Virola yasuniana D. Santam., 2022

Santamaria-Aguilar, Daniel & Lagomarsino, Laura P., 2022, New Species of Virola (Myristicaceae) from South America, PhytoKeys 197, pp. 81-148 : 81

10. Virola yasuniana D. Santam. sp. nov.

Type.

Ecuador. Pastaza: Pastaza Cantón, Pozo petrolero “Ramírez”, 20 km al sur de la población de Curaray, 300 m, 01°32'S, 076°51'W, 21-28 Feb 1990 (fr), V. Zak & S. Espinoza 5149 (holotype: MO! [accession 04782630, barcode MO-713299], isotypes: NY!, QCNE [n.v.], US [accession 3625319; image!). Fig. 17

Diagnosis.

Virola yasuniana morphologically differ from all others species by the combinations of large fruits (3.4-4.2 × 3.1-4 cm) with very conspicuous wings in the line of dehiscence, staminate flowers, with a filaments column that is wide at the base, constricted at the apex, and usually shorter (0.3-0.5 mm long) than the anthers (0.5-0.6 mm long).

Tree 15-30 m × 30-40 cm diameter, outer bark brown, powdery, rough and thin, inner bark orange-red. Exudate translucent on internal bark, or watery reddish or reddish purple, location of exudate on plant not stated. Twigs 0.2-0.4 cm thick, terete, puberulent to glabrescent, trichomes stellate, sessile, brown-reddish to whitish, sometimes slightly lenticellate. Leaves young terminal bud 1-2 × 0.19-0.28 cm; petiole 1.1-1.7 × 0.15-0.21 cm, canaliculate, sometimes very short alate, puberulent, sometimes tomentose, the trichomes stellate; leaf blades 15.7-27.5 × 4.4-6.6 cm, lanceolate to oblong; adaxial surface when drying on mature leaves pale to dark brown, grayish, or blackish, the surface smooth, sometimes shiny, glabrous; abaxial surface when drying grayish, pale to dark brown, or white-grayish, sparsely pubescent to glabrescent, the trichomes stellate, ca. 0.1 mm diameter, sessile, the central part of the trichome colorless or reddish, the branches brown-reddish or colorless; lateral veins 14-18 per side, 4-5 veins per 5 cm, spaced 0.9-1.5 (-1.9) cm, on adaxial side, the same color as the adaxial surface or a little darker, flat, on abaxial surface slightly raised, glabrous to scattered pubescent, arcuate-ascending, slightly anastomosing near the margin and without forming a very marked intramarginal vein; tertiary veins very slightly visible on both sides; midvein adaxially slightly elevated, abaxially raised, rounded to triangular, puberulent to glabrescent; base acute, not revolute, flat; margin flat; apex acute. Staminate inflorescence 6-6.7 cm long, axes flattened, tomentose, trichomes appressed dendritic, ferruginous; peduncle 1.2-1.7 × 0.19-0.26 cm; main axes with 6-9 ramifications, the first pair opposite to subopposite, the others alternate; bracts not seen. Staminate flowers (in bud) in dense terminal fascicles of 15-25+ flowers, on a receptacle 2.1-3 mm wide; perianth 1.3-1.8 mm long, subglobose to infundibuliform to ovate, subcarnose, brown when fresh, connate to 1.2-1.5 mm in length, external surface densely pubescent with ferruginous and dendritic-stellate trichomes, internal surface moderately pubescent (especially in the lobes); lobes 3, 0.7-1 × 0.5-0.8 mm, ca. 0.1 mm thick, without resinous punctuations when rehydrated; stamens 3, the filament column 0.3-0.5 mm long, ca. 0.2-0.3 mm wide, glabrous, wide at the base and constricted at the apex; anthers 0.5-0.6 mm long, and 0.3-0.4 mm wide; apiculus ca. 0.1 mm long, acuminate, connate. Pistillate inflorescence 2.6-.2.9 cm long, axes flattened, tomentose, with trichomes dendritic, ferruginous; peduncle ca. 1 × 0.2-0.3 cm; bracts not seen. Pistillate flowers in terminal fascicles of 1-2 flowers, on a receptacle 2.5-3.5 mm wide; perianth ca. 3-3.1 mm long, ovate, subcarnose, brown when fresh, connate by ca. 1.5-2 mm long, external surface densely pubescent with ferruginous and dendritic trichomes, internal surface moderately pubescent (especially in the lobes), sometimes slightly pubescent at the base; lobes 3, ca. 1.3-1.8 × 1.1-1.3 mm, and ca. 0.1 mm thick; gynoecium ca. 2-3 × 1.6-2.4 mm, globose, densely pubescent, with ferruginous trichomes; stigma 2-lobed, ca. 0.3-0.5 × 0.3 mm, erect, flat seen from above, drying blackish, slightly wavy at the margins. Infructescence 2.3-3.4 cm long, with 1-2 fruits, peduncle 0.7-1.5 × 0.34-0.6 cm. Fruits 3.4-4.2 × 3.1-4 cm (including wings), green when fresh (blackish when dry), ellipsoid to somewhat flattened (immature), shortly stipitate, puberulent, the trichomes stellate, sessile, ferruginous or whitish and not falling like dust, the surface rugulose, the line of dehiscence winged, the wing 0.4-0.7 cm long, the base rounded to subcordate, the apex rounded; pericarp 1.3 and 2.3 mm thick (measured from two specimens); pedicel 0.7-1 cm long. Seed ca. 2.5 × 1.9 cm, the testa drying dark brown to yellowish, slightly ribbed distally; aril color when fresh described once as red, brown-reddish to blackish when dry, the texture dry and thin, laciniate almost to the base, in narrow bands distally.

Distinctive characters.

The very distinctive fruits of Virola yasuniana , which are large with very conspicuous wings in the line of dehiscence (Fig. 6M ), make it almost impossible to confuse with any other species of Virola already described. Other characteristics that distinguish this new species include leaf blades that are abaxially covered with inconspicuous stellate and sessile trichomes, evenly spaced lateral veins that are comparatively spaced, and moderately pubescent internal perianth in staminate flowers, and a filaments column that is wide at the base, constricted at the apex, and usually shorter (0.3-0.5 mm long) than the anthers (0.5-0.6 mm long).

Etymology.

The specific epithet refers to Parque Nacional Yasuní, where most of the collections of this new species come from. At present, 2700 vascular plant species are documented from Yasuní, including a high diversity of lianas, epiphytes, and ferns; it is estimated its flora comprises approximately 3213 species; Yasuní is also home to ca. 1570 species of birds, fishes, mammals, amphibians and reptiles ( Bass et al. 2010; Pérez et al. 2014). The description of Virola yasuniana is one step closer to a full documentation of this region.

Distribution.

Virola yasuniana is known from the Napo and Pastaza provinces of Ecuador, where it occurs in primary forests, on hills with red soil, or soils composed of sedimentary rocks. Is also located in Acre state of Brazil, where it grows in terra firme on poorly drained terrace (Fig. 18A ). It ranges from 200-480 m in elevation, with a single collection reaching 1000 m (C. Cerón & F. Hurtado 6560).

Phenology.

Staminate flowers of Virola yasuniana have been collected in January, February and November, while pistillate flowers have been collected in April, May, and July. Fruits are known from February, March, June, and September.

Common name and uses.

Dobompapoca (Ecuador: Huaorani; M. Aulestia & O. Gonti 1969); guapa (Ecuador: Quichua; C. Cerón & F. Hurtado 6560). The wood has commercial use (C. Cerón & F. Hurtado 6560).

Preliminary Conservation Status.

Virola yasuniana is Vulnerable following IUCN criterion B2a. It is known from two localities, has an EOO of 117,581 km2, and an AOO of 32 km2. This species benefits from its occurrence in the Yasuní National Park of Ecuador, which experiences very low rates of deforestation ( Bass et al. 2010; van der Hoek 2017), even while the broader region is experiencing land use changes ( Heredia-R et al. 2021).

Discussion.

It is possible to confuse Virola yasuniana with V. parkeri from Peru due to their similar leaves (i.e. shape, color when dry, base, venations, and trichomes), staminate perianth that is pubescents on both surfaces, and markedly carinate fruit. Differences among the two species are summarized in Table 11 .

Herbarium specimens of Virola yasuniana were previously identified as V. calophylla , V. obovata , or V. peruviana , all of which have leaf blades with lateral veins that are well separated and stellate, sessile trichomes on abaxial leaf surface. Additionally, the new species shares fruits with a conspicuous carina with V. peruviana . Differences among these species are summarized in Table 10 .

Notes.

Several collections of Virola yasuniana were treated as V. obovata in Flora of Ecuador (H. Vargas & J. Cerda 678, V. Zak & S. Espinoza 4871, 5039, 5049, 5149; Jaramillo et al. 2004). Additionally, studied with " aberrant fruits " that is discussed under V. peruviana in Flora of Ecuador ( Jaramillo et al. 2004) correspond with this new species (C. Cerón & F. Hurtado 6560, M. Aulestia & G. Grefa 247, M. Aulestia & O. Gonti 1969).

Specimens examined.

Ecuador. Napo: Parque Nacional Yasuní, carretera y Oleoducto de Maxus en construcción, Km. 20, 00°33'S, 076°30'W, 250 m, 28-30 Jul 1993 (♀ fl), M. Aulestia & G. Grefa 247 (MO!, UPCB [n.v.]); Parque Nacional Yasuní, Carretera y oleoducto de Maxus en construcción, km 54-58, 00°48'S, 076°30'W, 250 m, 26-30 Sep 1993 (fr), M. Aulestia & N. Andi 783 (MO!, QCNE [n.v.], UPCB [n.v.]); Reserva Etnica Huaorani, carretera y oleoducto de Maxus en construcción Km. 92-96, al norte del Rio Yasun , 00°55'S, 076°09'W, 250 m, 20 March 1994 (fr), M. Aulestia & O. Gonti 1969 (MO!, UPCB [n.v.]); Archidona, Carretera Hollín-Loreto, Km 50, comunidad Guagua Sumaco, Faldas al sur del Volcán Sumaco, 00°38'S, 077°27'W, 1000 m, 29 Apr-2 May 1989 (♀ fl), C. Cerón & F. Hurtado 6560 (MO!, NY!); Parque Nacional Yasuni-ECY, Sendero “Napo” - 300 m, 00°40'40"S, 076°23'40"W, 200-300 m, 24 Sep 2009 (fr), Á. Pérez & W. Santillán 4361 (MO!); Parque Nacional Yasuni-ECY, Sendero “Chorongo” - 600 m, 00°40'40"S, 076°23'40"W, 200-300 m, 16 Nov 2009 (fl bud), Á. Pérez & W. Santillán 4402 (MO!); Loreto, 2 Km al oeste del rio Tutapishco , 00°36'S, 077°22'W, 480 m, 27 Jan 1996 (♂ fl bud), H. Vargas & J. Cerda 678 (MO!, QCA [image!], UPCB [n.v.]) . Pastaza: Pozo petrolero “Ramírez”, 20 km al sur de la población de Curaray, [01°32'S, 076°51'W], 300 m, 21-28 Feb 1990 (♂ fl), V. Zak & S. Espinoza 4871 (INPA [image!], MO!, NY!); ibid., 21-28 Feb 1990 (♂ fl), V. Zak & S. Espinoza 5039 (INPA [image!], MO!, NY!, QCNE [n.v.]); ibid., 21-28 Feb 1990 (♂ fl), V. Zak & S. Espinoza 5049 (INPA [image!], MO!, NY!) . Brazil. Acre: Mâncio Lima, Bacia do Alto Juruá, Rio Moa , Parque Nacional da Serra do Divisor , caminho para o rio Anil , 07°26'27"S, 073°39'28"W, [not elev.], 17 Jun 1996 (imm fr), M. Silveira et al. 1374 (NY!, UFACPZ [n.v.], UPCB [n.v.]); Mun. Tarauacá, Basin of Rio Jurua , Rio Tarauaca , right bank, Seringal Tamandare , Colocacao Santa Maria , Praia de Santa Maria , 08°35'12"S, 071°30'57"W, [not elev.], 18 Nov 1995 (♂ fl), D. C. Daly et al. 8594 (NY!, UFACPZ [n.v.], UPCB [n.v.]) .

New record

Figures

Figure 6. Comparison of fruits of newly described Virola species, with those species that are morphologically similar to them, noting the shape, indument, a pericarp thickness A V. aguarunana (C. Diaz et al. 7195, MO) B V. alvaroperezii (D. Rubio et al. 2205, MO) C V. bombuscaroensis (J. Homeier 4507, MO) D V. calimensis (M. Monsalve 158, MO) E V. calophylla (J. J. Pipoly 15614, MO) F V. calophylloidea (S. R. Lowrie et al. 54, MO) G V. cogolloi (D. Cardenas & E. Alvarez 3239, MO) H V. macrocarpa (A. E. Lawrance 675, MO) I V. excisa (W. Palacios 3186, MO) J V. obovata (R. Vasquez & N. Jaramillo 3822, MO) K V. peruviana (D. N. Smith & V. Garcia 13841, MO). L V. parkeri (A. Monteagudo et al. 10761, MO) M V. yasuniana (A. Perez & W. Santillan 4361, MO; right and below from V. Zak & S. Espinoza 5149, MO) N V. tuckerae (A. Cogollo et al. 3924, COL). Scale bars: 1 cm.

Figure 17. Virola yasuniana A branch with staminate inflorescence, with detail of midvein and trichomes (upper right) B partial staminate inflorescence C lateral view of staminate perianth D medial section of staminate flower (right) and androecium (left) E branch with pistillate inflorescence F lateral view perianth (right) of pistillate flower and gynoecium (left) G Medial section of pistillate flower, showing detail of trichomes on gynoecium (right) H different views of the fruits, and an open fruit (right) showing the seed covered by a laciniate aril. Drawn by Bobbi Angell based on V. Zak & S. Espinoza 5039 (A-D MO), C. Ceron & F. Hurtado 6560 (E-G MO); V. Zak & S. Espinoza 5149 (H MO).

Figure 18. Geographic distribution of the new species of Virola.