A NEW RUPICOLOUS PALM FROM THE CAMPOS RUPESTRES, MINAS GERAIS, BRAZIL

The Syagrus glaucescens species complex occurs in the Espinhaço Range in Minas Gerais state, Brazil. In addition to Syagrus duartei Glassman, S. glaucescens Glaz. ex Becc. and S. evansiana Noblick, a fourth undescribed species was previously identified by its morphology, leaf anatomy and geographical isolation. Here we formally describe this species as new to science and compare it with Syagrus evansiana , its closely related species. We also provide a distribution map, illustrations, photographs, taxonomic notes, and an IUCN conservation status assessment of Endangered.

Most acaulescent Syagrus species occur in dry and altitudinal environments such as the campos rupestres, where they are commonly found growing on rocky outcrops (Noblick, 2017a;Soares, 2022).In Brazil, campos rupestres are mainly found along the Espinhaço Range in Bahia and Minas Gerais (Giulietti et al., 1997).Although it constitutes a megadiverse environment with high endemism, the campos rupestres have been under severe and diverse socioeconomic exploitation, causing great concern about the extinction of rare or as-yet-unknown species (Giulietti et al., 1988;Alves et al., 2014;Fernandes, 2016;Batista et al., 2018;Costa et al., 2018;Fernandes et al., 2020;Sant'Anna-Santos,
Measurements of the vegetative and reproductive parts were taken in situ from 30 randomly chosen individuals of the new species.Herbarium material was examined to confirm the presence of some qualitative characters.Specimens were georeferenced and photographed in the field, using a digital camera.The flowers were stored in ethyl alcohol for further stereomicroscope analysis.Photographs of flowers were generated using a digital camera (CMOS 12 mp PLUS;Patrino Co.,Colombo,Brazil) coupled to a stereomicroscope (Bioptika L60T; Patrino Co.).For Syagrus evansiana, information on vegetative and reproductive parts was retrieved from the literature (Noblick, 2009(Noblick, , 2017a;;Firmo et al., 2021).
Distribution data were plotted on a map, using QGIS software version 3.16.2(QGIS Development Team, 2022) and assembled from the following data sources: states and cities (IBGE, 2020), Serra do Cabral State Park (Brasil, 2020), elevation (Miranda, 2005).The conservation status of the new species was evaluated according to the IUCN categories and criteria (IUCN Standards and Petitions Committee, 2022) and using the GeoCAT tool (Bachman et al., 2011).
Distribution.Syagrus aristeae is endemic to the Serra do Cabral mountain range, northcentral Minas Gerais state, Brazil (Figure 4).
Habitat and ecology.The species occurs in quartzitic campos rupestres, mainly on rocky outcrops at elevations between 867 and 1238 m (see Figures 2A-C, 3A,B).The campos rupestres are characterised by poor soils and harsh climate conditions (Almada et al., 2016;Fernandes et al., 2020).Recorded with flowers in July and fruits in December, January and July.
Etymology.Named in honor of Professor Aristea Alves Azevedo, one of the most prominent Brazilian botanists and the first woman hired as a professor by the Universidade Federal de Viçosa (UFV) in the 1970s.Recently, she received the Peter Henry Rolfs Medal of Merit in teaching, one of the UFV's highest honours.She mentored many botanists in plant anatomy, an inarguable source for the taxonomy of Arecaceae.Moreover, her former mentees carry out relevant research in plant conservation in Brazil, including for several botanical families of the campos rupestres of Minas Gerais.
Proposed IUCN conservation category.The extent of occurrence and the area of occupancy of Syagrus aristeae calculated using the online software GeoCAT (Bachman et al., 2011) were 178.741 km 2 and 32 km 2 , respectively.Therefore, following the IUCN criteria (IUCN Standards and Petitions Committee, 2022), this taxon should be classified as Endangered: EN B1b(ii,iii)c(i).
The pinnae of Syagrus aristeae are heavily consumed by locusts (see Figure 2J,K).However, the intense fires in the area (Figure 5A) are of more concern for the conservation of the species.Despite the important conservation role of the Serra do Cabral State Park, the area that the Park protects is relatively small (Costa et al., 2018).To illustrate, the populations of Syagrus aristeae are close to the limits of the Park (see Figure 4), near the plantations of exotic species such as Pinus sp., Eucalyptus sp. and Mangifera indica (Figure 5B-D).Some activities with potential negative impact occur in the vicinity of the Serra do Cabral State Park, as previously shown by Costa et al. (2018).Therefore, rare or endemic species from various botanical families are under pressure due to the impact caused by these anthropogenic activities on rocky outcrops (see Figure 5B).Recently, electrical poles were installed and there is a noticeable increase in housing construction (Figure 5E,F).Some anthropogenic activities also observed near the Park include gravel extraction (Figure 5G) and the use of ovens for charcoal production (Figure 5H).
The specimen (Marcato et al. 313) identified as the new species in this paper was the first (but erroneous) record of Syagrus glaucescens from the Serra do Cabral (SpeciesLink Network, 2022).However, at that time, some Brazilian taxonomists considered Syagrus duartei and S. glaucescens to be conspecific (Marcato & Pirani, 2001) and S. evansiana had not yet been described, which explains the mistake.Later, Syagrus evansiana was described as a new species from the northern portion of Minas Gerais (Noblick, 2009) and added to the S. glaucescens complex as the third taxon.Recently, the northern portion of the Serra do Cabral was included as the occurrence area of Syagrus evansiana (Noblick, 2017a), which led us to look for it in that region in our studies on the Arecaceae flora in the Serra do Cabral.
An unusual Syagrus population was found on the Serra do Cabral with younger individuals (already in reproductive phase) resembling S. evansiana, and mature specimens appearing to be larger (resembling S. duartei).This led them to be considered "confusing intermediates" belonging to the Syagrus glaucescens complex (Noblick, 2017a).However, the Serra do Cabral is isolated from the area of Espinhaço Range where Syagrus evansiana, S. duartei and these "confusing intermediates" are commonly found (Noblick, 2017a;Firmo et al., 2021).Thus, in the following years, we focused on searching for more mature specimens in the reproductive stage to confirm this unusual population of the Serra do Cabral as a new endemic species.As a result, we found specimens with two types of inflorescences (unbranched and branched), which resemble those of Syagrus evansiana and not S. duartei or S. glaucescens (Noblick, 2009(Noblick, , 2017a;;Firmo et al., 2021).Additionally, as previously discussed by Firmo et al. (2021), we observed that the number of endocarp pores varied between three and five, a character found in both the new Serra do Cabral species and Syagrus evansiana.A reassessment of the leaf anatomy of the entire complex highlighted that these individuals were anatomically distinct from the other species of the complex (see Firmo et al., 2021).

Figure 2 .
Figure 2. Syagrus aristeae B.F.Sant'Anna-Santos, sp.nov.A, Landscape photograph of the type locality in the Serra do Cabral State Park: individuals (white rectangles) growing in the rocky outcrops (Ro); B, specimen (black arrow) growing in the rocky outcrop (Ro); C, specimen (black arrow) growing on the sandy soils near rocky outcrops (Ro); D, pinnae irregularly arranged in the leaf rachis; E, dark-green adaxial (Ad) and glaucous abaxial (Ab) surfaces of the pinnae; F, the asymmetrical tip (white arrow); G, the long tapering tip (white arrow); H, abaxial side of the leaf rachis with white tomentum (To); I, leaf sheath with fibrous margins; J, pinnae consumed (white arrow) by locusts: abaxial surface (Ab); H, pinnae consumed (white arrow) by locusts: adaxial surface (Ad).Photographs: B. F. Sant'Anna-Santos.

Figure 3 .
Figure 3. Syagrus aristeae B.F.Sant'Anna-Santos, sp.nov.A, Habitat photograph of the type locality in the Serra do Cabral State Park: individual flowering (white circle); B, branched inflorescence; C, detail of branched inflorescence: floral visitor on the peduncular bract (PB); D, rachillae with pre-anthesis flowers stored in ethyl alcohol: triads (a central pistillate flower flanked by two staminate flowers) on the lower portion of the rachilla (black line) and isolated staminate flower occupying the upper half of the rachilla (blue line); E, deeply grooved peduncular bract (PB); F, prophyll (Pr); G, unbranched inflorescence; H, fruits (Fr): epicarp covered with crackled plates.Photographs: B. F. Sant'Anna-Santos.

Figure 5 .
Figure 5. Examples of diverse threats in the vicinity of the Serra do Cabral State Park: A, large-scale fire; B, plantation of Pinus sp.(black arrow) -the white circle shows a rare species of Cactaceae on a small rocky outcrop (Ro); C, plantation of Eucalyptus sp.(white arrow) near a rocky outcrop (Ro); D, plantation of Mangifera indica near a rocky outcrop (Ro); E, electrical poles recently installed; F, houses; G, gravel mining; H, charcoal plant.Photographs: B. F. Sant'Anna-Santos.