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International audience; Assessment methods have been developed to estimate a preliminary conservation status for species and subsequently to facilitate the building of Red Lists. Such pre-assessment methods could be particularly useful in the French Overseas Territories (FOTs) where Red Lists tend to be outdated or absent and where a high number of endemic species face detrimental anthropogenic pressures. We first aimed to conduct a preliminary assessment (hereafter, pre-assessment) of the conservation status of endemic plants from Guadeloupe, Martinique, Réunion, Mayotte, French sub-Antarctic islands, New Caledonia, and Scattered Islands. We then compared the various methods used in conducting the pre-assessment and discussed ways to adapt these methods to small territories. We compiled occurrence data of endemic species identified thanks to a previous taxonomic work and pre-assessed their conservation status under Red List criteria A and B and the use of a Random Forest algorithm. We then measured the accuracy, specificity, and sensitivity of each method based on existing Red Lists. The Random Forest algorithm and a method based on range-size performed best at correctly attributing conservation status. Using these pre-assessment methods, we estimated that up to 60% of the endemic flora of the FOTs is potentially threatened. Range restriction but also anthropogenic pressures were key factors that explained these risks. Pre-assessment methods are useful tools to get a first measure of species conservation status. These methods should be adapted to the territories considered and their conservation issues in order to reach a good performance.

New key to the Abrodictyum species in the Afro-Malagasy region (modified from Dubuisson et al. 2017) - Distal ultimate lobes or segment usually multi-veined and/or fused, often spatulate and appearing serrulate...... A. pachyphlebium 1. Distal ultimate lobes or segment usually single-veined, free, or sometimes fused by pair................................................................ 2 2. Lamina apparently absent or reduced to one row of cells on both sides of the veins........................................................................ 3 - Lamina always developed.................................................................................................................................................................. 4 3. Fronds subsessile or with short stipes not exceeding 4–5 cm, narrowly oblong to linear on herbarium, always with a narrowly cylindrical brush-like shape when fresh...................................................................................................................... A. cylindratum - Fronds with stipes usually longer than 4–5 cm, narrowly to widely lanceolate when dried, plane or with a lanceolate brush-like shape when fresh......................................................................................................................................................... A. parviflorum 4. Lamina of ultimate segments usually not exceeding 3 cells on both sides of the veins..................................................................... 5 - Lamina of ultimate segments with usually more than 3 cells on both sides of the veins................................................................... 6 5. Lamina width often variable (1 to 3 rows of cells on both sides of the veins) within the same frond; fronds narrowly to widely lanceolate, plane or with a brush-like shape; usually more than 6 sori per pinna....................................................... A. parviflorum - Lamina width usually not variable within the same frond; fronds narrowly oblong to linear, sometimes narrowly lanceolate but never widely lanceolate, always plane; often a single sorus per pinna, rarely more than 6 sori per pinna.................................................................................................................................................................................................................. A. angustimarginatum 6. Rhizomes erect; lamina without a clearly distinct marginal row of cells; plants usually terrestrial or saxicolous, rarely epiphytic............................................................................................................................................................................................................... 7 - Rhizomes short-creeping; lamina with a clearly distinct marginal row of cells; plants usually epiphytic, sometimes saxicolous..................................................................................................................................................................................... A. tamarisciforme 7. Fronds bipinnate-pinnatifid or more divided, always plane in the wild, never crispate or curled..................................................... 8 - Fronds rarely more than bipinnate-pinnatifid, usually with pinnules curled in the wild.................................................. A. franceae 8. Fronds often more divided than bipinnate-pinnatifid, broadly lanceolate to triangular, often exceeding 30 cm long; lamina dark green and opaque; sori cylindrical to slightly campanulate.................................................................................................. A. dregei - Fronds usually not more divided than bipinnate-pinnatifid, usually not exceeding 13.5 cm long, narrowly lanceolate; lamina light green and translucent; sori obconic (cup-shaped)....................................................................................... A. inexpectatum sp. nov., Published as part of Dubuisson, Jean-Yves, Bauret, Lucie, Boucheron-Dubuisson, Elodie & Rouhan, Germinal, 2022, Abrodictyum inexpectatum, an unexpected new fern species (Hymenophyllaceae, Polypodiidae) for Madagascar, as revealed by an integrative approach, pp. 83-91 in Phytotaxa 568 (1) on page 90, DOI: 10.11646/phytotaxa.568.1.6, http://zenodo.org/record/7184304, {"references":["Dubuisson, J. - Y., Bauret, L., Grall, A., Senterre, B., Said, A. H., Pynee, K., Ebihara, A. & Hennequin, S. (2017) Taxonomic study of the fern genera Abrodictyum C. Presl and Trichomanes L. (Hymenophyllaceae, Polypodiidae) in the western Indian Ocean, and description of a new Abrodictyum species for Madagascar. Phytotaxa 327: 201 - 222. https: // doi. org / 10.11646 / phytotaxa. 327.3.1"]}

Abrodictyum inexpectatum Dubuisson & Rouhan, sp. nov., Fig. 3. Plants similar to Abrodictyum franceae Bauret & Dubuisson, but smaller on average and with fronds plane in the wild (vs. usually crispate or curled for A. franceae) and genetically different; also first supposedly close to A. angustimarginatum (Bonap.) J.P. Roux, but genetically different and displaying ultimate segments with more than three rows of cells on both sides of the terminal veins (vs. not more than three rows of cells for A. angustimarginatum). It also differs from A. dregei (Bosch) Dubuisson & Rouhan in mature fronds smaller in average, usually not exceeding 13.5 cm long (reaching 37 cm for A. dregei), lamina light green and translucent (vs. dark green and opaque), and sori obconic or cup-shaped (vs. cylindrical to slightly campanulate). Type:— MADAGASCAR. Antsiranana: Andapa, Parc national de Marojejy, abords du camp 4 et le long de la rivière, 14°26’43”S, 49°44’31”E, 25 September 2015, G . Rouhan, L. Bauret, & D. Ravelonarivo s.n. (holotype: P [P02434058]!) Epiphytic at the base of trunks or saxicolous ferns. Rhizomes short, erect, 0.5–1.0 cm in diameter, bearing long tufted, erect, red-brown and more or less catenate pluricellular hairs, densely covering apex, and numerous robust roots. Fronds clustered, semi-erect; stipes 1–3 cm long, wingless and slightly canaliculate on the adaxial surface bearing numerous scattered hairs identical to those of rhizomes; rachises, with wings on their upper part only, and main costae with hairs similar to those on the stipes and rhizomes. Laminae 5.5–10.5 × 1.5–3.5 cm, narrowly lanceolate with truncate base and acute apex, bipinnate-pinnatifid, light green and translucent, plane in the wild; pinnae 0.5–2.5 × 0.2–1.8 cm, lanceolate or ovate to narrowly oblong, sub-horizontal to oblique, basally sub-opposite then alternate; pinnules pinnatifid, lanceolate or ovate to linear, with lamina slightly decurrent along the second order costules; ultimate or terminal segments 0.2–0.4 mm wide (> 3 cells on both sides of the veins), linear and uni-veined with mostly acute (less often rounded) ends, sometimes fused by pair, the veins not reaching the margin; venation pinnate and anadromous; laminar cells thick-walled with walls up to 10 µm thick and more or less wavy, very variable in shape, mostly longitudinally oriented and sometimes oblique, tetragonal to pentagonal, less often hexagonal, isodiametric or longer than wide, especially in fused segments parts. Sori paratactic, mostly on acroscopic basal-most segments of proximal pinnules, 1.0–1.4 × 0.5–0.9 mm, usually 1 per pinnule, up to 6 per pinna, free with usually a thin full longitudinal wing on both margins or less often at the base, obconic (cup-shaped), truncate or with a slightly dilated mouth; receptacle short to long-exerted. Distribution and habitat: —Endemic to Madagascar, in the understory of rainforests, at middle to high elevations (550–1,600 m), according to the examined specimens. The species seems to be restricted to the north-east of the island in the province of Antsiranana, but the low number of specimens attributed to this new taxon does not allow a precise definition of its distribution and abundance. Indeed, the species is either rare or has been under-collected because it has been confused with more abundant species, such as A. franceae or A. dregei. New surveys in the province and elsewhere on the island in the lowland and montane humid forests are therefore necessary. Etymology: —The specific epithet is related to the unexpected nature of the discovery of this new species, only revealed by the molecularly sequenced specimen collected and first incorrectly identified as A. angustimarginatum. Specimens examined (paratypes): — MADAGASCAR. Antsiranana: Partie occidentale du Massif de Marojejy de la vallée de l’Ambatoharanana au bassin supérieur de l’Antsahaberoka, 15-25 November 1959, H . Humbert 31865 (P [P01526301]!); River Ansaharatsy, 13°48’43”S, 48°47’59”E, 15 April 2000, C . Birkinshaw et al. 681 (P [P01627579]!).