{"title":"The ultimate Pulchelliidae (Ammonoidea, upper Barremian)","authors":"Didier Bert , Stéphane Bersac","doi":"10.1016/j.annpal.2024.102663","DOIUrl":null,"url":null,"abstract":"<div><p>Pulchelliidae are one of the most important ammonite groups for the Barremian biostratigraphy, and its last species <em>Gerhardtia provincialis</em> was deemed to be an end of lineage with no descendants. However, presence of Pulchelliidae was mentioned several times in levels clearly assigned to the <em>Hemihoplites feraudianus</em> Interval Horizon, while this family was deemed to be extinct in the <em>G.</em> <em>provincialis</em> Subzone; these specimens have never been depicted or described. The description of the both two antidimorphs of <em>Gerhardtia ultima</em> sp. nov., discovered in several sections of southeastern France, fills this gap. In terms of evolution, this ultimate species continues the channeling initiated by <em>Gerhardtia sartousiana</em> and <em>G.</em> <em>provincialis</em> with the setting up of the over deepening of the ventral furrow, which widens in order to occupy its entire width between the peripheral structures in <em>G.</em> <em>ultima</em> sp. nov. In parallel, the peripheral structures are attenuated, the ornamentation disappears on the flanks, and the adult size decreases together with the wide opening of the umbilicus. This hyper-paedomorphic tendency (neoteny and progenesis) occurs suddenly at the end of the lineage, at the same time <em>G.</em> <em>ultima</em> sp. nov. is under dramatic quantitative rarefaction, announcing the complete and definitive disappearance of the Pulchelliidae.</p></div>","PeriodicalId":50780,"journal":{"name":"Annales de Paleontologie","volume":"110 2","pages":"Article 102663"},"PeriodicalIF":1.0000,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Annales de Paleontologie","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0753396924000028","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PALEONTOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Pulchelliidae are one of the most important ammonite groups for the Barremian biostratigraphy, and its last species Gerhardtia provincialis was deemed to be an end of lineage with no descendants. However, presence of Pulchelliidae was mentioned several times in levels clearly assigned to the Hemihoplites feraudianus Interval Horizon, while this family was deemed to be extinct in the G.provincialis Subzone; these specimens have never been depicted or described. The description of the both two antidimorphs of Gerhardtia ultima sp. nov., discovered in several sections of southeastern France, fills this gap. In terms of evolution, this ultimate species continues the channeling initiated by Gerhardtia sartousiana and G.provincialis with the setting up of the over deepening of the ventral furrow, which widens in order to occupy its entire width between the peripheral structures in G.ultima sp. nov. In parallel, the peripheral structures are attenuated, the ornamentation disappears on the flanks, and the adult size decreases together with the wide opening of the umbilicus. This hyper-paedomorphic tendency (neoteny and progenesis) occurs suddenly at the end of the lineage, at the same time G.ultima sp. nov. is under dramatic quantitative rarefaction, announcing the complete and definitive disappearance of the Pulchelliidae.
期刊介绍:
Créées par Marcellin Boule en 1905, les Annales de Paléontologie publient 4 numéros par an traitant des fossiles animaux et végétaux, dans tous les domaines de la paléontologie incluant :
-La Paléoanatomie-
La Paléohistologie-
La Morphologie fonctionnelle-
La Systématique-
L''Évolution-
La Paléoécologie
... et toute les contributions susceptibles d''améliorer la compréhension des organismes et des environnements éteints.