Tovomita nebulosa (Clusiaceae), a new species from Cerro de la Neblina, Venezuela

Although the number of recently described Tovomita species is relatively high, much more remains to be done, given that each new survey of representative Amazonian collections reveals many potentially undescribed taxa. In the treatment for Tovomita published in Flora of the Venezuelan Guayana, at least six distinct morphotypes did not match any previously described species. Here we recognize morphotype “D” as a new endemic species from Cerro de la Neblina. Additionally, we provide an identification key to the Tovomita species in Venezuela.


INTRODUCTION
Recent estimates indicate there are around 16,000 vascular plant species reported for Venezuela, although many more taxa are yet to be described, particularly from the country's southern region (Huber 2008). The Guiana Shield has largely been considered one of the most biologically fascinating regions, given its physiographic complexity and high levels of endemism. Approximately 10,000 plant species are known from Venezuelan Guayana and about 40% of the species are restricted to the shield (Berry et al. 1995). Within the Guayana Shield, Cerro de la Neblina is the tallest mountain (3014 m) and has the highest level of endemism, with at least 104 endemic plant species (Riina et al. 2019).
Here we recognize morphotype "D" as a new endemic species from Cerro de la Neblina. Additionally, we provide an identification key to the species of Tovomita in Venezuela.

MATERIAL AND METHODS
The description is based on specimens at NY and VEN (abbreviations according to Thiers 2020). Leaf terminology follows Ellis et al. (2009) and flower terminology follows Radford et al. (1974). The conservation status of the new species was accessed according to IUCN (2012) criteria. The species distribution map was produced using the SimpleMappr website (Shorthouse 2010) with subsequent style modifications. Description: Small tree, up to c. 3 m tall, prop roots and exudate not seen. Petioles 0.9-1.3 cm long, color not seen, smooth, lenticels absent. Leaf blades 4-10 × 2.6-5 cm, dark brown adaxially and light brown abaxially in sicco, black dots absent, subcoriaceous, oblong to obovate, the base decurrent, the apex acute to rounded, sometimes slightly acuminate; exudate canals immersed on both surfaces, visible as thin nigrescent lines abaxially, parallel to the secondary veins. Venation: midvein prominent on both surfaces; secondary veins in 20-23 pairs, 2.5-3.2 mm apart, forming a 65º-75º angle to the midvein, prominent on both surfaces, slightly arcuate and connecting near the margin; intersecondary veins present, one or two per intercostal area, similar to the secondary veins, distal course reticulating, > 50% of the length of subjacent secondary veins; tertiary veins percurrent, sinuous; intramarginal vein present. Staminate inflorescences a lax dichasium with up to 35 flowers, with primary flower; bracts 2, c. 0.8 mm long, triangular, on the base of the inflorescence. Pedicel 4-9 mm long, color not seen, articulated in the middle in lateral flowers of the dichasia, distal portion of pedicel slightly dilated; bracteoles 2, c. 0.5 mm long, triangular; bracteoles not calyptrate, lenticels absent. Staminate floral buds 5-7 ×1.5-2 mm, narrowly oblong, apex cuspidate to slightly rostrate, whitish, lenticels absent, nigrescent in sicco. Sepals 2, 5-7 × 2.5-3 mm, oblong to narrowly ovate, apex cuspidate to acuminate, acumen 1.5-2 mm long, whitish; petals 4, c. 6.2 × 1.5 mm, the innermost petal c. 3.5 × 1 mm, smaller than the others, linear to narrowly oblong, the apex acute to cuspidate, color not seen. Staminate flowers with c. 20 stamens, arranged in two whorls, 3.3-4.8 mm long, slightly angular, heterodynamous, the central ones larger than the marginal ones; filaments terete, color not seen; anthers 0.3-0.5 mm long, with the same caliber as the filaments, connective not exceeding the thecae; pistillode c. 0.3 mm long, conical, angular, rudimentary stigmas 4, amorphous. Pistillate inflorescences, flowers and fruits not seen ( Figure 1).

Etymology:
The specific epithet refers to the adjective nebulous, which means vague or unclear, in reference to the long period of over 20 years during which this species has been known under the informal name "Tovomita sp. D" (see Cuello 1998). The epithet is also related to the type locality, Cerro de la Neblina. Both "nebulous" and "neblina" have the same origin and derive from the Latin word nebulosus, which means clouded or cloudy (Stern 1992).
Occurrence, habitat and conservation status: Tovomita nebulosa is presumably endemic to Amazonas State, Venezuela, near the border of Amazonas State, Brazil (Figure 2). The only known specimen of this taxon was collected in Cerro de la Neblina (Pico da Neblina, in Portuguese). Although this area is permanently preserved and part of Pico da Neblina National Park, a Brazilian conservation unit, and Serranía de la Neblina National Park, a Venezuelan conservation unit, we assessed the conservation status of the species as Data Deficient (DD), as the species is so far known from a single collection.

DISCUSSION
The arrangement and quantity of secondary and intersecondary veins, as well as floral bud shape (Barros and Mariz 1982;Marinho 2018), have typically been used as important characters to identify Tovomita species (Vesque 1893;Engler 1923;Cuello 1998;Marinho et al. 2016b Although the specimen used here to describe Tovomita nebulosa bears few floral buds, the combination of observable characters (i.e., > 20 pairs secondary veins, staminate floral buds with a cuspidate to slightly rostrate apex, and c. 20 terete stamens) is not found in any other species in the genus. Tovomita nebulosa shares with T. calophyllophylla García-Villacorta & Hammel the presence of > 20 pairs of secondary veins that are almost indistinguishable from the intersecondary ones. From this species, T. nebulosa can be distinguished by the smooth petiole (vs. longitudinally striated in T. calophyllophylla) and narrowly oblong floral bud with a cuspidate to slightly rostrate apex (vs. spherical with rounded apex in T. calophyllophylla).  Marinho, but these species lack floral buds that are narrowly oblong with cuspidate to slightly rostrate apex (i.e., oblong with rounded apex in T. colombiana and ovoid with rounded apex in T. nervosa). Floral buds with a similar shape are found in T. stylosa Hemsl., but this species has fewer secondary veins (8-9 pairs) and is endemic to Mesoamerica and the Chocoan region. Marinho (2018) pointed out that, due to the larger ovary, pistillate floral buds in species with narrowly oblong floral buds are typically wider than staminate buds in the same species. Although the pistillate individual of T. nebulosa was not described, we expect its pistillate floral buds to be slightly wider than the staminate ones, and the ovary to be 4-carpellate based on the number of pistillode stigmas observed in staminate buds.
Below, we provide an identification key to all species of Tovomita in Venezuela, which is based mostly on vegetative and floral bud characters. The species endemic to Venezuela are indicated with an asterisk (*).