crothfels
commented
10 months ago The cheilanthoid ferns are one of the most glaring (the most glaring?) areas of phylogenetic/taxonomic/nomenclatural uncertainty in PPG 1, and this proposal looks to me to be a good step forward. However, I know that Michael Windham, Kathleen Pryer, Eric Schuettpelz, and collaborators have been working on the phylogenetics and taxonomy of the hemionitids for a long time and will publish their results soon (I hope ;-) ). I'm not sure if this proposal fits with their results and proposed taxonomy or not, but perhaps some coordination with that group would be useful at this stage?
gyatskievych
joelnitta
MoniPonce
tomaranker
Author(s) of proposal
M. M. Ponce and M. A. Scataglini
Name of taxon
Cheilanthes Sw.
Rank of taxon
Genus
Approximate number of species affected
70
Description of change
From a total of about 100 species of Cheilanthes s.l. , in PPG I (2016), ca. 70 of them would belong to the s. str. clade, distributed in South America, Australasia, Africa, and Madagascar. In our recent studies (Ponce & Scataglini, 2020), in order to examine the phylogenetic position of Cheilanthes species from South America, we reconstructed a representative molecular phylogeny of the hemionitioid clade. As a result, from a total of ca. 35 South American Cheilanthes species, more than 20 of them appeared in the Cheilanthes s. str. clade with maximum support. We propose that the Cheilanthes s. str. clade contains three subclades: 1) exclusively South American species (≈10 spp.), 2) Australasia + ≈16 South American species, including the type C. micropteris, and 3) exclusively African and Madagascar species. Recently, Cheilanthes volcanensis de la Sota, a poorly known species restricted to North-western Argentina and Bolivia, was also confirmed in the exclusive South America clade (Ponce et al. 2023). On the other hand, three Cheilanthes species (C. geraniifolia, C. goyazensis and C. bradei) from Northern, Central Western and South Eastern Brazil, appear segregated from the Cheilanthes s. str. clade in our phylogeny. These three species plus two morphologically related taxa, C. eriophora and C. steyermarkii, were transferred to the new genus Mineirella Ponce & Scataglini (2020). (see Mineirella proposal)
Reason for change
The hemionitioid group is composed of three highly supported main clades: 1) Cheilanthes s. str., 2) Hemionitis clade + “Pellaeopsis” group (from Africa and Madagascar), and 3) Adiantopsis – Doryopteris clade, which also include neotropical (e.g. Mineirella) and paleotropical (e.g. Choristosoria) species groups. The relationships between these three main clades were showed in previous works but they have not been fully resolved yet (Eisenhardt et al. 2011; Yesilyurt et al. 2015, Ponce & Scataglini, 2018; 2020). The Cheilanthes s. str. is morphologically heterogeneous, but presents diagnostic characters that difference it from the remaining cheilantoids ferns : concolor rhizomatic scales (vs. bicolor rhizomatic scales in Adiantopsis, Doryopteris, Mineirella); free veins, apically widened (vs. not or slightly widened vein tips in Myriopteris), sporangia at the vein tips (vs. along the veins in Hemionitis); elongated cordiform or ribbon like, glabrous gametophytes (vs. pilose gametophytes in Hemionitis, and farinose glandular gametophytes in Notholaena). Root anatomy with whole cortex thinned cell walls or gradually thickened cell walls and wide lumen (vs. inner cortex with strongly thickened cell walls and narrow lumen in Adiantopsis, Doryopteris and Mineirella) (cfr. Hernández, 2019 Thesis). Also, the Australasian-South American Cheilanthes subclade presents exclusively 32 small spores per sporangium, in sexual condition (vs. 64 small spores per sporangium in sexual condition, present in most of the cheilanthoids species) (cfr. Gruzs & Windham, 2013; Ponce & Scataglini, 2018, 2020).
Reference(s) for publication of the name
Ponce, M. Mónica, and M. Amalia Scataglini. 2018. “Further Progress towards the Delimitation of Cheilanthes (Cheilanthoideae, Pteridaceae), with Emphasis on South American Species.” Organisms Diversity & Evolution 18 (2): 175–86. https://doi.org/10.1007/s13127-018-0366-6. Ponce & Scataglini_Further progress towards the delimitation of Cheilanthes_ODAE2018.pdf
Ponce, Marta Mónica, and María Amalia Scataglini. 2022. “Phylogenetic Position of South American Cheilanthes (Cheilanthoideae, Pteridaceae): Advances in the Generic Circumscription and Segregation of the New Genus Mineirella.” Journal of Systematics and Evolution 60 (2): 266–80. https://doi.org/10.1111/jse.12723. Ponce & Scataglini_Phylogeny of Cheilanthes .pdf
Ponce, M. Mónica, M. Amalia Scataglini, Marcela A. Hernández, and Olga G. Martínez. 2023. “Análisis Moleculares y Observaciones Morfo-Anatómicas de Cheilanthes Volcanensis (Pteridaceae) Definen Sus Relaciones Dentro de La Subfamilia Cheilanthoideae En Sudamérica.” Darwiniana, Nueva Serie 11 (1): 101–14. https://doi.org/10.14522/darwiniana.2023.111.1118. Ponce et al_Cheilanthes volcanensis_DWN2023.pdf
List the numbers of any related issues
40
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