Nuevos Registros De Helechos Y Coníferas Del Cretácico Inferior en La Cuenca Del Valle Superior Del Magdalena, Colombia

Abstract

Forma de citar:Monje-Dussan, C., Martínez, C., Escapa, I., y Madriñán, S. 2016. Nuevos registros de helechos y coníferas del Cretácico Inferior en la cuenca del Valle Superior del Magdalena, Colombia. Boletín de Geología, 38(4): 29-42. RESUMENEn este trabajo se describen nuevos registros de la macroflora del Cretácico Inferior (Aptiano-Albiano) de Colombia. El material estudiado fue colectado en la Cuenca del Valle Superior del Magdalena en tres localidades del departamento del Tolima, en las formaciones Yaví y Caballos. Los restos fósiles comprenden especímenes de filicopsidas y coníferas. Entre los helechos se encuentra la familia Marsileaceae, un grupo importante identificado en la flora fósil ya que se propone como el primer registro de un helecho acuático para el Cretácico Inferior en Colombia. Adicionalmente, abundantes restos de frondes estériles al menos bipinnadas con pínulas lanceoladas y venación pecopteridea son asignadas al morfogénero Cladophlebis sp. Las coníferas por su parte, presentan estructuras vegetativas asociadas a estructuras reproductivas. Los ejes con hojas más frecuentes fueron asignados al morfogénero Brachyphyllum sp. mientras que las escamas ovulíferas aisladas poseen características morfológicas de tipo Araucarites sp. (Araucariaceae). En conjunto, estos hallazgos constituyen un punto clave para entender la biogeografía y evolución de estos grupos y así mismo contribuyen a ampliar el conocimiento de la flora del Cretácico en Colombia.Palabras clave: Cretácico, Colombia, Valle Superior del Magdalena, pteridofitas, gimnospermas NEW RECORDS OF FERNS AND CONIFERS FROM THE LOWER CRETACEOUS IN THE UPPER MAGDALENA VALLEY BASIN, COLOMBIA ABSTRACTDescriptions of new plant macrofossils from the Lower Cretaceous (Aptian-Albian) of Colombia are presented. The studied material was collected in the Upper Magdalena Valley Basin in three exposing levels from the Yaví and Caballos formations. The fossil remains are associated to filicopsids and conifers. Within the ferns, the family Marsileaceae, constitutes an important group identified in the fossil flora because it is proposed as the first record of aquatic ferns for the Lower Cretaceous of Colombia. Additionally, abundant sterile bipinnate fronds with lanceolate pinnule and pecopteridea venation remains were included in the morphogenus Cladophlebis sp. The studied conifers presented vegetative structures associated to reproductive organs. The most abundant sterile fragments were included within the morphogenus Brachyphyllum sp. and ovuliferous scales of Araucarites sp.(Araucariaceae) type. Together these new findings represent a key aspect to understand the biogeography of the mentioned groups and, simultaneously, contribute to the knowledge of the Cretaceous plant fossils from Colombia.

First fossil-leaf floras from Brunei Darussalam show dipterocarp dominance in Borneo by the Pliocene

“…110 Ma (latest Early Cretaceous), before India-plus-Madagascar and Africa began to separate from the remaining landmass ( e.g ., Jokat et al, 2021 ; Scotese, 2021 ). However, the literature regarding out-of-Gondwana origins for dipterocarps seems to omit that Early Cretaceous deposits have been sampled across Gondwana for decades, and no fossil dipterocarps or likely relatives have been reported from hundreds of publications (among many others, Archangelsky, 1963 ; Banerji, 2000 ; Mohr & Friis, 2000 ; McLoughlin, Pott & Elliott, 2010 ; Nagalingum & Cantrill, 2015 ; Monje-Dussán et al, 2016 ). Importantly, angiosperms in Gondwanan Early Cretaceous floras are rare, show early stages in the evolution of leaf organization and other characters, and are not allied with derived eudicot families ( Mohr & Friis, 2000 ; Cúneo & Gandolfo, 2005 ; Nagalingum & Cantrill, 2015 ; Coiro et al, 2020 ; Pessoa, Ribeiro & Jud, 2021 ).…”

New plant fossils from the Lower Cretaceous of the Parnaíba Basin, Northeastern Brazil: Southern Laurasia links

“…In South America, diversified species of Brachyphyllum were also register to the rain shadow areas of the western Andean basins, Chile to Venezuela (Berry 1922, Archangelsky 1963, Baldoni 1979, Romero et al 1995, Van Waveren et al 2002, Monje-Dussán et al 2016.…”

Reinterpretation ofPaleoazolla: a heterosporous water fern from the Late Cretaceous of Patagonia, Argentina

“…The fossil record of the water ferns indicates a past worldwide distribution and goes back to the Late Jurassic or Early Cretaceous, although the group seems to have diversified during the Late Cretaceous, at the same time as the flowering plants. Fossils with putative affinities to Marsileaceae have been recorded from the Late Jurassic or Early Cretaceous (Yamada and Kato, 2002), although most of the macrofossils remains have been recovered from Late Cretaceous deposits (Sahni and Sitholey, 1943;Chitaley and Paradkar, 1972;Banerji, 1987;Skog and Dilcher, 1992;Lupia et al, 2000;Rich et al, 2001;Nagalingum, 2007;Hu et al, 2008;Herman and Kvaček, 2010;Cúneo et al, 2013;Hermsen et al, 2013;Puebla et al, 2014;Sender et al, 2014;Sun et al, 2014;Monje Dussán et al, 2016;Vallati et al, 2017;Estrada-Ruiz et al, 2018;Hermsen, 2019). The fossil record of Salviniaceae starts later, in the Late Cretaceous, and it is mostly based on dispersed megaspores and microspore massulae, while sporophytes are scarcely recorded (Hall, 1968;Bůžek et al, 1971Bůžek et al, , 1988Sweet and Chandrasekharam, 1973;Lucas and Ducket, 1980;Melchior and Hall, 1983;Kovach and Batten, 1989;Batten and Kovach, 1990;McIver and Basinger, 1993;Hoffman and Stockey, 1994;Collinson et al, 2013;Wang et al, 2014;Vallati et al, 2017;De Benedetti et al, 2018;Hermsen et al 2019).…”