Pleurothallis kashi-menkakarai Mashendo-Jimbicti, 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 kashi-Menkakarai

description: 1. Pleurothallis kashi-menkakarai Mashendo-Jimbicti, Vélez-Abarca & M.M.Jiménez, sp. nov. (Figures 1–2).
Type:— ECUADOR. Zamora Chinchipe: El Pangui, Cordillera del Cóndor flank, 3°38’32’’ S, 78°30’37” W, 1302 m, 23 October 2021, L. Vélez LV-0069 (holotype: HUTPL 14771!)
Similar to Pleurothallis fossulata Luer & Escobar from which it differs by its shorter, elliptic dorsal sepal (7.5–8 mm vs. 11 mm long, oblong), shorter, translucent green synsepal (6.5–7.0 mm vs. 10 mm long, red brown), crenulate, verrucose petals, equal in length to the lip (vs. entire, glabrous, shorter than the lip), and involute, thickened, verrucose, crenulate lip margins (vs. revolute, thin, smooth, entire).
Description:— Plant epiphytic, caespitose, to 30 cm tall. Roots slender, white, flexuous, 1 mm in diameter. Ramicauls erect, green, 8.9–20.1 long and 0.1 cm in diameter enclosed by two papyraceous sheaths at the base and one below the middle. Leaves 6.6–11.0 × 2.1–4.5 cm, sessile, coriaceous, erect to suberect, ovate, long acuminate, shiny, cordate at the base, with faintly raised lateral nerves, margin revolute, purplish. Inflorescence single-flowered, resupinate, produced in a successive fascicle from a reclining spathaceous bract to 1.4 cm long; peduncle abbreviate ca. 1 mm long, concealed within a spathaceous bract, floral bract tubular ca. 4 mm long, pedicel cylindrical, verrucose, straight, 3.9–5.0 mm long. Sepals glandulous-cellular, translucent yellow to reddish brown with red-brown and yellow veins, rarely in almost purely translucent yellow; dorsal sepal 7.5–8 × 4.5–5.0 mm, broadly elliptic, obtuse, concave, 3-veined; lateral sepals connate into a broadly ovate, subacute, synsepal, 6.5–7.0 × 4.5–5.0 mm, 4-veined, slightly concave at the base; Petals 4.5–5.0 × 0.9–1.0 mm, narrowly oblong, slightly falcate at the base, acute, inconspicuously 1-veined, papillose-verrucose, reddish brown to red purple, rarely tan yellow, margins yellow and crenulate-erose. Lip 5 × 2.5–2.7 mm, shortly unguiculate, oblong-ovate, obtuse and incurved at the apex, slightly convex above the middle, 3-veined abaxially, papillose-verrucose, reddish brown to red-purple, rarely tan yellow, margins crenulate, thickened, purple; the base concave, hinged to the column-foot; a small, narrowly elliptic glenion in the middle. Column purple, stout, complanate, papillose, 2.0 mm long, 1.5–1.8 mm wide, 2-channeled dorsally, widening to the base, column-foot glandulous, paler. Anther narrowly obovate, purplish with a touch of yellow, papillose, stigma apical, bilobed, 0.7 mm long. Pollinia 2, clavate, 0.6 mm long. Ovary cylindrical, subverrucose, brownish purple, slightly curved at the joint with the pedicel, 3.5–4.6 mm long, 0.8 mm wide.
Distribution and ecology: — Pleurothallis kashi-menkakarai is known from two locations within the Cordillera del Cóndor in south-eastern Ecuador (Figure 3). The species is found around 1400 m in elevation in lower montane forests near watercourses of sandstone plateaus. The holotype of this species was found growing sympatrically with Maxillaria grayi Dodson (1994a: 69), P. cordata (Ruiz & Pavón 1798: 234) Lindley (1830: 5) and P. adeleae Luer (1981: 200), between the lower and middle strata of the forest. This forest is characterized by a mixture of Andean and lowland trees of the Amazon, where the canopy can grow up to 30 m in height and the understory is dense. It was also found growing together with Dichaea histrio Reichenbach (1859: 330), Epilyna embreei Dodson (1994b: 146) and Maxillaria bicallosa (Reichenbach 1878: 9) Garay (1962: 527), over the roots of Socratea exorrhiza (Martius 1824: 36) Wendland (1860: 103) palms, in a nearby location. This species has been only recorded in the province of Zamora Chinchipe and is considered as endemic.
Etymology: —From the words kashi (night), and menkakarai (lost), meaning “lost at night” in the Shuar language, because the new species was discovered at night when researchers were lost in the forest of a Shuar community.
Taxonomic discussion: — Pleurothallis kashi-menkakarai is similar to Pleurothallis angusta Ames & C. Schweinfurth (1925: 23–24) from Costa Rica and P. fossulata from Colombia with which it shares flowers with a maroon-burgundy colored lip, a triangular, cream-colored area between the apex and edges of the lip and glenion and two calli flanking the deep glenion. The new species is distinguished from Pleurothallis fossulata (Figure 2) by its smaller plants (30 cm vs. 42 cm tall), the narrower (3.0– 4.5 cm vs. 5–7 cm wide), cordate, attenuate leaves (vs. deeply cordate, acuminate), the shorter pedicel (3.9–5.0 mm vs. 10 mm long), the shorter ovary (3.5–4.6 vs. 6 mm long), the one flower produced per fascicle (vs. to 2–3 often simultaneous), the non-dilated petals (vs. dilated at the base), the subacute synsepal (vs. obtuse) and the strongly incurved apex of the lip (vs. convex).
It is also similar to Pleurothallis angusta but is distinguished by the smaller plants (30 cm vs. 50 cm tall), the shorter (6.6–11.0 cm vs. 8.0– 16.5 cm wide), ovate, long-acuminate leaves (vs. lanceolate, acute), the shorter pedicel (3.9–5.0 mm vs. 14 mm long), the shorter ovary (3.5–4.6 mm vs. 5.0–7.0 mm long), the translucent yellow or reddish brown flowers (vs. dark purple), the shorter (8 mm vs. 11 mm long), broadly elliptic, obtuse dorsal sepal (vs. ovate, acute), the 4-veined synsepal (vs. 5-veined), the smaller (4.5–5.0 × 0.9–1.0 mm vs. 6.3–7.0 × 1.5–2.0 mm), narrowly oblong, acute petals (vs. falcate, obtuse), the lip with crenulate margins (vs. minutely ciliate) and the narrowly obovate anther cap (vs. obtriangular) (Pupulin 2021).
Conservation status: — Pleurothallis kashi-menkakarai has not been reported within the Ecuadorian National System of Protected Areas. The species is known from two abundant populations, where a population density of 3 to 4 plants per phorophyte can be found. However, the range in which the species occurs is under threat by gold mining and grazing since P. kashi-menkakarai has only been observed within an area of 9 km 2 (Figure 3).
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 162-164, DOI: 10.11646/phytotaxa.607.3.1, http://zenodo.org/record/8243217