Monsanima tinguaensis R.Santos & Fontella, 2014

Monsanima tinguaensis R.Santos & Fontella View in CoL , sp. nov. ( Fig. 3 View FIGURE 3 ).

Monsanima tinguaensis is similar to M. morrenioides (Goyder) Liede & Meve because of the slender habit, extra-axillary inflorescences shorter than leaves, corona with fluted lobes, almost entirely connate, free only at the apex, where they arch over the gynostegium, and pollinaria with short, flattened, broader than long, hyaline caudicles. However, it differs by the longer petiole (> 1 cm vs. <0.3 cm long), larger (> 7.5 × 3 cm vs. <3.5 × 0.5 cm), elliptic to oblong (vs. linear to narrowly lanceolate) leaf blade, corymbiform (vs. umbelliform) inflorescences, larger (> 10 mm vs. <7 mm long), rotate (vs. campanulate) corolla, anthers with (vs. without) anther appendages, and longer pollinia (> 0.65 mm vs. ca. 0.5 mm long).

Type:― BRAZIL. Rio de Janeiro, Nova Iguaçu, “REBIO [Reserva Biológica] do Tinguá, trilha para o Pico, entre a primeira pedra e o pico” , 30 January 2002 (fl.), J. Silva Neto et al. 1654 (holotype RB!) .

Slender vine; branches hirsute. Leaves with 3 or 4 colleters at midrib base; petiole 1.3–2.9 cm long, hirsute; leaf blade 7.6– 8.3 × 3.4–4 cm, elliptic to oblong, apex acuminate to mucronate, base truncate to slightly cordate, hirsute on both surfaces, especially on midrib. Inflorescences extra-axillary, corymbiform, 3–5 flowered, shorter than the leaves; peduncle ca. 7 mm long, densely hirsute. Flowers with pedicel 1.2–1.4 cm long, densely hirsute; sepals 6–7 × 0.8–1.5 mm, surpassing the corolla tube, narrowly triangular, hirsute on the abaxial surface, 1 colleter in sinuses; corolla rotate, white with vinose stripes, tube 2–3 mm long, glabrous, lobes 8–12 × 4.5–6.5 mm, ovate, acuminate at the apex, glabrous; corona lobes 5–6 × 3–3.5 mm, slightly sigmoid, fluted, almost entirely connate, free only at the apex, longer than anthers, strongly incurvate over gynostegium. Gynostegium ca. 2 mm long, sessile; anthers 1.8–2 × ca. 2.2 mm, subtriangular, wings extended in a protuberant appendix over the dorsum, anther appendages ca. 0.5 mm long, ovate to slightly rhombical; retinaculum 0.47–0.49 × 0.09–0.15 mm, oblong, caudicles 0.13–0.14 mm long, horizontal, broader than long, flattened, hyaline, pollinia 0.66–0.68 × 0.23–0.26 mm, suboblong; style-head slightly mammillate. Fruits unknown.

Distribution and habitat: ― Monsanima tinguaensis is known only from the type specimen, collected at the Pico do Tinguá (Tinguá Peak), in the Tinguá Biological Reserve. The Reserve was created in 1989 and is a UNESCO Biosphere Reserve since 1991 ( IBAMA 2006). It is located between 22º28’– 22º40’S and 43º10’– 43º35’W, encompassing four municipalities (Nova Iguaçu, Duque de Caxias, Petrópolis and Miguel Pereira), and about 26,000 ha ( IBAMA 2006). Most of the reserve (ca. 90%) is located in Serra do Mar and is dominated by mountain rainforest. The Maciço do Tinguá (Tinguá Massif) is the highest spot in the region, reaching over 1,600 m at the “Topo da Pedra do Tinguá” (Top of Tinguá Rock) ( IBAMA 2006). At these high altitudes, beyond forest limits and at rock scrapes, an open vegetation called campos de altitude usually appears (Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, 2002). The narrow distribution of M. tinguaensis , restricted to high altitudes in Serra do Mar, reassembles the distribution of M. morrenioides , which is known only from Pico das Almas in Chapada Diamantina, Bahia State. This disjunction suggests that the first lineage(s) to diverge in the evolution of Orthosiinae are currently restricted to small relicts of preserved vegetation in mountain refuges.

Conservation status: ― Rio de Janeiro has being floristically explored since the first naturalists visited Brazil in the 18’s century and collecting a new species in this State, especially close to metropolitan areas, seems to be unlikely. However, it is a megadiverse State and shelters an exceptionally high number of species with narrow distribution (≤ 10,000 km 2), mainly in the Atlantic rainforest of Serra do Mar ( Rapini et al. 2009). This circumstance suggests that Monsanima tinguaensis is a rare species, whose distribution is naturally narrow, currently likely restricted to only one of the few preserved areas of Atlantic rainforest in Rio de Janeiro. Known from a single location only, the new species is probably threatened like its congeneric M. morrenioides , which is Critically Endangered ( Rapini et al. 2013). Nevertheless, it occurs in a reserve, with more than 20,000 km 2 of protected vegetation and should be classified as vulnerable according to the IUCN (2001) criterion D2.

In spite of the widespread destruction of Atlantic Forest, only 1% of its original area is under protection ( Ribeiro et al. 2009). The Tinguá Biological Reserve is an exception in this long history of environmental degradation: it is in a metropolitan area in Rio de Janeiro and still shelters some of the most preserved forests in southeastern Brazil. Such a high level of conservation is due to one of the first acts of nature protection in Brazil, dating back to 1833. At that time, Dom Pedro II, the country’s Emperor, declared an area comprising three farms in the slope of Tinguá Massif as “Floresta Protetora” (Protective Forest; Instituto de Pesquisas Jardim Botânico do Rio de Janeiro 2002). Since the region presents a high number of rare species, other new relict species are expected to be found in the reserve.

Etymology: ―The specific epithet ‘ tinguaensis ’ refers to the locality where the plant was collected.In Tupi-Guarani, a Brazilian indigenous language, “Tinguá” means “the shape of a nose” in reference of the scarp appearance.