Lycopsids from the Upper Devonian of northern Chile with remarks on the geographical distribution of the morphogenus Haplostigma Seward

Abstract

We here present the first systematic description of Devonian plant fossils from Chile. The material was collected from the Upper Devonian El Toco Formation in the Coastal Cordillera of northern Chile. Plant fossils occur as impressions of lycopsid axes in marine turbiditic greywacke beds and comprise Haplostigma furquei (Frenguelli) Gutiérrez, Malanzania cf. nana Archangelsky, Azcuy and Wagner, and further unidentifiable remains. The biostratigraphic ranges of these taxa agree well with previous age assessments for this sequence, based on conodonts and radiometric data. Haplostigma was widely distributed in the middle-to-high latitude, cool-temperate biome of southern Gondwana, providing further evidence that Middle to Late Devonian extra-tropical floras of Gondwana were dominated by low-diversity associations of herbaceous lycopsids.

Middle Devonian herbaceous lycopsid Haplostigma from the Paraná Basin, Brazil: Taxonomy, biostratigraphy and Phytogeography

“…The stratigraphic position of the fossil plants and marine invertebrates in the Devonian of Gondwana, together with palynological data, requires further study, except perhaps for data from Argentina, Bolivia and Brazil, where a robust framework has been built over the last ten years (Di Pasquo, 2007;2013;Di Pasquo and Noetinger, 2008; Page 13 of 55 A c c e p t e d M a n u s c r i p t Di Pasquo et al, 2009;2013;Amenábar, 2009;Grahn et al, 2013). Although different fossil groups were used, the main stratigraphic range of occurrence of Haplostigma is well marked within the Eifelian-Givetian interval, as observed by Di Pasquo et al (2013) and Moisan et al (2011) (Fig. 11).…”

“…A c c e p t e d M a n u s c r i p t As observed by Moisan et al (2011), small to medium-sized, fast-growing herbaceous lycopsids were apparently very successful and well adapted to the cool-temperate climate zones at these high latitudes, where the long annual periods of darkness were probably a significant limiting factor for the development of land plants, in addition to the low winter temperatures. The only geographic barriers that may have affected the distribution and longdistance dispersal of the herbaceous lycopsid Haplostigma through Gondwana were apparently epireic seas and uplands (Edwards, 1990a;Di Pasquo et al, 2009;Pfefferkorn et al, 2014).…”

“…In turn, from the Late (Matsumura et al, 2013;. From the Givetian/Early Frasnian interval to the Famennian, the genus has also been recorded, in Argentina, in the Lólen (Cingolani et al, 2002), Chiguá (Amenábar, 2009), and Punta Negra formations (Frenguelli, 1951;1952;Peralta, 2013); in Bolivia, in the Los Monos and Iquiri formations (Di Pasquo et al, 2013); in Chile, in the El Toco Formation (Moisan et al, 2011); in South Africa, in the Upper Bokkeveld and Lower Witteberg groups (Seward, 1932;Plumstead, 1967); in Antarctica, in the Wilkins Formation (Mildenhall and Schopf, 1980), Beacon Heights Orthoquartzite (Plumstead, 1962), Aztec Siltstone (McLoughlin and Long, 1994), and Dover Sandstone (Schopf, 1968); and in Australia, in the Fiery Range Porphyry (McLoughlin and Long, 1994).…”

Histórico e evolução do conhecimento sobre a paleoflora do Devoniano na Bacia do Paraná

“…Só mais recentemente, este registro paleobotânico vem sendo reconhecido e estudado de forma sistemática na região Oeste do Gondwana (GERRIENNE et al, 2001;MILAGRES et al, 2007). Nas últimas duas décadas, as descobertas de plantas vasculares devonianas em diferentes localidades da América do Sul [Brasil (Eodevoniano, GERRIENNE et al, 2001), Uruguai (Eodevoniano, SPRECHMANN et al, 1993), Bolívia (Eo/Mesodevoniano, NOETINGER, 2008;RACHEBOEUF et al, 2012), Colômbia (Mesodevoniano, BERRY et al, 2000), Argentina (Mesodevoniano, CINGOLANI et al, 2002;Di PASQUO et al, 2009), Venezuela (Meso/Neodevoniano, BERRY & EDWARDS, 1995) e Chile (Neodevoniano, MOISAN et al, 2011)] que integravam o Gondwana Ocidental, têm aberto novas possibilidades de aprofundamento e de revisões sobre pontos importantes da história inicial da evolução dessas plantas primitivas neste continente. Por exemplo, sabe-se que, diferentemente das províncias paleofitogeográficas contemporâneas situadas nas médias a baixas latitudes (Domínios Angárico, Euramericano e Norte do Gondwana, RAYMOND et al, 1985;RAYMOND, 1987;WNUK, 1996), cujos primeiros registros datam do Neossiluriano, a flora que ocupava o Gondwana Ocidental, sobretudo na Bacia do Paraná, teve o seu início apenas no Eodevoniano.…”

“…Neste sentido, os autores têm utilizado o referido táxon como um morfogênero para caules de licófitas herbáceas com apêndices espiniformes ocorrentes no Devoniano do Gondwana (PLUMSTEAD, 1967;MCLOUGHLIN & LONG, 1994;GUTIÉRREZ, 1996;GUTIÉRREZ & ARCHANGELSKY, 1997;CINGOLANI et al, 2002;DI PASQUO et al, 2009;MOISAN et al, 2011), transformando-o em um saco de gatos taxonômico. …”