Thibaudia shagmiana M. M. Jiménez, Luteyn & Darío García, 2025

Jiménez, Marco M., Luteyn, James L., Kuethe, J. R., García, Darío, Lapo-González, Nadia, Garzón-Suárez, Henry X. & Iturralde, Gabriel A., 2025, A new species of Thibaudia (Ericaceae, Vaccinieae) from the Cordillera del Cóndor in Ecuador, Biodiversity Data Journal 13, pp. e 157044-e 157044 : e157044-

Thibaudia shagmiana M. M. Jiménez, Luteyn & Darío García sp. nov.

Materials

Type status: Holotype. Occurrence: catalogNumber: HUTPL 15454 ; recordNumber: M. M. Jiménez & D. Medina 2512; recordedBy: Jiménez, M. M.; occurrenceID: D942499F-BBFF-55E4-B250-EBB45ADDC5DC; Taxon: scientificName: Thibaudia shagmiana M. M. Jiménez, Luteyn & Darío García ; Location: country: Ecuador; stateProvince: Zamora Chinchipe; locality: Cordillera de Shagmi, Cordillera del Cóndor flank, between El Pangui and Los Encuentros ; verbatimElevation: 1523 m; Event: year: 2025; month: 1; day: 29; Record Level: institutionCode: HUTPL!

Description

Plant erect, epiphytic shrub with fusiform lignotubers, 4.5–13.2 cm long, 4.0– 9.4 in circumference; stems suberect to descending, terete to subterete, to 31.5 cm long, arising from a lignotuber, epidermis cracking longitudinally and exfoliating, striate after exfoliation, glabrous, brown in color, rooting when in contact with humus litter; axillary buds compressed, emerging ca. 1 mm above leaf node, bracts papyraceous, 1.9–4.7 mm long, long-triangular to subulate, glabrous. Leaves pseudoverticillate at apex of branch, suberect, subfalcate, sessile to subsessile; petiole (when present), complanate, 1.7–4.7 × 2.4–2.5 mm, glabrous, suffused with pink; blades thick-coriaceous, lanceolate to rarely elliptic, 2.4–10.9 × 1.3–4.2 cm, dull dark green adaxially, paler abaxially, centrally channelled and finely wrinkled adaxially, base cuneate to slightly attenuate, apex subacute, margin revolute, slightly incurved; venation conspicuously 3–5 - plinerved from near base, midrib impressed and thickened in proximal 6–8 mm adaxially, raised and conspicuous abaxially, lateral nerves impressed adaxially and slightly raised abaxially, veinlets obscure, reticulate and anastomosing near margin. Inflorescence axillary, flowers solitary or 2 - fasciculate, produced in leaf axils or on leafless branches; rachis short, 0.9–1.7 mm long × 1.1–1.2 mm diam., subterete, greenish with a touch of brown, covered by up to 4 caducous bracts, 0.8–0.9 mm long, these green but becoming brown with age; pedicel straight to slightly curved, subterete to obconical, subverrucose, 3.8–5.2 × 1.8–2.1 mm, magenta to scarlet with a brownish green base; floral bract 1, caducous, convex, 0.4-0.9 mm long, ovate to broadly ovate, apex obtuse, pale green becoming brown with age; bracteoles 2, located at base of pedicel, caducous, ovate, acute, convex, 1.1–1.4 × 1.0– 1.1 mm, margin erose, whitish or brownish green with apex white, becoming brown with age. Flowers pentamerous, pendant, aestivation valvate; calyx articulate with pedicel, cupuliform overall, 3.9–4.4 × 2.8–3.6 mm, magenta to scarlet, paler at apex, glabrous but bearing scattered, short (ca. 0.2 mm long), brownish glandular fimbriae, hypanthium terete to subterete, slightly dilated to middle, rounded at base, 2.0–2.6 × 2.8–3.2 mm, limb cylindrical, 1.6–2.1 × 2.8–3.6 mm, lobes deltoid, apiculate, 0.4–0.5 × 0.8–0.9 mm, sinuses rounded; corolla carnose, bistratose, tubular, broadly and bluntly pentagonal (not angled or winged), narrowing to base, expanding slightly distally, glabrous, 11.1–14.0 mm long × 2.1 mm diam. at base, 3.0 mm diam. at throat, magenta to scarlet, lobes spreading, 0.8–1.3 × 1.5–2.0 mm, pinkish-white externally, internally glabrous, trigonous, dull, papillose. Stamens 10, shorter than corolla, equal with each other, 7.7–9.3 mm long; filaments equal, connate, 4.6–6.5 mm long, glabrous, pale pink; anthers 5.1–6.3 mm long overall, thecae 3.1–4.5 mm long, conspicuously papillose and prognathous at base, tubules 2, laterally connate, flattened, glabrous, 1.7–2.1 mm long, dehiscing by introrse apical slits ca. 1.4 mm long. Style 8.6–9.5 mm long, shorter than corolla, glabrous, white to pink or pink below middle, greenish at apex; stigma truncate; nectariferous disc annular. Fruit not seen. (Fig. 1 ).

Diagnosis

Thibaudia shagmiana is distinguished from other members of the genus by its combination of scrambling plant (to 30 cm) and lignotuberous with branches that root from nodes when in contact with mossy litter, lanceolate leaves that are pseudoverticillate at apex of branches, caducous bracteoles, solitary-flowered or 2 - fasciculate inflorescences on short rachis, glabrous flowers produced in axils of lower leaves or on leafless branches, cupuliform calyx with a cylindrical limb, corolla with trigonous lobes, stamens ⅔ the corolla length, staminal filaments connate, prognathous thecae, laterally connate tubules, and a style that is shorter than the corolla.

Etymology

The new species is named after the Cordillera de Shagmi, a west-facing slope of the Cordillera del Cóndor region in Zamora-Chinchipe province, Ecuador, where this species was found.

Distribution

Thibaudia shagmiana is currently known only from the type locality (around seven individuals recorded along a 230 - m transect), within an Andean tepui ( Neill et al. 2014) in the Shagmi sector, a mountainous chain located on the slopes of the Cordillera del Cóndor in Zamora Chinchipe province, southeastern Ecuador (Fig. 2 ). The tepui spans approximately 9000 m ² and comprises a sandstone plateau at elevations ranging from 1400 to 1700 m a. s. l. ( Vélez-Abarca et al. 2023).

Ecology

According to the Ministerio del Ambiente del Ecuador (2013), the ecosystem where Thibaudia shagmiana is found corresponds to the Low Montane Evergreen Forest on Sandstone Plateaus of the Cordillera del Cóndor-Kutukú region (BsBa 03). This area is characterized by a mean annual temperature of 20.4 ° C, and total annual precipitation of approximately 2148 mm. The climate is perhumid, with frequent fog and strong winds. The vegetation is generally low with scattered trees and extensive wooded shrub reaching a maximum height of 15 m (Fig. 3 ). The most common species include Podocarpus oleifolius D. Don , Vochysia condorensis Huamantupa & D. A. Neill , Schefflera harmsii J. F. Macbr. , and Magnolia yantzazana F. Arroyo , along with an abundance of epiphytic plants, particularly among which are bryophytes and orchids.

Conservation

Thibaudia shagmiana is known only from the Shagmi sandstone plateau in the Cordillera del Cóndor, which is near El Pangui. The vegetation and soil conditions of this area are not suitable for cattle grazing or drystock pastures, which consequently protects the species' habitat from excessive deforestation. Only several individuals are known from the type locality. Regardless, this population is located within an actively operating mining concession, which is currently in operation. This activity may put the long-term conservation of the virgin habitat and its soil / aquifer chemistry at risk (e. g., an access road has just been opened that transects the habitat where this species is found).

Applying conservation analysis with the georeferenced single locality, the calculated area of occupancy (AOO) is 4 km 2. The extent of occurrence (EOO) has not been calculated due to the limited number of populations sighted. We recommend a conservation status of Critically Endangered (CR) according to the IUCN (2024) criteria B 2 ab (i, ii), C 2 a (i), and D 1 is proposed here. The authors feel this assessment is accurate considering its presence outside of any protected area and the evident threat from the mining activity; this taxon is subject to higher levels of concern in the short term.

Figures

Figure 1. Thibaudia shagmiana M. M. Jiménez, Luteyn & Darío García. A Habit showing pseudoverticillate leaves (B), a close-up of a branch (C), inflorescence (D), and lignotuber (E). F Adaxial (right) and abaxial (left) views of leaves showing lateral margin (G) and adaxial base of leaf (H). I Corolla showing the ventral view of the corolla lobes (J) with a close-up of the surface (K). L Longitudinal section of calyx. M Calyx, pedicel and style with a close-up of lobes (N), hypanthium surface (O) and bracteole (P). Q Stamens with a close-up of apical slits of tubules (R) and the apex of thecae (S). Prepared by N. Lapo-González based on photographs by M. M. Jiménez of the type.

Figure 2. Geographic distribution of Thibaudia shagmiana in the southeastern region of Ecuador (prepared by H. X. Garzón-Suárez with ArcGIS).

Figure 3. Thibaudia shagmiana in situ. A Habitat of the species. B An individual on a fallen tree branch. C Holotype of the species on a tree trunk.