Revision of Fedekurtzia (pteridosperm) and allied
fronds from the Carboniferous of Gondwana
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1 |
División Paleobotánica, Museo de La Plata. Facultad de Ciencias Naturales y Museo, Universidad Nacional
de La Plata, Pasaje Teruggi s/no, Paseo del Bosque, B1900FWA, La Plata, Argentina |
2 |
Museo Argentino de Ciencias Naturales B. Rivadavia, CONICET, Av. Ángel Gallardo 470, C1405DJR,
Buenos Aires, Argentina |
Online publication date: 2017-12-19
Publication date: 2017-12-19
Acta Palaeobotanica 2017; 57(2): 135–151
ABSTRACT
Carboniferous foliage of Fedekurtzia argentina (Kurtz) Archangelsky from Gondwana is systematically
described and revised. The frond is reconstructed based on specimens of the late Serpukhovian–Bashkirian
Nothorhacopteris/Botrychiopsis/Ginkgophyllum flora of western Argentina, especially from the Jejenes, Tupe
and Volcán formations. The whole-frond reconstruction emphasizes the variation in pinnule shape throughout
the basal, medial and distal sections of the frond. The basalmost rachis possesses cyclopteroid pinnules grading
to pinnae with obovate to wedge-shaped pinnules at the medial section of the frond. Distal pinnae are shorter,
bearing imbricate and more dissected pinnules. Specimens from the same type locality from which F. argentina
comes, previously assigned to Triphyllopteris cuyana Leguizamón & Vega, are reassigned to F. argentina, as
well as ovuliferous and microsporangiate structures in organic connection. Two decades ago a revision of the
German Triphyllopteris genus rejected T. cuyana as representative of the taxon, and the Argentinian specimens
remained as indeterminate “triphyllopteroid” fronds. The ovulate organ Polycalyx Vega & Archangelsky is considered
to be in organic connection with vegetative fragments of F. argentina, and its cupulate character is discussed.
Pollen organs represented by multi-forked axes bearing fusiform sporangia of Rinconadia Vega are also
in organic attachment and included in the Fedekurtzia argentina reconstruction. The pollen or prepollen grains
are trilete and with granulate sculpture. The paper presents a comparison with Botrychiopsis weissiana Kurtz
emend. Archangelsky & Arrondo, which differs in its rounded and entire-margin pinnules. Similar specimens
from Australia formerly described as Rhacopteris, Sphenopteridium and Archaeopteris and currently included
in Fedekurtzia intermedia Rigby share morphological characters with the Argentinian species. A revision of the
Australian material is necessary to confirm synonymy. Fedekurtzia belongs to the pteridosperms based on the
reproductive organs and is here assigned to Austrocalyxaceae. Its reconstruction now constitutes one of the most
complete seed-ferns known from the Carboniferous of Gondwana.