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Pachydiscus (Pachydiscus) spp. juv. from: Ward, P.D..Kennedy, W.J.. (1993): Maastrichtian Ammonites from the Biscay Region (France, Spain) . Memoir (The Paleontological Society), Journal of Paleontology34 (Supplement to Vol. 67)(5) p. 1-58
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Anonymous: Unedited TaxonConcept data
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Subspecies Pachydiscus (Pachydiscus) spp. juv.


Alternative name:
Discussion / Comments:
Ward & Kennedy (1993):
Discussion. - Juveniles of Pachydiscus (P.) neubergicus. P. (P.) gollevillensis. P. (P.) armenicus, and P. (P.) jacquoti are initially smooth up to diameters of 12-16 mm, whereafter the first ornament to appear is feeble umbilical bullae. When crushed it is impossible to identify such specimens, which occur commonly in the Biscay sections, to species level. They can be distinguished from juvenile tetragonitids and gaudryceratids readily if bullae are present, but in their absence separation can be difficult unless coiling is clearly more evolute (as in Anagaudryceras and Saghalinites) or more involute (as in Pseudophyllites and Zelandites) or lime and/or constrictions are preserved. Occurrence. - In the Biscay sections such juveniles are found in all members.
Systematics:

38
 Ordo Ammonoidea
  Subordo Ammonitina
   Superfamilia Desmocerataceae
    Familia Pachydiscidae
     Genus Pachydiscus
      Subgenus Pachydiscus
       Subspecies Pachydiscus (Pachydiscus) spp. juv.
Synonym list:
Ward & Kennedy (1993):
1993 Pachydiscus (Pachydiscus) spp. juv. . - Ward & Kennedy : p.27 fig. 25.7
Stratigraphy - relative ages:
upper Maastrichtian - lower Maastrichtian: Ward & Kennedy (1993)
References:

Ward,P.D.. and Kennedy,W.J.. (1993):
Maastrichtian Ammonites from the Biscay Region (France, Spain) . Memoir (The Paleontological Society), Journal of Paleontology34 (Supplement to Vol. 67)(5) p. 1-58
Anonymous: Unedited TaxonConcept data
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