Pleurothallis marioandresavilae Velez-Abarca & M. M. Jimenez 2023, sp. nov.
Creators: name: Jiménez, Marco M.
name: Vélez-Abarca, Leisberth
name: Mashendo-Jimbicti, Viviana
name: Garzón-Suárez, Henry X.
name: Monteros, Marco F.
name: Wilson, Mark
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Asparagales
Orchidaceae
Pleurothallis
Pleurothallis marioandresavilae

description: 3. Pleurothallis marioandresavilae Vélez-Abarca & M.M.Jiménez sp. nov. (Figures 6–8).
Type: — ECUADOR. Zamora Chinchipe: Next to the El Quimi reserve, 820 m, 19 December 2021, L. Vélez LV-0072 (holotype: ECUAMZ 08648!)
Similar to Pleurothallis complanata Luer & Hirtz from differs by its yellowish-brown, verrucose, acute dorsal sepal (vs. light yellow green, glabrous, obtuse to rounded at the apex), 4–veined, elliptical-oblong, obtuse lateral sepals (vs. faintly 6–veined, ovate, acute) and smaller lip (2.1–2.3 × 1.6–1.8 mm vs. 4.0 × 2.5 mm), elliptical, obtuse, verrucose-striated (vs. oblong-ovate, obtuse, verrucose), and a glenion bilobed (vs. obovoid).
Description:— Plant epiphytic, up to 26 cm tall, erect; roots slender, flexuous, 0.5–0.7 mm in diameter. Ramicauls very slender, suberect, terete, 12.5–23.3 long and 0.1 cm in diameter, enclosed by papyraceous, tubular sheaths, upper sheath 2.8 mm long, basal sheath 1.25 mm long. Leaves erect, green suffused with purple at the margins and the underside, slightly convex, coriaceous, microscopically papillate, ovate, channeled in the middle, 5.5–7.4 × 1.5–1.8 cm, acuminate, slightly falcate at the apex, the base sessile, cordate. Inflorescence a fascicle of successive flowers produced from a suberect, spathaceous bract, ca. 0.9 mm long; floral bract infundibuliform, 3 mm long; pedicel tubular, 2.5 mm long. Flowers glossy, dorsal sepal yellowish-brown, slightly suffused with purple at the base, edges and veins, elliptical-obovate, 7.0–8.5 × 3.8–4.0 mm, 3-veined, subverrucose, convex in the apical third; lateral sepals connate into a 4-veined, elliptical-oblong, obtuse, minutely bifid pale purple with yellowish green base, 4.6–5.0 × 3.7–4.0 mm. Petals pale purple apex and base yellowish green, narrowly oblong, slightly constricted in the first apical third, acute, 3.8–4.0 × 0.6–0.8 mm, 1-veined, papillose, margins entire. Lip red purple combined with orange in the base and margins, elliptical, obtuse, verrucose-striated, convex, 2.1–2.3 x 1.6–1.8 mm, 3-veined, margin irregular; the base truncate, centrally channeled towards the apex of the lip, hinged to the column foot. Column yellowish green, transversely subrectangular, dorsally complanate, 1.3–1.5 × 1.0– 1.2 mm, glabrous, stout, 3-ribbed dorsally, stigma transversely bilobed with entire margins, rostellar flap 0.8 mm long. Anther cordiform, yellowish green, 0.3 mm long. Pollinarium with 2 obovoid, yellow pollinia, 0.2 mm long. Ovary subverrucose, curved in the middle, 2.0–2.3 × 1.0 mm.
Distribution and ecology: —The new species has been recorded in Zamora Chinchipe, Ecuador. It apparently also occurs in Piura department, northern Peru, where it was previously recorded photographically by Benavente et al. (2020) without any herbarium voucher, as Pleurothallis compress a Luer (1996a: 75), a Costa Rican species with different habit and flower morphology. The species has been found growing as an epiphyte on Pouteria caimito (Ruiz & Pavón 1802: 18) Radlkofer (1882: 333) (Sapotaceae) (Figure 9) and Andesanthus lepidotus (Bonpland 1808: 38) Guimar „es & Michelangeli (2019: 948) (Melastomataceae). The population of Pleurothallis marioandresavilae occurs in unprotected areas where selective timber extraction is common. The specimens were found growing together with other small orchids such as Brachionidium sp., Macroclinium sp., Pleurothallis ariana-dayanae Vélez-Abarca, Jiménez & Gutiérrez del Pozo (2022: 109), Maxillaria splendens Poeppig & Endlicher (1836: 66) and Stelis spp.
Additional specimens examined: — ECUADOR. Zamora Chinchipe: San Andrés, close to a river, 2075 m, 29 November 2022, M. Jiménez & G. Iturralde 1619 (HUTPL 14756!).
Etymology: —Named after Mario Andrés Ávila, professor at the Universidad Estatal Amazónica, in Ecuador, in gratitude for his unconditional help and educational support.
Taxonomic discussion:— Pleurothallis marioandresavilae (Figure 10C) has been confused in cultivated specimens with P. complanata, (Figure 10D) which is the most similar species. But the new species differs by shorter leaves (5.5–7.4 × 1.5–1.8 cm vs. 8.5–10.5 × 2.5–3), shorter pedicel (2.5 vs. 6.0–7.0 mm long), acute, yellowish-brown, verrucose dorsal sepal (vs. obtuse to rounded, yellow-green, glabrous), 4-veined, elliptical-oblong, obtuse lateral sepals (vs. 6–veined, ovate, acute), narrowly oblong petals (vs. narrowly linear-triangular), elliptical, verrucose-striated lip (vs. oblong-ovate, minutely verrucose), and bilobed glenion (vs. obovoid) (Figure 10).
Conservation status: — Pleurothallis marioandresavilae is known from only two localities, one near the protected forests of the El Quimi Biological Reserve, the other near the border with Peru, both in the Province of Zamora Chinchipe, in the southeast of Ecuador (Fig. 3), and apparently it also occurs in northern Peru. Both localities have been influenced by the strong anthropogenic activities (mining, logging and cattle grazing); however, it is not ruled out that the species may be present within the aforementioned reserve.
description: Published as part of Jiménez, Marco M., Vélez-Abarca, Leisberth, Mashendo-Jimbicti, Viviana, Garzón-Suárez, Henry X., Monteros, Marco F. & Wilson, Mark, 2023, Five new species of Pleurothallis (Orchidaceae: Pleurothallidinae) in subsection Macrophyllae-Fasciculatae from Southeastern Ecuador, pp. 161-181 in Phytotaxa 607 (3) on pages 168-170, DOI: 10.11646/phytotaxa.607.3.1, http://zenodo.org/record/8243217