A new bluish-leaved Syagrus (Arecaceae) from an overlooked OCBIL in the Espinhaço Range (Brazil)

Abstract

Background and aims – This study is part of ongoing research on the Arecaceae Flora of the Serra do Cabral, an isolated massif in the southwest of the Espinhaço Range in Minas Gerais State. Because of the isolation of the massif, the area has a rich biodiversity and a high level of endemism. While searching for populations of the rare and critically endangered Syagrus cabraliensis, a new bluish-leaved palm species was discovered and it is described here. Material and methods – The new species’ morphology is described based on field collections. The pinnae were analysed using SEM and LM cross- and longitudinal sections following default methodology. In addition, we compared the species to S. cabraliensis and provided ecological notes and a conservation status assessment. Key results – Syagrus carvalhoi resembles S. cabraliensis but they can easily be distinguished by morphoanatomical characters. Both species occur non-sympatrically in the Serra do Cabral, in contrasting microhabitats: S. carvalhoi in the southern quartzitic campos rupestres and S. cabraliensis in the northern ferruginous campos rupestres. A key to the known grass-like Syagrus species from the massif is provided. Based on the restricted area of occurrence and the anthropogenic threats, Syagrus carvalhoi is assessed as critically endangered. Conclusion – Syagrus carvalhoi is the second grass-like endemic Syagrus species from the Serra do Cabral and presents rare characters within the genus (grass-like aspect, colonial habit, flowers in tetrads, and the stem forking at or below the ground). This discovery corroborates that this isolated OCBIL is a home for endemic and rare palm species. The Serra do Cabral massif has proved a source of morphological and anatomical novelties in Arecaceae, affecting the taxonomy and understanding of the evolution and ecology of palms. Our results reinforce the notion that it is important to conserve this area with rich and rare biodiversity but under alarming and unprecedented threats.

A New Rupicolous Palm From the Campos Rupestres, Minas Gerais, Brazil

“…The present study is based on field observations and collections in the Serra do Cabral State Park, Minas Gerais, Brazil, and herbarium material from MCMG, SPF and UPCB (herbarium codes follow Thiers et al, continuously updated). In the literature review, all available publications on the taxonomy of the genus were considered (Glassman, 1965(Glassman, , 1967(Glassman, , 1968a(Glassman, , 1968b(Glassman, , 1987Henderson et al, 1995;Marcato & Pirani, 2001;Noblick, 2004aNoblick, , 2004bNoblick, , 2004cMarcato & Pirani, 2006;Dransfield et al, 2008;Meerow et al, 2009;Noblick, 2009Noblick, , 2010Noblick & Lorenzi, 2010a, 2010bNoblick, 2012;Martel et al, 2013;Noblick, 2013a;Soares et al, 2013;Noblick, 2014;Noblick et al, 2014;Noblick, 2017a;Silva-Cardoso et al, 2017;Noblick, 2018Noblick, , 2019Soares & Guimarães, 2019;Firmo et al, 2021;Soares, 2022;Sant'Anna-Santos et al, 2023a, 2023b. The circumscription adopted here for Syagrus is based on Noblick (2017a), and the terminology adopted for the morphological and anatomical descriptions follows Dransfield et al (2008) and Noblick (2017aNoblick ( , 2017b.…”

“…Syagrus duartei is endemic to Serra do Cipó, whereas S. glaucescens is more abundant in the region of Diamantina, although some latter specimens could be found near the distribution limits of S. duartei (Noblick, 2017a). Syagrus evansiana occurs further north than S. duartei and S. glaucescens (Noblick, 2017a), whereas S. aristeae is endemic to the Serra do Cabral, a massif that shows a remarkable degree of endemism and holds rare species from several botanical families, including recent newly described species in Arecaceae (Noblick et al, 2014;Costa et al, 2018;Firmo et al, 2021;Sant'Anna-Santos et al, 2023a, 2023b.…”

“…The monophyletic genus Syagrus comprises 70 species, mostly native to Brazil, with 33 being acaulescent (lacking a visible stem or short-stemmed) species (Dransfield et al, 2008;Meerow et al, 2009;Noblick et al, 2014;Noblick & Meerow, 2015;Noblick, 2017aNoblick, , 2018Soares & Guimarães, 2019;Firmo et al, 2021;Soares, 2022;Sant'Anna-Santos et al, 2023a, 2023b. More than half of the acaulescent Syagrus species bear similar unbranched inflorescences, flowers and fruits (Dransfield et al, 2008;Noblick, 2013bNoblick, , 2017a.…”

“…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 et al, 2023a, 2023b. Among acaulescent Syagrus species, the S. glaucescens complex, which occurs exclusively in the Minas Gerais portion of the Espinhaço Range, includes S. glaucescens Glaz.…”