Abstract
The border area between south-eastern Yunnan, China and northern Vietnam is one of the regions with richest biological diversity including that of the fern genus Angiopteris (Marattiaceae). Based on the analysis of morphology and DNA sequences of multiple chloroplast regions (atpB, rbcL, rps4-trnS spacer and trnL-F spacer), we revised Angiopteris tonkinensis (Hayata) J.M.Camus and proposed a new combination Angiopteris tamdaoensis (Hayata) J.Y.Xiang & T.Wang, comb. nov., which was previously regarded as a synonym of A. tonkinensis. We found support for a monophyletic Angiopteris including Protomarattia. This discovery adds two new distribution sites of A. tonkinensis, one in China (Malipo, Yunnan) and one in Vietnam (Quan Ba, Ha Giang). We suggest A. tonkinensis should be categorised as Critically Endangered (CR) species according to the criteria of IUCN.
Highlights
The fern genus Angiopteris Hoffmann (1796) comprises about 30–40 species in the world and 28 species (17 endemic) in China (He and Christenhusz 2013)
We identified them as Protomarattia tonkinensis Hayata (1919), a very rare species known only from the type specimen collected in Monte Tamdao (Tonkin) of Vietnam and that had never been recorded again since 1919
Protomarattia tonkinensis is morphologically quite similar to Archangiopteris tamdaoensis Hayata (Table 3), especially the horizontal dorsiventral rhizomes and pinnate fronds, but the former has submarginal synangia, ca. 4–6 mm, sporangia fully fused into synangia which lack pedicels, whereas the latter has medial sori, ca. 7–10 mm, sporangia respectively fused at base into receptacles (Hayata 1919; He and Christenhusz 2013)
Summary
The fern genus Angiopteris Hoffmann (1796) comprises about 30–40 species in the world and 28 species (17 endemic) in China (He and Christenhusz 2013). The border area between south-eastern Yunnan, China and northern Vietnam is one of the regions with the richest biological diversity including that of Angiopteris. According to He and Christenhusz (2013), there are 16 species (five endemic) in this area. The endemic species in this area include Angiopteris bipinnata (Ching) J.M.Camus (Camus 1989), A. dianyuecola Z.R.He & W.M.Chu (He and Chu 2006), A. latipinna (Ching) Z.R.He, W.M.Chu & Christenh. During our fieldwork in Malipo (south-western China) on 18 May 2018 and Quan Ba (northern Vietnam) on 10 Oct 2019, two small populations of ferns caught our attention (Fig. 1). We identified them as Protomarattia tonkinensis Hayata (1919), a very rare species known only from the type specimen collected in Monte Tamdao (Tonkin) of Vietnam and that had never been recorded again since 1919
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
