Utricularia ariramba Gonella, Baleeiro & Andrino, 2020

Gonella, Paulo Minatel, Barbosa-Silva, Rafael Gomes, Fleischmann, Andreas S., Zappi, Daniela C., Baleeiro, Paulo Cesar & Andrino, Caroline Oliveira, 2020, Hidden biodiversity of Amazonian white-sand ecosystems: two distinctive new species of Utricularia (Lentibulariaceae) from Para, Brazil, PhytoKeys 169, pp. 75-98 : 75

Utricularia ariramba Gonella, Baleeiro & Andrino sp. nov. Figs 1 , 2 , 3

Type.

Brazil. Pará: Floresta Estadual de Trombetas, comunidade Jaramacaru, cachoeira do Rio Jaramacaru; 9 Jun. 2019; D.C. Zappi, C.O. Andrino, R.G. Barbosa-Silva & C. Maurity 4853 (holotype MG; isotype SPF).

Diagnosis.

Utricularia ariramba belongs to U. sect Aranella (Barnhart) P.Taylor, being most similar to U. costata P.Taylor, but distinguished by its taller inflorescences 5.3-12.0 cm long (vs. 2-7 cm long), the less conspicuous nerves on the calyx lobes, the upper calyx lobe with acute apex (vs. obtuse and obscurely denticulate), spur swollen and dorsiventrally flattened in the apical 2/3 (vs. cylindrical with apex narrowing towards the tip), lower corolla lip trapezoid with margin entire or finely denticulate (vs. transversely oblong with margin entire or shallowly 3-lobed), and upper corolla lip narrowly ovate with acute apex (vs. ovate, with apex rounded or subacute).

Description.

Small-sized, probably annual, terrestrial. Rhizoids few, capillary, from the peduncle base, sometimes also from the basalmost scales, with short papillose branches, up to 0.8 mm long, 0.1-0.2 mm in diameter. Stolons few, capillary, terete, sparsely branched, a few cms long, c. 0.1 mm in diameter. Leaves few, on the stolons, petiolate, lamina narrowly linear, 1-nerved, up to 5 mm long, 0.1-0.2 mm wide. Traps numerous on the leaves and stolons, ovoid, stalked, 0.15-0.20 mm long, the mouth lateral with a single, conical, dorsal appendage and a longer, deeply bifid, ventral appendage. Inflorescence a bracteose raceme, erect, simple, solitary, 53-120 mm long; peduncle capillary, terete, glabrous, 0.2-0.3 mm in diameter, reddish-green. Scales, bracts, and bracteoles basifixed and single-nerved. Scales few to numerous, ovate-deltoid to ovate, with apex acute, 0.5-1.0 mm long. Bracts ovate-deltoid to lanceolate, with apex acute, 0.7-1.1 mm long. Bracteoles subulate, slightly shorter than the bract, with apex acute, 0.7-1.0 mm long. Flowers 1-6; pedicel ascending, filiform, terete, 0.5-2 mm long, c. 0.1 mm in diameter. Calyx lobes unequal, glabrous, with 9-13 very conspicuous, simple, parallel, raised nerves, green to greenish-red in color; upper lobe ovate with apex acute, convex, 2.0-2.5 × 1.2-1.5 mm; lower lobe ovate, convex, with apex bifid, 2.6-3.3 × 1.5-2.0 mm. Corolla white or lavender, with the lower lip with a yellow-orange mark on the top and violet nerves on the limb, 8-11 mm long, finely papillose; upper lip narrowly ovate 4.0-5.5 × 2-3 mm, apex acute, lateral margins retroflexed, basal sac with ciliated rim; lower lip limb trapezoid, margin entire or finely denticulate, straight or retroflexed, shallowly 3 lobed, 3-5 × 3-7 mm, palate with papillose rim; spur conical, swollen and dorsoventrally flattened in the apical 2/3, the apex truncate to sub-acute, projected to the front, longer than and +/- parallel to the lower lip, 5.0-6.1 × 2.2-3.1 mm, papillose and finely ciliated. Filaments curved, c. 0.8 mm long, the anther thecae sub-distinct, anther c. 0.70 × 0.25 mm. Ovary globose, 0.5 mm long; style short, c. 0.2 mm long; stigma bilabiate, lower lip semicircular, 0.3 mm wide, upper lip broadly deltoid. Capsule and seeds not seen.

Etymology.

The epithet " ariramba " is a name in apposition, referring to the Campos de Ariramba, where this new species was discovered. The word " ariramba " comes from the Tupi language " uarirámba " and refers to the birds of the Galbulidae family, which are commonly found in the area.

Phenology.

The species was collected in full bloom at the end of the rainy season, in May and June.

Distribution and habitat.

So far, only known from two subpopulations at the margins of the Jaramacaru River, in the Campos do Ariramba region. The area lies within the conservation unit of the Floresta Estadual de Trombetas (FLOTA Trombetas), in western Pará state, N Brazil. The species occurs on white sandy soils on a flat sandstone outcrop in campinarana (white sand vegetation).

Conservation status.

Vulnerable: VU D2. Utricularia ariramba is known from only three collections, one of which was made over 60 years ago and lacked georeferenced data. The recently collected specimens were found ca. 3 km distant from each other, near the border of the FLOTA Trombetas (Fig. 1 ). Areas under active deforestation were observed just outside the conservation unit (Fig. 1 ), and during the fieldwork activities in 2019, fire was observed in a waterfall 6 km upriver from the Jaramacaru community, suggesting environmental disturbance generated by cattle farming and other human activities. In fact, large areas were recently impacted by fires less than 1 km away from the subpopulations (Fig. 1 ; data from Assis et al. 2019). In addition, the site is sought by tourists from nearby municipalities because of the Jaramacaru waterfall, therefore leading to negative anthropogenic impact on the populations. Although the Campos do Ariramba are a botanically unexplored region with vast areas of habitats similar to those where the species was collected and the population size has not been ascertained, the available data suggests that the species is restricted to a few locations. An AOO of just 8 km2 was calculated for this species, and we observed threats that might impact its habitat quality and AOO in the short term and lead to a reduction in population size and area of occupancy. Therefore, we assign the species to the Vulnerable category based on criterion D2 of IUCN (2012).

Taxonomic notes.

Utricularia ariramba is placed in U. sect. Aranella based on its characteristic trap morphology (a single subulate dorsal appendage and a deeply bifid ventral appendage), and the presence of a clearly defined basal sac in the upper corolla lip.

Utricularia ariramba is the eleventh species of Utricularia sect. Aranella ( Taylor 1989; Fleischmann and Rivadavia 2009), a section almost completely endemic to tropical South America, with a single species ( U. simulans Pilger) extending to Central America, the Caribbean and tropical Africa ( Taylor 1989).

Utricularia ariramba is most similar to U. costata , sharing similar bract and bracteole morphology, and the lavender (to white) corolla with darker violet venation in the lower lobe. It is distinguished by the relatively larger inflorescences 5.3-12.0 cm tall (vs. 2-7 cm tall), the less prominent nerves on the calyx lobes, the upper calyx lobe with acute apex (vs. obtuse and obscurely denticulate), the swollen spur in the apical 2/3 (vs. apex tapering towards the tip), the lower corolla lip trapezoid with margin entire or finely denticulate (vs. transversely oblong with margin entire or shallowly 3-lobed), and the upper corolla lip narrowly ovate with acute apex (vs. ovate, with apex rounded or subacute). For photos of U. costata , see Costa et al. (2016: 11, Fig. 3D, E ) and Mota and Zappi (2018: 126, Fig. 3a-c ).

Utricularia costata occurs in Venezuela and Brazil, where it is recorded from the states of Roraima, Pará, Mato Grosso, Goiás, Bahia, Sergipe and Alagoas ( Taylor 1989, 1999; Fleischmann and Rivadavia 2009; Carregosa and Costa 2014; Costa et al. 2016; Guedes et al. 2018; Flora do Brasil 2020 under construction). In Pará, the species is recorded from the southeast region of the state, in the Serra dos Carajás ( Mota and Zappi 2018).

Variation in corolla color and spur morphology was observed in the studied specimens of U. ariramba , where it varies from white to lavender, and the different corolla colors are associated with different spur shapes: both variants show a dorsoventrally flattened spur in the apical 2/3, but the white variant (represented by the type specimen) shows a higher degree of flattening, a ventral concavity (Fig. 2c ), and a truncate apex (Fig. 3a ), while the lavender variant (represented by the paratypes) has a spur only slightly flattened, without the concavity, and with an acute apex (Figs 2i , 3b, d ). Furthermore, in the white morphotype, the apex of the lower corolla lip is reflexed (Figs 2h , 3a ). Despite these differences in corolla color and shape, both morphotypes are considered conspecific as the specimens share similar morphology in all other characters. Variation in corolla color and shape is common in other species of U. sect. Aranella , as exemplified by intra-populational variation observed in U. laciniata A.St.-Hil. & Girard and U. purpureocaerulea A.St.-Hil. & Girard in several areas across their range (PMG pers. obs.), as well as in lavender- and white-flowered color morphs of U. blanchetii A.DC. in the Chapada Diamantina ( Taylor 1989; Rivadavia 2000).

Seeds were not available for study, however, Taylor (1989: 237) notes that seed morphology is rather uniform in U. sect. Aranella , hence not having great taxonomic significance (compared to other sections of the genus, where some species might be identified by a single seed grain alone; Taylor 1964, 1989).

Additional specimens examined

(paratypes). Brazil • Pará; [ Óbidos]; Campo do Jamaracarú [sic], perto do barracão, região do Ariramba; 26 May 1957; G.A. Black, W. Egler, P. Cavalcante & A. Silva 57-19633 (IAN 95750) • Óbidos; FLOTA Trombetas, comunidade Jaramacaru; 10 Jun. 2019; C.O. Andrino 560 (MG, SPF).

Figures

Figure 1. Distribution map of the new species of Utricularia in the Amazon. On the left map, the main rivers of the hydrographic basin of the region and which cross the FLOTA Trombetas (highlighted in green). The map to the right shows the records of Utricularia ariramba (squares) and Utricularia jaramacaru (triangle), which are near the FLOTA limits, as well the as threats to the area, including recent fires, full deforestation, and selective deforestation of timber species.

Figure 2. Utricularia ariramba a, b habit, in flower c base of plant with stolons, rhizoids, and peduncle base d part of stolon, with rhizoids, and leaves with traps e utricle, side view f scale g, h flower of the white morphotype in anterior (g) and side (h) view i, j flower of the lavender morphotype in anterior (i) and side (j) view k flower of the white morphotype in posterior view l upper lip of the corolla, androecium, and gynoecium m stamen n pistil a, c-h, k-n based on the holotype; b, i, j based on C. O. Andrino 560. Illustrations by Joao Silveira.

Figure 3. Utricularia ariramba a inflorescence apex with flowers and bud of the white corolla morphotype, showing the reflexed apex of lower corolla lip b flowers of the lavender corolla morphotype, with a calyx of a developing fruit to the left c flower of the white corolla morphotype in posterior view, showing the calyx lobes and the concavity in the ventral portion of the spur d flowers of the lavender corolla morphotype e inflorescence apex of the white corolla morphotype showing variation in spur morphology.