Utricularia jaramacaru 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 jaramacaru Gonella, Baleeiro & Andrino sp. nov. Figs 1 , 4 , 5 , 6

Type.

Brazil. Pará: Óbidos; Floresta Estadual de Trombetas, Ariramba, Rio Jaramacaru; 10 Jun. 2019; C.O. Andrino, R.G. Barbosa-Silva, D.C. Zappi & C. Maurity 559 (holotype MG; isotypes M, SPF).

Diagnosis.

Utricularia jaramacaru belongs to U. sect. Setiscapella (Barnhart) P.Taylor but is distinct from all other members of this section by the traps with reduced, denticulate appendages (vs. subulate, branched), white corolla (vs. yellow or lilac), the upper corolla lip with bilobate apex (vs. obtuse, rounded, truncate or retuse), and the lower corolla lip narrowly rhombic (vs. cuneate, trullate, rhombic to very broadly rhombic in outline).

Description.

Small-sized, probably annual, terrestrial. Rhizoids 2-4, from the base of peduncle, terete, with short papillose branches, up to 1 cm long, c. 0.25 mm in diameter. Stolons numerous, capillary, sparsely branched, up to 1 cm long (in the available material), up to 0.1 mm in diameter. Leaves numerous, at the base of the peduncle and on the stolons, lamina narrowly linear, simple, the base narrowing gradually into a short petiole, apex obtuse to acute, green to reddish, 1-nerved, 2-6 × 0.2-0.5 mm. Traps numerous on the stolons and leaves, ovate, stalked, 0.1-0.2 mm long, the mouth lateral with two dorsal and very short denticulate, simple appendages. Inflorescence a bracteose raceme, erect, solitary, 60-130 mm tall. Peduncle capillary, terete, simple or eventually laterally simple-branched, glabrous, 0.2-0.3 mm in diameter, wine red. Scales numerous, peltate, ovate to narrowly ovate, inferior apex rounded to obtuse, superior apex acute, 0.5-0.9 mm long, similar to the bracts. Bracts ovate, basisolute, peltate, 0.5-0.7 × 0.4-0.5 mm, amplexicaul, the inferior apex rounded, the superior apex rounded to obtuse. Bracteoles absent. Flowers 4-13, the rhachis elongate, flexuous, without sterile bracts; pedicels ascending, capillary, terete, 3-9 mm long (longer towards the base of the inflorescence), pedicels with a mucilage droplet at their base in living specimens. Calyx lobes unequal, glabrous, nerves inconspicuous, simple, not extending to the margin; upper lobe ovate, with apex obtuse, convex, 0.9-1.1 mm long in flower, up to 1.3 mm in fruit; lower lobe obovate, with apex emarginate to rounded, convex, equal in length with the upper lobe in flower, slightly longer in fruit, up to 1.7 mm in fruit. Corolla 5 mm long, lower lip white with a pale yellow mark on the gibbose palate, spur pale yellow, upper lip pale yellow with reddish marks; upper lip oblong with apex bilobed, the basal sac with an eglandular pubescent marginal rim, the pubescence spreading towards the apex, c. 1.5 mm long; lower lip limb narrowly rhombic in outline, the base with a very prominent bilobed swelling, the apex 3-lobed, 0.3-4.5 mm; palate pubescent; spur cylindrical, apex rounded, equal to or slightly longer or shorter than the lower lip, 0.35-0.40 mm long. Filaments curved, 0.8-1.0 mm long, the anther thecae sub-distinct, anther 0.4-0.5 mm long. Ovary globose, 0.8-0.9 mm long; style very short; stigma lower lip nearly circular, upper lip obsolete. Capsule globose, c. 1.2 mm in diam., shorter than the calyx lobes, dehiscing by an elliptic ventral pore. Seeds obovoid to angulate-ellipsoid, 0.20-0.25 mm long, 0.13-0.20 mm wide, testa cells c. 0.01 mm wide, elongate, anticlinal boundaries deeply sunken and more or less straight, periclinal walls convex, smooth.

Etymology.

The epithet " jaramacaru " is a noun in apposition (hence it is invariant), referring to the Jaramacarú river, where the new species was discovered. “Jaramacarú” comes from the Tupi language " iamandakarú ", referring to species of the genus Cereus Mill. ( Cactaceae ). However, no cactus of this genus was located during the field trip undertaken by COA, RGBS, and DCZ in 2019.

Phenology.

Utricularia jaramacaru was collected with flowers in April, May, and June.

Distribution and habitat.

So far, only known from two very close localities near the Jaramacaru waterfall, in the Campos do Ariramba, part of the FLOTA Trombetas, western Pará, N Brazil. The species occurs on white sandy soils with outcrops of sandstone, in campinarana vegetation.

Conservation status.

Vulnerable: VU D2. Similarly to that described for U. ariramba , U. jaramacaru is known from only two localities (AOO=8 km2) near the limits of FLOTA Trombetas and the threats the populations are subject to are fully explained in the above species. Therefore, based on available data, U. jaramacaru is to be assigned to the category of Vulnerable based on criterion D2 of IUCN (2012).

Taxonomic notes.

The basisolute, peltate scales and bracts, and the calyx and seed morphology (Figs 4 - 6 ) undoubtedly place this species in U. sect. Setiscapella , representing the tenth species of the section (following the species circumscriptions of Taylor 1989). However, based on morphology alone, it is not possible to assign the closest affinity of U. jaramacaru , as it bears several apomorphic characteristics, most remarkably regarding its trap and corolla morphology.

Up to now, U. sect. Setiscapella was composed of nine species ( Taylor 1989), of which eight have yellow corollas (regarding the phylogenetic switch from lilac to yellow corolla color in Utricularia and Genlisea , see Fleischmann et al. 2010). One exception in terms of color is U. physoceras P.Taylor, also endemic to the state of Pará, but with larger (7-10 mm long vs. 5 mm) pink to lilac corolla. The whitish corolla of U. jaramacaru is, therefore, a second exception among the species of the section. Utricularia physoceras also shares the short spur with rounded apex with U. jaramacaru and similar seed morphology. Utricularia physoceras occurs in the cangas (ferruginous campo rupestre) of the Serra dos Carajás ( Taylor 1989; Mota and Zappi 2018; Giulietti et al. 2019), distant ca. 815 km to the southeast from the area where U. jaramacaru was collected. For photos of U. physoceras , see Mota and Zappi (2018: 129, Fig. 4a-e ) and Giulietti et al. (2019: 369, fig. 7 bottom three images).

Traps of U. jaramacaru are unlike any other species of U. sect. Setiscapella in that the appendages are reduced to two denticulate structures (Fig. 4d ). All other species of the section bear subulate or filiform appendages near the trap door that are sparsely to copiously branched. Reduced appendages are found in different sections of Utricularia , which suggests it is a homoplastic character in the genus. Taylor (1989) enumerates a few species with reduced trap appendages, such as U. cornuta Michx. and U. juncea Vahl (both of U. sect. Stomoisia (Raf.) Komiya), U. nana A.St.-Hil. & Girard ( U. sect. Benjaminia P.Taylor), U. guyanensis A.DC. ( U. sect. Stylotheca A.DC.) and U. viscosa Spruce ex Oliv. ( U. sect. Sprucea P.Taylor), all presenting only a small prolongation of the body of the trap on the dorsal side of the door.

The presence of a droplet of mucilage at the insertion of the pedicel in the peduncle (Fig. 5b ) is shared with U. flaccida , U. nigrescens Sylvén and U. pusilla Vahl (P.M. Gonella and A. Fleischmann, pers. obs.), and its function remains unclear.

Additional specimens examined

(paratypes). Brazil • Pará; [ Óbidos]; Rio Jaramacaru, entre o acampamento e a cachoeira; 26 May 1957; G.A. Black, W. Egler, P. Cavalcante & A. Silva 57-19500 (IAN 95620) • ibid.; trilha após a ponte do rio Jamaracaru [sic], em direção à cachoeira; 01°10'12.99"S, 055°41'50.69"W; 80 m; 27 Apr. 2018; J.A. Siqueira Filho 4112 (HVASF 23703).

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 4. Utricularia jaramacaru a habit, in flower b base of plant with stolons with traps, rhizoids, leaves with traps, and peduncle base c leave with traps d utricle, side view e scale f base of the pedicel, and bract g flower, in anterior h flower, in posterior view i flower, in lateral view j upper lip of the corolla k stamens l pistil m fruit n seed. All based on the holotype. Illustrations by Joao Silveira.

Figure 5. Utricularia jaramacaru a inflorescence apex with open flowers and bud b detail of inflorescence apex showing mucilage droplet in the axil of a pedicel c inflorescence apex with a flower in posterior view, highlighting the calyx (c 1) d flower in anterior view; e, peduncle bases with stolons and leaves.

Figure 6. SEM microphotographs of seeds of Utricularia jaramacaru at 420 x magnification, in dorsal, lateral and oblique view (from the holotype).