Proetida - a new order of tril obites

During the course of studying early Ordovician faunas from Spits ber gen and Ireland (R.A. F.) and Lower Pala eozoic Proeti dae and Ota rionidae (R.M. O.), we were led independently to re­ examine critica lly the syste mati c position use d in the Treatise (Pa rt O) of the tr ilob it e fami­ lies Aula cop leurida e, Bathyur ida e, Celmi dae , Dimer opygidae , Glaphuridae , Otari onidae and Pro etidae , and the sub fam ily Hystr ic urina e. We now beli eve that together these families con­ stitute a majo r natu raI group of the Trilob ita -the order Proetida. In this paper we summa r­ ise the evidence for such a reor gani sation, which is based on exa mination of a wide vari ety of species of the group , and brief ly consider some asp ects of its evol ution . Vari ous inter ­ relati onship s between some of the fa

[1]  T. Crimes Organisation, life and systematics of trilobites: Jan Bergström, 1974. Fossils and Strata, 2. Universitetsforlaget, Oslo, 69 pp., 5 plates, US $9.00 , 1975 .

[2]  H. B. Whittington,et al.  Ordovician geography and faunal provinces deduced from trilobite distribution , 1972 .

[3]  C. Chamberlain CARBONIFEROUS TRILOBITES: UTAH SPECIES AND EVOLUTION IN NORTH AMERICA , 1969 .

[4]  K. Campbell,et al.  Silurian trilobites from Maine , 1967 .

[5]  J. Prentice Lower Carboniferous trilobites of North Devon and related species from northern England , 1967 .

[6]  H. B. Whittington Phylogeny and distribution of Ordovician trilobites , 1966 .

[7]  H. B. Whittington Trilobites of the Ordovician Table Head formationc western Newfoundland , 1965 .

[8]  H. B. Whittington Cordania and other trilobites from the Lower and Middle Devonian , 1960 .

[9]  T. Tjernvik On the Early Ordovician of Sweden. Stratigraphy and fauna. , 1956 .

[10]  R. Ross Additional Garden City Early Ordovician trilobites , 1954 .

[11]  Christina L. Balk Lower Ordovician Trilobites from Western Utah and Eastern Nevada , 1954 .

[12]  Teiichi Kobayashi Lower Ordovician fossils from Junee, Tasmania. , 1939 .

[13]  E. Ulrich Ordovician trilobites of the family Telephidae and concerned stratigraphic correlations , 1930 .

[14]  S. Reynolds,et al.  On the Igneous and Associated Sedimentary Rocks of the Tourmakeady District, County Mayo , 1909, Quarterly Journal of the Geological Society of London.