gonggashan88
commented
2 weeks ago Dr. He (and Joel), thanks for the interesting proposal. It might be premature to lump all these 7 genera into Selliguea, some of which, e.g., Arthromeris, Gymnogrammitis, are well defined morphologically and have a long tradition. Basically, the relationships within these 8 genera were not well resolved. Yes, your additional characters (dataset 2) still did not resolve the relationships, but was this because the markers you added (atpA, atpB, and matK) evolved too slowly, especially the atpA and atpB? I think poorly resolved relationships should not be used as evidence for lumping taxa together. “Absence of evidence does not mean evidence of absence” :-).
Wei et al. (2021), based on plastomes, well resolved the relationships but only 11 species were sampled. Putting these two papers together, it appears that alternative treatment would be recognizing at least Phymatopteris (type: Ph. palmata = Ph. taeniata), Arthromeris (type: A. wallichiana), and Selliguea (type: S. feei) [?and Gymnogrammitis (type: G. dareiformis)].
Given that the relationships are still largely unresolved, that very little is known about the ploidy levels, hybridization, polyploidization, and character evolution, and that there is no nuclear phylogeny yet, would it be wise to wait for further studies? PPG I recognized all these genera and the proposed change affects a lot of names.
Best wishes, Libing
Author(s) of proposal
Lijuan He (submitted by Joel Nitta)
Name of taxon
Selliguea, Arthromeris, Gymnogrammitis, Himalayopteris, Paraselliguea, Phymatopteris, Pichisermollodes, Polypodiopteris
Rank of taxon
Genus
Approximate number of species affected
80-100
Description of change
This proposal places all members of Selligueoids including Arthromeris (T.Moore) J.Sm., Gymnogrammitis Griff., Himalayopteris W.Shao & S.G.Lu, Paraselliguea Hovenkamp, Phymatopteris Pic.Serm., Pichisermollodes Fraser-Jenk. and Polypodiopteris C.F.Reed into synonymy with Selliguea Bory.
Reason for change
Several proposed genera including Arthromeris (T.Moore) J.Sm., Gymnogrammitis Griff., Himalayopteris W.Shao & S.G.Lu, Phymatopteris Pic.Serm., Pichisermollodes Fraser-Jenk., Polypodiopteris C.F.Reed and Selliguea Bory together form a clade sister to Aglaomorpha Schott (sensu PPGI, 2016). However, the monophyly of all these genera with the exception of Arthromeris was rejected (He et al. 2018).
There are still some uncertainties for this group, e.g. the systematic position of Paraselliguea hasn’t been validated and several endemic island species are lack of investigation. Low branch support for some relationships could be caused by rapid radiation. Nowadays, we need a stable classification and a broadly defined Selliguea would achieve long-term taxonomic stability in the future.
The name Selliguea Bory was published in 1824 and is the earliest available name for this group. For phylogenetic analyses and taxonomical treatment, see He et al. 2018.
Reference(s) for publication of the name
He LJ, Schneider H, Hovenkamp P, Marquardt J, Wei R, Wei XP, Zhang XC, Xiang QP. 2018. A molecular phylogeny of selligueoid ferns (Polypodiaceae): Implications for a natural delimitation despite homoplasy and rapid radiation. Taxon, 67 (2): 237-249. PDF
Wei R, Yang J, He LJ, Liu HM, Hu JY, Liang SQ, Wei XP, Zhao CF, Zhang XC. 2021. Plastid phylogenomics provides novel insights into the infrafamilial relationship of Polypodiaceae. Cladistics, 37(6), 717-727. PDF
List the numbers of any related issues
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