Pleurothallis austrorientalis M. M. Jimenez & Mark Wilson 2026, sp. nov.

Pleurothallis austrorientalis M. M. Jiménez & Mark Wilson sp. nov. Figs 9, 10 Diagnosis. Similar to Pleurothallis crateriformis, from which it differs in the glabrous ramicaul sheaths (vs. hispid), the ovate-lanceolate leaves (vs. broadly ovate), the subterete, subverrucose ovary (vs. obconic, coarsely papillose), the elliptic-ovate, obtuse dorsal sepal (vs. round-ovate, rounded), the obovate, subacute, 7.2–7.9 mm wide synsepal (vs. oblong-ovate, obtuse, ca. 4.2 mm wide), the recurved, 7.4–8.4 × 1.3 mm, partially spreading petals (vs. incurved, 4.0 × 3.0 mm, porrect), the saccate lip with obtuse angles at the base and a rounded apex (vs. saccate-navicular with subacute angles at the base and a subacute apex), and the reniform stigma (vs. trigonous). Holotype. Ecuador • Zamora-Chinchipe: Vía Loja-Zamora, cerca de El Tambo, 2441 m, 14 April 2022, flowered in cultivation 15 February 2025, M. M. Jiménez León & M. Jiménez Villalta 1658 (HUTPL 15448!). Description. Epiphytic herb, caespitose, up to 19 cm tall. Roots slender, white, flexuous, 0.8 mm in diameter. Ramicauls suberect, green, 9.9–20.0 cm long, 0.2 cm in diameter, ascending at the base, enclosed by two papery basal sheaths at the base and one below the middle, bracts infundibuliform, glabrous, upper bracts 3.4–3.6 cm long, 0.2 cm in diameter. Leaves reflexed, sessile, pale green, ovate-lanceolate, concave, 7.2–10.3 × 3.2–5.4 cm, subplicate, thinly coriaceous, base cordate, lobes unequal and sometimes overlapping, margins slightly involute; apex attenuate. Inflorescence forming successive multi-flowered coflorescences with up to three open flowers, subtended by a prostrate, papyraceous spathe, 7.8–10.6 mm long; pseudopeduncle short, ca. 2.4 mm long, floral bract infundibuliform, ca. 5.3 mm long; pedicel very long, verrucose, dilated at the junction with the ovary, 10.9–12.3 mm long; ovary pale green suffused with brown to the apex, subterete, 4.3–4.7 × 1.7–1.9 mm, subverrucose-foveolate, furrowed, with black dots over the surface. Flowers resupinate or not resupinate, with sepals, petals, and lip pale green to yellow-green, adaxially covered with purple, coarse papillae (pustulate on sepals and petals and mamillate in the lip), petals apex chocolate-colored, lip whitish to the base, column whitish yellow, suffused with purple above, clinandrium purple. Sepals abaxially papillose-subverrucose, veins hollow adaxially and carinate abaxially, dorsal sepal 5 - veined, elliptic-ovate, 9.5–10.0 × 7.4–8.3 mm, hollow below the middle, convex above the middle, apex obtuse; synsepal 6 - veined, broadly obovate, 9.1–9.7 × 6.9. 2 – 7.7 mm, deeply concave, apex subacute. Petals 1 - veined, forward projecting, partially spreading, oblique, linear-falcate, 7.2–8.4 × 1.3 mm, convex adaxially, margins slightly involute, apex acute, recurved. Lip 3 - veined, saccate, sometimes laterally complanate, 3.2–3.7 × 2.7–3.6 mm, 2.8 mm tall, elliptic to obovate-subhastate as seen from the front, with a lanceolate to narrowly ovate cavity in the middle, dilated at the base seen laterally; base subtruncate, hinged to the column-foot, with short, obtuse angles, margins slightly revolute, apex rounded. Column complanate, 3.4–3.5 × 2.2–2.4 mm, papillose in the upper half, clinandrium sinuate, rostellar flap 0.7 mm long; stigma apical, reniform. Anther cap whitish yellow, narrowly ovate, subcordate, ca. 1.4 × 0.8 mm. Pollinia yellow, narrowly obovoid, ca. 1.2 mm long. Etymology. The specific epithet austrorientalis, refers to the geographical distribution of this species in southeastern Ecuador. Distribution and ecology. Pleurothallis austrorientalis is known from the eastern slope of the southern Ecuadorian Andes, forming part of the ecosystem known as evergreen montane forest at the south of the Cordillera Oriental of the Andes (BsMn 02) (Ministerio de Ambiente del Ecuador 2013), between 2400 and 2700 m in elevation. This region corresponds to the southern Ecuadorian provinces of Azuay, Loja, and Zamora-Chinchipe (Fig. 8), which is known as a biological ‘ hotspot’ due to its extraordinarily high diversity and endemism levels (Quizhpe et al. 2002; Tapia-Armijos et al. 2015). This area is the weather divide between the humid Amazon (“ Oriente ”) and the dry Inter-Andean region, and it is the transition zone between the perhumid montane broad-leaved forest and the upper montane forests (Beck et al. 2018). Individuals of this species grow as epiphytes close to the ground in the understory over ravines. The flowering of this species occurs between February and May. It grows together with other orchid species such as Cyrtochilum funis (F. Lehm. & Kraenzl.) Kraenzl., Masdevallia mandarina (Luer & R. Escobar) Luer, M. norops Luer & Andreetta, Maxillaria hastulata Lindl., Pleurothallis bivalvis Lindl. and P. omoglossa Luer. Conservation assessment. The species is known from four occurrences representing four localities: Zamora-Chinchipe Province (holotype near El Tambo), one record near Estación Científica San Francisco, approximately 3 km to the south, one near Cajanuma (approximately 20 km to the south), and Azuay Province (near Jima, approximately 85 km to the north). The calculated extent of occurrence (EOO) of Pleurothallis austrorientalis is 430 km 2, and the area of occupancy (AOO) is 16 km 2. Studies have documented a pronounced trend of habitat loss and fragmentation in the southeastern provinces of Ecuador. Tapia-Armijos et al. (2015) reported that between 1976 and 2008, the region experienced annual deforestation rates ranging from 0.75 % to 2.86 %, accompanied by a drastic reduction in the average size of forest fragments and increased isolation. Approximately 46 % of the original forest has been converted into landscapes dominated by agricultural activities, compromising ecological connectivity and ecosystem resilience. This fragmentation is not restricted to unprotected areas; even within the National System of Protected Areas (SNAP) and protective forests, patterns of forest cover loss and declining structural and functional connectivity have been observed (Kleemann et al. 2022; Noh et al. 2022). The expansion of pastures and crops remains the main driver of fragmentation in Andean and Amazonian ecosystems, compounded by external pressures such as road construction and mining (Mestanza-Ramón et al. 2022; Mena-Quintana et al. 2025). Given the restricted known distribution (EOO