Thismia ribeiroi Engels, D.
Creators: name: Silva, Diego Ferreira Da
name: Engels, Mathias Erich
name: Soares-Lopes, Célia Regina Araújo
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Dioscoreales
Burmanniaceae
Thismia
Thismia ribeiroi

description: 3. Thismia ribeiroi Engels, D. Ferreira-da-Silva & Soares-Lopes sp. nov. (Fig. 5–6)
Type:— BRAZIL. Mato Grosso: Nova Bandeirantes, Comunidade Sagrada Família, Sítio Colorado/2 R 2, near to MT-208 road, fl.,fr., 02 March 2017, Ribeiro, R. S. 212 (Holotype: HERBAM!).
Diagnosis: — Thismia caudata Maas et al. (1986: 162) et Thismia fungiformis (Taubert ex Warming 1901: 178) Maas et al. (1986: 165) similis sed lata aequalis, inseta idem loco exterioribus tub; ab interiori tub lenis; basi antheris auriculatis differt.
Herb 4–7 cm tall. Roots 1,7–4,3 × 0,2–0,6 cm, thickened, brownish. Tuber absent. Stem 2,5–6,4 × 0,1–0,3 cm, white-brownish. Leaves alternated, 3–6 scattered in the stem and 3 at the base of flower; leaves scattered 3–5 × 2–3 mm, scale-like, narrowly-triangular to deltoid, base truncate, margin entire, apex acute, whitish; leaves at the base of flower 5–9 × 3–5 mm, laminar, wide-elliptical, sub oblong to lanceolate, base acute to sub truncate, margin entire, apex acute to obtuse, whitish. Flower 0,9–1,5 × 1–1,5 cm, sessile; ovary 2–3 × 3–4 mm, conical, pale brown-orange; placentation parietal; flower tube 0,8–1 × 0,7–0,8 cm, obovoid, inner surface smooth, pale brown; tepals inserted all at the same height in the distal portion of the flower tube, equal to each other 7–11 × 5–7 mm, patent to deflexed, lanceolate-ovoid, base cuneate and becoming slightly decurrent, margin entire, apex rounded to sub truncate, pale brown; annulus 1–2,5 mm diam., sub hexagonal. Anther ca. 2,5 × 1 mm, oblanceoloid, flattened, auriculate at the base; filament ca. 0,5 mm length, deltoid. Stigma ca. 2,5 × 2,5 mm, pyramidal-capitate, pale brown-orange; lobes descendant-patent. Fruit ca. 8 × 7 mm, pale brown-orange; not estiolated.
Additional specimens examined (Paratypes): — BRAZIL. Mato Grosso: Alta Floresta: RPPN Cristalino, Alluvial Ombrophilous Dense Forest, margin of Cristalino river, 25 February 2017, fr., D. F. Silva et al. 39 (HERBAM!); Nova Bandeirantes: Sítio Colorado /2 R2, comunidade Sagrada Família, 7 February 2016, fl. and fr., R. S. Ribeiro 163 (HERBAM!); Ibidem, Sítio Colorado /2 R2, comunidade Sagrada Família, 13 March 2016, fl., D. F. Silva & R. S. Ribeiro 42 (HERBAM!); Ibidem, Marupá farm, 28 May 2017, fl. and fr., D. F. Silva 40 (HERBAM!).
Geographic distribution: —Known for Nova Bandeirantes and Novo Mundo counties, in Mato Grosso state, Brazil.
Discussion: — Thismia ribeiroi belongs to Thismia Griffith (1845: 221) subg. Ophiomeris (Miers 1847: 328) Maas et al. (1986: 145) sect. Pyramidalis Maas et al. (1986: 161), due to the presence of horizontal cylindrical roots, terete stem with scattered leaves on the stem, reflexed tepals, pyramidal-capitate stigma, stamens flattened and connective not dilated, and the ovary with parietal placentation. This new species has tepals inserted all at the same height in the distal portion of the flower tube, which differs from what is described by Maas et al. (1986) for the sect. Pyramidalis, which have the tepals inserted at two different heights in the flower tube.
The species may be recognized among the species of the section by its flowers with similar tepals (vs. outer tepals different from the inner tepals), reflexed (vs. outer reflexed e inner ascending) and inserted all at the same height in the distal portion of the flower tube (vs. inserted in two different heights in the flower tube); inner surface of the tube smooth (vs. with papillary longitudinal lines in T. fungiformis); and by the auriculate base of the anthers (vs. base without auricles). Found flowering and fruiting between February and May.
The monospecific genus Tiputinia Woodward et al. (2007: 158) was described for Ecuador and has affinities with the Thismia sect. Pyramidalis (see Woodward et al. 2007). Thismia ribeiroi can be easily differentiated from Tiputinia foetida Woodward et al. (2007: 158) by the tepals with apex rounded to sub truncate (vs. truncate) and by descending stamens with filament without appendages (vs. initially ascending and becoming curved and descending at the apex, and by filament with five or six pairs of fimbriate appendages). Additionally, the flowers of T. ribeiroi are pale brown and in T. foetida are olive yellow with orange stamens.
Etymology: —The species epithet is a homage to Ricardo da Silva Ribeiro, the collector of the type material, at the time, biology student and scholarship holder in Mato Grosso State University, linked to HERBAM.
description: Published as part of Silva, Diego Ferreira Da, Engels, Mathias Erich & Soares-Lopes, Célia Regina Araújo, 2020, Novelties in Thismia (Thismiaceae) from South Brazilian Amazon with the description of a new species, pp. 261-273 in Phytotaxa 429 (4) on page 268, DOI: 10.11646/phytotaxa.429.4.2, http://zenodo.org/record/13877007