Libristoma

Belongs within: Trilobita.
Contains: Onchonotellus, Ptychoparioidea, Ellipsocephaloidea, Asaphida, Phacopida, Olenacea, Harpina, Proetida.

The Libristoma are a clade of trilobites in which the hypostome is ancestrally not exosternally connected to the cephalic doublure (Fortey 1990). The order Ptychopariida has been recognised for basal members of this clade known from the Middle Cambrian to the Late Ordovician. However, this order is probably paraphyletic with a number of later trilobite groups, some surviving into the Devonian, derived from within the ptychopariidans (Prothero 1998).

<==Libristoma [Ptychopariida]F90
    |--PtychopariinaRC93
    |    |--PtychoparioideaP98
    |    `--EllipsocephaloideaRC93
    |--+--AsaphidaF90
    |  `--PhacopidaF90
    `--+--OlenaceaF90
       `--+--HarpinaF90
          `--ProetidaF90

Libristoma incertae sedis:
  OnchonotinidaeS80
    |--Onchonotina Lu 1961S80
    |    `--O. vigilansCT83
    `--Onchonotus Raymond 1924S80
  QuebecaspisS80
  TaenicephalusS80
    |--T. megalops Kobayashi 1938S80
    `--T. polyaricus Rosova 1963S80
  Guizhoucephalina Chien 1961S80
    `--*G. longispina Chien 1961S80
  Catillicephalidae [Catillicephalacea]SS84
    |--OnchonotellusSS84
    |--Pseudopetigurus Prantl & Přibyl 1950SS84
    `--Parahystricurus Ross 1951SS84
         `--P. oculirotundus Ross 1951F90
  AlokistocaridaeF90
    |--Elrathia kingiFO99
    `--DunderbergiaF90
         |--*D. nitida (Hall & Whitfield 1877)S80
         |--D. bigranulosa Palmer 1960S80
         |--D. brevispina Palmer 1965S80
         `--D. simplex Rasetti 1961S80
  Koldinia Walcott & Resser 1924SS84
  Wanwanaspis Kobayashi 1966SS84
  Wanwanoglobus Kobayashi 1966SS84
  Koldiniella Lermontova 1940SS84
    `--K. mitellaSS84
  PlethopeltidaeSS84
    |--Plethopeltis arbucklensisSS84, LM05
    |--Stenopilus latusSS84, LM05
    |--Leiocoryphe transversa Rasetti 1945SS84
    `--Plethometopus [Plethometopidae]SS84
         `--P. obtususLM05
  Genevieviella neunia Lochman 1936SS84
  Raashellina paula Rozova 1963SS84
  EokosovopeltisJB12
  BienvilliaF90
    |--B. coraxS80
    `--B. tetragonalisF90
         |--B. t. tetragonalisF90
         `--B. t. broeggeriF90
  Ehmaniella waptaensisF90
  Kirengina Ogienko 1974F90

*Type species of generic name indicated

References

[CT83] Chen J.-Y. & C. Teichert. 1983. Cambrian Cephalopoda of China. Palaeontographica Abteilung A: Paläozoologie—Stratigraphie 181 (1–3): 1–102.

[F90] Fortey, R. A. 1990. Ontogeny, hypostome attachment and trilobite classification. Palaeontology 33 (3): 529–576.

[JB12] Johnson, M. E., & B. G. Baarli. 2012. Development of intertidal biotas through Phanerozoic time. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 63–128. Springer.

[LM05] Lehnert, O., J. F. Miller, S. A. Leslie, J. E. Repetski & R. L. Ethington. 2005. Cambro-Ordovician sea-level fluctuations and sequence boundaries: the missing record and the evolution of new taxa. Special Papers in Palaeontology 73: 117–134.

[P98] Prothero, D. R. 1998. Bringing Fossils to Life: An introduction to paleobiology. WCB McGraw-Hill: Boston.

[RC93] Romano, M., W. T. Chang, W. T. Dean, G. D. Edgecombe, R. A. Fortey, D. J. Holloway, P. D. Lane, A. W. Owen, R. M. Owens, A. R. Palmer, A. W. A. Rushton, J. H. Shergold, D. J. Siveter & M. A. Whyte. 1993. Arthropoda (Trilobita). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 279–296. Chapman & Hall: London.

[S80] Shergold, J. H. 1980. Late Cambrian trilobites from the Chatsworth Limestone, western Queensland. Bureau of Mineral Resources, Geology and Geophysics—Bulletin 186: 1–111.

[SS84] Shergold, J. H., & K. Sdzuy. 1984. Cambrian and early Tremadocian trilobites from Sultan Dağ, central Turkey. Senckenbergiana Lethaea 65 (1–3): 51–135.