Research Article |
Corresponding author: John L. Clark ( jclark@selby.org ) Academic editor: Alexander Sennikov
© 2023 John L. Clark, David A. Neill.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Clark JL, Neill DA (2023) Amanoa condorensis (Phyllanthaceae), a new shrubby species from the Cordillera del Condor in southern Ecuador. PhytoKeys 227: 89-97. https://doi.org/10.3897/phytokeys.227.104703
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A new species of Amanoa (Phyllanthaceae) is described from the sandstone Nangaritza Plateau in the Cordillera del Cóndor Region in southern Ecuador. Amanoa condorensis J.L.Clark & D.A.Neill is a small tree, 4 m tall that is only known from the type collection. The new species is distinct by a shrub habit, presence of coriaceous leaves with an acuminate apex, and congested inflorescences. The relatively high elevation of the type locality, presence of an androphore, and the habit as shrub or low tree are an unusual combination for Amanoa. The conservation status of A. condorensis is assessed as Critically Endangered (CR), based on IUCN Criteria.
Se describe una nueva especie de Amanoa (Phyllanthaceae) de la meseta de arenisca de Nangaritza en la región de la Cordillera del Cóndor en el sur de Ecuador. Amanoa condorensis J.L.Clark & D.A.Neill es un pequeño árbol de 4 metros de altura que sólo se conoce de la colección tipo. La nueva especie se distingue por la presencia de inflorescencias congestionadas, hojas coriáceas con ápice acuminado, y porte arbustivo. La elevación relativamente más alta de la localidad tipo, la presencia de un andróforo, y el hábito de arbusto o árbol pequeño son una combinación inusual para Amanoa. El estado de conservación de A. condorensis se evalúa como En Peligro Crítico (CR) según los Criterios de la UICN.
Andean tepui, Andes, androphore, Ecuador, Nangaritza Plateau, Phyllanthaceae, taxonomy
Amanoa Aublet is a genus with a trans-Atlantic disjunct distribution. Most species of Amanoa are endemic to the Neotropics (14 species presently known: Ulloa Ulloa et al. (2018)) and two species are endemic to Africa. The most recent monograph is by
Phylogenetic studies (
Plants were vouchered and photographed during a 2017 field expedition to Ecuador. Specimens were deposited at the Universidad Estatal Amazónica (
We assessed the extinction risk of Amanoa condorensis following the
Amongst the Neotropical species of Amanoa, A. condorensis shares with A. almerindae Leal. and A. caribaea Krug & Urb. the presence of an androphore, formed from the fusion of the basal filaments. Differs from Amanoa almerindae by the densely pubescent and more widely-spaced flowers along an inflorescence axis 5.5–11 cm long in A. almerindae vs. nearly glabrous inflorescence axis to 4.5 cm long in A. condorensis. Differs from A. caribaea by the presence of inflorescences in an elongate erect raceme appearing congested throughout vs. inflorescences in elongate erect spikes with evenly-spaced fascicles (i.e. not congested throughout) in A. caribaea.
Ecuador. Zamora-Chinchipe: Nangaritza Cantón, Cordillera del Cóndor, trail west of Cabañas Yankuam in conservation area that is owned/operated by ATASMO (Asociación de Trabajadores Autónomos San Miguel de las Orquídeas). Forested tepui (sandstone plateau). Summit ridge and sandstone cliff face. Low scrub and elfin forest, canopy mostly 2–3 m tall, occasional emergent trees to 5 m, 4°15'47.5"S, 78°41'28.1"W, 1840 m elev., 10 Mar 2017, J.L. Clark, J.A. Mayr & D.A. Neill 15257 (holotype:
Tree, 4 m tall. Leaves 1.2–2.5 × 3–4.5 cm, oblong to ovate, coriaceous, glabrous, secondary venation suppressed adaxially when live and becoming prominent when dry, abaxial secondary venation prominent when live and dry, sparsely pubescent on abaxial and adaxial surface, blade flat, base narrowly cuneate to acute, apex acute; petiole 4–8 mm long, slender, black, rugose, sparsely pilose, sometimes appearing sessile from the intrapetiolar stipule; stipules conspicuous, to 0.5 mm long, triangular and glabrous. Inflorescence terminal or lateral, to 4.5 cm long, in congested erect elongate raceme-like inflorescences derived from reduced cymules, the primary inflorescence branch dark black, nearly glabrous to sparsely pubescent with short curved trichomes of 3–5 cells, each flower or pair of flowers subtended by a prominent brown triangular bracteole, 2–3 mm long and glabrous. Staminate flowers actinomorphic, 5-merous, 6.5–7.5 mm in diam. during anthesis, on short pedicels and appearing sessile; sepals 3.0–3.5 × 1.5–2.0 mm, broadly ovate, glabrous, white; petals ca. 1 × 1.5 mm, reniform, margins entire, glabrous; androecium surrounded by a prominent hypogynous extra-staminal disc, stamens fused at base, forming a short androphore, filaments 1.5–2 mm long, anthers 1–2 mm long, dehiscing longitudinally; pistillode ca. 2.5 mm long with trilobed apex, mature gynoecium or pistillate flowers not observed. Fruits not observed.
Mature male flowers were observed in March.
The specific epithet is derived from the Cordillera del Cóndor mountain range in southern Ecuador where this species is presumably endemic.
Amanoa condorensis is only known from the type collection. It is presumed endemic to the Cordillera del Condór from where it was collected during a collaborative field course in 2017 with the Lawrenceville School (Lawrenceville, NJ, USA) and the Universidad Estatal Amazónica (Puyo, Ecuador). The type locality is situated at the summit ridge of a sloping plateau (1840 m elevation) west of the upper Nangaritza River, with nutrient-poor soil derived from the Cretaceous Hollín sandstone formation. The vegetation at the site is a low, dense scrub, dominated by shrubs and low trees 3–5 m high. These environments in the Cordillera del Cóndor and other mountain ranges east of the main Andean chain in Ecuador and Peru have been referred to as “Andean tepuis” in recognition of the similarity in vegetation and some phytogeographic connections with the low-nutrient sandstone tepuis of the Guiana Shield Region (
The type locality is located within a community-based protected forest managed by the Asociación de Trabajadores Autónomos San Miguel de las Orquídeas (ATASMO) on the remote summit ridge of a sloping Andean tepui at 1840 m elevation, accessible via a 6 km trail from the Cabañas Yankuam (= Yankuam Lodge) located at 890 m elevation on the banks of the Río Nangaritza. Yankuam is a family-owned lodge specializing in bird tours and ecotourism. The Río Nangaritza is at risk from ongoing illegal mining. Many of the areas visited in 2017 (especially along the Río Nangaritza) have been invaded by illegal mining operations. The forest that corresponds to the only known population of Amanoa condorensis is protected by the local community, which was granted this jurisdiction by the Ministry of Environment of Ecuador. Between 2017 and 2019 (three years), annual field courses were run with Cabañas Yankuam and the local community to different sandstone tepuis. Amanoa condorensis was only observed once throughout three consecutive years of field courses. Following the
Most species of Amanoa are canopy to sub-canopy trees in the lowland tropics. The only other species that is known to occur above 1000 m is Amanoa steyermarkii Jabl. in the riparian and tepui forests of the Venezuelan Guayana Region at 1500–2100 m elevation (
Amanoa condorensis differs from most other congeners in its relatively small height of 4 m. Most other Amanoa species are understory to emergent canopy trees above 12 m tall (e.g. A. guianensis Aubl. reaches 35 m tall). It is also distinguished by the relatively small, thick and sclerophyllous leaves, characters that are shared by many plants in different genera that occur in the dense scrub vegetation of the Andean tepuis (
Amanoa condorensis shares the following characters with other congeners: an extra-staminal disc (Fig.
Amanoa condorensis has an androphore, a structure formed by the basal fusion of the filaments (Fig.
Amanoa pubescens was previously considered a synonym of A. almerindae, but was separated and resurrected by
We are grateful to Steve Ginzbarg from The University of Alabama Herbarium (UNA) for processing our plant specimens. The participants from the 2017 Lawrenceville School in Ecuador program are acknowledged for their engagement in learning field biology and the science of biodiversity. Special thanks to the Asociación de Trabajadores Autónomos San Miguel de las Orquídeas (ATASMO) for providing access to their reserve. We are especially grateful for logistical support from our local guides, Segundo Velez, Iván Merino, Laura Merino, María Tillaguango and Luis Jiménez. We are also grateful to Clara Guillermina León García and Carlos Humberto Gálvez Guamán from Cabañas Yankuam (Yankuam Lodge) for hosting us throughout three consecutive years of field courses. We thank Yeison Londoño-Echeverri and Ana María Trujillo López (Herbario Nacional Colombiano) for facilitating the initial determination of our field collection. We thank Paul Berry and Ricardo de Secco for their constructive comments on an earlier version of the manuscript.
No conflict of interest was declared.
No ethical statement was reported.
No funding was reported.
JLC and DN wrote the manuscript and conducted the field work.
John L. Clark https://orcid.org/0000-0002-1414-6380
David A. Neill https://orcid.org/0000-0002-5143-9430
All of the data that support the findings of this study are available in the main text or Supplementary Information.