Piper oteguanum W. Trujillo-C. & M.A.Jaram

Trujillo, William, Jaramillo, M. Alejandra, Toro, Diego & Balslev, Henrik, 2023, Over- and under-described: new species, new synonyms, and a new name in the megadiverse genus Piper (Piperaceae) on the east Andean slopes, Phytotaxa 601 (3), pp. 263-284 : 273-276

Piper oteguanum W. Trujillo-C. & M.A.Jaram ., stat. nov., nom. nov., Figs. 1 , 2 , 7 , 8 .

Type:— COLOMBIA: Caquetá, Río Orteguaza , 2 August 1926, G . Woronow & S . Juzepczuk 6364 (holotype ILL!) .

Basionym:— Piper cajambrense var. caquetanum Trel. & Yunk. , The Piperaceae of northern South America 1: 27. 1950.

Shrubs 3 m tall, loosely branched. Internodes 8–10 cm long on monopodial axes, 5–7 cm long on sympodial axes, smooth, light green in fresh specimens and yellow when dry, glabrous, idioblasts not evident in any part of the plant. Prophylls not developed. Petioles (8–)12–15(–17.5) cm long, margins vaginate for ½ to 4 / 5 of the length of the petiole, glabrous, slightly canaliculate. Leaf blades uniform in shape and size along all axes, (32–)35–48(–53) × (16–)20–(33–) 37 cm long including the basal extension, elliptic, base cordate, inequilateral on both monopodial and sympodial axes, sinus closed, with one lobe (5–) 7–9 cm long and exceeding the other, the longest lobe rotundate and fully overlapping the petiole, the shorter one rotundate and shorter than the petiole, base insertion symmetric, blade basally and medially symmetric, glabrous on both sides, coriaceous, pinnately nerved from the lower half of the midvein with one or two minor veins along the distal third, 6–7 pairs of secondary nerves, festooned brochidodromous, the three or four proximal pairs diverging between the base and the lower third, the fifth and sixth pair diverging from the distal third; higher order veins reticulate, apex acuminate, leaf blade fresh dark green above, light green below in living material, light yellow to olive green when dry. Inflorescences and infructescences simple spikes, terminal, pendulous; peduncles 6–7 × 2–3 mm, glabrous, light green; rachis (27–) 33–43 cm long; fruits sessile, densely arranged. Floral bracts cucullate at anthesis, triangular to rectangular when seen from above, 1.8–2.1 × 0.7–0.9 mm, forming bands around the rachis, fimbriate. Flowers with four stamens, filament 4.1–4.6 mm long, anthers 0.5 × 0.2 mm, with two thecae, with longitudinal dehiscence and a pellucidly dotted connective; stigmas three, on a 0.4–0.7 mm long style. Fruits drupes, pyramidal, apically obtuse, 2.4–2.6 × 1–1.3 mm, immersed in rachis, papillate to rugulose, with aristate, 0.6–0.9 mm long style, 3–4 stigmas to 0.6 mm long, glabrous, black when dry and light green in fresh material.

Taxonomic history:— Piper cajambrense var. caquetanum Trel. & Yunk. (1950: 27) was published by Trelease and Yuncker (1950) based on a specimen from the municipality La Montañita on Río Orteguaza, department of Caquetá in Colombia (G. Woronow & S. Juzepczuk 6364, ILL). Based on examination of the original herbarium material and new field collections made in the vicinity of the type locality, we provide morphological and molecular evidence that suggest P. cajambrense var. caquetanum should be treated as a separate species. It can be distinguished from the typical variety, P. cajambrense var. cajambrense , in having glabrous leaves and petioles without epidermal warty outgrowths. The geographic distributions of the two entities are distinct; P. cajambrense var. cajambrense occur in the rainforests of the Pacific region of Colombia below 50 m elevation, whereas P. cajambrense var. caquetanum , here elevated to species as P. oteguanum , occurs in the premontane forest and foothills on the Amazonian slope of the Andes.Apart from our own collections from Colombia, it is also known from two locations in Ecuador. Since the epithet “ caquetanum ” is already in use as Piper caquetanum Yunck. (1957: 530) , a new name is presented. The new epithet, oteguanum , honors the Otegua indigenous people who inhabited the headwaters of the Orteguaza River in Caquetá, and from which the river derives its name. The Otegua lived in the region during the 16th century and the Spanish conquest. The type specimen of this species was collected in a locality on the Orteguaza River.

Distribution:— Piper oteguanum is distributed along the Amazonian slope of the Andes of Colombia and Ecuador, at 600–1500 m elevation in the Tropical premontane wet forest (TPwf).

Habitat and ecology:—It is a shade-loving species in the understory of well-preserved and secondary forests.

Phenology:—Flowering specimens were collected in February, August, and October and fruiting specimens were collected in May, July, and October and.

Conservation status:—This species is known from eight collections representing three subpopulations. The locations are threatened by deforestation and expansion of the agricultural frontier. The extent of occurrence (EOO) is 2695 km 2 and area of occupancy (AOO) is 20 km 2, which, together with the continuing decline in quality of its habitat, suggests that it is Endangered [EN B1a+B2a].

Phylogenetic relationships:— Piper oteguanum belongs to the Macrostachys clade, which is a group of shrubs or treelets with sheathing petioles 2/3 or entire length on monopodial and sympodial branches, pinnately nerved leaves, and mostly long inflorescences with densely arranged flowers forming bands around the rachis, flowers with four long stamens ( Jaramillo et al. 2008). Piper oteguanum together with P. obtusilimbum C. DC. (1905: 105) , P. marsupiiferum Trel. (1936: 189) , and P. cochleatum Sodiro (1905: 203) form a monophyletic clade with strong support ( Figure 1 , BS=99). Species in this subclade are distributed in northwestern Amazonia in Colombia, Ecuador, and Peru. These taxa have a strongly asymmetrical leaf base, with one side of the leaf forming a pronounced lobe that overlaps the petiole. Piper oteguanum is distinct from the others in having glabrate leaves. Furthermore, our phylogenetic reconstructions shows that P. cajambrense , from the Pacific coast of Colombia, is not closely related to these Amazonian taxa ( Figure 1 ). On the contrary, P. cajambrense shares a recent common ancestor with other species distributed in the Pacific lowlands of Colombia such as P. spoliatum Trel. & Yunck. (1950: 118) ( Figure 1 , BS=85).

Comments:—The four species in the Macrostachys clade to which P. oteguanum is related have stylose fruits and long stigmas. Piper oteguanum differs from P. obtusilimbum and P. cochleatum in having glabrous leaves and it differs from the similar P. marsupiiferum in having smooth leaves vs. bullate leaves.

Key to Piper oteguanum and related species in the Macrostachys clade

1. Leaves bullate........................................................................................................................................................... P. marsupiiferum

– Leaves smooth....................................................................................................................................................................................2

2. Abaxial leaf surfaces, petioles, and internodes glabrous............................................................................................... P. oteguanum

– Abaxial leaf surfaces, petioles, and internodes pubescent .................................................................................................................3

3. Peduncles 4–5 cm long, rachis> 8 cm long ............................................................................................................... P. obtusilimbum

– Peduncles 2.5 cm long, rachis <5 cm long ................................................................................................................... P. cochleatum

Additional specimens examined:— COLOMBIA: Caquetá Belén de los Andakíes: Parque Natural Municipal Andakí , La Mina , Las Verdes canyon, 1°37’50”N, 75°54’23”W, 730 m, 1 February 2017 [fl], N. Castaño et al. 9322 ( COAH!). Florencia: Trail to Sucre, Finca campamento Sucre , 1°46’52”N, 75°39’5.1”W, 1050 m, 5 July 2012 [fr], W. Trujillo & C. Malambo 2406 ( COL!); El Caraño, Las Brisas farm, 1°44’14.7”N, 75°40’35.3”W, 1116 m, 18 October 2013 [fl], W. Trujillo et al. 3007 ( COL!); El Caraño, Las Brisas farm, 1°44’14.5”N, 75°40’35.4”W, 1100 m, 10 May 2012 [fr], W. Trujillo & O. Perdomo 2075 ( COAH!, COL!); El Caraño, trail to Quindío, 550 m, 16 July 2014 [fr], W. Trujillo et al. 3183 ( COL!); El Caraño, trail to Sucre , 1076 m, 1°47’5.8”N, 75°38’50.5”W, 8 July 2014, W. Trujillo et al. 3189 ( COL!). ECUADOR: Napo-Pastaza, between Tena and Archidona , 9 October 1939 [fr], E. Asplund 9176 ( NY!); Napo, Misahualli, along Misahualli river , 1°02’S, 77°40’W, 12 August 1990 [fl], B. Bennett 4489 ( NY!) .

Figures

FIGURE 1. Phylogenetic relationships of the species Piper oteguanum, P. rubrifolium, P. laperdizense, P. calanyanum and P. morelianum based on Maximum Likelihood analysis of nrITS sequences. Names with taxonomic novelties are shown in bold. Names of clades follow Jaramillo et al. (2008), and Callejas-Posada (2020). Numbers above branches are ML bootstrap support values (>80).

FIGURE 2. The localities of four new Piper species on the east Andes slopes of Colombia, and Ecuador.

FIGURE 7. Piper oteguanum. A. Sympodial branch. B. Detail of papillae on leaf abaxial surface. C. Petiole on sympodial branch. D. Petiole on monopodial branch. E. Detail of infructescence. F. Floral bract adaxial view. G. Stamen. H. Detail of the anthers and connective. I. Fruit lateral view. J. Floral diagram. Illustration by Marcela Morales based on W. Trujillo & C. Malambo 2406 (COL).

FIGURE 8. Piper oteguanum A. monopodial and sympodial branches and inflorescences. B. Detail of flowering spike showing long filaments and stigmas. Photos by William Trujillo based on W. Trujillo 2075 (COAH).