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Ontogeny of the trilobite Parabolina spinulosa (Wahlenberg, 1818) from the upper Cambrian Alum Shales of Sweden

  • Euan N. K. Clarkson (a1), Cecilia M. Taylor (a1) and Per Ahlberg (a2)


The ontogeny of Parabolina spinulosa is described on the basis of material from Andrarum (Skåne) and Jämtland in Sweden. Protaspides are rare, and indifferently preserved, but well-preserved isolated tagmata and complete specimens from the early meraspid stages onwards were available for study. Whereas the ontogeny is broadly similar to that of the earlier Olenus wahlenbergi, there are subtle differences, notably in a greater spinosity from the earlier stages and a gradual, rather than a sudden, change of surface sculpture in the early holaspid. P. spinulosa at all stages of growth is much more variable than is Olenus. Meraspides have larger articulating halfrings anteriorly and the first thoracic segments are of greater sagittal length than in the adult; these were adaptations which enabled Parabolina to undergo cylindrical enrollment from an early stage.

Parabolina is considered to have arisen from the earlier genus Olenus, and on the basis of comparative ontogeny many, though not all, features of Parabolina appear to be of paedomorphic origin. These include the reduction of the preglabellar field, retention of the visual surface, position of the eyes set close to the glabella, retention of a conterminant hypostome, yoking of the librigenae, spinosity of the thorax and pygidium, more numerous glabellar furrows and reduction in number of thoracic segments. Olenus attenuatus has several features intermediate between those of earlier Olenus species and Parabolina, and the origin of the latter genus is best considered in terms of a mosaic paedomorphocline.



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Ahlgren, J. & Ahlberg, P. 1996. Olenus henningsmoeni, a new trilobite from the Upper Cambrian Olenus Zone in Västergötland, Sweden. GFF 118, 73–7.
Bergström, J. 1973. Organisation, life, and systematics of trilobites. Fossils & Strata 2, 169.
Clarkson, E. N. K. 1973. Morphology and evolution of the eye in Upper Cambrian Olenidae (Trilobita). Palaeontology 16, 735–63.
Clarkson, E. N. K. & Henry, J-L. 1973. Structures coaptatives et enroulement chez quelques Trilobites ordoviciens et siluriens. Lethaia 6, 105–32.
Clarkson, E. N. K. & Taylor, C. M. 1995a. Ontogeny of the trilobite Olenus wahlenbergi Westergård, 1922 from the upper Cambrian Alum Shales of Andrarum, Skåne, Sweden. Trans R Soc Edinburgh: Earth Sci 86, 1334.
Clarkson, E. N. K. & Taylor, C. M. 1995b. The lost world of the olenid trilobites. Geology Today 11, 147–54.
Clarkson, E. N. K. & Zhang, X. G. 1991. Ontogeny of the Carboniferous trilobite Paladin eichwaldi shunnerensis (King 1914). Trans R Soc Edinburgh: Earth Sci 82, 277–95.
Fortey, R. A. 1974. The Ordovician trilobites of Spitzbergen. 1. Olenidae. Norsk Polarinst Skr 160, 1129.
Fortey, R. A. 1990. Ontogeny, hypostome attachment and trilobite classification. Palaeontology 33, 529–76.
Henningsmoen, G. 1957. The trilobite family Olenidae. Skr Nor Vidensk Akad Oslo 1. Mat-Naturv Kl 1, 1303.
Henningsmoen, G. 1975. Moulting in trilobites. Fossils & Strata 4, 197200.
Henry, J-L. & Clarkson, E. N. K. 1975. Enrollment and coaptations in some species of the Ordovician trilobite genus Placoparia. Fossils & Strata 4, 8795.
Hoffmann, A. & Reif, W. E. 1994. Rudolf Kaufmann's work on iterative evolution in the Upper Cambrian trilobite genus Olenus: A reappraisal. Paläont Z 68, 7187.
Hu, Chung-hung. 1971. Ontogeny and sexual dimorphism of Lower Palaeozoic trilobites. Paleontogr Am 7, 31155.
Hughes, N. C. 1994. Ontogeny, intraspecific variation, and systematics of the late Cambrian trilobite Dikelocephalus. Smithsonian Contrib Paleobiol 79, 189.
Karis, L. & Larsson, K. 1982. Jämtland road-log. In Bruton, D. L. & Williams, S. H. (eds) Field Excursion Guide; IV International Symposium on the Ordovician System, 64–76. Paleont Contrib Univ Oslo 279, 1217.
Kaufmann, R. 1933. Variationsstatistisches Untersuchungen uber die ‘Artabwandlung’ und ‘Artumbildung’ an der Oberkambrischen Trilobitengattung Olenus Dalm. Abh Geol Paleont Inst Univ Greifswald 10, 154.
Lake, P. 1908. British Cambrian trilobites Palaeontogr Soc (Monogr), part 3 (1908), 4964.
Lindström, M. & Sturkell, E. F. F. 1992. Geology of the Early Palaeozoic Lockne impact structure, Central Sweden. Tectonophyscs 216, 169–85.
McKinney, M. L. & McNamara, K. J. 1991. Heterochrony; the evolution of ontogeny. New York: Plenum.
McNamara, K. J. 1982. Heterochrony and phylogenetic trends. Paleobiology 8, 130–42.
McNamara, K. J. 1986. The role of heterochrony in the evolution of Cambrian trilobites. Biol Rev 61, 121–56.
McNamara, K. J. & Rudkin, D. 1984. Techniques of trilobite exuviation. Lethaia 17, 153–73.
Nielsen, A. T. 1996. Iltmangel, sort slam og trilobiter—en kambrisk cocktail. Varv 1, 139.
Öpik, A. A. 1963. Early Upper Cambrian fossils from Queensland. Bur Miner Resour Aust Geol Geophys Bull 64, 1133.
Reyment, R. 1976. Biographical note of Goran (Georg) Wahlenberg. Pages 1–11 in De Rebus in Palaeontologico Museo Upsaliensi Collectis; Illustrated catalogue of the type collections of the palaeontological Museum of the University of Uppsala 3. Uppsala: Palaeontological Institute.
Rushton, A. W. A. 1983. Trilobites from the upper Cambrian Olenus Zone in central England. In Briggs, D. E. G. & Lane, P. D. (eds) Trilobites and other early arthropods: papers in honour of Professor H. B. Whittington. F. R. S. Spec Pap Palaeont 30, 107–39.
Speyer, S. & Brett, C. G. 1985. Clustered trilobite assemblages in the Middle Devonian Hamilton Group. Lethaia 18, 85103.
Størmer, L. 1942. Studies on trilobite morphology, Part II. The larval development, the segmentation and the sutures, and their bearing on trilobite classification. Nor Geol Tidsskr 21, 49164.
Wahlenberg, G. 1818. Petrifacta telluris Svecanae. Acta Societas Regiae Scientiarum 8, (1821), 1116.
Westergård, A. H. 1922. Sveriges Olenidskiffer. Sver Geol Unders Ser C 18, 1215.
Westergård, A. H. 1944. Borrningar genom Skånes Alunskiffer 1941–42. Sver Geol Unders Ser C 459, 145.
Westergård, A. H. 1947. Supplementary notes on the Upper Cambrian trilobites of Sweden. Sver Geol Unders Ser C 489, 134.
Whitworth, P. H. 1970. Ontogeny of the Upper Cambrian trilobite Leptoplastus crassicornis (Westergaard) from Sweden. Palaeontology 13, 100–11.
Whittington, H. B. 1996. Spheroidal enrolment and thoracic characters in Beltella and other olenid trilobites. Palaeontology 39, 377–88.
Wilmot, N. V. 1990. Cuticular structure of the agnostine trilobite Homagnostus obesus Lethaia 23, 8792.



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