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Functional morphology of the prosoma of Baltoeurypterus tetragonophthalmus (Fischer) (Chelicerata: Eurypterida)

  • Paul A. Selden (a1)


The prosomal morphology of Baltoeurypterus tetragonophthalmus (Fischer) from the Baltic Silurian is redescribed and reconstructed. The first eurypterid labrum and new secondary sexual characters of Baltoeurypterus are described. The radially-arranged coxae of Baltoeurypterus were capable of adduction and abduction for food mastication, but not promotor-remotor movements for locomotion. Joint diagrams are presented for the first time for an extinct arthropod. Promotion and remotion of the limbs occurred about subvertical trochanteral pivots, as in all other chelicerates except xiphosurans. Baltoeurypterus probably walked in a “slow” gait; a method of choosing possible gaits for extinct arthropods is outlined. Swimming in Baltoeurypterus was effected by means of a rowing action of the posterior limb pair, which is provided with complex joints for collapsing the paddle during the recovery stroke. The limb arrangement and joint mechanisms of Baltoeurypterus are intermediate between those of the xiphosurans and the arachnids. It is possible that a sister relationship exists between the eurypterids and some arachnid groups, which would render Merostomata and Arachnida unnatural assemblages.



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Andrews, H. E., Brower, J. C, Gould, S. J. & Reyment, R. A. 1974. Growth and variation in Eurypterus remipes DeKay. BULL GEOL INST UNIV UPSALA 4, 81114.
Barber, S. B. 1956. Chemoreception and proprioception in Limulus. J EXP ZOOL 131, 5174.
Barbour, E. H. 1914. Carboniferous eurypterids of Nebraska. AM J SCI 38, 507–10.
Barr, D. & Smith, B. P. 1979. The contribution of setal blades to effective swimming in the aquatic mite Limnochares americana (Acari: Prostigmata: Limnocharidae). ZOOL J LINN SOC 65, 5569.
Briggs, D. E. G., Rolfe, W. D. I. & Brannan, J. 1979. A giant myriapod trail from the Namurian of Arran, Scotland. PALAEONTOLOGY 22, 273–91.
Bristowe, W. S. 1958. The World of Spiders. London: Collins. Bruton D. L. 1981. The Middle Cambrian arthropod Sidneyia, Burgess Shale, British Columbia. PHILOS TRANS R SOC LONDON B, in press.
Clark, B. D. & Bemis, W. 1979. Kinematics of swimming of penguins at the Detroit Zoo. J ZOOL LONDON 188, 411–28.
Clarke, J. M. & Ruedemann, R. 1912. The Eurypterida of New York. MEM NEW YORK STATE MUS NAT HIST 14, vol. I pp. 1439, vol. II plates.
Clarkson, E. N. K. 1975. The evolution of the eye in trilobites. FOSSILS AND STRATA 4, 731.
Couzijn, H. W. C. 1976. Functional anatomy of the walking-legs of Scorpionida with remarks on terminology and homologization of leg segments. NETH J ZOOL 26, 453501.
Dalingwater, J. E. 1973. The cuticle of a eurypterid. LETHAIA 6, 179–86.
Dalingwater, J. E. 1975. Further observations on eurypterid cuticles. FOSSILS AND STRATA 4, 271–9.
Dalingwater, J. E. 1980. SEM observations on the cuticles of some chelicerates. 8th INT ARACHNOL CONGR VIENNA 1980, 285–9.
DeKay, J. E. 1825. Observations on a fossil crustaceous animal of the order Branchiopoda. ANN LYCEUM NAT HIST 1, 375–7.
Dennell, R. 1960. Integument and exoskeleton. In Waterman, T. H. (ed.) The Physiology of Crustacea, vol. 1, 449–72. New York: Academic Press.
Depitout, A. 1962. Etude des gigantostraces siluriens du Sahara central. PUBL CENT RECH SAHARIENNES GEOL 2, 1141.
Edel, R. K. & Winn, H. E. 1978. Observations on underwater locomotion and flipper movement of the humpback whale Megaptera novaeangliae. MAR BIOL BERLIN 48, 279–87.
Eichwald, E. von 1854. Die Grauwackenschichten von Liev- und Esthland. BULL SOC NAT MOSCOU 27, 3111.
Eichwald, E. von 1860. Lethaea Rossica, vol. 1. Stuttgart: Schweizerbart.
Eisenack, A. 1956. Beobachtungen an Fragmenten von Eurypteriden-Panzern. NEUES JAHRB GEOL PALAEONTOL ABH 104, 119–28.
English, A. W. 1976. Limb movements and locomotor function in the California sea lion (Zalophus californianus). J ZOOL LONDON 178, 341–64.
Evans, M. E. G. 1977. Locomotion in the Coleoptera Adephaga, especially Carabidae. J ZOOL LONDON 181, 189226.
Firstman, B. 1973. The relationship of the chelicerate arterial system to the evolution of the endosternite. J ARACHNOL 1, 154.
Fischer de Waldheim, G. 1839. Notice sur un crustace fossile du genre Eurypterus de Podolie. BULL SOC NAT MOSCOU 11, 125–8.
Fisher, D. C. 1975. Swimming and burrowing in Limulus and Mesolimulus. FOSSILS AND STRATA 4, 281–90.
Fisher, D. C. 1979. Evidence for subaerial activity of Euproops danae (Merostomata, Xiphosurida). In Nitecki, M. H. (ed.) Mazon Creek Fossils, 379447. New York: Academic Press.
Fortey, R. A. & Clarkson, E. N. K. 1976. The function of the glabellar ‘tubercle’ in Nileus and other trilobites. LETHAIA 9, 101–6.
Gnatzy, W. & Tautz, J. 1977. Sensitivity of an insect mechanoreceptor during moulting. PHYSIOL ENTOMOL 2, 279–88.
Gray, J. 1968. Animal Locomotion. London: Weidenfeld & Nicholson.
Hall, J. 1859. Palaeontology of New York, Vol. 3 (In Natural History of New York Part 4) part 1, 382419; part 2, plates 80–84A. Albany: New York State Museum.
Hammen, L. van der 1977. A new classification of Chelicerata. ZOOL MEDED LEIDEN 51, 307–19.
Hammen, L. van der 1979. Comparative studies on Chelicerata I. The Cryptognomae (Ricinulei, Architarbi and Anactinotrichida). ZOOL VERH 174, 162.
Hanken, N.-M. & Stø;rmer, L. 1975. The trail of a large Silurian eurypterid. FOSSILS AND STRATA 4, 255–70.
Hansen, H. J. 1925. Studies on Arthropoda II. On the Comparative Morphology of the Appendages in the Arthropoda. A. Crustacea. Copenhagen: Gyldendalske Boghandel.
Hansen, H. J. 1930. Studies on the Arthropoda III. On the Comparative Morphology of the Appendages in the Arthropoda. B. Crustacea (Supplement), Insecta, Myriapoda and Arachnida. Copenhagen: Gyldendalske Boghandel.
Hartnoll, R. G. 1971. The occurrence and significance of swimming in the Brachyura. ANIM BEHAV 19, 3450.
Haupt, i. & Coineau, Y. 1978. Moulting and morphogenesis of sensilla in a prostigmatic mite (Acari, Actinotrichida, Actinedida: Caeculidae). 1. Mechanoreceptive bristles. CELL TISSUE RES 186, 6379.
Hede, J. E. 1929. Berggrunden (Silursystemet). In Munthe, H., Hede, J. E. & Lundqvist, G.Beskrivning till kartbladet Katthammarsvik. SVER GEOL UNDERS ser. Aa 170, 1457.
Holm, G. 1896. Uber eine neue Bearbeitung des Eurypterus fischeri Eichw. BULL ACAD SCI ST PETERSBOURG 4, 369–72.
Holiti, G. 1898. Uber die Organisation des Eurypterus fischeri Eichw. MEM ACAD SCI ST PETERSBOURG 8, 157.
Holm, G. 1899. Palaeontologiska notiser: 13. Om den yttre anatomien hos Eurypterus fischeri. GEOL FOEREN STOCKHOLM FOERH 21, 83128.
Hoyle, G. 1976. Arthropod walking. In Herman, R. M., Grillner, S., Stein, P. S. G. & Stuart, D. G. (eds) Neural Control of Locomotion. ADV BEHAV BIOL 18, 137–79, New York: Plenum Press.
Hughes, C. P. 1975. Redescription of Burgessia bella from the Middle Cambrian Burgess Shale, British Columbia. FOSSILS AND STRATA 4, 415–35.
Hughes, G. M. 1958. The co-ordination of insect movements. III. Swimming in Dytiscus, Hydrophilus, and a dragonfly nymph. J EXP BIOL 35, 567–83.
Hughes, G. M. & Mill, P. J. 1974. Locomotion: terrestrial. In Rockstein, M. (ed.) The Physiology of Insecta, 2nd edn, vol. III, 335–79. New York: Academic Press.
Kaestner, A. 1968. Invertebrate Zoology II – Arthropod relatives, Chelicerala, Myriapoda (translated and adapted from the German by Levi, H. W. & Levi, L. R.) 2nd edn.New York: Interscience.
Kaljo, D. 1970. Silur Estonii. Tallin: Institut Geologii Akademii Nauk Estonickoi CCP.
Kennedy, T. S. 1945. Observations on the mass migration of desert locust hoppers. TRANS R ENTOMOL SOC LONDON 95, 247–62.
Kjellesvig-Waering, E. N. 1979. Eurypterids. In Jaanusson, V., Laufeld, S. & Skoglund, R. (eds). Lower Wenlock faunal and floral dynamics – Vattenfallet section, Gotland. SVER GEOL UNDERS AFH C 762, 5764.
Kiihl, H. 1933. Die Fortbewegung der Schwimmkrabben mit Bezug auf die Plastizitat des Nervensystems. Z VGL PHYSIOL 19, 489521.
Lankester, E. R., Benham, W. B. S. & Beck, E. J. 1885. On the muscular and endoskeletal systems of Limulus and Scorpio; with some notes on the anatomy and generic characters of scorpions. TRANS ZOOL SOC LONDON 11, 311–84.
Lauck, D. R. 1959. Locomotion of Lethocerus (Hemiptera: Belostomatidae). ANN ENTOMOL SOC AM 52, 93–9.
Laurie, M. 1893. The anatomy and relations of the Eurypteridae. TRANS R SOC EDINBURGH 37, 509–28.
Levi-Setti, R. 1975. Trilobites: A Photographic Atlas. Chicago: University of Chicago Press.
Lochhead, J. H. 1961. Locomotion. In Waterman, T. H. (ed.) The Physiology of Crustacea, vol. II, 313–64. New York: Academic Press.
Manten, A. A. 1971. Silurian Reefs of Gotland. Developments in Sedimentology 13. Amsterdam: Elsevier.
Manton, S. M. 1952. The evolution of arthropodan locomotory mechanisms. Part 2. General introduction to the locomotory mechanisms of the Arthropoda. J LINN SOC (ZOOL) 42, 93117.
Manton, S. M. 1958. Hydrostatic pressure and leg extension in arthropods, with special reference to arachnids. ANN MAG NAT HIST 1, 161–82.
Manton, S. M. 1964. Mandibular mechanisms and the evolution of arthropods. PHILOS TRANS R SOC LONDON B 247, 1183.
Manton, S. M. 1965. The evolution of arthropodan locomotory mechanisms. Part 8. Functional requirements and body design in Chilopoda, together with a comparative account of their skeleto-muscular systems and an appendix on a comparison between burrowing forces of annelids and chilopods and its bearing upon the evolution of the arthropodan haemocoel. J LINN SOC (ZOOL) 45, 251484.
Manton, S. M. 1972. The evolution of arthropodan locomotory mechanisms. Part 10. Locomotory habits, morphology and evolution of the hexapod classes. ZOOL J LINN SOC 51, 203400.
Manton, S. M. 1973a. Arthropod phylogeny – a modern synthesis. J ZOOL LONDON 171, 111–30.
Manton, S. M. 1973b. The evolution of arthropodan locomotory mechanisms. Part 11. Habits, morphology and evolution of the Uniramia (Onychophora, Myriapoda, Hexapoda) and comparisons with the Arachnida, together with a functional review of uniramian musculature. ZOOL J LINN SOC 53, 257375.
Manton, S. M. 1977. The Arthropoda: Habits, Functional Morphology, and Evolution. Oxford: Oxford University Press.
Miller, J. 1975. Structure and function of trilobite terrace lines. FOSSILS AND STRATA 4, 155–78.
Miller, J. 1976. The sensory fields and life mode of Phacops rana (Green, 1832) (Trilobita). TRANS R SOC EDINBURGH 69, 337–67.
Miller, P. L. 1972. Swimming in mantids. J ENTOMOL LONDON 46, 91–7.
Milne, L. & Milne, M. 1967. The Crab that Crawled out of the Past. London: Bell.
Mitchill, S. L. 1818. An account of the impressions of a fish in the rocks of Oneida county, New York. AM MON MAG CRIT REV 3, 291.
Mutvei, H. 1977. SEM studies of arthropod exoskeletons. 2. Horseshoe crab Limulus polyphemus (L.) in comparison with extinct eurypterids and recent scorpions. ZOOL SCR 6, 203–13.
Nachtigall, W. 1960. Uber Kinematik, Dynamik und Energetik des Schwimmens einheimischer Dytisciden. Z VGL PHYSIOL 43, 48118.
Nachtigall, W. 1962. Funktionelle Morphologie, Kinematik und Hydromechanik des Ruderapparates von Gyrinus. Z VGL PHYSIOL 45, 193226.
Nachtigall, W. 1974. Locomotion: mechanics and hydrodynamics of swimming in aquatic insects. In Rockstein, M. (ed.) The Physiology of Insecta, 2nd edn, vol. III, 382432. New York: Academic Press.
Nieszkowski, J. 1858. De Euryptero Remipede. (dissertation). Dorpat: Glaser.
Nieszkowski, J. 1859. Der Eurypterus remipes aus den obersilurischen Schichten der Insel Oesel. ARCH NATURKD LIVEST-KURLANDS 2, 299344.
Patten, W. 1894. On the morphology and physiology of the brain and sense organs of Limulus. Q J MICROSC SCI 35, 196.
Petrunkevitch, A. 1955. Arachnida. In Moore, R. C. (ed.) Treatise on Invertebrate Paleontology. P. Arthropoda 2, P42–P162. Lawrence, Kansas: University of Kansas & Geological Society of America.
Robinson, J. A. 1975. The locomotion of plesiosaurs. NEUES JAHRB GEOL PALAEONTOL ABH 149, 286332.
Rosenheim, O. 1905. Chitin in the carapace of Pterygotus osiliensis, from the Silurian rocks of Oesel. PROC R SOC LONDON B 76, 398400.
Savory, T. H. 1964. Arachnida. London: Academic Press.
Schenke, G. 1963. Untersuchungen zum Bau und zur Funktion der Schwimmenextremitaten von Corixa punctata Illig. ENTOMOL BER 1, 8392.
Schenke, G. 1965a. Die Ruderbewegungen von Corixa punctata Illig. (Cryptocerata). INT REV GESTAMTEN HYDROBIOL 50, 7384.
Schenke, G. 1965b. Schwimmgeschwindigkeit, Schlagfrequenz und Steuern von Corixa punctata Illig. ZOOL ANZ 176, 512.
Schenke, G. 1965c. Zu einigen morphologischen Voraussetzungen des Schwimmens von Corixa punctata Illig. 1807 (Hemiptera, Heteroptera). WISS Z PAEDAGOG HOCHSCH POTSDAM 9, 399408.
Schenke, G. 1965d. Schwimmhaarsystem und Rudern von Notonecta glauca. Z MORPHOL OEKOL TIERE 55, 631–40.
Schmidt, F. 1883. Die Crustaceenfauna der Eurypterenschichten von Rootzikiill auf Oesel – Miscellanea silurica III. MEM ACAD SCI ST PETERSBOURG 31, 2885.
Schrenk, A. 1854. Uebersicht des oberen silurischen Schichtensystems Liv- und Esthlands, vornahmlich ihrer Inselgruppe. ARCH NATURKD LIV- EST- KURLANDS 1, 1112.
Shelton, R. G. J. & Laverack, M. S. 1968. Observations on a redescribed crustacean cuticular sense organ. COMP BIOCHEM PHYSIOL 25, 1049–59.
Smith, B. P. & Barr, D. 1977. Swimming by the water mite Limnochares americana Lundblad (Acari, Parasitengona, Limnocharidae). CAN J ZOOL 55, 2050–9.
Spirito, C. P. 1972. An analysis of the swimming behavior of the portunid crab Callinectes sapidus. MAR BEHAV PHYSIOL 1, 261–76.
Stockton, W. L. & Cowen, R. 1976. Stereoscopic vision in one eye: paleophysiology of the schizochroal eye of trilobites. PALEOBIOLOGY 2, 304–15.
Størmer, L. 1934. Merostomata from the Downtonian sandstone of Ringerike, Norway. SKR NOR VIDENSK-AKAD MATNATURVIDENSK KL 1933 10, 1125.
Størmer, L. 1936. Eurypteriden aus den Rheinischen Unterdevon. ABH PREUSS GEOL LANDESANST 175, 174.
Størmer, L. 1938. Ewypterus fischeri in Ludlow beds (9d) at Ringerike. NOR GEOL TIDSKR 18, 6970.
Størmer, L. 1944. On the relationships and phytogeny of fossil and Recent Arachnomorpha. (A comparative study on Arachnida, Xiphosura, Eurypterida, Trilobita, and other fossil Arthropoda). SKR NOR VIDENSK-AKAD MATNATURVIDENSK KL 1944 5, 1158.
Størmer, L. 1955. Merostomata. In Moore, R. C. (ed.) Treatise on Invertebrate Paleontology. P. Arthropoda 2, P1–P41. Lawrence, Kansas: University of Kansas & Geological Society of America.
Størmer, L. 1963. Gigantoscorpio willsi, a new scorpion from the Lower Carboniferous of Scotland and its associated preying microorganisms. SKR NOR VIDENSK-AKAD MATNATURVIDENSK KL 1963 8, 1171.
Størmer, L. 1972. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 2: Xiphosura. SENCKENBERGIANA LETHAEA 53, 129.
Størmer, L. 1973. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 3: Eurypterida, Hughmilleriidae. SENCKENBERGIANA LETHAEA 54,119205.
Størmer, L. 1974. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 4: Eurypterida, Drepanopteridae, and other groups. SENCKENBERGIANA LETHAEA 54, 359451.
Størmer, L. 1976. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 5: Myriapoda and additional forms, with general remarks on fauna and problems regarding invasion of land by arthropods. SENCKENBERGIANA LETHAEA 57, 87183.
Størmer, L. 1980. Sculpture and microstructure of the exoskeleton in chasmopinid and phacopid trilobites. PALAEONTOLOGY 23, 237–71.
Størmer, L. & Kjellesvig-Waering, E. N. 1969. Sexual dimorphism in eurypterids. In Westermann, G. E. G. (ed.) Sexual Dimorphism in Fossil Metazoa and Taxonomic Implications. International Union of Geological Sciences Ser. A, No. 1, 201–14. Stuttgart: Schweizerbart.
Tarasoff, F. J., Bisaillon, A., Pierard, J. & Whitt, A. P. 1972. Locomotory patterns and external morphology of the river otter, sea otter and harp seal. CAN J ZOOL 50, 915–31.
Tobien, H. 1937. Uber Sinneshaare bei Pterygotus (Erettopterus) osiliensis Schmidt aus dem Obersilur von Oesel. PALAEONTOL Z 19, 254–66.
Vachon, M. 1945. Remarques sur les appendices du prosoma des Limules at leur arthrogenese. ARCH ZOOL EXP GEN 84, 271300.
Vascautanu, T. 1932. Formatiunile Siluriene din Malul Romanesc al Nistrului (Contributiuni al Cunoasterea Paleozoicului din Basinul Moldo-podolic). ANU INST GEOL ROM 15, 425663.
Versluys, J. & Demoll, R. 1923. Das Limulus-Problem. Die Verwandtschaftsbeziehungen der Merostomen und Arachnoiden unter sich und mit anderen Arthropoden. ERGEB FORTSCHR ZOOL 5, 67388.
Walker, W. F. 1971. Swimming in sea turtles of the family Cheloniidae. COPEIA 1971, 229–33.
Ward, D. V. 1969. Leg extension in Limulus. BIOL BULL MAR BIOL LAB WOODS HOLE 136, 288300.
Warner, G. F. 1977. The Biology of Crabs. London: Elek Science.
Waterston, C. D. 1964. Observations on pterygotid eurypterids. TRANS R SOC EDINBURGH 66, 933.
Waterston, C. D. 1979. Problems of functional morphology and classification in stylonuroid eurypterids (Chelicerata, Merostomata), with observations on the Scottish Silurian Stylonuroidea. TRANS R SOC EDINBURGH 70, 251322.
Whittington, H. B. 1975. Trilobites with appendages from the Burgess Shale, Middle Cambrian, British Columbia. FOSSILS AND STRATA 4, 97136.
Whittington, H. B. 1980. Exoskeleton, moult stage, appendage morphology, and habits of the Middle Cambrian trilobite Olenoides serratus. PALAEONTOLOGY 23, 171204.
Wills, L. J. 1965. A supplement to Gerhard Holm's “Uber die Organisation des Eurypterus fischeri Eichw”.with special reference to the organs of sight, respiration and reproduction. ARK ZOOL 18, 93145.
Wyse, G. A. & Dwyer, N. K. 1973. The neuromuscular basis of coxal feeding and locomotory movements in Limulus. BIOL BULL MAR BIOL LAB WOODS HOLE 144, 567–79.
Zug, G. R. 1971. Buoyancy, locomotion, morphology of the pelvic girdle and hindlimb and systematics of cryptodiran turtles. MISC PUBL MUS ZOOL UNIV MICHIGAN 142, 198.


Functional morphology of the prosoma of Baltoeurypterus tetragonophthalmus (Fischer) (Chelicerata: Eurypterida)

  • Paul A. Selden (a1)


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