Abuta alto-macahensis Feliz & J.M.A.Braga, 2022

Feliz, Pablo Fernando, Fernandes, Thiago, Joffily, Ana, Bovini, Massimo Giuseppe & Braga, João Marcelo Alvarenga, 2022, A new species of Abuta (Menispermaceae) from the Brazilian Atlantic Forest, Phytotaxa 556 (2), pp. 193-200 : 194-198

Abuta alto-macahensis Feliz & J.M.A.Braga , sp. nov. ( Figures 1–5 )

Diagnosis: —Similar to A. rufescens , but differs by the leaf blades adpressed tomentose abaxially, and drupelets ≥ 5 cm long, glabrous.

Type: — BRAZIL. Rio de Janeiro, Macaé, estrada Frade - Tapera, próximo ao desvio do Pico do Frade , 4 march 2004, fl. ♀, R. C. Forzza et al. 2899 (holotype RB 827493 [barcode 01457839]; isotypes: NY, R) .

Lianas, up to 25 m tall; older stems ca. 10 cm diameter at base, younger stems and branches cylindrical, cinereous to brownish, smooth, tomentose to glabrous with age, lenticellate, sometimes marked with thin streaks. Leaves with petiole 6–15 cm long, cinereous to brownish, adpressed tomentose, smooth or finely striated longitudinally, tips slightly dilated, apex usually curved; blades 8–24 × 5–16 cm, flat, thick, chartaceous to coriaceous, ovate, widely elliptic or suborbiculate, base obtuse, apex acute or acuminate, sometimes with the apex damaged giving it the false appearance of obtuse or emarginated, margin entire; adaxial surface greenish, or brownish to blackish when dried, glabrous, abaxial surface whitish, or cinereous when dried, densely adpressed tomentose; venation basal actinodromous, 5- veined prominent abaxially, midvein giving rise to two pairs of larger secondary veins, the first pair of lateral veins starting at the base and ascending, nearly reaching the apex, giving rise to 2–3 more distinct veins that extend nearly to the margin, the second pair of lateral veins thinner, curved-ascending to the middle third of the blade, adjacent veins distinct, reticulate with lax areoles. Pistillate inflorescences racemose, supra-axillary, solitary; rachis 2–7 cm long, thinner, finely striated longitudinally or smooth, cinereous to brownish, adpressed tomentose, or robust, lenticellate, glabrous when fruiting. Bracts 0.5–1 × 0.3–0.6 mm, lanceolate or elliptic, densely brownish-tomentose; pedicels 2–4 mm long or up to 10 mm when fruiting, brownish, adpressed tomentose. Pistillate flowers brownish, densely tomentose; sepals 9, the outer 3, 0.7–1 × 0.6–0.7 mm, the medians 3, 1–1.3 × 0.9–1.5 mm, the inner 3, 1.5–2 × 1.5–2 mm, ovate or orbiculate, base obtuse, rounded or cordate, apex obtuse or rounded; staminodes 6, 1.2–1.6 mm long, threadlike, brownish, densely tomentose to velutinous, except apex black and glabrous; carpels 3, 1.4–1.5 × 0.8–1 mm, sessile, brownish, densely tomentose to velutinous, style 0.1–0.2 mm long, reflexed, stigma 2-lobed, sometimes entire. Drupelets 5–5.5 × 2.5 cm; epicarp mature orange, or black when dried, glabrous; endocarp ca. 4.5 × 2 cm, woody, with a hippocrepiform groove starting at the style scar and running along the long axis of the endocarp, both having impressed veins on each lateral surface, condyle deeply ensconced in the seed, giving it a hippocrepiform appearance. Seed ca. 3.5 × 1.5 cm, with a membranous coat, hyaline, adhered to the wall of the storage tissue; endosperm abundant, viscous and ruminate, made up of vesiculate parts surrounding the entire embryo. Staminate inflorescences and flowers unknown.

Etymology: —The name refers to the locality where the species was found. Despite the Recommendation 23A.3j of the International Code of Botanical Nomenclature ( Turland et al. 2018) which advises against the use of littleknown or very restricted localities for species names, we chose to keep the name originally suggested by Rupert C. Barneby ( Figure 1B ), in honor of his work and discovery.

Distribution, habitat and conservation:— The species is known only from two montane regions in the Brazilian State of Rio de Janeiro, where it inhabits well-preserved montane rainforests at elevations of 1,000 –1,300 m ( Figures 4A , 5 ). Considering the extent of available suitable habitat, its Extent of Occurrence (EOO) has been calculated to range between 3 and 3,500 km ². The presently known occurrence records are from protected areas (“Área de Proteção Ambiental de Macaé de Cima” and “Monumento Natural do Pico do Frade”), however these are for sustainable use, with human activities still permitted. Therefore, these protected areas still face threats of habitat loss by fire, expansion of rural properties and especially deforestation to create new pasture and farming areas (see Guedes-Bruni & Lima 1996; Lima & Guedes-Bruni 1997; INEA 2014; Costa et al. 2021). From these observations, we suggest the status of Endangered (EN) based on the criteria B1abiii ( IUCN 2012, 2019).

Notes:— The affinity of Abuta alto-macahensis to Abuta sect. Abuta and the relationship of this species to A. rufescens Aublet (1775: 618) [syn.: A. convexa (Vell.) Diels (1910: 193) ] was previously pointed out by Braga (1996), who illustrated and identified the specimen Pessoa 549 et al. (RB) as Abuta sp. The new species is distinguished by leaf blades abaxial surface adpressed tomentose and drupelets glabrous (vs. abaxial surface and drupelets densely tomentose to velutinous).

Barneby & Krukoff (1971) cited two species of Abuta for southeastern Brazil, including A. selloana Eichler (1864: 389) . The latter was also found in the area during the Reserva Ecológica de Macaé de Cima floristic inventory ( Braga 1996), but it has glabrous branches and leaves, 3-nervate, more delicate secondary veins and dense reticulum, pistillate flowers with 6 sepals and drupelets up to 4 cm long (see the identification key below).

Additional specimens (paratypes):— BRAZIL. Rio de Janeiro: Nova Friburgo, Reserva Ecológica de Macaé de Cima , 16 January 1991, fr., S.V.A. Pessoa et al. 549 ( RB); Macaé, Glicério , Tapera , Serra de Crubixais, Fazenda Crubixais, base do Pico do Frade , trilha para o Ponto de Decisão , 29 June 2016, st., J. M. A. Braga & M.G. Bovini 16- 019 (RB) .

Figures

FIGURE 1. Abuta alto-macahensis. A. Holotype with ♀ flowers (Forzza et al. 2899 RB[barcode 01457839]). B. Paratype with mature drupelets, and Barneby’s signature identifying the new species (Pessoa et al. 549 RB[barcode 01457851]). Reproduced with permission from Herbário do Jardim Botânico do Rio de Janeiro.

FIGURE 2. Morphological characters of Abuta alto-macahensis. A. Flowering branch. B. Detail of leaf hairiness on the abaxial surface. C. Pistillate inflorescence. D. Pistillate flower. E. Sepals. F. Staminode. G. Carpels. H. Drupelet. I. Endocarp. J. Seed. A–G. Forzza et al. 2899 (RB) and H–J. Pessoa et al. 549 (RB).

FIGURE 3. Morphological features of Abuta alto-macahensis. A. Flowering branch. B. Detail of leaf hairiness on the abaxial surface. C. Pistillate flower. D. Sepals. E. Staminode. F. Carpels. G. Detail of carpel with 2-lobed stigma. H. Drupelet. I. Endocarp. J. Seed. A–G. Forzza et al. 2899 (RB) and H–J. Pessoa et al. 549 (RB). Drawing by Rachel Dana.

FIGURE 4. Abuta alto-macahensis. A. Habitat in Pico do Frade, located in the Atlantic Forest of southeastern Brazil. B. Liana stem. C. Branches in the forest canopy. D. Detail of leaves in the forest canopy. E. Leaves showing the adaxial surface. F. Leaves showing the abaxial surface. Photos: J.M.A. Braga taken on 29 June 2016.

FIGURE 5. Map of occurrence records of Abuta alto-macahensis. Black contours represent the limits between the Brazilian States.