New data on the stem and leaf anatomy of two conifers from the Lower Cretaceous of the Araripe Basin, northeastern Brazil, and their taxonomic and paleoecological implications.

Maria Edenilce Peixoto Batista,Artur A Sá,Marcos A F Sales,Delmira Da Costa Silva,Maria Iracema Bezerra Loiola,Antônio A F Saraiva,William Oki Wong

doi:10.1371/journal.pone.0173090

Abstract

Pseudofrenelopsis and Brachyphyllum are two conifers that were part of the Lower Cretaceous (Aptian) taphoflora of the Crato Formation, Araripe Basin, northeastern Brazil. The former genus includes, so far, P. capillata and indeterminate species, whilst the latter is mainly represented by B. obesum, the most common plant megafossil recovered from that stratigraphic unit. Here, the stem and leaf anatomy of Pseudofrenelopsis sp. and B. obesum specimens is revisited, including the first report of some epidermal and vascular traits for both taxa from the Crato Formation. Along with its paleoecological significance, the new data suggest the presence of more than one Pseudofrenelopsis species in the Aptian taphoflora of the Araripe Basin and further support the taxonomic placement of B. obesum within Araucariaceae.

Highlights

During most of the Mesozoic, landscapes were dominated worldwide by gymnosperms
We present additional data on the anatomy of B. obesum and Pseudofrenelopsis sp. branches from the Crato Formation of the Araripe Basin based on new specimens
The studied material comprises specimens properly housed at the following public institutions: Laboratorio de Paleontologia of the Universidade Regional do Cariri (LPU), Crato Municipality, and Museu de Paleontologia de Santana do Cariri (MPSC), Santana do Cariri Municipality, both located in the state of Ceara, Brazil

Summary

Introduction

During most of the Mesozoic, landscapes were dominated worldwide by gymnosperms. Throughout the Upper Cretaceous, the gymnosperm-dominated floras became restricted mainly to high latitudes as they were gradually replaced by angiosperms, whose evolutionary radiation had begun in low latitudes during the Lower Cretaceous and extended globally [1,2,3,4].Pseudofrenolopsis and Brachyphyllum are two conifers among the most abundant and diverse gymnosperms of the Mesozoic with their demise at the end of the Cretaceous [5,6,7,8].PLOS ONE | DOI:10.1371/journal.pone.0173090 March 3, 2017Anatomy of two Lower Cretaceous conifers productivity grant to MIBL by the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (CNPq). During most of the Mesozoic, landscapes were dominated worldwide by gymnosperms. Throughout the Upper Cretaceous, the gymnosperm-dominated floras became restricted mainly to high latitudes as they were gradually replaced by angiosperms, whose evolutionary radiation had begun in low latitudes during the Lower Cretaceous and extended globally [1,2,3,4]. Pseudofrenolopsis and Brachyphyllum are two conifers among the most abundant and diverse gymnosperms of the Mesozoic with their demise at the end of the Cretaceous [5,6,7,8]. Anatomy of two Lower Cretaceous conifers productivity grant to MIBL by the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (CNPq). There was no additional external funding received for this study

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