (2013) Arthropod fossil data increase congruence of morphological and molecular phylogenies. Nature Communications 4, 2485.CrossRefGoogle ScholarPubMed
Lerosey-Aubril, R, Paterson, JR, Gibb, S and Chatterton, BDE (2017a) Exceptionally-preserved Late Cambrian fossils from the McKay Group (British Columbia, Canada) and the evolution of tagmosis in aglaspidid arthropods. Gondwana Research 42, 264–79.CrossRefGoogle Scholar
Lerosey-Aubril, R, Zhu, X and Ortega-Hernández, J (2017b) The Vicissicaudata revisited: insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China. Scientific Reports 7, 11117.CrossRefGoogle ScholarPubMed
Marshall, DJ, Lamsdell, JC, Shpinev, E and Braddy, SJ 2014. A diverse chasmataspidid (Arthropoda: Chelicerata) fauna from the Early Devonian (Lochkovian) of Siberia. Palaeontology 57, 631–55.CrossRefGoogle Scholar
Mikuláš, R (1998a) Ordovician of the Barrandian area: reconstruction of the sedimentary basin; its benthic communities and ichnoassemblages. Journal of the Czech Geological Society 43, 143–59.Google Scholar
Mikuláš, R (1998b) Trace fossils from the Letná Formation (Ordovician, Czech Republic). Sborník geologických Věd, Paleontologie 34, 5–25.Google Scholar
Mikulic, DG, Briggs, DEG and Kluessendorf, J (1985a) A Silurian soft-bodied biota. Science 228, 715–17.CrossRefGoogle ScholarPubMed
Mikulic, DG, Briggs, DEG and Kluessendorf, J (1985b) A new exceptionally preserved biota from the lower Silurian of Wisconsin, USA. Philosophical Transactions of the Royal Society of London B 311, 75–85.Google Scholar
Neumayr, M (1887) Erdgeschichte. Band II: Beschreibende Geologie. Leipzig: Bibliographisches Institut, 704 pp.Google Scholar
Noailles, F, Lefebvre, B and Kašička, L (2014) A probable case of heterochrony in the solutan Dendrocystites Barrande, 1887 (Echinodermata: Blastozoa) from the Upper Ordovician of the Prague Basin (Czech Republic) and a revision of the family Dendrocystitidae Bassler, 1938. Bulletin of Geosciences 1887, 451–76.CrossRefGoogle Scholar
Novák, O (1885) Studien an Hypostomen böhmischer Trilobiten, III. Sitzungsberichten der Kaiserlichen böhmischen Gesellschaft der Wissenschaften, mathematisch-naturwissenschaftliche Klasse 1885, 581–7.Google Scholar
Ortega-Hernández, J (2016) Making sense of ‘lower’ and ‘upper’ stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848. Biological Reviews 91, 255–73.CrossRefGoogle ScholarPubMed
Ortega-Hernández, J, Braddy, SJ and Rak, Š (2010) Trilobite and xiphosuran affinities for putative aglaspidid arthropods Caryon and Drabovaspis, Upper Ordovician, Czech Republic. Lethaia 43, 427–31.Google Scholar
Ortega-Hernández, J, Legg, DA and Braddy, SJ (2013) The phylogeny of aglaspidid arthropods and the internal relationships within Artiopoda. Cladistics 29, 15–45.CrossRefGoogle ScholarPubMed
Polechová, M (2022) The bivalve fauna from the Letná Formation (Upper Ordovician) of Bohemia: significance for palaeobiogeography, palaeoecology and diversification of bivalves. Geobios 70, 55–73.CrossRefGoogle Scholar
Prestwich, J (1840) XXXII.—On the geology of Coalbrook Dale. Transactions of the Geological Society of London, Series 2 5, 413–95.CrossRefGoogle Scholar
Přibyl, A and Vaněk, J (1969) Trilobites of the family Trinucleidae Hawle et Corda, 1847, from the Ordovician of Bohemia. Sborník geologických věd, Paleontologie 11, 85–137.Google Scholar
Quenstedt, W (1932) Die Geschichte der Chitonen und ihre allgemeine Bedeutung (mit Zusätzen). Paläontologische Zeitschrift 14, 77–96.CrossRefGoogle Scholar
Rak, Š, Bergström, J, Fatka, O and Budil, P (2009) The upper Ordovician arthropod Zonozoe drabowiensis Barrande (Libeň and Letná formations, Sandbian, Barrandian area, Czech Republic). Bulletin of Geosciences 84, 185–8.CrossRefGoogle Scholar
Rak, Š, Ortega-Hernández, J and Legg, DA (2013) A revision of the Late Ordovician marrellomorph arthropod Furca bohemica from Czech Republic. Acta Palaeontologica Polonica 58, 615–28.Google Scholar
Selden, PA and White, DE (1983) A new Silurian arthropod from Lesmahagow, Scotland. In Trilobites and Other Early Arthropods: Papers in Honour of Prof. H. B. Whittington. FRS Special Papers in Palaeontology 30 (eds Briggs, DEG and Lane, PD), pp. 43–9. London: The Palaeontological Association.Google Scholar
Simonetta, AM and Delle Cave, L (1991) Early Palaeozoic arthropods and problems of arthropod phylogeny; with some notes on taxa of doubtful affinities. In The Early Evolution of Metazoa and the Significance of Problematic Taxa (eds Simonetta, AM and Conway Morris, S), pp. 189–244. Cambridge: Cambridge University Press.Google Scholar
Šnajdr, M (1990) Bohemian Trilobites. Prague: Czech Geological Survey, 265 pp.Google Scholar
Šnajdr, M (1991) Zažívací trakt trilobita Deanaspis goldfussi (Barrande) [On the digestive system of Deanaspis goldfussi (Barrande)]. Časopis Národního muzea, Řada přírodovědná 156, 8–16.Google Scholar
Ssolbergi (2011) A blank political map of Europe. Derivative work Dbachmann. https://commons.wikimedia.org/w/index.php?curid=14871393.Google Scholar
Størmer, L (1944) On the relationships and phylogeny of fossil and Recent Arachnomorpha: a comparative study on Arachnida, Xiphosura, Eurypterida, Trilobita and other fossil Arthropoda. Skrifter utgitt av Det Norske Videnskaps-Akademi i Oslo. I. Matematisk-Naturvidenskapelig Klasse 5, 1–158.Google Scholar
Størmer, L (1959) Trilobitomorpha. Trilobitoidea. In Treatise on Invertebrate Paleontology. Part O. Arthropoda 1 (ed. Moore, RC), pp. O22–37. Lawrence: Geological Society of America and University of Kansas Press.Google Scholar
Stürmer, W and Bergström, J (1978) The arthropod Cheloniellon from the Devonian Hunsrück Shale. Paläontologische Zeitschrift 52, 57–81.CrossRefGoogle Scholar
Van Roy, P (2006a) An aglaspidid arthropod from the Upper Ordovician of Morocco with remarks on the affinities and limitations of Aglaspidida. Transactions of the Royal Society of Edinburgh, Earth Sciences 96, 327–50.CrossRefGoogle Scholar
Van Roy, P (2006b) Non-Trilobite Arthropods from the Ordovician of Morocco. Ghent: Ghent University, 258 pp.Google Scholar
Van Roy, P, Briggs, DEG and Gaines, RR (2015) The Fezouata fossils of Morocco: an extraordinary record of marine life in the Early Ordovician. Journal of the Geological Society 172, 541–9.CrossRefGoogle Scholar
Van Roy, P, Orr, PJ, Botting, JP, Muir, LA, Vinther, J, Lefebvre, B, Hariri, KE and Briggs, DEG (2010) Ordovician faunas of Burgess Shale type. Nature 465, 215–18.CrossRefGoogle ScholarPubMed
Van Roy, P, Rak, Š, Budil, P and Fatka, O (2021) Upper Ordovician Thylacocephala (Euarthropoda, Eucrustacea) from Bohemia indicate early ecological differentiation. Papers in Palaeontology 7, 1727–51.CrossRefGoogle Scholar
Walcott, CD (1912) Cambrian geology and paleontology II. No. 6. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Smithsonian Miscellaneous Collections 57, 145–228.Google Scholar
Wendruff, AJ, Babcock, LE, Mikulic, DG and Kluessendorf, J (2018) New cheloniellid arthropod with large raptorial appendages from the Silurian of Wisconsin, USA. bioRxiv, 407379.Google Scholar
Wendruff, AJ, Babcock, LE, Mikulic, DG and Kluessendorf, J (2020b) Palaeobiology and taphonomy of exceptionally preserved organisms from the Waukesha Biota (Silurian), Wisconsin, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 546, 109631.CrossRefGoogle Scholar
Wendruff, AJ, Babcock, LE, Wirkner, CS, Kluessendorf, J and Mikulic, DG (2020a) A Silurian ancestral scorpion with internal anatomy illustrating a pathway to arachnid terrestrialisation. Scientific Reports 10, 14.CrossRefGoogle ScholarPubMed
Whittington, HB (1994) Burlingiids: small proparian Cambrian trilobites of enigmatic origin. Palaeontology 37, 1–16.Google Scholar
Wills, MA, Briggs, DEG, Fortey, RA and Wilkinson, M (1995) The significance of fossils in understanding arthropod evolution. Verhandlungen der deutschen zoologischen Gesellschaft 88, 203–15.Google Scholar
Wills, MA, Briggs, DEG, Fortey, RA, Wilkinson, M and Sneath, PHA (1998) An arthropod phylogeny based on fossil and recent taxa. In Arthropod Fossils and Phylogeny (ed. Edgecombe, GD), pp. 33–105. New York: Columbia University Press.Google Scholar