Ceratostema moronasantiagoensis M. M. Jiménez & H. Garzón, 2025

Ceratostema moronasantiagoensis M. M. Jiménez & H. Garzón sp. nov.

Materials

Type status: Holotype. Occurrence: recordNumber: H. Garzón 297; recordedBy: H. Garzón; occurrenceID: 4D149160-74F4-5EAD-8B32-DCB3753B4513; Taxon: scientificName: Ceratostema moronasantiagoensis M. M. Jiménez & H. Garzón ; Location: country: Ecuador; stateProvince: Morona Santiago; locality: Cerca de San Juan Bosco ; verbatimElevation: 1492 m; Event: year: 2025; month: 5; day: 8; Record Level: institutionCode: HUTPL!

Description

Shrubs pendant, lianoid epiphytic; indumentum consisting of almost persistent trichomes, white, eglandular, 0.1–0.6 mm long, arranged unevenly, sparsely to densely on younger branches, petioles, underside of leaves, inflorescences and flowers, including stamens and style; axonomorphous roots with a woody, fusiform, well-developed lignotuber-like swelling, ca. 4.3–7.4 cm × 3.1–6.3 cm in diameter. Stems terete to subterete, ca. 52 cm long, glabrous, slightly arching, arising from the swelling, older stems dark brown, cracking longitudinally and exfoliating; younger branches subterete, ca. 51 cm long, 4.2 mm wide, descending to pendant, slightly arcuate, pale green, sometimes suffused with brownish-pink, pilose, becoming glabrous, striate and dark brown when old or after exfoliation; axillary buds emerging 1 mm below the leaf node. Leaves spirally arranged, pendulous to descending, new leaves mahogany red; petioles subterete, ca. 3.1 mm × 2.6 mm, pilose, becoming glabrous with age; blades dark green adaxially, pale green abaxially, ovate, convex, 6.8–14.3 cm × 4.5–6.9 cm, coriaceous, glabrous adaxially and abaxially, lustrous adaxially, dull abaxially, pinnately nerved with 3–4 lateral nerves per side, mid-vein raised along almost its length adaxially, impressed and hollow abaxially, the secondary veins slightly raised adaxially, impressed abaxially, branching, anastomosing distally with reticulate veinlets, obscure, base deeply cordate, partially folded downwards exposing the flowers, lobes auriculate, overlapping, apex acuminate to long-acuminate. Inflorescence axillary, a cincinnus with very compact internodes, 2–5 - flowered, sessile; rachis obconical, ca. 9.9 mm long, 2.0– 2.8 mm thick, covered at the base by several bracts; bracts persistent, pale green, ovate, ca. 1.2 mm long, pubescent, seemingly obtuse at the apex; floral bracts persistent, similar in colour and texture to the peduncle bracts, seemingly ovate, 2.8–3.1 mm long, acuminate; pedicel articulate with the calyx, whitish-green, subterete, 4.9–5.6 mm long, 3.0– 3.5 mm thick, pubescent; bracteoles 2, located near the base and opposite, whitish-green, ovate-triangular, 1.0– 1.9 mm × 0.8–1.1 mm, pubescent, apex acuminate, long-ciliate along the margins. Flowers pentamerous, reflexed, with pale green calyx and fuchsia red corolla, paler and whitish at the angles; calyx 6.0– 7.5 mm × 5.2–6.4 mm, pubescent adaxially and sparsely pubescent abaxially; hypanthium obconical, 5 - winged, 2.7–3.8 mm × 4.6–5.0 mm, truncate; limb spreading, open, 3.5–4.0 mm × 5.2–6.4 mm; lobes 5, deltate, 3.0– 3.4 mm × 2.6–3.2 mm, slightly incurved at the apex, acuminate, sinuses acute. Corolla tubular, but narrowing distally and proximally, thick-carnose, bistratose, bluntly 5 - angled, 4.3–4.5 cm long (including the lobes), 6.0 mm in diameter at the base, 5.0 mm in diameter at the throat, pubescent along the angles externally and in the internal apical half; lobes 5, spreading, narrowly linear-triangular, 17.5–20.9 mm × 1.8–2.3 mm, pubescent externally, glabrous internally, channelled and subverrucose internally, apex acuminate, slightly incurved. Stamens 10, with white filaments, golden yellow tubules and darker thecae, nearly equalling the corolla in overall length, 4.0– 4.3 cm long; filaments connate forming a tubular staminal tube, 12.8–13.2 mm long, sparsely puberulent in both sides; anthers 3.5–3.6 cm long, each pair of thecae unequal, prognathous, 6.2–6.8 mm long, conspicuously granulose; tubules distinct, slightly unequal, seemingly connate in the distal 3 / 5, 2.8–3.0 cm long, glabrous, dehiscing by terminal pores, ca. 0.8 mm × 0.3 mm. Style pale green, exserted, 4.6–4.8 cm long, pilose, stigma truncated. Fruits not seen. (Fig. 4 View Figure 4 )

Diagnosis

The new species is most similar to C. auriculatum , but it is distinguished by the calyx limb without lobes at the base (vs. lobed), the smaller, acuminate calyx lobes, 3.0– 3.4 mm × 2.6–3.2 mm (vs. acute, 9.0–10.0 mm × ca. 5.0 mm), not conspicuously nerved, pubescent (vs. prominently and reticulate nerved, weakly ciliate at the margin), the fuchsia red, pubescent corolla (vs. black-purple, weakly pilose), with longer lobes, 17.5–20.9 mm long (vs. 11.0–13.0 mm long) and the puberulent, longer filaments, 12.8–13.2 mm long (vs. glabrous, 6.0–7.0 mm long).

Etymology

The name of the new species is dedicated to its primary geographical distribution, the Province of Morona Santiago.

Distribution

Ceratostema moronasantiagoensis is known only from the area surrounding the town of San Juan Bosco in south-eastern Ecuador. (Fig. 2 View Figure 2 ).

Ecology

Ceratostema moronasantiagoensis is found as an epiphyte on tree trunks and branches near the canopy, showing no preference for a particular forest stratum. The species was seen at elevations between 1300 and 1600 m in the interior of mature primary forests with predominantly clayish soil conditions (Fig. 5 View Figure 5 ). The type locality forest is predominantly represented by Alchornea glandulosa Poepp. , Inga oerstediana Benth. and Neea divaricata Poepp. & Endl. Specimens of Ceratostema moronasantiagoensis were found sympatric with other flora such as Dracontium fuscopunctatum Cornejo, Croat & G. Tello , Drymonia cf. coccinea (Aubl.) Wiehler , Glossoloma subglabrum J. L. Clark , Pleurothallis valvola Luer & Hirtz and Sobralia pardalina Garay.

Conservation

Ceratostema moronasantiagoensis was found near sites of forest clearing and agriculture, livestock farming and mining activities, consequently exhibiting the destructive, unsustainable nature of these operations within Ecuador. About ten individuals are known from four populations near San Juan Bosco in southern Morona Santiago Province, Ecuador. The extent of occurrence (EEO) calculated for the new species resulted in an area of 20 km 2 with an area of occupancy (AAO) of 5.94 km 2. Given the aforementioned parameters, we recommend including the new species under the category of Critically Endangered (CR) according to the IUCN Criteria B 1, B 2, C 2 a (i) and D 1 ( IUCN 2024).

Taxon discussion

Ceratostema moronasantiagoensis is most similar to C. auriculatum by the lianoid plants and the deeply cordate, pinnately nerved, glabrous leaves that are distinctly auriculate at the base. The basal lobes of the leaves are reflexed and do not conceal the flowers as seen in other members of this taxonomic lineage. This morphological trait extends to part of the inflorescence, where the reflexed leaves more or less obscure the inflorescence in C. auriculatum as is mentioned by Luteyn (1996). However, in C. moronasantiagoensis the inflorescences are likewise reflexed, thereby revealing the flowers. In consideration of the other members of the aforementioned “ auriculatum ” group, the leaves are generally folded at the base to fully conceal the flowers at all times. Further differences between C. moronasantiagoensis and C. auriculatum are the acuminate, narrower leaves that measure 4.5–6.9 cm wide (vs. short-acuminate, 5.5–9.6 cm wide); the shorter (4.9–5.6 mm long vs. 5.0–8.0 mm long), subterete pedicel (vs. bluntly-angled); the deltate calyx lobes (vs. ovate); the corolla being pubescent along the veinal angles (vs. glabrous or weakly pilose) and the lobes being incurved (vs. reflexed) upon anthesis ( Luteyn 1996).

A dichotomous key and a table of morphological characters for the species of Ceratostema auriculatum group are provided below (see Table 1 View Table 1 ).