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Key to the species of Thismia subgen. Ophiomeris Thismia iguassensis (Miers 1847: 329) Warming (1901: 182) is excluded due to lack of the necessary morphological information. This species was described by Miers (1847) based only on a single fruiting specimen, and has never been recollected since then. In the absence of data of floral structure, it is impossible to include it in the key (see Maas et al. 1986). 1. Underground part vermiform; stem terete with leaves distributed lenghtwise; stamen connective usually entire (only basally lobed in T. ribeiroi); stigma with basal lobes (absent in T. caudata)........................................................................... 2 (sect. Pyramidalis) - Underground part tubercular; stem sulcate; stamen connective basally and/or apically lobed; stigma without basal lobes.............8 2. Tepals homomorphic, inserted almost at the same level; stamen connective basally lobulated; basal lobe of stigma divaricate.......................................................................................................................................................................................... Thismia ribeiroi - Tepals heteromorphic, inserted at different levels; stamen connective basally without lobes; basal lobe of stigma incurved toward style or absent.....................................................................................................................................................................................3 3. Inner tepals free..................................................................................................................................................................................4 - Inner tepals connate............................................................................................................................................................................5 4. Inner tepals non-appendaged; stigma apex truncate................................................................................................... Thismia singeri - Inner tepals each with bowl-shaped appendage; stigma apex trilobed............................................................... Thismia fungiformis 5. Inner tepals each with linear-triangular appendage with, subclavate apex; style apex covered by glandular spots; stigma apex acute, basal lobe absent....................................................................................................................................................... Thismia caudata - Inner tepals non-appendaged; style apex glabrous; stigma apex acute or trilobed, base with basal lobe incurved towards style...................................................................................................................................................................................................................6 6. Outer surface of hypanthium smooth; inner surface of hypanthium transversely with a lobed and striated laminar projections; outer tepals lanceolate, twisted; inner tepals forming a slightly triangular mitre without foveae.............................. Thismia petasiformis - Outer surface of hypanthium ornamented; inner surface of hypanthium transversely with striated laminar projections; outer tepals orbicular or ovate, straight; inner tepals forming a hexagonal or subglobose mitre with foveae......................................................7 7. Outer tepals ovate, margin flat; mitre hexagonal, outer surface ornamented with six triangles foveate on top; outer surface of ovary keeled, verrucose.............................................................................................................................................. Thismia melanomitra - Outer tepals orbicular, margin revolute; mitre subglobose, outer surface ornamented with irregularly foveate on top; outer surface of ovary flat, smooth............................................................................................................................. Thismia pseudomelanomitra 8. Flower pedicellate; stamen filament linear; stamen connective basally bilobed, apically entire; interstaminal lobes absent; peduncle accrescent..................................................................................................................................... Thismia hyalina (sect. Myostoma) - Flower sessile to subsessile; stamen filament laminar; stamen connective basally and apically bilobed (apically entire in T. mantiqueirensis); interstaminal lobes present or absent; peduncle non-acrescent..............................................9 (sect. Ophiomeris) 9. Inner tepals non-appendaged and apically not tapering into a cauda....................................................... Thismia espirito-santensis - Inner tepals appendaged or apically tapering into a long linear-filiform cauda...............................................................................10 10. Inner tepals appendaged......................................................................................................................................... Thismia saulensis - Inner tepals apically tapering into a long linear-filiform cauda.......................................................................................................11 11. Hypanthium campanulate.................................................................................................................................................................12 - Hypanthium strongly gibbous or tubular to slightly gibbous...........................................................................................................13 12. Hypanthium base without internal foveae; stamen connective with entire apex........................................ Thismia mantiqueirensis - Hypanthium base with internal foveae; stamen connective with bilobed apex....................................................... Thismia glaziovii 13. Hypanthium tubular to slightly gibbous...........................................................................................................................................14 - Hypanthium strongly gibbous..........................................................................................................................................................15 14. Outer surface of hypanthium ornamented longitudinally by six double lamellae; annulus orifice surrounded by a ring of six foveae; interstaminal lobes globose; stigma entirely covered by papillae........................................................................ Thismia prataensis - Outer surface of hypanthium unornamented, smooth; annulus orifice not surrounded by foveae; interstaminal lobes triangular; stigma proximally covered by papillae, distally covered by tufts of trichomes.................................................. Thismia janeirensis 15. Hypanthium with a longitudinal slit resembling a spur; interstaminal lobes absent; margin of outer tepals lacerate, slightly toothed to ciliate; stamen connective with slightly mammiform, inconspicuous basal lobes............................................. Thismia calcarata - Hypanthium without longitudinal slits; interstaminal lobes present; margin of outer tepals entire; stamen connective with filiform, linear or falcate, conspicuous basal lobes.........................................................................................................................................16 16. Thecae not fused, dehiscence line linear; distal portion of the connective covered by a tuft of trichomes.....................................17 - Thecae fused, dehiscence line hippocrepiform; connective glabrous..............................................................................................18 17. Outer tepals reflexed to spreading; each segment of annulus ornamented by three prominent crests: bilobed outer crest, and entire middle and inner crests; stamens homomorphic; thecae inserted into the middle of the stamen connective; stigma cylindrical; pollen size greater than 25µm............................................................................................................................ Thismia panamensis - Upper outer tepal incurved, lateral outer tepals declinate and slightly twisted laterally outside; each segment of annulus ornamented by three entire prominent crests; stamens dimorphic; thecae inserted into the upper part of the stamen connective; stigma conical; pollen size less than 25µm.................................................................................................................................. Thismia paradisiaca 18. Stigma obovoid, covered by trichomes of uniform shape and size......................................................................... Thismia andicola - Stigma conical or ovoid, covered proximally by short trichomes or papillae (0.1–0.3 mm long) and distally or towards the margins by long trichomes (0.3–1 mm long).................................................................................................................................................19 19. Outer tepals cordate at base; annulus composed of a disc ornamented by six prominent contiguous triangular lobes forming a star, densely pilose............................................................................................................................................................ Thismia cordata - Outer tepals truncate at base; annulus composed of three connate segments, each segment ornamented with three prominent crests, arranged parallel to the orifice, glabrous..........................................................................................................................................20 20. Inner tepals with swollen apex of cauda........................................................................................................... Thismia luetzelburgii - Inner tepals with apex of cauda not swollen....................................................................................................................................21 21. Inner tepals 10–15 mm long; each segment of annulus ornamented by three prominent entire crests.............. Thismia macahensis - Inner tepales 17.2–55.5 mm long; each segment of annulus ornamented by three prominent crests: bilobed outer crest, and entire middle and inner crests........................................................................................................................................... Thismia variabilis, Published as part of Guzmán-Guzmán, Santiago & Plata-Torres, Angelo, 2023, A flower in paradise: citizen science helps to discover Thismia paradisiaca (Thismiaceae), a new species from the Chocó Biogeographic region in Colombia, pp. 27-42 in Phytotaxa 603 (1) on pages 38-39, DOI: 10.11646/phytotaxa.603.1.2, http://zenodo.org/record/8153612, {"references":["Miers, J. (1847) On a new genus of plants of the family Burmanniaceae. Proceedings of Linnean Society of London 1: 328 - 329.","Warming, E. (1901) Sur quelques Burmanniacees recueillies au Bresil par le Dr. A. Glaziou. Oversigt Over Det Kgl. Danse Videnskabernes Selskabs Forhandlinger 1901: 173 - 188.","Maas, P. J. M., Maas-van de Kamer, H., van Benthem, J., Snelders, H. C. M. & Rubsamen, T. (1986) Burmanniaceae. Flora Neotropica Monograph 42: 1 - 189."]}

Guzmán-Guzmán, Santiago, Plata-Torres, Angelo (2023): A flower in paradise: citizen science helps to discover Thismia paradisiaca (Thismiaceae), a new species from the Chocó Biogeographic region in Colombia. Phytotaxa 603 (1): 27-42, DOI: 10.11646/phytotaxa.603.1.2, URL: http://dx.doi.org/10.11646/phytotaxa.603.1.2

Thismia paradisiaca S.Guzm. -Guzm., sp. nov. (Fig. 2–5). Diagnosis — Thismia paradisiaca is similar to T. panamensis mainly because it has the distal portion of the stamen connective bearing a tuft of trichomes, free ellipsoid thecae and the stigma proximally puberulous and distally hispid. The new species differs from the latter by hypanthium color (dark purple vs whitish tinged with greenish–brown to colorless or pinkish) (Fig. 5A, B), shape of outer tepals (upper outer tepal incurved, lateral outer tepals declinate and slightly twisted laterally outside vs outer tepals reflexed) (Fig. 5C, D), dimorphic (vs homomorphic) stamens (Fig. 5E, F) and conical (vs cylindrical) stigma. Type: — COLOMBIA. Valle del Cauca: Dagua municipality, La Cascada village, El Paraíso Natural Reserve, El Danubio River, tributary of Anchicayá River, located approximately 50 meters from the river, on the right side of the path towards the reserve, 716 m, 3°37’40.66”N, 76°50’1.47”W, 10 February 2023 (fl., fr.), B. C. Corrales Restrepo, S. Guzmán-Guzmán & E. Restrepo 001 (Holotype: FAUC!, in alcohol+glycerine). Terrestrial achlorophyllous herb, 3.7–5.0 cm tall, generally glabrous (where not stated otherwise) (Fig. 2A 1; 3A). Tuber obovoid, 7.0–11.0 × 4.0–8.0 mm, cream (rapidly turning tawny after being collected) (Fig. 2A2); roots filiform, up to 60.0 mm long, cream (Fig. 2A2). Stem 1 or 2, erect to flexuous, longitudinally bisulcate, 16.0–20.0 × 1.2–1.5 mm, cream at the base turning chestnut towards the apex, basally ensheathed by an inconspicuous triangular volva 1.0 × 1.0 mm (Fig. 2A 1–A 2; 3A). Involucral bracts 4, crowded at apex of stem, surrounding the base of ovary, sessile, decussate, appressed, navicular, ovate–lanceolate, 2.5–3.0 × 4.5–5.0 mm, chestnut-coloured, margin entire, base truncate, apex acute, venation hyphodromous (Fig. 2A 1; 3A). Flower terminal, zygomorphic, solitary, sessile (Fig. 2A–C; 3A–B). Hypanthium gibbous, 10.0–16.0 × 7.0–10.0 mm (largest diam.); outer surface vesicular, indigo to black with 12 flattened vertical veins slightly darker than surrounding tissue (surrounding tissue turns light green in backlight) (Fig. 2A 3; 3C 2); inner surface papillose with papillae to 0.5 mm long, indigo to dark purple, dorsally with five prominent cream to mauve vertical veins densely covered by tiny gland-like protrusions, ventrally with seven prominent indigo to dark purple vertical veins at base suddenly flattening distally and densely papillose with papillae to 0.5 mm long (Fig. 2D 1; 3C 1–C 4); bases of all veins forming a prominent cream-coloured crenate ring (Fig. 2E; 3G). Tepals 6, inserted more or less at the same level in the distal portion of the hypanthium, heteromorphic. Outer tepals alternate with the segments of the annulus; upper outer tepal incurved, elliptic, 7.0–7.5 × 4.0– 4.5 mm, indigo to dark purple, vesicular, margin entire, base subcordate, apex rounded, venation hyphodromous (Fig. 3D 1); lateral outer tepals declinate and slightly twisted laterally outside, elliptic, 6.0–6.5 × 4.0– 4.5 mm, indigo to dark purple, vesicular, margin entire, base slightly revolute, apex rounded, venation hyphodromous (Fig. 3D 2). Inner tepals opposite to segments of the annulus, assurgent, narrowly triangular, 5.0–7.0 × 1.5–3.0 mm, dark violet, vesicular, apex tapering abruptly into a cauda; cauda 30.0–57.0 × 0.5 mm, tawny turning cream, apex slightly acute (Fig. 2A 1; 3A). Annulus consisting into three connate segments opposite to inner tepals, reclinate, each segment 4.0–5.0 × 2.0– 2.5 mm, lavender to brilliant white, ornamented with three finely raised crests on the upper side, arranged parallel to the orifice, outer crest 0.6–1.0 mm high, middle crest 0.3–0.4 mm high and inner crest 0.3 mm high, separated by gaps 0.5–0.6 mm wide (Fig. 2B–D; 3C 1). Orifice of annulus circular, ca. 2.5 mm diam. (Fig. 2C; 3B). Stamens 6, dimorphic, arranged in the radii of tepals, inserted along the inner edge of annulus segments, pendulous and hanging into the hypanthium; bases of stamen filament expanded laterally and fused into a ring ca. 0.4 mm in diam. (Fig. 2D; 3C 1). Dorsal stamens 3 (Fig. 2D2; 3E; 5E); each with filament laminar, 0.7 × 1.0 mm, coral to white (Fig. 3E 1); connective dilated, bilobed basally and apically (apical lobes branching off immediately below the point of insertion of thecae), 1.0 × 1.0 mm (including apical lobes), rufous, distal portion bearing a tuft of trichomes at the point of insertion with the thecae; trichomes unicellular, erect, 0.4–0.9 mm long (Fig. 3E 2); basal lobes of connective appressed to the filament, linear, 1.0 × 0.4 mm, rufous (Fig. 3E 1); apical lobes of connective narrowly ovate, 0.3–0.4 × 0.5–0.6 mm, dark purple, apex rounded to truncate, papillose; papillae 0.09–0.12 mm long, dark purple (Fig. 3E3); interstaminal lobes inserted ca. 0.5 mm below the filaments, mammiliform to shortly triangulate, 0.3–0.5 × 0.3–0.5 mm, dark purple (Fig. E1). Ventral stamens 3; 2 lateral stamens each with filament laminar, 1.0 × 1.0 mm, coral to white (Fig. 3F 1); connective dilated, at the margin adjacent to dorsal stamen lobed basally and apically, at the margin adjacent to central stamen lobed laterally lobed by fusion of basal and apical lobe (apical and lateral lobes branching off immediately below the point of insertion of the thecae), 1.0 × 0.8 mm, rufous, distal portion bearing a tuft of trichomes at the point of insertion with thecae; trichomes unicellular, erect, 0.4–0.9 mm long (Fig. 3F 2); basal lobe, appresed to the filament, linear, 1.0 × 0.4 mm, rufous (Fig. 3F 1); apical lobe narrowly ovate, 0.3–0.4 × 0.5–0.6 mm, dark purple, apex rounded to truncate, papillose; papillae 0.09–0.12 mm long, dark purple; lateral lobe divaricate, falcate, 1.0 × 0.7 mm, rufous, outer margin proximally papillose; papillae 0.09–0.12 mm long (Fig. 3F 1); single central stamen with filament laminar, 1.0 × 1.0 mm, coral to white (Fig. 3F 2); connective dilated, laterally lobulated by fusion of basal and apical lobe, 1.0 × 0.8 mm, rufous, distal portion bearing a tuft of trichomes at the point of insertion with thecae; trichomes unicellular, erect, 0.4– 0.9 mm long (Fig. 3F 2); lateral lobes 2, divaricate, falcate, 1.0 × 0.7 mm, rufous, outer margin proximally papillose; papillae 0.09–0.12 mm long (Fig. 3F 2–F 3); interstaminal lobes inserted ca. 0.5 mm below the filament, linear, 1.0 × 0.3 mm, dark purple (Fig. 3F 1). Thecae 2, inserted at the distal part of the connective, free, ellipsoid, 1.0–1.2 × 0.5– 0.7 mm, longitudinally dehiscent, white (Fig. 3E 2; 3F 2). Pollen in monades, bilaterally symmetrical, isopolar, amb circular to slightly elliptic, spheroidal shape, (22.0–)23.2(–24.0) µm in diam., monoporate with simple circular pore; exine intectate, 1.0 µm thick; sculpture psilate (Fig. 4, Table 1). Ovary inferior, broadly obconical, 2.0–2.5 × 3.7–4.0 mm, unilocular; placentation parietal; placentas 3, inserted in the basal part of the locule, bearing numerous ovules; style erect, cylindrical to shortly conical, 0.6–0.7 × 0.6–1.0 mm, dark purple (Fig. 2E; 3G); stigma divaricate, trilobed, each conical lobe, 1.0–1.3 × 0.9 mm, dark purple and covered abaxially by multicellular uniseriate simple trichomes; proximally densely puberulous with 0.1–0.3 mm long trichomes, dark purple and distally hispid with 0.3–0.5 mm long trichomes, light green (Fig. 2E; 3G). Immature fruit cupuliform, 3.6 × 5.3 mm, dark purple, surrounded by persistent involucral bracts (Fig. 2A–2F). Additional specimen examined (paratype): — COLOMBIA. Valle del Cauca: Buenaventura municipality, El Paraíso Natural Reserve, Danubio Stream, tributary of El Danubio River, located approximately seven meters from the river, among leaf litter, 737 m, 3°37’55.09”N, 76°49’59.37”W, 10 February 2023, B. C . Corrales Restrepo, S. Guzmán-Guzmán & E. Restrepo 002 (FAUC). Photographic records examined: — COLOMBIA. Valle del Cauca: Cali municipality, 3°26’48.8”N, 76°39’23.9”W (approximate coordinates), 9 February 2018, Sasha Robinson, Recorded in iNaturalist (https://www. inaturalist.org/observations/10252116); Valle del Cauca: Dagua municipality, 384 m, 3°36’0.3”N, 76°51’0.2”W, 8 January 2021, Mauricio Morales, Recorded in iNaturalist (https://www.inaturalist.org/observations/81910064). Etymology: —The specific epithet of Thismia paradisiaca refers to the Latin word “ paradisiacus ” which means “belonging to paradise”. In turn, this word derives from the Latin term “ paradisus ” which is related to “garden of sublime exuberance and beauty”. This name is a tribute to the El Paraíso Natural Reserve. Distribution and habitat: — Thismia paradisiaca is found in the Pacific Domain, specifically in Chocó –Darién Moist Forests Ecoregion on the Pacific slope of the Western Cordillera of the Andes (Fig. 1A; 6) (Olson et al. 2001, Rangel 2004, Morrone 2022), located in the immeasurable and ineffable diversity of the Biogeographic Chocó, where the reserve owners are currently working hard to conserve this area through endangered species conservation plans, such as Lehmann’s poison frog (Oophaga lehmannii, Dendrobatidae), the long-wattled umbrellabird (Cephalopterus penduliger, Cotingidae) and now the thismia of paradise (Thismia paradisiaca). This species inhabits elevations of 710–750 m in riparian forests near the Danubio River and Danubio Stream (Fig. 1B), with the two known localities placed in approximately 470 m from each other. The first (holotype) locality is in about 50 m from the Danubio River, next to a little-traveled path that leads to the cabin of the El Paraíso Nature Reserve (Fig. 1D). A total of five individuals were recorded in this locality, two of which had flower buds, one had an anthetic flower and immature fruit, one had an in immature fruit, and the last one had no flowering stem (only the tuber was observed). Additionally, two abscised hypanthia were recorded on the ground, right next to the immature fruits. These individuals were located in a layer of leaf litter 3 to 5 cm deep dominated by leaves of Ficus tonduzii Standley (Moraceae) and Inga sp. Miller (Fabaceae) in a small (2 m 2) landslide. This landslide was possibly formed after heavy rains that occurred days before the collection; it was composed mainly of small rocks, soil, and small shrubs. In an area of 5 m 2 in the first locality, the herbaceous layer between 0.5 to 1 m in height comprised Diplazium macrodictyon (Baker)Diels (Athyriaceae), Mickelia nicotianifolia (Sw.)R.C.Moran,Labial&Sundue(Dryopteridaceae), Campyloneurum sphenodes Fée (Polypodiaceae), Dicranopygium sp. (Cyclanthaceae), Costus sp. (Costaceae), Pilea pteropodon Wedd. and P. umbriana Killip. (Urticaceae). The lower tree layer is dominated by Inga psittacorum L.Uribe (Fabaceae) and Saurauia sp. (Actinidiaceae) with heights between 5 to 7 m, and by an upper tree layer between 20 to 25 m in height consisting of F. tonduzii and Inga sp. The second (paratype) locality is located in approximately 7 meters from the Danubio Stream. It had a layer of leaf litter between 5 to 7 cm deep, mainly composed of leaves of F. tonduzii and two lianas, Coussapoa contorta Cuatrec. (Urticaceae) and Clusia hirsuta Hammel (Clusiaceae). In this locality, the leaf litter was accumulated in cavities formed by thick superficial roots above ground of Turpinia occidentalis (Sw.) G.Don (Staphyleaceae) and Guatteria alta R.E.Fr. (Annonaceae) (Fig. 1C), right next to a runoff drain that flows from the top of the mountain. Only two individuals were found for this locality: one in anthesis and the other one with immature fruit and its corresponding abscised hypanthium on the ground. In an area of 5 m 2 in the second locality, the herbaceous layer between 0.5to 1 m in height comprised Campyloneurum sphenodes (Polypodiaceae), Anthurium spp. and Xanthosoma daguense Engl. (Araceae), Dicranopygium sp. (Cyclanthaceae), Costus sp. (Costaceae) and Pilea umbriana (Urticaceae). The lower tree layer comprised Eugenia victoriana Cuatrec. (Myrtaceae) and G. alta with heights between 7 to 9 m and a upper tree layer dominated by F. tonduzii and T. occidentalis. Of the mentioned species, E. victoriana and G. alta are endemic to Colombia (Bernal et al. 2019), and along with C. contorta and C. hirsuta, they have a restricted distribution to the Chocó –Darién Moist Forests Ecoregion (Bert et al. 1990, Luján et al. 2018). Phenology: —Both populations were collected in flower and fruit on February 10, however, according to the reports in iNaturalist and the monitoring and photographic recording by the reserve’s tour guides, the flowering season take place from January to March in both locations. Ecological interactions: —The knowledge about the floral biology of Thismia was for a long time limited to various hypotheses based on its floral morphology and particularly on the arrangement of androecial and gynoecial organs inside the floral chamber, the presence of nectaries at the base of the perianth or on the anthers, the presence of osmophores and filiform appendages in the tepals, and narrowly spaced filaments of the stamens. These features correspond to a myiophilous pollination syndrome. Various lineages of flies, and mainly fungus gnats and scuttle flies, were identified as possible pollinators (Poulsen 1890, Groom 1895, Faegri & Van Der Pijil 1979, Stone 1980, Maas et al. 1986). Only recently the first direct observations on floral visitors and/or pollinators were conducted, thereby confirming some of these hypotheses. All the hitherto published observations were made in Asian species of the genus. Li & Bi (2013) recorded a dipteran species visiting a flower of T.gongshanensis Li & Bi (2013: 25) during collection of the type specimen. Subsequently, Mar & Saunders (2015) reported the presence of a fungus gnat (Mycetophilidae or Sciaridae, Diptera) and a scuttle fly wing (Phoridae, Diptera) inside the floral chamber of T. hongkongensis Mar & R.M.K.Saunders (2015: 23). Both records, while being significant, did not provide insight into the role of these visitors and their role in pollination. Guo et al. (2019) conducted a remarkable study on the reproductive biology of T. tentaculata Larsen & Averyanov (2007: 16), where they recorded insects from various families and other invertebrates as floral visitors. They identified a species of fungus gnats from the genus Corynoptera (Sciaridae: Diptera) as the pollinator of this species, observing that the gnats are retained inside the floral chamber for a significant time, interact with the stigmatic region, and carry pollen grains on their bodies. Likewise, Yudina et al. (2021) recorded 35 floral visitors from various insect and other invertebrate families in T. puberula Nuraliev (2015: 135) (16 visitors), T. mucronata Nuraliev (2014: 246) (18 visitors) and T. annamensis Larsen & Averyanov (2007: 13) (one visitor). Among them, they highlighted the scuttle flies and parasitic wasps from the families Braconidae, Diapriidae and Scelionidae (Hymenoptera) as potential pollinators since these insects were demonstrated to carry pollen grains of Thismia. These studies support the earlier hypotheses based on floral morphology and demonstrate sapromyophilous pollination especially by fungus gnats and scuttle flies. To date, no floral visitors have ever been recorded for the Neotropical species of Thismia, i.e. subgenus Ophiomeris. During dissection of an alcohol-stored flower of T. paradisiaca, a small dipteran was found inside the floral chamber (Fig. 1E), firmly retained between the inner surface of the hypanthium and the dorsal stamens. It is impossible to determine whether it was actually interacting with the stamens, as not a single fly approaching the flowers or interacting with them was recorded during observation and specimen collection. Nevertheless, the record of this dipteran within the flower suggests an evident floral visitation, especially considering the reported close relationship between Diptera and the Asian species mentioned above, as well as a combination of floral characters of T. paradisiaca consistent with the typical pattern of sapromyophilous pollination syndrome. This is the first record of floral visitors for subgen. Ophiomeris, and further studies focused on the floral biology of T. paradisiaca may provide additional insights into its pollination mechanisms and the role of floral visitors. The relationship between the dimorphic stamens and pollination of T. paradisiaca is noteworthy. The stamen dimorphism has not been reported for any other species of family Thismiaceae. The dorsal stamens, lose to which the dipteran was found, forms a barrier due to the proximity of the stamens (including the basal lobes of the connectives) to the interstaminal lobes (Fig. 3E). The ventral stamens, in contrast, are more distantly spaced, and the lateral lobes of the connectives form openings (Fig. 3F). As a result, the dorsal stamens possibly act as a barrier that directs floral visitors to pass through the openings between the ventral stamens, hindering their exit and ensuring interaction with pollen grains before leaving the floral chamber. Taxonomic relationships: —We assign Thismia paradisiaca to the subgen. Ophiomeris sect. Ophiomeris, because of its underground part represented by a tuber, sulcate stem, sessile flower, laminar staminal filament and parietal placentas inserted in the basal part of the ovary. With T. paradisiaca, sect. Ophiomeris comprises 15 species (Kumar et al. 2017). Thismia paradisiaca differs from all the other species of the section by having dimorphic (vs homomorphic) stamens, incurved (vs reflexed to patent) upper outer tepal and lateral outer tepals slightly revolute (vs truncate or cordate) at base. Thismia paradisiaca occurs in the Chocó –Darién Moist Forests Ecoregion (Olson et al. 2001) along with T. luetzelburgii K.I.Goebel & Suess. (1924: 56) and T. panamensis. The new species differs from T. luetzelburgii by having not swoll, Published as part of Guzmán-Guzmán, Santiago & Plata-Torres, Angelo, 2023, A flower in paradise: citizen science helps to discover Thismia paradisiaca (Thismiaceae), a new species from the Chocó Biogeographic region in Colombia, pp. 27-42 in Phytotaxa 603 (1) on pages 29-38, DOI: 10.11646/phytotaxa.603.1.2, http://zenodo.org/record/8153612, {"references":["Olson, D. M., Dinerstein, E., Wikramanayake, E. D., Burgess, N. D., Powell, G. V. N., Underwood, E. C., D'amico, J. A., Itoua, I., Strand, H. E., Morrison, J. C., Loucks, C. J., Allnutt, T. F., Ricketts, T. H., Kura, Y., Lamoreux, J. F., Wettengel, W. W., Hedao, P. & Kassem, K. R. (2001) Terrestrial ecoregions of the World: A new map of life on Earth: A new global map of terrestrial ecoregions provides an innovative tool for conserving biodiversity. BioScience 51: 933 - 938. https: // doi. org / 10.1641 / 0006 - 3568 (2001) 051 [0933: TEOTWA] 2.0. CO; 2","Morrone, J. J., Escalante, T., Rodriguez-Rapia, G., Carmona, A., Arana, M. & Mercado-Gomez, J. D. (2022) Biogeographic regionalization of the Neotropical region: New map and shapefile. Anais da Academia Brasileira de Ciencias 94 (1): e 20211167. https: // doi. org / 10.1590 / 0001 - 3765202220211167","Bernal, R., Gradstein, S. R. & Celis, M. (eds.) (2019) Catalogo de plantas y liquenes de Colombia. Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogota, D. C. Available from: http: // catalogoplantasdecolombia. unal. edu. co","Lujan, M., Idarraga, A. & Hammel, B. (2018) Clusia hirsuta, a new species from Clusia sect. Retinostemon and the first description of trichomes in the genus. Novon 26 (2): 154 - 158. https: // doi. org / 10.3417 / 2018064","Poulsen, M. V. A. (1890) Thismia glaziovii nov. sp. Bidrag til de brasilianske Saprofyters Naturhistorie. Oversigt over det kongelige danske videnskabernes selskabs forhandlinger og dets medlemmers arbeider 1890: 18 - 38.","Groom, P. 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Phytotaxa 167 (3): 245 - 255. https: // doi. org / 10.11646 / phytotaxa. 167.3.3","Kumar, P., Gale, S. W., Li, J. H., Bouamanivong, S. & Fischer, G. A. (2017) Thismia nigricoronata, a new species of Burmanniaceae (Thismieae, Dioscoreales) from Vang Vieng, Vientiane Province, Laos, and a key to subgeneric classification. Phytotaxa 319 (3): 225 - 240. https: // doi. org / 10.11646 / phytotaxa. 319.3.2","Maas, P. J. M. & Maas-van de Kamer, H. (1988) Burmanniaceae. Flora de Colombia 7: 33 - 125.","Poulsen, M. V. A. (1889) Une nouvelle phanerogame sans chlorophylle (Thismia glaziovii). Note preliminaire. Revue Generale de Botanique 1: 549 - 550."]}