PHYLOGENETIC RELATIONSHIPS AND EVOLUTIONARY HISTORY OF THE PALEOGENE GENUS IGORINA THROUGH PARSIMONY ANALYSIS

Abstract

Research Article| July 01, 2011 PHYLOGENETIC RELATIONSHIPS AND EVOLUTIONARY HISTORY OF THE PALEOGENE GENUS IGORINA THROUGH PARSIMONY ANALYSIS Dario M. Soldan; Dario M. Soldan 3 1Dipartimento di Scienze della Terra “A. Desio”, Università degli Studi di Milano, via Mangiagalli 34, Milano, Italy 3Correspondence author: E-mail: dario.soldan@unimi.it Search for other works by this author on: GSW Google Scholar Maria Rose Petrizzo; Maria Rose Petrizzo 1Dipartimento di Scienze della Terra “A. Desio”, Università degli Studi di Milano, via Mangiagalli 34, Milano, Italy Search for other works by this author on: GSW Google Scholar Isabella Premoli Silva; Isabella Premoli Silva 1Dipartimento di Scienze della Terra “A. Desio”, Università degli Studi di Milano, via Mangiagalli 34, Milano, Italy Search for other works by this author on: GSW Google Scholar Andrea Cau Andrea Cau 2Museo Geologico “Giovanni Capellini”, via Zamboni 63, Bologna, Italy Search for other works by this author on: GSW Google Scholar Author and Article Information Dario M. Soldan 3 1Dipartimento di Scienze della Terra “A. Desio”, Università degli Studi di Milano, via Mangiagalli 34, Milano, Italy Maria Rose Petrizzo 1Dipartimento di Scienze della Terra “A. Desio”, Università degli Studi di Milano, via Mangiagalli 34, Milano, Italy Isabella Premoli Silva 1Dipartimento di Scienze della Terra “A. Desio”, Università degli Studi di Milano, via Mangiagalli 34, Milano, Italy Andrea Cau 2Museo Geologico “Giovanni Capellini”, via Zamboni 63, Bologna, Italy 3Correspondence author: E-mail: dario.soldan@unimi.it Publisher: Cushman Foundation for Foraminiferal Research Received: 28 Sep 2010 Accepted: 20 Jan 2011 First Online: 03 Mar 2017 Online ISSN: 1943-264X Print ISSN: 0096-1191 © 2011 Journal of Foraminiferal Research Journal of Foraminiferal Research (2011) 41 (3): 260–284. https://doi.org/10.2113/gsjfr.41.3.260 Article history Received: 28 Sep 2010 Accepted: 20 Jan 2011 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Dario M. Soldan, Maria Rose Petrizzo, Isabella Premoli Silva, Andrea Cau; PHYLOGENETIC RELATIONSHIPS AND EVOLUTIONARY HISTORY OF THE PALEOGENE GENUS IGORINA THROUGH PARSIMONY ANALYSIS. Journal of Foraminiferal Research 2011;; 41 (3): 260–284. doi: https://doi.org/10.2113/gsjfr.41.3.260 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyJournal of Foraminiferal Research Search Advanced Search Abstract The evolution of planktic foraminifera in the Paleocene–Eocene time interval is characterized by a high rate of diversification after the major extinction event observed at the Cretaceous/Paleogene boundary. An accelerated speciation rate resulted in the appearance of several new genera. Phylogenetic relationships among many of genera are still poorly understood. This study investigates the origin and phylogeny of the genus Igorina, which is characterized by a thick, nonspinose and incrusted wall. Igorina appears in Subzone P3a (early late Paleocene) and disappears in Zone P11 (middle Eocene). To date, nine species have been assigned to the genus Igorina (I. pusilla, I. trichotrocha, I. tadjikistanensis, I. convexa, I. albeari, I. laevigata, I. lodoensis, I. broedermanni, and I. anapetes) based on both wall texture and morphologic similarities. However, the taxonomic identification at species level is affected by several problems, mainly those resulting from poor descriptions and illustrations of the primary type specimens of several species. This study reconstructs the phylogeny and evolution of the igorinids through cladistic analysis by applying the method of parsimony.Phylogenetic relationships of the species assigned to Igorina are determined through stratocladistic analysis by using a data matrix of 23 taxa (including key species of Acarinina), 31 morphological characters (unordered), and a stratigraphic character (ordered) mapping the first occurrence of the taxa under investigation. The matrix (Appendix 1) was processed with PAUP* 4.0b10 software by using the heuristic search option to discover the most parsimonious trees. Results suggest that I. pusilla is the first representative of the Igorina lineage, and it is followed by I. laevigata, I. convexa, and I. albeari. Morphotypes of uncertain taxonomic identification have been coded and analyzed separately as morphotypes A–F to determine their ancestor-descendant relationships and to evaluate their validity as discrete species. As the result of our analysis, two new species are formally described as I. praecarinata (= morphotype A) and I. paraspiralis (= morphotypes C, E, and F). Finally, our analysis provides evidence that I. lodoensis, I. broedermanni, and I. anapetes are more closely related to Acarinina than to Igorina and clearly belong to a different lineage. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.