A morphological comparison of two cladopyxidacean dinoflagellates: the extant Micracanthodinium setiferum and the fossil Cladopyxidium saeptum (Dinophyceae, Gonyaulacales). (2nd January 2022)

• Record Type: Journal Article
• Authors: Mertens, Kenneth Neil; Carbonell-Moore, M. Consuelo; Gardner, Kristina
• Is Part Of: Palynology. Volume 46:Number 1(2022)
• Page Start: 1
• Page End: 17
• Publication Date: 2022-01-02
• Subjects: dinoflagellates -- partiform -- Kofoidian -- porichnion -- Paleocene -- Eocene; Palynology -- Periodicals; Paleobotany -- Periodicals; 571.8452
• DOI: 10.1080/01916122.2021.1934908
• Languages: English
• ISSNs: 0191-6122

Abstract

Abstract: Among dinoflagellates, extant cladopyxidaceans may provide a missing link to better understand the first evolutionary transformations from ancestral configurations toward the more abundant and more derived patterns in Gonyaulacales and Peridiniales. A restudy of the extant, motile-defined Micracanthodinium setiferum using plankton samples from the Indian and Atlantic oceans and the Mediterranean Sea demonstrates that the correct plate formula is Po, Pt, X, 3′ + *4′, 4a, 7′′, 7C, 4S, ?6′′′, 0p, 2′′′′. A ventral pore is found between 1′, 3′ and *4′. A restudy of the extinct, fossil-defined Cladopyxidium saeptum from the upper Paleocene of Delaware (USA), demonstrated the presence of an identical tabulation. A ventral pore (= porichnion) was positioned between *1′ and 7′′. Cladopyxidium is morphologically closer to Micracanthodinium than to Cladopyxis . Since Cladopyxidium has been extinct since the middle Eocene, it is unlikely that Micracanthodinium and Cladopyxidium have a direct biological link; the close morphological similarity between them does, however, suggest an important phylogenetic relationship between them in the evolution of cladopyxidaceans.