caa a22 4500 388017899 CHVBK 20180307124916.0 cr unu---uuuuu 161130e199805 xx s 000 0 eng 10.1017/S0022336000024185 doi S0022336000024185 pii (NATIONALLICENCE)cambridge-10.1017/S0022336000024185 Kulumbella and Microcardinalia (Chiastodoca) new subgenus, Early Silurian divaricate stricklandiid brachiopods from Anticosti Island, eastern Canada [Elektronische Daten] [Jisuo Jin, Paul Copper] Ribbing became an increasingly common feature of pentamerid shells, especially the family Stricklandiidae, during the later Llandovery (Early Silurian). The thin shells of stricklandiids from the Llandovery (Aeronian-Telychian) equatorial carbonate rampshelf of Anticosti Island reveal at least three ribbing designs in various genera; 1) radially arranged ribs, e.g., Costistricklandia; 2) divergent, chevron-like ribs, e.g., Ehlersella; and 3) diagonally criss-cross, mutually intersecting divaricate ribs, as in Kulumbella and Microcardinalia (Chiastodoca) new subgenus. Weakly divaricate species previously assigned to Kulumbella, Stricklandia or Microcardinalia from Anticosti Island, South China and the Baltic region, are assigned to the new subgenus Chiastodoca (type Stricklandinia salterii Billings, 1868), and they are suggested to have evolved their divaricate ribbing from smooth forms, independently from the earlier genus Kulumbella, in the same sense that radial or divergent ribbing was developed separately in a number of pentamerid and stricklandiid lineages in the late Llandovery and Wenlock. In Anticosti, the divaricate genus Kulumbella, originally described from Siberia, appeared, without a known ancestral form, in the Anticosti Basin (as K. xacta n.sp.), and became extinct equally suddenly in the upper part of the Gun River Formation (mid-Aeronian). This sudden arrival of immigrant taxa, originally appearing earlier in other areas, is matched in other brachiopod groups and corals in the Anticosti section. Weakly divaricate ribbing in Chiastodoca is characteristic of the early Telychian (Ferrum Member, Jupiter Formation), and radial ribbing is typical of the late Telychian genus Costistricklandia (Pavillon Member, Jupiter Formation). Copyright © The Paleontological Society Jin Jisuo Geology, University of Regina, Regina, Saskatchewan, Canada S4S 0A2 <jinjis@leroy.cc.uregina.ca> aut Copper Paul Earth Sciences, Laurentian University, Sudbury, Canada, P3E 2C6 aut Journal of Paleontology Cambridge University Press 72/3(1998-05), 441-453 0022-3360 72:3<441 1998 72 JPA https://doi.org/10.1017/S0022336000024185 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0022336000024185 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jin Jisuo Geology, University of Regina, Regina, Saskatchewan, Canada S4S 0A2 <jinjis@leroy.cc.uregina.ca> aut NATIONALLICENCE 700 1- Copper Paul Earth Sciences, Laurentian University, Sudbury, Canada, P3E 2C6 aut NATIONALLICENCE 773 0- Journal of Paleontology Cambridge University Press 72/3(1998-05), 441-453 0022-3360 72:3<441 1998 72 JPA CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge