Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-27T10:28:30.610Z Has data issue: false hasContentIssue false
  • English
  • Français

Stygina, Eobronteus (Ordovician Styginidae, Trilobita): Morphology, classification, and affinities of Illaenidae

Published online by Cambridge University Press:  20 May 2016

Harry B. Whittington
Harry B. Whittington*
Affiliation:
Sedgwick Museum, Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, U.K.
Get access Rights & Permissions [Opens in a new window]

Abstract

The fulcrate thorax of Stygina has the articulating furrow and a long articulating halfring, no pleural furrow, and the facetted outer portion of the pleura has the doublure terminating outside the fulcrum. In the type species the glabella is inflated and the axial furrows partially effaced; in other species inflation is not accompanied by such effacement. Distinctions between genera of Stygininae are based on cephalic characters, including the length (sag. and exs.) of the preglabellar area; the variability of these characters makes such distinctions difficult to define. Eobronteus has the forwardly-expanding glabella, three pairs of glabellar furrows, rostral plate and hypostome typical of Siluro-Devonian Scutelluinae. The relationship between the two subfamilies is shown by morphology and by ontogeny. It is doubted that Styginidae had an origin in common with Illaenidae; the characters suggesting a relationship between Nileus and illaenids are explored. To improve the classification of Trilobita, the search for Cambrian ancestors of Ordovician families needs to be intensified, and characters of the entire axial region should be taken into account. The impendent condition of the hypostome is homeomorphic and is of less significance in classification than the natant and conterminant conditions. Effacement of axial furrows of the cephalon is a trend displayed in Stygininae, and is another homeomorphic character that is not a reliable guide to relationship.

Type
Research Article
Information
Journal of Paleontology , Volume 74 , Issue 5 , September 2000 , pp. 879 - 889
Copyright
Copyright © The Paleontological Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Adrain, J. M., and Fortey, R. A. 1997. Ordovician trilobites from the Tourmakeady Limestone, western Ireland. Bulletin of the Natural History Museum, Geology Series, 53:79–115.Google Scholar
Balashova, E. A. 1960. Trilobites of the Middle and Upper Ordovician and Lower Silurian of Eastern Taimir. Leningrad, University Publishing House, 111 p. (In Russian)Google Scholar
Bowring, S. A., and Erwin, D. H. 1998. A new look at evolutionary rates in deep time: uniting Paleontology and high-precision Geochronology. GSA Today, 8:1–8.Google Scholar
Bruton, D. L., and Williams, S. H. 1982. Field Excursion Guide, IV International Symposium on the Ordovician System. Palaeontological Contributions from the University of Oslo, 279, iii + 217 p.Google Scholar
Chatterton, B. D. E. 1971. Taxonomy and ontogeny of Siluro-Devonian trilobites from near Yass, New South Wales. Palaeontographica A, 137, 108 p.Google Scholar
Chatterton, B. D. E. 1980. Ontogenetic studies of Middle Ordovician trilobites from the Esbataottine Formation, Mackenzie Mountains, Canada. Palaeontographica A, 171:1–74.Google Scholar
Chugaeva, M. N. 1958. Ordovician trilobites of the Chu-Iliiski mountains. Trudy of the Geological Institute, Moscow, 9, 137 p. (In Russian)Google Scholar
Cooper, B. N. 1953. Trilobites from the lower Champlainian formations of the Appalachian Valley. Geological Society of America, Memoir 55, 69 p.Google Scholar
Feist, R. 1970. Breviscutellum (Meridioscutellum) n.sg. (Trilobite) et son developpement larvaire. Geobios, 3:41–73.CrossRefGoogle Scholar
Fortey, R. A. 1975. The Ordovician trilobites of Spitsbergen. 11. Asaphidae, Nileidae, Raphiophoridae and Telephinidae of the Valhallfonna Formation. Norsk Polarinstitutt, Skrifter, 162, 207 p.Google Scholar
Fortey, R. A. 1980. The Ordovician trilobites of Spitsbergen. III. Remaining trilobites of the Valhallfonna Formation. Norsk Polarinstitutt, Skrifter, 171, 163 p.Google Scholar
Fortey, R. A. 1990. Ontogeny, hypostome attachment and trilobite classification. Palaeontology, 33:529–576.Google Scholar
Fortey, R. A., and Clarkson, E. N. K. 1976. The function of the glabellar ‘tubercle’ in Nileus and other trilobites. Lethaia, 9:101–106.CrossRefGoogle Scholar
Fortey, R. A., and Chatterton, B. D. E. 1988. Classification of the trilobite Suborder Asaphina. Palaeontology, 31:165–222.Google Scholar
Gradstein, F. M., and Ogg, J. 1996. A Phanerozoic time scale. Episodes, 19:3–5.CrossRefGoogle Scholar
Ingham, J. K. 1970. The Upper Ordovician trilobites from the Cautley and Dent districts of Westmoreland and Yorkshire. Palaeontographical Society, London, Monograph, Part 1, 1–58 p.Google Scholar
Ingham, J. K., and Tripp, R. P. 1991. The trilobite fauna of the Middle Ordovician Doularg Formation of the Girvan district, Scotland, and its palaeoenvironmental significance. Transactions of the Royal Society of Edinburgh: Earth Sciences, 82:27–54.CrossRefGoogle Scholar
Kácha, P., and Šarič, R. 1991. Ontogeny of the trilobite Kosovopeltis syobodai . Šnajdr from the Bohemian Silurian. V Sestník Ústredního Ústavu Geologického, 66(5):257–273. Věstník Ustředníko.Google Scholar
Kaesler, R. L. (ed.) 1997. Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, Trilobita, Revised, volume 1. Geological Society of America and University of Kansas Press, Lawrence, 530 p.Google Scholar
Kindle, C. H. 1982. The C.H. Kindle collection: Middle Cambrian to Lower Ordovician trilobites from the Cow Head Group, western Newfoundland. Geological Survey of Canada, Current Research, Part C, Paper 82–1C, 17 p.CrossRefGoogle Scholar
Koroleva, M. N. 1984. Ordovician trilobites of the Family Scutelluidae in Kazakhstan. Paleontological Journal, 18(4):79–87. [Translation of Paleontologicheskiy Zhurnal, Nauka]Google Scholar
Lane, P. D., and Thomas, A. T. 1983. A review of the trilobite Suborder Scutelluina, p. 141–160. In Briggs, D. E. G. and Lane, P. D. (eds.), Trilobites and other early arthropods: papers in honour of Professor H. B. Whittington, F. R. S. Special Papers in Palaeontology, 30.Google Scholar
Ludvigsen, R., and Tripp, R. P. 1990. Silurian trilobites from the Northern Yukon Territory. Life Sciences Contributions, Royal Ontario Museum, Toronto, 153, 58 p.Google Scholar
Ludvigsen, R., Westrop, S. R., and Kindle, C. H. 1989. Sunwaptan (Upper Cambrian) trilobites of the Cow Head Group, western Newfoundland, Canada. Palaeontographica Canadiana, 6, 175 p.Google Scholar
Miller, J. 1975. Structure and function of trilobite terrace lines. Fossils and Strata, 4:155–178.Google Scholar
Moberg, J. C., and Segerberg, C. O. 1906. Bidrag till Kännedomen om Ceratopygeregionen. Lunds Universitets Årsskrift, new series 2(2):113 p.Google Scholar
Moore, R. C. 1959. Treatise on Invertebrate Paleontology, Part O, Arthropoda 1. Geological Society of America and University of Kansas Press, Lawrence, 560 p.Google Scholar
Morris, S. F. 1988. A review of British trilobites, including a synoptic revision of Salter's monograph. Palaeontographical Society, London, no. 574, 316 p.Google Scholar
Morris, S. F., and Tripp, R. P. 1986. Lectotype selections for Ordovician trilobites from the Girvan District, Strathclyde. Bulletin of the British Museum (Natural History), Geology Series, 40:161–176.Google Scholar
Nielsen, A. T. 1995. Trilobite systematics, biostratigraphy and palaeoecology of the Lower Ordovician Komstad Limestone and Huk Formations, southern Scandinavia. Fossils and Strata, 38:1–374.Google Scholar
Owen, A. W. 1981. The Ashgill trilobites of the Oslo region, Norway. Palaeontographica, Abteilung A, 175:1–88.Google Scholar
Owen, A. W., and Bruton, D. L. 1980. Late Caradoc-early Ashgill trilobites of the central Oslo region, Norway. Paleontologisk Museum, Oslo, 62 p.Google Scholar
Palmer, A. R. 1968. Cambrian trilobites of East-Central Alaska. U.S. Geological Survey, Professional Paper 559-B, 115 p.Google Scholar
Peel, J. S. (ed.). 1988. Stratigraphy and Palaeontology of the Holm Dal Formation (late Middle Cambrian) central North Greenland. Meddelelser om Grønland. Geoscience 20, 168 p.Google Scholar
Prantl, F., and Pribyl, A. 1949. Some new or imperfectly known Ordovician trilobites from Bohemia. Bulletin international de l'Acadèmie tchèque des Sciences, 49(8):1–23.Google Scholar
PŘibyl, A., and Vaněk, J. 1972. Studie über die Familie Scutelluidae Richter et Richter (Trilobita) und ihre phylogenetische entwicklung. Acta Universitatis Carolinae, Geologica, 4:361–394.Google Scholar
Rasetti, F. 1946. Early Upper Cambrian trilobites from western Gaspé. Journal of Paleontology, 20:442–462.Google Scholar
Rasetti, F. 1967. Lower and Middle Cambrian trilobite faunas from the Taconic sequence of New York. Smithsonian Miscellaneous Collections, 152:1–111.Google Scholar
Raymond, P. E. 1937. Upper Cambrian and Lower Ordovician Trilobita and Ostracoda from Vermont. Geological Society of America Bulletin, 48:1079–1146.CrossRefGoogle Scholar
Reed, F. R. C. 1904. The Lower Palaeozoic trilobites of Girvan, Part 2. Palaeontographical Society, London, Monograph, 58:49–96.CrossRefGoogle Scholar
Reed, F. R. C. 1928. Notes on the Bronteidae [= Gołdiidae]. Annals and Magazine of Natural History, Series 10, 1:49–78.CrossRefGoogle Scholar
Richter, R., and Richter, E. 1955. Scutelluidae n. n. (Tril.). Senckenbergiana Lethaea, 36:291–293.Google Scholar
Richter, R., and Richter, E. 1956. Grundlagen für die Beurteilung und Einteilung der Scutelluidae (Tril.) Senckenbergiana Lethaea, 37:79–124.Google Scholar
Robison, R. A. 1964. Late Middle Cambrian faunas from western Utah. Journal of Paleontology, 38:510–566.Google Scholar
Ross, R. J. 1967. Some Middle Ordovician brachiopods and trilobites from the Basin Ranges, western United States. U.S. Geological Survey Professional Paper 523 D, 43 p.Google Scholar
Ross, R. J. 1970. Ordovician brachiopods, trilobites and stratigraphy in eastern and central Nevada. U.S. Geological Survey, Professional Paper 639, 103 p.Google Scholar
Shaw, A. B. 1966. Paleontology of northwestern Vermont. X. Fossils from the (Cambrian) Skeels Corner Formation. Journal of Paleontology, 40:269–295.Google Scholar
Sinclair, G. W. 1949. The Ordovician trilobite Eobronteus . Journal of Paleontology, 23:45–56.Google Scholar
Skjeseth, S. 1955. The Middle Ordovician of the Oslo region, Norway. 5. The trilobite family Styginidae. Norsk geologisk tidsskrift. 35:9–28.Google Scholar
Šnajdr, M. 1960. Studie o celedi Scutelluidae (Trilobitae). Rozpravy, Ústredního Ústavu Geologického, 26:1–263. (In Czech, English summary)Google Scholar
Thorslund, P. 1936. Siljansområdets brännkalkstenar och kalkindustri. Sveriges Geologiska Undersökning, C 398, 64 p. (In Swedish)Google Scholar
Tripp, R. P. 1993. Review of the trilobites from the Middle Ordovician Barr Group, Girvan District, Scotland. Transactions of the Royal Society of Edinburgh, Earth Sciences, 84:87–102.CrossRefGoogle Scholar
Vogdes, A. W. 1890. A bibliography of Palaeozoic Crustacea from 1698 to 1889. United States Geological Survey, Bulletin 63, 177 p.Google Scholar
Wahlenberg, G. 1818. Petrificata Telluris Suecanae. Nova Acta Regiae Societatis Scientiarum Upsaliensis, 8:1–116.Google Scholar
Warburg, E. 1925. The trilobites of the Leptaena Limestone in Dalarna. Bulletin Geological Institute, Upsala, 17, 446 p.Google Scholar
Webby, B. D. 1974. Upper Ordovician trilobites from central New South Wales. Palaeontology, 17:203–252.Google Scholar
Whittington, H. B. 1950. Sixteen Ordovician genotype trilobites. Journal of Paleontology, 24:531–565.Google Scholar
Whittington, H. B. 1963. Middle Ordovician trilobites from Lower Head, western Newfoundland. Bulletin of the Museum of Comparative Zoology at Harvard College, 129:1–118.Google Scholar
Whittington, H. B. 1965. Trilobites of the Ordovician Table Head Formation, western Newfoundland. Bulletin of the Museum of Comparative Zoology, Harvard University, 132:277–441.Google Scholar
Whittington, H. B. 1997. Illaenidae (Trilobita): morphology of thorax, classification, and mode of life. Journal of Paleontology, 71:878–896.CrossRefGoogle Scholar
Whittington, H. B. 1999. Siluro-Devonian Scutelluinae (Trilobita) from the Czech Republic: morphology and classification. Journal of Paleontology, 73:414–430.CrossRefGoogle Scholar