Skip to main content
    • Aa
    • Aa

Exceptionally preserved conodont apparatuses with giant elements from the Middle Ordovician Winneshiek Konservat-Lagerstätte, Iowa, USA

  • Huaibao P. Liu (a1), Stig M. Bergström (a2), Brian J. Witzke (a3), Derek E. G. Briggs (a4), Robert M. McKay (a1) and Annalisa Ferretti (a5)...

Considerable numbers of exceptionally preserved conodont apparatuses with hyaline elements are present in the middle-upper Darriwilian (Middle Ordovician, Whiterockian) Winneshiek Konservat-Lagerstätte in northeastern Iowa. These fossils, which are associated with a restricted biota including other conodonts, occur in fine-grained clastic sediments deposited in a meteorite impact crater. Among these conodont apparatuses, the common ones are identified as Archeognathus primus Cullison, 1938 and Iowagnathus grandis new genus new species. The 6-element apparatus of A. primus comprises two pairs of archeognathiform (P) and one pair of coleodiform (S) elements. The 15-element apparatus of I. grandis n. gen. n. sp. is somewhat reminiscent of the prioniodinid type and contains ramiform elements of alate (one element) and digyrate, bipennate, or tertiopedate types (7 pairs). Both conodont taxa are characterized by giant elements and the preservation of both crowns and basal bodies, the latter not previously reported in Ordovician conodont apparatuses. Comparison of the apparatus size in the Winneshiek specimens with that of the Scottish Carboniferous soft-part-preserved conodont animals suggests that the Iowa animals were significantly larger than the latter. The apparatus of A. primus differs conspicuously from the apparatuses of the prioniodontid Promissum from the Upper Ordovician Soom Shale of South Africa although the apparatus architecture of I. grandis n. gen. n. sp. shows some similarity to it. Based on the Winneshiek collections, a new family Iowagnathidae in Conodonta is proposed.

Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

R.J. Aldridge , D.E.G. Briggs , E.N.K. Clarkson , and M.P. Smith , 1986, The affinities of conodonts—new evidence from the Carboniferous of Edinburgh, Scotland: Lethaia, v. 19, p. 279291.

R.J. Aldridge , D.E.G. Briggs , M.P. Smith , E.N.K. Clarkson , and N.D.L. Clark , 1993, The anatomy of conodonts: Philosophical Transactions of the Royal Society, London, Series B, v. 340, p. 405421.

R.J. Aldridge , M.A. Purnell , S.E. Gabbott , and J. Theron , 1995, The apparatus architecture and function of Promissum pulchrum Kovács−Endrödy (Conodonta, Upper Ordovician) and the prioniodontid plan: Philosophical Transactions of the Royal Society of London, Series B, v. 347, p. 275291.

R.J. Aldridge , J.E. Murdock , S.E. Gabbott , and J.N. Theron , 2013, A 17-element conodont apparatus from the Soom Shale Lagerstätte (Upper Ordovician), South Africa: Palaeontology, v. 56, p. 261276.

J.A. Bauer , 1989, Conodont biostratigraphy and paleoecology of Middle Ordovician rocks in eastern Oklahoma: Journal of Paleontology, v. 63, p. 92107.

S.M. Bergström , and A. Ferretti , 2015, Conodonts in the Upper Ordovician Keisley Limestone of northern England: Taxonomy, biostratigraphical significance and biogeographical relationships: Papers in Palaeontology, v. 1, p. 132.

D.E.G. Briggs , E.N.K. Clarkson , and R.J. Aldridge , 1983, The conodont animal: Lethaia, v. 16, p. 114.

P.C.J. Donoghue , M.A. Purnell , R.J. Aldridge , and S. Zhang , 2008, The Interrelationships of ‘complex’ conodonts (Vertebrata): Journal of Systematic Palaeontology, v. 6, no. 2, p. 119153.

W. Eichenberg , 1930, Conodonten aus dem Culm des Harzes: Paläontologische Zeitschrift, v. 12, p. 177182.

D. Jensen , and H.W. Miller , 1969, A second specimen of Youngquistina mitteni from the Harding Sandstone (Ordovician) of Colorado: Transactions of the Kansas Academy of Science, v. 72, p. 527532.

J. Jin , D.A.T. Harper , L.R.M. Cocks , P.J.A. McCusland , C.M.Ö. Rasmussen , and P.M. Sheehan , 2013, Precisely locating the Ordovician equator in Laurentia: Geology, v. 41, p. 107110.

J.C. Lamsdell , D.E.G. Briggs , H.P. Liu , B.J. Witzke , and R.M. McKay , 2015b, The oldest described eurypterid: a giant Middle Ordovician (Darriwilian) megalograptid from the Winneshiek Lagerstätte of Iowa: BMC Evolutionary Biology, v. 15, 169, p. 131. DOI: 10.1186/s12862-015-0443-9.

H.P. Liu , R.M. McKay , J.N. Young , B.J. Witzke , K. McVey , and X. Liu , 2006, A new Lagerstätte from the Middle Ordovician St. Peter Formation in northeast Iowa: Geology, v. 34, p. 969972.

H.W. Miller , 1969, Youngquistina mitteni, new genus and species of Chordate from the Harding Sandstone (Ordovician) of Colorado: Transactions of the Kansas Academy of Science, v. 71, p. 504508.

H.W. Miller , J.S. Cullison , and W.L. Youngquist , 1947, Lower Ordovician fish remains from Missouri: American Journal of Science, v. 245, p. 3134.

L.C. Mosher , and F. Bodenstein , 1969, A unique conodont basal structure from the Ordovician of Alabama: Geological Society of America Bulletin, v. 80, p. 14011402.

C.M. Niocaill , B.A. van den Plum , and R. van der Voo , 1997, Ordovician paleogeography and the evolution of the Iapetus Ocean: Geology, v. 25, p. 159162.

M.A. Purnell , 1994, Skeletal ontogeny and feeding mechanisms in conodonts: Lethaia, v. 27, p. 129138.

M.A. Purnell , 1995, Large eyes and vision in conodonts: Lethaia, v. 28, p. 187188.

M.A. Purnell , P.C.J. Donoghue , and R.J. Aldridge , 2000, Orientation and anatomical notation in conodonts: Journal of Paleontology, v. 74, p. 113122.

F.H.T. Rhodes , 1953, Some British Lower Palaeozoic conodont faunas: Philosophical Transactions of the Royal Society London Series B, v. 237, p. 261334.

I.J. Sansom , M.P. Smith , and M.M. Smith , 1994, Dentine in conodonts: Nature, v. 368, p. 591.

C.R. Stauffer , 1935, Conodonts of the Glenwood beds: Geological Society of America Bulletin, v. 46, p. 125168.

T. Tolmacheva , and M. Purnell , 2002, Apparatus composition, growth, and survivorship of the Lower Ordovician conodont Paracordylodus gracilis Lindström, 1955: Palaeontology, v. 45, p. 209228.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Paleontology
  • ISSN: 0022-3360
  • EISSN: 1937-2337
  • URL: /core/journals/journal-of-paleontology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Full text views

Total number of HTML views: 3
Total number of PDF views: 41 *
Loading metrics...

Abstract views

Total abstract views: 226 *
Loading metrics...

* Views captured on Cambridge Core between 28th February 2017 - 29th March 2017. This data will be updated every 24 hours.