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| Paepalanthus magnus L.H.Rocha, Gonella & Andrino, et Rocha, Gonella et Andrino, 2024. |
Abstract
Paepalanthus is a diverse genus characteristic of the campos rupestres, a megadiverse vegetation found on mountaintops of mainly quartzitic mountain ranges of central-eastern Brazil. Recent efforts on prospecting the biodiversity of Serra do Padre Ângelo, a small mountain complex in eastern Minas Gerais, yielded several new plant and animal species, highlighting the urgency of conservation actions towards this still unprotected area. Here, we describe yet another new species found in the campos rupestres of these mountains, Paepalanthus magnus, a mountaintop microendemic species morphologically similar to taxa found in the Espinhaço Range, over 200 km distant, a biogeographic pattern shared by several other species. The affinities of the new species are discussed, and we provide illustrations, photographs, and SEM photomicrographs of the seed. We also discuss the conservation status of the species, which is preliminarily assessed as Critically Endangered, reinforcing the urgent need to address the conservation of the unique biodiversity of Serra do Padre Ângelo.
Key words: Atlantic Forest, endemism, João Pinto Formation, Serra do Padre Ângelo, threatened species
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| Paepalanthus magnus A habit B leaf apex C spathe, detail of the opening D capitula in dorsal (left) and ventral (right) view E involucral bract F floral bract G staminate flower in lateral view H staminate flower with sectioned corolla, exposing the stamens and pistillodes I pistillate flower in lateral view J pistillate flower with petals and sepals distended, exposing the gynoecium K seed with numerous appendices along the periclinal walls. Illustration by Klei Souza based on the holotype (P.M. Gonella et al. 3402). |
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| Paepalanthus magnus A habitat at Pico do Pinhão, with the Pico da Bela Adormecida (Pico do Padre Ângelo) in the background B habit among grasses and quartzitic rocks C rosette in detail D leaves, showing ciliate margin and striate abaxial surface E the base of the leaves, showing the adaxial surface and a scape enclosed by a spathe emerging from a leaf axil F spathe opening G capitulum in posterior view evidencing the involucral bracts H capitulum, lateral view I capitulum, frontal view. A by Lucian Medeiros B–I by Paulo Minatel Gonella. |
Paepalanthus magnus L.H.Rocha, Gonella & Andrino, sp. nov.
Diagnosis: The new species is most similar to Paepalanthus regelianus Körn., with which it shares the pilose abaxial surface of the leaves. However, P. regelianus presents scapes that are about twice as long as the leaves and tomentose (vs. scapes at least 3 times longer than the leaves, and glabrous in P. magnus) and involucral bracts with a glabrous abaxial surface and ciliated margin (vs. pilose in P. magnus). Furthermore, the spathes of P. regelianus are shorter than its leaves, approximately half as long as the leaves (vs. spathes about as long as the leaves), present uniformly distributed trichomes (vs. along longitudinal nerves), and possess a short opening, no longer than 1 cm long (vs. opening distinctly longer, 2.5–6.0 cm long).
Etymology: The epithet “magnus” derives from the Latin “great”, “large”. This epithet was selected to denote the characteristic of the species being large in size, contrasting with the majority of Eriocaulaceae species found in the region where it occurs but also a reference to its larger size compared to its putative closest taxa.
Luiz Henrique Rocha, Paulo Minatel Gonella and Caroline Oliveira Andrino. 2024. A Missing Piece is Found: A New Species of Paepalanthus (Poales, Eriocaulaceae) and the puzzling relations of the campos rupestres Mountaintop Floras of eastern Minas Gerais, Brazil. PhytoKeys. 242: 317-332. DOI: 10.3897/phytokeys.242.122824
Resumo: Paepalanthus é um gênero característico dos campos rupestres, uma vegetação megadiversa encontrada no topo de montanhas de cadeias montanhosas, principalmente quartzíticas, do centro-leste do Brasil. Esforços recentes de inventariar a biodiversidade da Serra do Padre Ângelo, um pequeno complexo montanhoso no leste de Minas Gerais, resultaram na descoberta de várias novas espécies de plantas e animais, destacando a urgência de ações de conservação para esta área ainda não protegida. Aqui, descrevemos mais uma nova espécie encontrada nos campos rupestres dessas montanhas, Paepalanthus magnus, uma espécie microendêmica, morfologicamente semelhante a táxons encontrados na Serra do Espinhaço, a mais de 200 km de distância, um padrão biogeográfico repetido por várias outras espécies. As afinidades da nova espécie são discutidas e fornecemos ilustrações, fotografias da planta e de microscopia eletrônica de varredura (MEV) da semente. Também discutimos o status de conservação da espécie, que é preliminarmente avaliada como Criticamente Em Perigo, reforçando a necessidade urgente de abordar a conservação da biodiversidade única da Serra do Padre Ângelo.
Palavras-chave: Espécie ameaçada, endemismo, Formação João Pinto, Mata Atlântica, Serra do Padre Ângelo