The Botrychiopsis genus and its biostratigraphic implications in Southern Paraná Basin

Botrychiopsis has been considered an important floristic element of Westphalian/Artinskian associations of the Paraná Basin. The occurrence of Botrychiopsis in roof-shales of the Rio Bonito Formation in Southern Paraná Basin (Quitéria area), supported by the identification of Botrychiopsis valida, enlarges the genus biochron. Consequently, the stratigraphic hierarchy for Botrychiopsis plantiana and Botrychiopsis valida was defined for the Paraná Basin. Although it is climatically controlled and related to a deglaciation icehouse stage, stratigraphic distribution of the genus presents a substantial climate tolerance, from cold/cool to warm/temperate conditions. A new phytostratigraphic zonation is proposed for the southern portion of the basin that includes the Botrychiopsis Zone (Asselian/Kungurian), which is subdivided into the Botrychiopsis plantiana (Asselian/Artinskian) and Botrychiopsis valida (Late Artinskian/Kungurian) subzones.

sic -Early Cretaceous and Late Cretaceous) encompass continental strata and volcanic rocks.Each megasequence corresponds to previously proposed lithostratigraphic units.
The Carboniferous -Early Triassic (CET) megasequence represents a second-order transgressive -regressive cycle.It contains a basal transgressive unit overlain by a regressive succession.The basal succession includes the Itararé Group and Rio Bonito and Palermo formations.
The synonymization of distinct taxa to this morphogenus, which is characterized by heteromorphy, took place for more than a century  during which several Earth Science paradigms were established and abandoned, from the Fixist models to Plate Tectonics.The main studies that produced the current genus conception are presented in Fig. 1.
The paleofloristic assemblages show a homogeneous composition dominated by foliar organs of plants with arborescent habit as well as remnant shrub-like plants, such as Botrychiopsis plantiana.
Shrub-like plants identified as Botrychiopsis plantiana have also been recorded in the southernmost portion of the Paraná Basin, within the Glossopteris Flora and are associated with fluvial, delta and estuarine sedimentary rocks at the base of the Rio Bonito Formation (Pasqualini et al. 1986).
In their description of the Glossopteris Flora Early Permian evolution in Southern Brazil, Guerra-Sommer et al. (1991, 2001) regarded Botrychiopsis plantiana as a remnant plant from a rigorous periglacial cold climate.
The first records of Botrychiopsis within roof-shales in Southern Paraná Basin (Quitéria area), as discussed herein, allow to infer the relationship between the biostratigraphic distribution of this genus and its tolerance to climate changes.In this case, climate change has been associated with a deglaciation phase of an icehouse period and is represented by an evolution from cool-temperate to warm-temperate climate.The validation of this hypothesis would then broaden the current parameters used to interpret the climatic conditions favorable for the development of these plants.This paper comprises the first step of a larger project that aims to evaluate the chronostratigraphic significance of the Botrychiopsis within Gondwana.It was carried out to verify earlier taxonomic and biostratigraphic descriptions of Botrychiopsis forms of the Southern Paraná Basin.This revision was required due to the reduced nature of previous descriptions, which did not define the diagnostic differences between previously identified and original material.
Forms related to Botrychiopsis have been identified in Rio Grande do Sul State in Faxinal, Base of Morro Papaléo and Quitéria outcrops (Fig. 2).
The Faxinal outcrop, described by Morgenthal et al. (1970) and later by Andreis et al. (1979), is located in the northeastern portion of the Barão do Triunfo topographic Sheet, close to the confluence of the Grande and Faxinal creeks, about 10 km westnorthwestward from the Mariana Pimentel District.
The exposure includes variable amounts of sandstone and mudstone related to the uppermost part of the Itararé Group in the Rio Grande do Sul State.It represents the westernmost exposure of a paleovalley that extends from Potreiro Grande, 4 kM eastwards from the Mariana Pimentel District.Andreis et al. (1979) recognized two informal siltstone facies (white and grayish brown siltstone facies).Isolated Rubidgea-type leaves, Botrychiopsis fronds and small platispermic seeds represent most of the quantitatively poor megafloristic association.Minor amounts of the Cordaites, Glos- sopteris, Gangamopteris and Ginkgoites genera as well as articulate stems and conifer branches are also present.
According to Andreis et al. (1979) both white and grayish brown facies represent the final filling stage of large lakes, and considered then as related to the end of the Itararé Group sedimentary cycle (Corrêa da Silva 1970 andBossi andPiccoli 1979).
According to Milani et al. (1998), these sediments correspond to lowland glaciocontinental sed-iments, deposited during the deglaciation produced by warming of a glacial climate.
The specimens hereby presented were previously studied by Guerra-Sommer et al. (1980) and Cazzulo-Klepzig and Guerra-Sommer (1983)   of long bipinnate fronds (3,9 to 8,2 cm long and 0,6 to 2,9 cm wide).They present a main robust rachis, between 0,6 cm (proximal part) and 0,2 cm (distal portion) wide, which features a solid longitudinal nervure (Fig. 3b).From the widely decurrent (Fig. 3e), separated (Fig. 3f) to slightly imbricated (Fig. 3b) rachis, minor sessile pines displaying complete limbus emanate with a somewhat acute angle of insertion (50˚a 70˚).The pines outline is subcircular and either smooth (Fig. 3f) or showing small insertions (Fig. 3a,b, and d).These insertions origi-nate their bipinnate aspect, with pines ranging from oblong and rhomboidal at their base (Fig. 3e and f) to oblong-elliptical or elliptical at their apex (Fig. 3a), being 0,4 to 3,2 cm long and 1,1 to 1,4 cm wide.These pines present an open venation, derived from the rachis nervures, which is denser at its base and that disperses along the pinnules (Fig. 3a,b,c and  d).As the nervures go along the pinnules they suffer dichotomy, which can occur twice or four times (Fig. 3a).Pinnules are strongly decurrent and the more developed ones are free down to their base and may present an asymmetrical, subcircular to slightly oblong outline.The associated microflora, composed of trilete spores (75%) and monosaccate pollen (15%), rare bisaccate and striate pollens, was related by Andreis et al. (1979) to the H1/H2 biostratigraphic interval of Daemon and Quadros (1970).It corresponds to the upper part of the Potonieisporites-Lundbladispora Zone proposed by Archangelsky and Marques-Toigo (1978) for the Chaco-Paraná Basin (Argentina).According to Andreis et al. (1979), this interval is equivalent to either the Stephanian C -Sakmarian boundary or, according to Faddeieva (1976), to the base of the Asselian in Russia.
The outcrop Base Morro Papaléo is situated in the Barão do Triunfo topographic sheet (SH-22-0-1-2), 8 Km northwestward of Mariana Pimentel.It is located in a ravine on the lower part of the southwestern border of the Morro Papaléo (UTM 0438317 E and 6647584 N).
This outcrop, described by Pasqualini et al. (1986), comprises an alternation of carbonaceous, fossiliferous siltstone, mica-rich, fine-grained sandstone, lenticular, coarse-grained sandstone and conglomerate, and sandstone exhibiting iron-rich concretions.Plane bedded siltstone and sandstone and cross-bedded sandstone are common sedimentary features.Pasqualini et al. (1986) related the fossiliferous beds to the bottom of efemerous water bodies associated with the margins of interdistributary lakes.
Some specimens formerly described by Pasqualini et al. (1986) were analyzed herein, as well as others stored in the Paleobotanic Sector of the Earth Science Institute at UFRGS.The samples comprise basal and medial-basal fragments of elongated and bipinnate fronds (3,8 to 9,0 cm long and 0,6 to 7,9 cm wide).They present a robust main rachis, with strong longitudinal nervures, which can be 0,9 cm wide at its proximal portion and disperse at the more distal pines (Fig. 3b).In a subordinate way, and showing somewhat acute insertion angles (50˚to 70˚), sessile, widely decurrent to pseudopetiolate pines emanate from the rachis.They change from isolated to slightly imbricated, show complete limbus, and can either present or lack insertions on their borders, therefore producing their bipinnate aspect.
The pines from the medial-basal portions of the fronds are rather imbricated and change from extensively decurrent to pseudopetiolate.They present either an elliptical-elongated or oblong-elliptical outline that can display slight to strong insertions on their borders.In this latter case a bipinnate morphology is produced and the lobes correspond to the pinnules.The pine length spans from 0,7 to 5,4 cm and their width between 0,9 and 2,8 cm.They present an open venation, derived from the rachis nervures, which is denser at its base and more disperse along the pinnules.As the nervures go along the pinnules they suffer dichotomy, from twice to four times.The pinnules are strongly decurrent and the more developed ones are free down to their base.They always present an asymmetrical outline that can be subcircular to slightly oblong (Fig. 3).
One of the samples (PB 2575), previously described by Guerra-Sommer et al. (1986), presents the central axis of the plant perpendicularly positioned relative to the bedding planes and from which four fronds radiate (3,3 cm long and 1,8 cm wide)  Cienc (2003) 75 (4) and a rachis (0,6 cm wide) with strong longitudinal nervures.From the rachis subaltern, separated, sessile, extensively decurrent pines emanate, exhibiting entire limbus, slightly acute insertion angles (50˚a 70˚) and a reniform morphology.These pines are 0.6 cm long and 1.3 cm wide and show venation derived for the rachis nervures.Venation is open, denser at its base (dispersing towards the apex) and can dichotomize twice to three times.

An Acad Bras
Samples from Base of Morro do Papaléo lack spores and pollen probably due to non-preservation.
The Quitéria outcrop is located in the Pantano Grande County (Rio Grande do Sul State), in the southeastern border of the Paraná Basin (UTM 0387516 E and 6643183 N).It is about 130 km from Porto Alegre, along the BR 290 freeway, and can be localized in the Quitéria topographic sheet (SH22-NH).It comprises a sedimentary package about 8 meters thick, characterized by the intercalation of carbonaceous shale, argillite, fine-to coarse-grained sandstone, matrix-supported (silty to sandy) conglomerate and thin, up to 25 cm thick coal beds.
The fronds are preserved in a light-yellow, finegrained sandstone bed (45 cm thick) that exhibits plane bedding and is situated immediately above a carbonaceous argillite bed.Both horizontal and insitu lycophyte stems (Brasilodendron) occur in association with this level, as well as Coniferophyta, Cordaites, Filicophyta and scattered fragments of glossopterids (Rubidgea sp. and Glossopteris sp.).Piccoli et al. (1991) related the sedimentary succession to a delta system dominated by lowenergy fluvial processes, with well-developed alluvial plain facies and peat-forming swamps in the interdistributary lowlands.
The samples are stored in the Botany and Paleobotany Sector of the UNIVATES Natural Sciences Museum and in the Paleobotany Sector of the DPE/UFRGS.
The samples from Quitéria include basal and medial-basal fragments of elliptical, elongated and bipinnate fronds (3,5 to 11,6 cm long and 0,4 to 5,1 cm wide).They present a robust main rachis (0,1 to 0,9 cm thick) that encompasses strong longitudinal nervures (Fig. 4 and Fig. 5a) from which sessile pines in a sub-opposite trend emanate with slightly acute insertion angles (60˚to 80˚).These pines are decurrent to extensively decurrent, separated to slightly imbricated, and present complete limbus, with (bipinnate morphology) or without insertions on their borders.
The pines of the medial-basal portions of the fronds are slightly imbricated and vary from decurrent (Fig. 6b) to extensively decurrent (Fig. 6a).They present an elliptical or elliptical-elongated outline and can present insertions (bipinnate morphology) on their borders (Fig. 6d).Their lengths vary from 0,5 to 5,0 cm and their width from 0,7 to 2,8 cm.These pines display an open venation, derived from the rachis nervures, which is denser at its basal and central portions and disperses along the pinnules.As the nervures go along the pinnules they dichotomize twice to four times (Fig. 4 and Fig. 6).Pinnules are strongly decurrent and the more developed ones are free down to their base, presenting a subcircular to elliptical-elongated outline.
A palynological study on samples collected in    Due to the predominance of species related to Zonati and Cingulicavati spores the palynoflora is comparable, in the Paraná Basin, to the microfloristic association identified in the Candiota Superior and Banco Louco beds in the Candiota Coalfield by Meyer (1999).
Among the spore-pollinnic associations proposed by Marques-Toigo and Corrêa da Silva (1984) for the coal measures of the Rio Grande do Sul State, this type of palynoflora is comparable to the Puntatisporites, Lundbladispora and Portalites Association, which is related to plants of hydrophylous to hygrophilous environments.
In terms of biostratigraphy, the microflora identified in the Candiota Upper Coal Seams was included in the Caheniasaccites ovatus Zone of Marques-Toigo (1988) -Artinskian/Kungurian.Based on isotopic dating of tonstein beds interbedded in the coal seams, Cazzulo-Klepzig (2001) linked this zone to Late Kungurian/Early Roadian age.

TAXONOMIC AFFINITIES
In this chapter, the taxonomic affinities of the previously described material (Faxinal, base of the Morro Papaléo and Quitéria) are re-evaluated.
The Eusphenopteris Novik (1947) genus is characterized by a bipinnate frond, with alate rachis and alternated pines.These pines show a poorly defined rachis as the pinnule limbus presents decurrent spreading.Pinnules are trilobate and deeply incised, with an open, dichotomized venation that arises from a central nervure starting from the rachis.Within Carboniferous Gondwana successions these forms have been considered intermediate between Botrychiopsis and Dactylophylum (Zampirolli 2001).In Western Gondwana this genus was recorded by Cúneo (1990), in the Mojón de Hierro Formation (Upper Paleozoic Tepuel Group), Arroyo Garrido area (Chubut Province of Argentina).It was also found by Zampirolli (2001), in the Santa Marta Farm (Itapeva region in the São Paulo State), within Neo-Carboniferous interglacial rocks (Itararé Subgroup of the Paraná Basin).
Among the main features of the Eusphenopteris genus are its tripinnate frond with trilobate pinnules, deeply incised margins and subtriangular outline, showing an open and dichotomized venation that arises from a single and thick nervure going into the pinnules from the rachis.Although presenting an open and dichotomized venation in the pinnules, the studied material does not show all other features of the Eusphenopteris genus.
The morphology of the analyzed material points towards the Botrychiopsis (Kurtz) Archangelsky and Arrondo (1971).
A review of Paleozoic fronds related to Botrychiopsis, taking into account not only morpho-logical and taxonomic data, but also stratigraphic implications, was presented by Archangelsky and Arrondo (1971).The authors, based on Argentinean material and relating it to Gondwana and extra-Gondwana data, confirmed Kurtz's (1895a, b) original interpretations.A new diagnosis was defined and the concepts of frond, pines and pinnules were reviewed.Furthermore, descriptive features diagnostic of the following three species were presented: Botrychiopsis weissiana (Kurtz) Archangelsky and Arrondo (1971), Botrychiopsis plantiana (Carruthers) Archangelsky and Arrondo (1971) and Botrychiopsis valida (Feistmantel) Archangelsky and Arrondo (1971), the latter only compared with the Upper Paleozoic of India.According to Archangelsky and Arrondo (1971) the different species present a wide geographic distribution and clear chronostratigraphic boundaries that allow some phylogenetic assumptions in terms of an ascendancy of Botrychiopsis weissiana in relation to Botrychiopsis plantiana, and of this one to Botrychiopsis valida.Cúneo (1990) confirms the genus features pointing out that the pines are arranged in a slightly subopposite way, with a rachis that goes to the base of the apical pinnule.Furthermore, pines are lobate with deccurent insertions, its venation is open and can be dichotomized up to three times.
In this study, both generic and specific propositions of Archangelsky and Arrondo (1971) are accepted.A pteridophytic or pteridospermic affinity has been proposed for this genus.
Considering the original diagnosis of Kurtz (1895a,b), emended by Archangelsky and Arrondo (1971), Botrychiopsis weissiana presents some features that were not seen in the studied samples of the Faxinal and Base of Morro Papaléo outcrops.The morphological characters of Botrychiopsis weissiana include an alate basal portion of the frond, a twisted insertion of the pines with a pronounced imbrication, and an ovoid-spatulated morphology of the frond apical pinnule.
Similarly, it is not possible to correlate the studied samples with Botrychiopsis valida.In Feistmantel's (1879) previous description, also emended by Archangelsky and Arrondo (1971), this species presents divided basal frond pinnules, confluent along the entire frond and presenting subrhombic morphology with sinuous margins.These characteristics are not present in the studied samples.
The main morphological features of this material are apical, medial and medial-basal fragments of the pines.The pines have long and bipinnate fronds presenting a robust main rachis that can disperse in the distal pines.The rachis presents strong longitudinal nervures from which minor sessile pinnules radiate displaying slightly acute insertion angles (50˚to 70˚).The pinnules are generally decurrent to pseudopetiolate, separated to slightly imbricated, presenting entire limbus with or without insertions on their borders.They may assume a sublobate morphology, from rhomboidal, rhomboidal-ovaled or rhomboidal-elongated to elliptical, ellipticalelongated or oblong-elliptical morphology.They present an open venation derived from the rachis nervures, which is denser at their base and disperse along their limbus, which can dichotomize twice to four times.These elements link this material to Botrychiopsis plantiana (Archangelsky and Arrondo 1971).
This conclusion is reinforced by comparative analysis of the samples discussed herein and the specimens shown by Archangelsky and Arrondo (1971, Slide V, Fig. 1 and 2, Slide VI, Fig. 1, 2 and 3) and their diagnoses.

Botrychiopsis valida
The Quitéria frond samples were not correlated to Botrychiopsis weissiana due to the lack of some critical morphological features, such as the basal portion of the alate frond, the twisted insertion of the pines displaying heavily delineated imbrication and the ovoid-spatulated morphology of the frond apical pinnules.
On the other hand, the Quitéria forms can not be associated with Botrychiopsis plantiana due to An Acad Bras Cienc (2003) 75 (4) the absence of characteristics such as the connected to slightly imbricate pinnules of the frond base and the spatulate shape with the rounded distal margin of the apical pinnules.
The pines and pinnules morphology along the fronds supports the identification of the Quitéria material with Botrychiopsis valida.Among the main features used for its identification the presence of a robust and well-defined main rachis can be considered, with solid longitudinal nervures, from which subopposite sessile pinnules emanate with slightly acute insertion angles (60˚to 80˚).These pinnules are extensively decurrent to decurrent, separated to slightly imbricated, and have entire limbus presenting, or not, insertions on their borders.
Furthermore, the decurrent aspect of the separated basal pines, with rhomboidal, elongaterhomboidal or reniform outline, are very similar to the material previously related to Botrychiopsis plantiana by Gould (1975, Fig. 3C and D) and later on to Botrychiopsis valida by Retallack (1980).
Some other aspects also evidence the association of the specimen hereby analyzed to Botrychiopsis valida, largely by comparison with the material described and synonymized by Archangelsky and Arrondo (1971) as well as that identified by Rigby (1973), Anderson and Anderson (1985), Gould (1975), Retallack (1980) and Rayner (1995).Among these evidences, the presence of slightly imbricate, highly decurrent to decurrent pinnules with elliptical or elongated-elliptical outline and sub-lobate border insertions was observed.The pinnules present an open venation, derived from the rachis nervures, denser at their basal and central portions and dispersing along the upper portions of the pinnules, which dichotomize twice to four times (similar to the basal pinnules).
Even so, in this paper the designation Botrychiopsis valida is maintained in accordance with Archangelsky and Arrondo (1971) criteria.
According to Archangelsky and Arrondo (1971), the description of distinct biocrons for the species of the Botrychiopsis genus highlights not just its phylogenetic relationship but also its chronostratigraphic importance.The phylogenetic associations come from the Botrychiopsis weissiana and Botrychiopsis plantiana sequential record within Argentinean Gondwana associations.Forms related to Botrychiopsis valida would also be descended from Botrychiopsis weissiana developed in distant areas, hence differentiating from the Western Gondwana coeval forms.Based on these evidences and the inferences of Gothan and Sahni (1937), it seems that the group development occurred from an ancestral stock identified in Peninsular India and Australia Namurian successions.
However, some aspects of this evidence, such as the presence of Botrychiopsis weissiana and Botrychiopsis plantiana as coeval elements within Argentinean Paleozoic floras (Archangelsky and Azcuy 1985), suggest the need of re-evaluating presupposed phylogenetic relations.Although these data support the idea that the specific relations should be reviewed, studies on distinct basins have confirmed the stratigraphic importance of the different morpho-species.
In a first inference to the Botrychiopsis chronostratigraphic impact Archangelsky and Arrondo (1971) indicated a time span from Upper Carboniferous (Westphalian) to Lower Permian (Artinskian) for the genus.The Botrychiopsis weissiana biochron was restricted to the Carboniferous System (Tupense local age -Westphalian/Stephanian of Western Europe).This geochronological position was corroborated by marine invertebrates (Antelo 1972) and palynology (Menéndez 1965).
Botrychiopsis plantiana is linked to the earliest Conifers and Ginkgoales occurrences in the Trampeadero and Libertad formations (Paganzo Basin), in Upper Carboniferous sequences of Trampeaderense local age.
The record of Botrychiopsis plantiana in the Nueva Lubecka Formation, referred to the Lubekense A/B (Sakmarian/Artinskian), according to palynological and marine invertebrates (Antelo 1972), is considered as a Carboniferous relict.Archangelsky and Arrondo (1971) considered Botrychiopsis valida as exclusive to Indian successions (Kaharbari Formation).The age interval was attributed to the Artinskian through the analysis of marine invertebrates (Robison 1967), hence comprising the youngest species of the genus (Archangelsky and Arrondo 1971).
In an attempt to characterize a Pre-Glossopteris Flora for Upper Paleozoic successions of the Northern Paraná Basin (Monte Mor outcrop -Itararé Group, São Paulo State), Millan (1975Millan ( , 1979) ) pointed out Botrychiopsis plantiana as the diagnostic element.A Westphalian/Stephanian age was proposed for the succession based on palynological data (Trindade 1970).According to Iannuzzi (pess. comm. 2002), however, from the analysis of the An Acad Bras Cienc (2003) 75 (4) available type-material studied by Millan (1975Millan ( , 1979)), which is now kept in the Museu Nacional (UFRJ), it is impossible to establish the specific affinity of the material.Therefore, the specimens described by Millan (1975Millan ( , 1979) ) remain here termed Botrychiopsis sp.
On the informal phytostratigraphic zonation of the Late Paleozoic Paraná Basin, Rösler (1978) recorded the presence of Botrychiopsis plantiana in Taphoflora A, relating it to the early stages of deglaciation in the Paraná Basin (Sakmarian/ Artinskian).Andreis and Archangelsky (1996), in a review of the Neopaleozoic basins of South America, related the Taphoflora A to a probable Stephanian age, taking into account the lack of the Glossopteris genus.According to Guerra-Sommer and Cazzulo-Klepzig (1981) the Itararé Group taphoflora in the Rio Grande do Sul State, including Botrychiopsis plantiana, can be related to the Cerquilho (Taphoflora A and B of Rösler 1978) and Argentinean Bajo de Veliz (Lubekense A) taphoflora.
Studies of Millan (1987a) on the megafloristic association of coal-bearing strata from Itapeva (São Paulo State) -the Santa Marta Flora of the Itararé Group -record a large amount of Botrychiopsis plantiana fronds and subordinate Sphenopsida (Paracalamites, Sphenophyllum), Cordaitales (Cordaites) and platispermics seeds (Cordaicarpus).An Itapevense local age was indicated for this association.
In an attempt to define floristic stages for coalbeds of the Itararé Group, Millan (1987b) 1980).This taphoflora is regarded as Westphalian/ Stephanian and correlated to the Potonieisporites-Lundbladispora Zone (Archangelsky and Césari 1986).According to Millan (1987b), Botrychiopsis plantiana is the leading element of the Itapevense Sub-Stage (Itapeva Flora).A Stephanian age for the Itapevense Sub-Stage was estimated by correlation with palynological data (Lima et al. 1976).Zampirolli (2001) carried out a detailed review of the formerly described Santa Marta Taphoflora (Millan 1987a), using the same material that is now stored in the National Museum (Universidade Federal do Rio de Janeiro).In this review, in addition to Botrychiopsis, other important diagnostic elements have been included, such as Sphenopteris sp. and Nothorhacopteris cf.argentinica.Palynological data from the same strata are comparable with the Ahrensisporites cristatus Interval Zone of the Itararé Group lower portion (Zampirolli et al. 2000, Souza 2000).Taking in account mega-and microfloristic data, Zampirolli (2001) estimated a Westphalian age for the Santa Marta Flora.According to Zampirolli (2001) this association is comparable to the NBG Zone of Argentina (Middle to Late Carboniferous -Tupense -according to Archangelsky and Cúneo 1991).
In a study on the biostratigraphic importance of the upper Paleozoic taphofloras in Southern Paraná Basin, Guerra-Sommer and Cazzulo-Klepzig (1993) characterized some morphogenera as very important in terms of dating and correlation.In their attempt to establish paleofloristic associations based on observable boundaries of lithostratigraphic units, Botrychiopsis plantiana (recorded in the Faxinal and Francisquinho outcrops by Andreis et al. 1979) was regarded as one of the main elements related to the interval of deposition of the Itararé sequences in the Rio Grande do Sul State (Sakmarian).
Botrychiopsis plantiana remains a significant component of the Eopermian Glossopteris flora, then associated with Glossopteris, Gangamopteris, Phyllotheca, Buriadia (Pasqualini et al. 1986), which was related by Guerra-Sommer et al. (1986) to the basal sequences of the Rio Bonito Formation.
In a preliminary biozoning of the Southern Paraná Basin (Guerra-Sommer and Cazzulo-Klepzig 1993) the Botrychiopsis plantiana Zone was identified (Itararé Group and base of the Rio Bonito Formation) and related to the Sakmarian-Artinskian.
Recent data have shown that paleofloristic evolution in the Southern Paraná Basin during deposition of the Carboniferous -Early Triassic Megase-quence was closely related to palaeoclimate, in addition to biostratigraphic and paleoecological controls (Guerra-Sommer et al. 2001).This assumption was confirmed by the evaluation of taphofloristic parameters from different biostratigraphic units.
The homogeneous composition of Early Permian (Sakmarian) wet lowland biomes, characterized by the Glossopteris flora and herbaceous to shrub-like plants considered to be relicts from a rigorous cold climate (e.g.Botrychiopsis plantiana), suggests the persistence of an ice age.The progressive colonization of the lowland clastic habitats by Cordaitales, Ginkgoales, Coniferales, in addition to the herbaceous articulates, indicates an Early Artinskian climate warming.
Glossopterids with pinnate venation and related to Glossopteris are common in Early Permian coal-bearing strata (Artinskian/Kungurian) whereas Gangamopteris (palmate form) is poorly represented.The sudden enrichment of filicoid fronds is characteristic of the landscape units in this stage.Arborescent lycophyte communities become important, associated with glossopterid-dominated communities.This event coincides with the waning of the Permian icehouse stage, which reached its peak around the Asselian/Sakmarian boundary.

CONCLUSIONS
Botrychiopsis has been considered an important floristic element of Westphalian/Artinskian associations of the Paraná Basin.In the Southern Paraná Basin, several authors have related its occurrence to glacial-influenced environments.This genus has been recorded within associations related to a Permian glacier retreat (icehouse stage -Asselian/Kungurian).During the early deglaciation phases (cold/cool temperate climate), the Glossopteris Flora, linked to wet biomes, changed gradually.However, during the latest deglaciation stages, when a fast transition took place in the wet biomes  due to warming (warm temperate climate), in association with peat formation, the Botrychiopsis genus persisted, then represented by Botrychiopsis valida.
The new data here presented enlarge the Botrychiopsis genus biochron and define a stratigraphic hierarchy between Botrychiopsis plantiana and Botrychiopsis valida.In the Southern Paraná Basin, Botrychiopsis plantiana is restricted to Asselian/ Artinskian and Botrychiopsis valida to Kungurian.It is also reported that the stratigraphic range of the Botrychiopsis genus in Southern Paraná Basin is related to a deglaciation stage (icehouse) and, therefore, to a wide climate range, from cold/cool temperate to warm temperate.Megafloristic association in biomes cold-cool, cool and warm-temperate climates were identified, in the Lower and Midle/ Upper Permian in Southernwest Paraná Basin (Fig. 7  and 8).
The Faxinal microflora associated with the Botrychiopsis plantiana Subzone suggests a Stephanian C/Sakmarian or lower Asselian age.The Quitéria microflora on the other hand, is related to the Caheniasaccites ovatus Zone (Kungurian to lower Roadian).

Fig. 3 -
Fig. 3 -Botrychiopsis plantiana fronds from Faxinal and Base of Morro Papaléo: (a) apical portion of the frond with pines whit complete limbus, presenting small insertions and venation -PB 2677; (b) detail from the average portion of a frond -PB 2935; (c) detail from pines and it insertion in the rachis -PB 3009; (d) detail of a pine with venation -PB 3097; (e) basal portion of the frond -PB 2679; (f) basal portion of the frond, representing the morphological differentiation -PB 2499.

Fig. 4 -
Fig. 4 -Botrychiopsis valida fronds from Quitéria.(a) middle portion of a frond with pines, showing the venation of the rachis, the insertion of the pines in the rachis and is venation -PbU 0281; (b) middle portion of the frond with complete limbus presenting small insertions and the venation of the rachis and pines -PbU 0233; (c) basal portion of the frond with the insertion of the pines and venation -PbU 0252; (d) basal portion of the frond with the insertion of the pines and venation -PbU 0062.

Fig. 5 -
Fig. 5 -Botrychiopsis valida.frondsfrom Quitéria (a) detail of the middle portion of a frond with pines and it insertion in the rachis -PbU 0281; (b) middle portion of the frond with complete limbus presenting small insertions and venation -PbU 0233; (c) basal portion of the frond with the insertion of the pines -PbU 0062; (d) apical portion of the frond with pines presenting a complete limbus with insertions and venation -PbU 0061.
correlated the Monte Mor Taphoflora (Montemorense Stage) to the Trampeaderense Megafloristic Zone of the Argentinean Paganzo Basin (Azcuy and Jelin
and are stored (samples PB 3097 e PB 3098) in the Paleobotanic Sector of the Earth Sciences Institute of the Federal University of the Rio Grande do Sul State (UFRGS).
Samples from Faxinal include basal fragments 516 ANDRÉ JASPER ET AL.
Cannanoropollis genera) is less common and indicates the occurrence of Cordaitophyta.On the other hand, bisaccate pollen, such as Scheuringipollenites, Vesicaspora and Limitisporites, is related to Glossopteridophyta.The identified striated pollen specimens have a botanical affinity with Coniferophyta, such as Protohaploxypinus, Vittatina and Lunatisporites.Monolete spores are rare and essentially represented by forms of Cycadopites.