﻿A new species of Mollinedia (Monimiaceae, Laurales) from the Quadrilátero Ferrífero, Brazil

﻿Abstract Monimiaceae comprises approximately 26 genera and 250 species, with a pantropical distribution, predominantly occurring in humid forests. In Brazil, it is represented by five genera and 47 species, most of which are found in the Atlantic Forest, particularly in dense ombrophilous forest. Nevertheless, studies on this family in other biomes and vegetation types in Brazil are still scarce. The Quadrilátero Ferrífero (QF), a region located in the state of Minas Gerais, exhibits high plant species richness and endemism. During collections and analysis of herbarium materials from this region, some specimens of Mollinedia caught our attention due to a combination of characteristics that do not match those of any described species within the genus. For this reason, we describe this new taxon and assess its risk of extinction. Additionally, we review the occurrences of Monimiaceae in the QF and provide maps of its geographical distribution. With the description of this new species, the region now hosts eight species of Monimiaceae, two from the genus Macropeplus and six from Mollinedia. The new species is the first endemic species of the Monimiaceae family to be described in the QF. Concerning the extinction risk assessment, the new species was assessed as critically endangered.


Introduction
Monimiaceae is a pantropical family of shrubs, trees or lianescent plants with opposite leaves showing acuminate-convex teeth on the margin and venation entering the tooth medially and not joined by lateral veins, called "monimioid teeth" (Hickey and Wolf 1975).The family has 26 genera and c. 250 spp.occurring mainly in humid forests (Philipson 1993;Renner et al. 2010;Lírio et al. 2020a).On the American continent, ca.60 species occur in six genera: Grazielanthus Peixoto & Per.-Moura, Hennecartia J. Poiss., Macrotorus Perkins, Macropeplus Perkins, Mollinedia Ruiz and Pavón and Peumus Molina (Lorence 1999;Lírio et al. 2020a, b).Mollinedia is the richest Neotropical genus of the family, with c. 45 species, occurring in southern Mexico and Central and South America (Lírio et al. 2015(Lírio et al. , 2020a)).Mollinedia is characterized by staminate flowers with nearly rounded buds, tepals with a ratio of ca.1:1 in relation to the length of the flower, ovate or rounded stamens, and locules with two longitudinal openings and an extended connection or confluence at the apex, making the anther horseshoe-shaped (Perkins 1898(Perkins , 1900;;Lírio et al. 2020a).However, phylogenetic analyses suggest that this morphologically well-circumscribed genus is not monophyletic, albeit with low statistical support (Renner et al. 2010).In Brazil, there are 38 species of Mollinedia, 33 of which occur in the Atlantic forest, four in the Amazon forest, three in the Cerrado, and one in Pantanal (Lírio et al. 2020a).To date, 28 species of Mollinedia have been officially assessed at the national level following IUCN criteria, with 11 of them being considered threatened with extinction and one as deficient data (Lírio et al. 2023a).In addition, many Mollinedia species are microendemic, known by few collections in herbaria and/or considered rare (Lírio et al. 2018(Lírio et al. , 2023a)).
The "Quadrilátero Ferrífero" (QF) region belongs to Minas Gerais state (Brazil) and is situated in a transition zone between the Atlantic Forest and Cerrado domains.The total area is approximately 7,200 km 2 and has significant iron ore reserves (Jacobi et al. 2007;Messias et al. 2012).At the highest altitudes, ironstone outcrop vegetation (named "canga") can be found.This ecosystem is considered a center of high diversity, including the occurrence of poorly known, endemic and endangered plant and animal species (Jacobi et al. 2007;Zappi et al. 2017).
Seven species of Monimiaceae have been registered in the QF region, none of which are restricted to this area, five of which belong to Mollinedia and two of which belong to Macropeplus (Fig. 1).Here, a new species of Mollinedia endemic to the QF is described and illustrated.Additionally, its conservation status is evaluated, and its morphological affinities are discussed.
Phenology.The species was collected with flowers in November and fruits in March.
Etymology.The epithet of this species is a homage to Dra.Fátima Otavina de Souza Buturi, an inspiring Brazilian botanist who dedicates her career studying Asteraceae, mentoring several biologists and botanists, including the first author of this paper (DAZ).
Habitat and distribution.Mollinedia fatimae occurs at an average altitude of 1527 m (min.: 1354 m; max.: 1673 m), on mountain slopes or in river drainage ravines (Fig. 4A), predominantly in Haplic Cambisols -typical dystrophic, texture medium (code RLd10 in Fig. 4B), formed from matrix rocks of phyl-   lite, schist, dolomite and quartzite.The vegetation is defined as mountainous semideciduous seasonal forest in intermediate to advanced stages of regeneration, with perceptible variations in the NDVI (Fig. 4C).Its individuals grow in extensive forest fragments at lower elevations but with most occurrences in small forest enclaves in areas with a predominance of "campo rupestre", where vegetation indices indicate open formations in the surroundings (Fig. 4D).
Conservation status.Most species' populations are inside the integrally protected Itacolomi State Park, on the boundaries of the Ouro Preto and Mariana municipalities, with an EOO of 11.06 km 2 and AOO of 16 km 2 (Fig. 4E).Accord-ing to the B1ab (iii, iv) criteria (IUCN 2012(IUCN , 2022)), the species should be considered critically endangered (CR).The main threats are stochastic events due to seasonal variations and climate change but mainly due to fires in the region.In high areas, fire is ignited by rare natural phenomena (i.e., lightning) and mainly by artificial fires (Schumacher et al. 2022).These fires spread quickly through campo rupestre, invading forests with significant dry biomass accumulation.Four of the six species records occur in these vegetation contact zones, with severe population decline projections if fires intensify in the region.The expansion of burned areas and the calorific power of fires have intensified in the last five years (INPE 2023).Furthermore, restricted endemism impacts potentialize the overall occurrence of the species, even with localized events.
Similar species and remarks.Mollinedia fatimae does not co-occur with other species of the genus.The new species resembles Mollinedia boracensis Peixoto due to its coriaceous leaves; however, it can be easily differentiated by the length of the petioles and the indumentum of leaves and flowers.Additionally, the farinose-pilose flower indumentum in Mollinedia fatimae resembles that in Mollinedia arianeae Lírio & M. Pignal and Mollinedia leucantha M. Molz & D. Silveira, but the species can be differentiated from M. arianeae by the branch indumentum, leaf consistency, and color when dried and can be distinguished from M. leucantha mainly by its leaf consistency, indumentum, color when dried and number of carpels.The new species was recorded in herbaria as Mollinedia engleriana Perkins, probably due to the dark-brown color of the leaves when dried (darkish in M. engleriana), but it can be differentiated from this species mainly by its leaves and flower indumentum and the length proportion of the staminate tepals in relation to the receptacle.All the comparisons with related species are summarized in Table 1.

Figure 1 .
Figure 1.Geographic distribution map of Monimiaceae species in the Quadrilátero Ferrífero, state of Minas Gerais, Brazil, showing the limits of the region, mountainous areas and elevations.

Figure 2 .
Figure 2. A branch with staminate flowers B staminate flower in lateral view C staminate flower with tepals removed, showing the stamens D stamen E branch with pistillate flowers F detail of cataphylls G detail of leaf abaxial surface H pistillate flower in lateral view I pistillate flower dissected, showing the carpels J carpel K composed fruit.(Illustrated by Susana Souza based on Zavatin 1326 and 1327 and Pedrosa 46 specimens).

Figure 3 .
Figure 3.A branch with staminate flowers B monimioid tooth C branch with pistillate flowers D magnification of a young reddish branch showing a lenticel E staminate flower F staminate flower with the removal of tepals showing the androecium G-H stamens I staminate flower with removed tepals in upper view J staminate flower in upper view, almost complete anthesis K pistillate flower L pistillate flower starting scission in the tepals M early opening of calyptra N opened calyptra exposing the carpels O carpel P pistillate flower in upper view in anthesis Q pistillate flower in longitudinal section R bractlets S cataphylls.(Image authorship: Danilo A. Zavatin).

Figure 4 .
Figure 4. Environmental and Conservation spatial data A digital elevation model of the terrain B soil classes C normalized difference vegetation index (NDVI) D natural vegetation and anthropic use classes E AOO and EOO analyses.