Distribution of Heliamphora

Heliamphora nutans (centre) growing with sympatric Orectanthe sceptrum on Mount Roraima, where it was discovered in 1838 as the first member of its genus.

The natural range of the carnivorous plant genus Heliamphora is restricted to the southern Venezuelan states of Amazonas and Bolívar, and to adjacent portions of northern Brazil and western Guyana, an area corresponding to the western part of the Guayana Shield. These plants are largely confined to the summits and foothills of the sandstone table-top mountains of the region, known as tepuis.

The genus has a highly disjunct distribution spread across two major groups of tepuis: the western range in Amazonas and the eastern range in Bolívar.^[1] The western range can be further subdivided into two complexes of neighbouring tepuis. The more southerly of these consists of Cerro de la Neblina, Cerro Aracamuni, and Cerro Avispa, and supports four Heliamphora species. The more northerly group of the western range, home to only two species, includes the massive Cerro Duida and neighbouring Cerro Huachamacari and Cerro Marahuaca. The remaining 17–19 species are native to the eastern range, which includes the Aprada Massif, Auyán Massif, Chimantá Massif, Eastern Tepuis chain, Los Testigos chain, and a number of outlying tepuis. Many of the summits of the eastern range are situated on a vast plateau known as the Gran Sabana. Only two species (H. ciliata and H. heterodoxa) are known with certainty from the Gran Sabana, and only H. ciliata is endemic to this habitat.^[2]

The altitudinal distribution of Heliamphora ranges from 860 m above sea level for populations of H. neblinae on Cerro Avispa to as much as 2994 m for plants of H. hispida growing near the summit of Pico da Neblina in Cerro de la Neblina.^[2]

Key

Tepui names shown in the tables are those used in Flora of the Venezuelan Guayana and Sarraceniaceae of South America, with alternate names and spellings given in brackets. Many additional orthographic variants are likely to exist and some localities remain the subject of considerable toponymic confusion; these cases are covered in the Notes section. Many of the tepui heights are approximate and likely to change as more accurate measurements become available. Only tepuis known to support Heliamphora are included in the tables (for example, not all parts of the Chimantá Massif or Eastern Tepuis chain are listed). Formally described species are listed first, followed by undescribed species, and finally natural hybrids. Where published information is available, the altitudinal distribution of a taxon at a particular locality is given. In cases of unconfirmed locality records, the taxon name is preceded by a question mark (?).

Coordinates given correspond to the approximate centre points of tepui summit plateaus (though in the case of fragmented tepui complexes such as Cerro de la Neblina, the centre point itself may not lie on any plateau). Unless otherwise indicated, all other information presented in the tables is sourced from Sarraceniaceae of South America.

Caracas

Cerro Marahuaca

Cerro Huachamacari

Cerro Duida

Cerro Aracamuni

Cerro Avispa

Cerro de la Neblina

Auyán Massif

Chimantá Massif

Aprada Massif

Ptari Tepui

Eastern Tepuis

Serra do Sol

  Los Testigos

Gran Sabana

Sierra de Lema

Map of Venezuela showing the major tepuis, massifs and uplands to which Heliamphora are native. The distribution of this genus is highly disjunct, with all known species concentrated in three major areas: the Duida and Neblina complexes of Amazonas, and the tepuis and uplands of southeastern Bolívar.^[2]

Western range

The western range of the genus is confined almost entirely to Amazonas state, Venezuela, but extends slightly into northernmost Brazil.

Neblina Massif

The Neblina Massif is located in the extreme south of Amazonas and is dominated by the highly fragmented complex known as Cerro de la Neblina. This complex has many plateaus averaging 2000–2400 m in elevation, and includes Brazil's two highest peaks: Pico da Neblina (2994 m) and Pico 31 de Março (2973 m), known as Pico Phelps in Venezuela.^{[nb b]} A giant valley, Cañón Grande, runs southwest to northeast through the middle of Cerro de la Neblina. The smaller outcrops of Cerro Aracamuni and Cerro Avispa, both reaching approximately 1600 m, lie to the north of this complex.^[3] The name Neblina Massif is sometimes applied specifically to Cerro de la Neblina, to the exclusion of Cerro Aracamuni and Cerro Avispa.^[2]

Four species are native to this area, all local endemics: H. ceracea, H. hispida, H. neblinae, and H. parva, though only the range of H. neblinae extends to the two northern cerro-plateaus. No Heliamphora are found on the small granitic outcrop of Cerro Aratitiyope (1700 m) to the north of the Neblina Massif.^[2]

Duida group

This area consists of the giant Cerro Duida as well as the much smaller Cerro Huachamacari to the northwest and Cerro Marahuaca to the northeast. Cerro Duida and Cerro Marahuaca share a common base and together form the Duida–Marahuaca Massif, while Cerro Huachamacari is derived from a separate base. The uneven plateau of Cerro Duida is heavily inclined, rising north to south from around 1300–1400 m to a maximum of 2358 m. But the highest point of the massif, at 2832 m, is found on Cerro Marahuaca, this being the second-highest mountain of the entire Guayana Shield (after Cerro de la Neblina). Cerro Marahuaca actually consists of two summit plateaus, the slightly larger northern one going by the Yekwana Amerindian name Fufha or Huha (3°46′53″N 65°29′32″W / 3.781355°N 65.492352°W / 3.781355; -65.492352 (Fufha)). The southern plateau (3°39′04″N 65°25′03″W / 3.651167°N 65.417507°W / 3.651167; -65.417507 (Cerro Marahuaca southern plateau)) is known by two local names; its northwestern edge is called Fuif (or Fhuif), whereas its southeastern portion is called Atahua'shiho (or Atawa Shisho). A massive ridge known as Cerro Petaca (3°39′36″N 65°30′47″W / 3.660075°N 65.512951°W / 3.660075; -65.512951 (Cerro Petaca)) rises to at least 2700 m just west of these two plateaus. The third major tepui of the Duida group, Cerro Huachamacari, is comparatively low, reaching only 1900 m.^[3]

Two species are recognised from this complex and found nowhere else: H. macdonaldae and H. tatei. A third described species, H. tyleri, is universally treated as a synonym of H. tatei.^[2]

Eastern range

The eastern range of the genus includes the vast majority of species. It is largely encompassed by Bolívar state, Venezuela, but also extends into portions of western Guyana and northern Brazil.

Angasima and Upuigma

The imposing peaks of Angasima Tepui (2250 m) and Upuigma Tepui (2100 m) lie south of the much larger Chimantá Massif, from which they are separated by the Río Aparurén valley.^[3] Three Heliamphora species are native to Angasima Tepui: the undescribed endemic H. sp. 'Angasima Tepui' and two species shared with the nearby Chimantá Massif (H. huberi and H. pulchella). Only the range of H. pulchella extends to the isolated peak of Upuigma Tepui.^[2]

Aprada Massif

The Aprada Massif consists of Aprada Tepui (2500 m) and the smaller Araopán Tepui (2450 m) to the east. A steep, semi-circular ridge connects these two summits.^[3] The Aprada Massif lies northwest of the much larger Chimantá Massif, with which it shares its two native species: H. exappendiculata and H. pulchella.^[2]

Auyán Massif

The Auyán Massif is dominated by Auyán Tepui, a vast U-shaped plateau incised from the north by a deep central valley. It rises from 1600 m in the northwest to 2450 m in the southeast, where the world's highest uninterrupted waterfall, Angel Falls, is located. While Auyán Tepui is one of the largest tepuis, it hosts only a single Heliamphora species, H. minor, of which two varieties are recognised. Both varieties are present on Auyán Tepui itself and on the comparatively tiny Cerro La Luna (1650 m), located off its northern flank.^{[nb c]} Neither has been recorded from nearby Cerro El Sol (1750 m), otherwise known as Wei or Uei Tepui (6°06′46″N 62°33′01″W / 6.112734°N 62.550329°W / 6.112734; -62.550329 (Cerro El Sol)). The southernmost component of the Auyán Massif is the 1950 m high Uaipán Tepui or Waipán Tepui (5°39′18″N 62°37′12″W / 5.654935°N 62.620036°W / 5.654935; -62.620036 (Uaipán Tepui)),^[3] which likewise has no recorded Heliamphora.

Chimantá Massif

The Chimantá Massif is a huge, highly fragmented complex with a total summit area of 615 square kilometres. It is dissected across the middle by the Río Tírica.^[3] The massif is notable for its species richness (among the greatest in the region), for its varied habitat types, and for its elevation, reaching 2698 m on its highest peak, Murey Tepui (Eruoda Tepui).^[6] Murey Tepui is joined in the northern portion by Abacapá Tepui, Agparamán Tepui (5°14′50″N 62°12′29″W / 5.247205°N 62.208075°W / 5.247205; -62.208075 (Agparamán Tepui)), Apacará Tepui, Chimantá Tepui, Tirepón Tepui, and Toronó Tepui (an additional summit, Sarvén Tepui, may also be distinguished around 5°17′55″N 62°04′17″W / 5.298485°N 62.071432°W / 5.298485; -62.071432 (Sarvén Tepui)). The smaller southern portion comprises Akopán Tepui, Amurí Tepui, and Churí Tepui.^[3][7]

The Chimantá Massif is home to five described species (H. chimantensis, H. exappendiculata, H. huberi, H. pulchella, and H. uncinata) and one undescribed species (H. sp. 'Akopán Tepui'). Many of its species are spread across several adjacent tepuis due to their close geographical proximity.^[2]

Kukenán Tepui (left) and Mount Roraima, the two most visited of the Eastern Tepuis. The Tëk River and the relatively dry grasslands of the Gran Sabana are visible in the foreground.

Eastern Tepuis

The Eastern Tepuis chain, or Roraima–Ilú range, stretches in a northwesterly direction from the tripoint of Brazil, Guyana, and Venezuela, closely following the Guyana–Venezuela border, with an isolated double-peaked plateau (Serra do Sol or Uei Tepui) to the south. Moving in a northwesterly direction from Serra do Sol (2150 m), the major summits of this chain are Mount Roraima (2810 m), Kukenán Tepui (2650 m), Yuruaní Tepui (2400 m), Wadakapiapué Tepui (2000 m), Karaurín Tepui (2500 m), Ilú Tepui (2700 m), and Tramen Tepui.^[3] With the exception of the tiny Wadakapiapué Tepui (5°18′59″N 60°55′23″W / 5.316261°N 60.923017°W / 5.316261; -60.923017 (Wadakapiapué Tepui)), all of these peaks are known to support Heliamphora. The Eastern Tepuis chain includes some of the most widely visited tepuis, particularly Roraima and nearby Kukenán. The Ilú (Uru) and Tramen Tepuis are treated here as a single locality since they are joined by a common base and share the same assemblage of Heliamphora taxa.^[2][3]

Five closely allied species are recognised from this region—H. arenicola, H. elongata, H. glabra, H. ionasi, and H. nutans—all of which are endemic.^[2]

Panoramic view of the Eastern Tepuis chain. From left to right: Tramen Tepui, Ilú Tepui, Karaurín Tepui, Wadakapiapué Tepui (obscured by clouds), Yuruaní Tepui, Kukenán Tepui, and Mount Roraima (obscured by Kukenán and clouds).

Los Testigos

Los Testigos, or the Aparamán range, is a chain of four rather small and floristically similar tepuis forming a bridge between Auyán Tepui in the west and Ptari Tepui in the east. From west to east the four major peaks are: Aparamán Tepui (2100 m), Murisipán Tepui (2350 m), Tereke-yurén Tepui (1900 m), and Kamarkawarai Tepui (2400 m), the latter three sharing a common slope area.^[3] There however remains some confusion in the literature regarding the names of these peaks.^{[nb e]}

Two closely related species are recognised from Los Testigos—H. collina and H. folliculata—both of which are endemic or almost so (see Ptari Tepui).^[2]

In line with and to the west of the Los Testigos chain lies the Los Hermanos massif, which consists of two upland peaks: Amaruay Tepui (5°54′58″N 62°14′44″W / 5.916239°N 62.245497°W / 5.916239; -62.245497 (Amaruay Tepui)) and Padapué Tepui (5°54′39″N 62°11′47″W / 5.910775°N 62.196402°W / 5.910775; -62.196402 (Padapué Tepui)).^[3] No Heliamphora have been recorded from this group.

View from Kavanayén in the Gran Sabana, looking northwards. The large forested ridge taking up much of the frame is Sororopán Tepui, with Ptari Tepui visible just behind. Moving left is Moná Tepui and then, off in the distance, the Los Testigos chain, beginning with Kamarkawarai Tepui.

Ptari Tepui

Ptari Tepui (2400 m) is a relatively isolated tepui to the east of the Los Testigos chain. It forms part of the Ptari Massif, which also includes the 2200 m high Carrao Tepui (Karrao Tepui) (5°47′33″N 61°46′10″W / 5.792434°N 61.769528°W / 5.792434; -61.769528 (Carrao Tepui)) to the northeast and the 10 km long ridge known as Sororopán Tepui (2050 m) (5°41′40″N 61°45′37″W / 5.694309°N 61.760345°W / 5.694309; -61.760345 (Sororopán Tepui)) to the southeast. Of the three, only Ptari Tepui has an open, rocky summit mostly free of vegetation cover,^[3] and only this peak is known to host Heliamphora.^[2]

Two species are known with certainty from Ptari Tepui (H. purpurascens and H. sarracenioides, both endemic) and a further two (H. collina and H. heterodoxa) may also be present.^[2]

The flat, symmetrical peak on the left is Ptari Tepui, with the long southwestern face of Sororopán Tepui extending to the right.

Uplands

The uplands of the Venezuelan Guayana are regarded as those areas with an elevation of approximately 500–1500 m, with higher elevations being highland and lower ones lowland.^[3]

The Gran Sabana (literally "Great Savannah") is a vast area of tropical uplands covering nearly 30,000 km², which surrounds many of the tepuis of the eastern range. It gradually rises in elevation from 750 m in the south to 1450 m in the north.^[3] The rocky uplands of Sierra de Lema and Sierra Senkopirén lie to the north and northwest of the Gran Sabana and surround the Auyán Massif. They have an elevational range of around 700 to 1650 m.^[3] Cerro Venamo is a sandstone mountain near the border between Venezuela and Guyana, at the northeastern tip of the Gran Sabana. With a height of 1600 m it falls somewhere between an upland and a true highland area.^[3] As with many other localities in the Guayana Highlands, the name Cerro Venamo has been inconsistently applied to a number of adjacent areas.^{[nb f]}

Heliamphora ciliata is endemic to these upland areas and H. heterodoxa may also be (though see Ptari Tepui).^{[2][nb g]}

A typical landscape of the Gran Sabana as seen from Kavanayén. The tepuis in the distance are (moving left): Sororopán Tepui, Ptari Tepui, Moná Tepui, and far off in the distance, Kamarkawarai Tepui and the rest of the Los Testigos chain.

Notes

References