Abstract Detail

Pteridology

Martinez, Ana Gabriela [1], Vasco, Alejandra [2].

Disentangling the systematics of the Elaphoglossum petiolatum complex (Dryopteridaceae).

Elaphoglossum is a very diverse genus of ferns with ca. 600 species distributed worldwide, mainly in the tropics. In the last twenty years, molecular phylogenetic studies based on plastid markers, have contributed greatly to advancing the understanding and study of Elaphoglossum and have promoted monographic work in several small and well-defined monophyletic groups. The focus of this study is a group of 11 species informally called the Elaphoglossum petiolatum complex. Species in the E. petiolatum complex are distributed in the Old and New World tropics and are characterized by resinous dots in the abaxial surface of the lamina, black rhizome scales, petiole scales with dark apices, entire margins, and spiny perispores. Previous molecular phylogenetic studies suggested that the complex was polyphyletic, but surprisingly all the Mexican species of the complex were recovered in the same clade (the Mexican Clade). Nevertheless, these phylogenetic studies did not include all the species of the complex, nor samples of E. petiolatum from Jamaica (where the nomenclatural type of this species comes from). The main objectives of this study were to further explore the phylogeny of the E. petiolatum complex and to define and monograph the clade of the Mexican species, using molecular and morphological evidence. We sequenced three plastid markers and assembled a dataset of 194 species including 9 of the 11 species belonging to the E. petiolatum complex, samples of E. petiolatum from Jamaica, other Elaphoglossum species morphologically related to species in the E. petiolatum complex, other Elaphoglossum species covering the main clades of the genus, and three species of bolbitidoids ferns. For the Mexican clade, we studied and compared the morphology of each species using herbarium specimens. Additionally, we studied spore micromorphology using scanning electron microscope images. Our molecular results support the non-monophyly of the E. petiolatum complex, recovering its species in two non-sister clades: The Mexican Clade (which includes five species from Mexico, Central America, and the West Indies) and a Worldwide Clade (which includes nine species from the Old World and South America). Our taxonomic studies indicate that the specimens identified as E. petiolatum in Mexico are different from those from the West Indies and probably from those of Central America, and can be classified into three different morphotypes. Spore micromorphology is useful in distinguishing some species of the Mexican Clade and suggests there might be polyploid species in this clade.

1 - National Autonomous University of Mexico, UNAM., Faculty of Higher Stu, Plant Systematics and Soil Unit., Batalla 5 de mayo s.n., Ejercito de Oriente, Mexico City, 09230, Mexico
2 - Botanical Research Institute Of Texas, 1700 University Drive, Fort Worth, TX, 76107, United States

Keywords:
ferns
Mexico
Taxonomy
phylogeny
species complex
spore morphology.

Presentation Type: Oral Paper
Session: PTR1, Pteridology I
Location: /
Date: Monday, July 19th, 2021
Time: 10:45 AM(EDT)
Number: PTR1004
Abstract ID:236
Candidate for Awards:Edgar T. Wherry award