area of 615 square kilometres. It is dissected across the middle by the Río Tírica. 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). Murey Tepui is joined in the northern portion by Abacapá Tepui, Agparamán Tepui (), Apacará Tepui, Chimantá Tepui, Tirepón Tepui, and Toronó Tepui (an additional summit, Sarvén Tepui, may also be distinguished around ). The smaller southern portion comprises Akopán Tepui, Amurí Tepui, and Churí Tepui. 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. 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. With the exception of the tiny 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. 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. 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. There however remains some confusion in the literature regarding the names of these peaks. 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). 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 () and Padapué Tepui (). No Heliamphora have been recorded from this group. 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) () to the northeast and the 10 km long ridge known as Sororopán Tepui (2050 m) () to the southeast. Of the three, only Ptari Tepui has an open, rocky summit mostly free of vegetation cover, and only this peak is known to host Heliamphora. 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. 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. The Gran Sabana (literally "Great Savannah")