Fissidens trindadensis Alkimim-Faria & Teixeira, 2025

Alkimim-Faria, Allan Laid, Teixeira, Tamara Poliana De Oliveira, Bordin, Juçara & Carvalho-Silva, Micheline, 2025, The genus Fissidens (Fissidentaceae) from Brazilian Oceanic Islands: Trindade Island and Martin Vaz Archipelago, Phytotaxa 714 (1), pp. 89-93 : 90-91

Fissidens trindadensis Alkimim-Faria & Teixeira , sp. nov. ( Fig 2. A–G )

Type: — BRAZIL, Trindade Island : leito do córrego e ponta do Noroeste Ilha da Trindade. Lat: -20.509167 long: -29.337222 WGS84, Alt. 332m. 28.II.2011, A. L. Faria 420 ( holotype: UB, barcode UB0041496 ; isotype: SP) .

Specimens examined: Faria 321, Faria 331, Faria 420, Faria 456 and Faria 457.

Diagnosis. Fissidens trindadensis differs from the species F. zollingeri by presenting morphological differences such as large leaves, quadratic and isodiametric cells; limbidium in the vaginal laminae with 4 cells wide at the base. The species F. zollingeri has palmately arranged leaves, hexagonal cells and axillary hyaline nodules.

Description: Plants usually light green to brown. Stems monomorphic, unbranched and branched, quite variable in length, 1.5–2.5x 0.7–1.3mm, rhizoids, basal and axillary, smooth, reddish, axillary hyaline nodules present. Leaves crispate when dry, usually loosely imbricate, often palmately arranged, as many as 5 pairs, oblong, acute, ca. 1.6x 0.28mm, margin entire, cells isodiametric quadratic, limbate on all lamina, costa percurrent, bryoides type; vaginant laminae ± ½ leaf length, acute, unequal, lamina cells, rectangular (above you say isodiametric -quadratic), limbidium in the vaginant laminae with 4 cells at the base. Perichaetia terminal. Sporophyte not observed.

Distribution and habitat: Fissidens trindadensis is distributed on Trindade Island in drier locations (Morro Vermelho and Praia do Príncipe trail and Praia das Tartarugas trail), and in forest environments (Fazendinha) only on the edges between 400 and 600 m above sea level. It occurs among rocks and holes with little light, sometimes close to running water (Praia do M trail and Pico do Noroeste trail), and can be found together with populations of Fissidens hornschuchii in the same environments on the island.

Conservation status: Fissidens trindadensis is known only from the type locality Área de Proteção Ambiental (APA) of the Trindade and Martim Vaz Archipelago, although this species is found only on Trindade Island. The new species may be protected because it is within the APA. For a better assessment of its conservation, additional data on its distribution and abundance are required. We recommend Fissidens trindadensis be characterized as Data Defficient (DD) according to the IUCN red list ( IUCN 2024).

Etymology: The new species was named trindadensis, referring to the name of Trindade Island. The name Fissidens trindadensis was used by Teixeira et al. (2022) to determinates a clade with species different of F. zollingeri (a species erroneously cited for Trindade Island by Faria et al. (2012).

The F. zollingeri clade is represented by specimens from the island of Fernando de Noronha and the state of Bahia, on the Brazilian coast. Considering the differences between Fissidens trindadensis and F. zollingeri cited in the diagnosis of this work, Teixeira et al. (2022) found 16 mutations for the rps4 marker, 11 transitions and 5 transversions, and show the species in different clades. The morphological characteristics of the species F. zollingeri containing palmately arranged leaves, hexagonal cells and axillary hyaline nodules had already been described by Pursell (2007) and Bordin & Yano (2013). However, the material analyzed from Trindade Island did not present long and pellucid rectangular cells in the median region of the vaginant laminae found in F. zollingeri .

Figures

FIGURE 2. Fissidens trindadensis sp. nov.: (A) Vegetative plant, (B) leaf, (C) axillary nodules, (D) cross section vaginant laminae, (E) leaf apex, (F) basal part of leaf, (G) mid leaf.