Caperonia amarumayu Kulkamp & Cordeiro 2021, sp. nov.
Creators: name: Külkamp, Josimar
name: Iganci, João R. V.
name: Cordeiro, Inês
name: Baumgratz, José Fernando A.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Malpighiales
Euphorbiaceae
Caperonia
Caperonia amarumayu

description: Caperonia amarumayu Külkamp & Cordeiro, sp. nov. (Fig. 1)
Type:— BOLIVIA. Pando: Manuripi, Conquista, embarcadero sobre el Madre de Dios, 150 m, 1 February 1983, J. Fernández Casas & A. Susanna 8571 (holotype: NY [NY03950229]!; isotypes: MA [MA01-00694614]!, MO [MO1266996], TEX [TEX00528089]!).
Diagnosis:— Caperonia amarumayu is similar to C. palustris due to the penninerved leaves and pistillate flowers with 5–6 sepals, but differs by the prickly stem, staminate flowers with unequal and pubescent petals, 10 stamens, and pistillate flowers with 18–24-laciniate styles (versus non-prickly stems, equal and glabrous petals, 8 stamens, and pistillate flowers with 10–14-laciniate styles).
Description:—Herb, ca. 1 m tall, monoecious; internodes 2–4 cm long, stem longitudinally striate, with prickles 0.5–0.7 mm long, simple and glandular trichomes at the apex of branches. Stipules ca. 0.3 × 0.15 cm, triangular, ciliate, with simple trichomes on the abaxial surface. Leaves: petiole 3–5 mm long; blade 6.9–14.7 × 1.1–1.7 cm, lanceolate to linear, base rounded, apex acute, penninerved, secondary veins 9–16; indumentum with simple trichomes, and caducous glandular trichomes on young leaves. Inflorescences 3.2–6.1 cm long; axis with simple, malpighiaceous and glandular trichomes; bracts 1–1.5 × 0.8–0.9 mm, lanceolate; staminate flowers 8–16, pedicel ca. 1 mm long, articulated in middle, with simple, malpighiaceous and glandular trichomes; sepals 5, 2–2.2 × 0.9–1.1 mm, equal, lanceolate, fused at the base, apex acute, margin entire, pubescent on both surfaces; petals 5, with simple trichomes on the abaxial surface, unequal, 3 of them oblong to elliptic, 1.9–2.5 × 0.9–1.1 mm, adnate to the base of the staminal column, the other 2 linear, 0.7–0.8 × 0.4–0.45 mm, adnate to the middle of the staminal column; stamens 10, staminal column ca. 0.8 mm long, glabrous, pistillode globose; pistillate flowers 1–2, pedicel 1–1.6 mm long, articulated at the middle; sepals 5–6, 2.8–3.2 × 1.8–2.1 mm, unequal, lanceolate, base fused to the receptacle, apex acute, margin entire, ciliate, simple trichomes on the abaxial surface; petals not seen; ovary with simple and glandular trichomes; styles ca. 1.5 mm long, 18–24 laciniate, glabrous. Fruit 6–8 mm diam. Seeds ca. 3 × 2.7 mm, globose to ovoid.
Distribution and habitat:— Caperonia amarumayu is only known from its type collection in northernmost Bolivia (Fig. 2), in a low elevation (ca. 150 m) area in the Amazon rainforest domain with many rivers, according to Navarro (2011). Like all other species of the genus, C. amarumayu has a wetland habit, in this case the floodplain of the Madre de Dios river.
Conservation status:— Caperonia amarumayu is considered as Data Deficient (DD) in terms of conservation status assessment (IUCN 2013), but deforestation and gold mining are considerable threats in the Madre de Dios river region.
Phenology:—Flowering and fruiting in February.
Etymology:—In the Quechua indigenous language, Amaru = serpent, and mayu = river. Amarumayu was the name given by the Quechua people to the river currently known as Madre de Dios, where the species was collected.
Notes:—Due to its prickly stem (Fig. 1B) this new species must be classified in Caperonia sect. Aculeolatae. The characters that distinguish it from the other Bolivian species of the genus, C. castaneifolia, C. glabrata Pax & Hoffmann (1912: 43) and C. palustris (fide Jørgensen et al. 2014), and C. zaponzeta, that is first recorded in Bolivia here, are presented in Table 1.
description: Published as part of Külkamp, Josimar, Iganci, João R. V., Cordeiro, Inês & Baumgratz, José Fernando A., 2021, New species and occurrences of Caperonia (Euphorbiaceae) for South America, pp. 86-92 in Phytotaxa 529 (1) on pages 87-89, DOI: 10.11646/phytotaxa.529.1.6, http://zenodo.org/record/5814310