Otoba scottmorii D. Santam., 2021

Santamaria-Aguilar, Daniel & Lagomarsino, Laura P., 2021, Two new species of Otoba (Myristicaceae) from Colombia, PhytoKeys 178, pp. 147-170 : 147

Otoba scottmorii D. Santam. sp. nov. Figs 3 , 5B , 6C

Type.

Colombia. Antioquia: [Municipio] Mpio. Segovia, 24.5 km N of Remedios (17 km N of La Cruzada) on road to Zaragoza, hills side forest above río Poconé, 07°12'N, 074°48'W, [not elev.], 20 Jul. 1987 (♂ fl), W.W. Thomas & C.J. Castaño 5501 (holotype: NY! [04206141]; isotypes: INPA-159329 [digital image!], UPCB-35245 [n.v.]).

Diagnosis.

Otoba scottmorii is similar to O. cyclobasis from Ecuador. However, it differs in having smaller leaves (5.5-8.5 [-11.2] vs. 9-14 [-18] cm long) with an attenuate to acuminate apex (vs. cuspidate), inconspicuous marginal and secondary veins (vs. conspicuous), fewer lateral veins (4-7 vs. 14-17), straight axes of staminate inflorescences (vs. zig zag), a longer filament column ([1.3-] 1.5-1.6 vs. 1 mm long), larger fruits (1.8-2.1 vs. 1.5-2.5 mm long) with thinner pericarp (0.68-0.89 vs. 1-2 mm thick), and seeds that are gibbose at the apex (vs. near-basal and lateral gibba).

Description.

Tree (2-) 15-20 m tall × 45 cm diam., external and internal bark not described. Exudate once described as red in the bark, transparent and without specifying from where, or without exudate. Twigs 0.88-0.1 cm thick, terete to slightly flattened laterally, the external bark brown to grayish, with malpighiaceous trichomes that are 0.2-0.3 mm long, brown to ferruginous or sometimes glabrescent. Young foliar bud 0.6-1.2 cm long, densely pubescent. Leaves: petiole 0.5-1.1 × 0.055-0.1 cm, canaliculate, not winged; lamina 5.5-8.5 (-11.2) × 1.7-2.5 (-3.7) cm, elliptic; adaxial side glabrous, drying blackish, sometimes brown in young leaves, the surface muricate; abaxial side drying brown to whitish grayish, the surface wrinkled to muricate, sparsely pubescent to glabrescent, with malpighiaceous trichomes that are 0.2-0.4 mm long, sessile, and ferruginous, and squamate trichomes that are ca. 0.08 mm diam. with the central portion dark and sides lighter (sometimes these sides appearing absent), with whitish crystals; vernation line absent; midvein flat to very slightly ribbed on adaxial side, the same color as the surface, abaxially 0.2-0.4 mm wide, slightly raised, darker than the surface; secondary veins brochidodromous, the loops 0.1-0.3 cm from the margin (sometimes the loops not visible), lateral veins 4-7 per side, 3-5 veins per 3 cm, on adaxial side flat and visible, on abaxial side flat and not very conspicuous, arcuate distally, the marginal vein not visible on adaxial side, slightly visible on abaxial side; tertiary veins indistinct; base attenuate, not revolute; margin entire, not revolute; apex attenuate to acuminate, the acumen 0.6-1 (-2) cm long. Staminate inflorescence: axillary (only very young twigs) or supraaxillary, with 1-2 (-3) main axes, spiciform, these axes 1.5-4.3 cm × 0.41-0.1 mm, pubescent, the trichomes ferruginous to coppery, each axis compound with 2-3 (-6) fascicles of flowers, each fascicle with 1-5 (-8) flowers, alternate; bracts not seen; pedicel 3-5 mm long, pubescent; bracteoles absent. Staminate flowers: flower bud 1-2.5 × 0.6-0.1 mm, elliptic to lanceolate; perianth 2-2.5 mm long, yellow or orange (in fresh material), sub-membranaceous, connate by 0.5-0.7 (-1) mm; lobes 3 (4), 1.5-1.8 × 0.8-1.1 mm, without resinous punctuations or lines, pubescent outside, the trichomes ferruginous to coppery, inside glabrous, the apex acute to obtuse, without inflexed-apiculo, the edges flat or slightly turned inwards distally, without a swollen lobed ring; filament column (1.3-) 1.5-1.6 mm long, bowling pin-shaped, fleshy, connate, glabrous; anthers 3, 0.2-0.4 mm long, free, lanceolate to oblong, apex slightly incurved. Pistillate inflorescence and flowers: not seen. Infructescence 2-4 cm long, with a solitary fruit; pedicel 1.2-1.6 cm long. Fruits 1.8-2.1 × 1.5-1.7 cm, green when fresh, globose, surface glabrous, colliculate-rugose, sometimes with whitish lenticels (J. Brand 682), the line of dehiscence smooth, the base obtuse, apex apiculate, the acumen 0.1-0.3 cm long; pericarp 0.68-0.89 mm thick; seed ca. 1.6 × 1.5 cm, similar in shape to the fruit, brownish (in dry material), gibbose at the apex (ca. 0.3 mm wide), the testa ca. 0.4 mm thick; aril described once as red (E. Renteria 4680), brownish to yellowish translucent in dry material, dry and membranous in texture.

Distinctive characters.

Otoba scottmorii is recognized by a combination of leaf, inflorescence, and fruit traits. Its small leaf blades have long apices and thin petioles, and lack vernation lines on the abaxial surface. The staminate inflorescences are delicate with flowers on relatively thin, long pedicels; these flowers have sub-membranaceous perianth and lack a swollen-lobed ring, a bowling pin-shaped filament column, and anthers that are lanceolate to oblong. Finally, fruits are small with thin pericarp and membranous aril.

Etymology.

Is a pleasure to name this species after Dr. Scott A. Mori (1941-2020), a wonderful person and skilled botanist; a dedicated explorer of Central and South America humid forests (where this species occurs), especially in the Guianas and the Amazon basin; and an authority on Neotropical Lecythidaceae . His taxonomic and ecological publications gave great inspiration to the first author, as did Dr. Mori’s personal support. For an account of Dr. Mori’s legacy, see Boom (2020), Forget (2020), and Prance et al. (2021).

Common name.

Cuángare otobo ( Cogollo et al. 2007).

Distribution.

Otoba scottmorii is known only from the humid forests in the Department of Antioquia in northwestern Colombia in the Municipios of Mutatá, Segovia, Tarazá, Turbo, and Valdivia (Fig. 4 ). Three collections were collected under 100 m elevation (20-80 m), and three others above 400 m elevation (410-730 m).

Phenology.

Herbarium specimens of Otoba scottmorii have been collected with staminate flowers in May, July, and November, and with fruits in November. Pistillate flowers have yet to be observed.

Preliminary conservation status.

Otoba scottmorii is Endangered following IUCN criteria B2a. Justifying this status, it is known from five localities, has an EOO of 5,341 km2, and an AOO of 20 km2. The regions where it occurs are threatened by high levels of deforestation ( González-Caro and Vásquez 2017). Of the relatively few specimens of this species that we were able to verify, the most recent specimen was collected in 1993.

Discussion.

Otoba scottmorii is similar to O. acuminata and O. vespertilio D. Santam. & J.E. Jiménez, from Costa Rica and Panama, and O. cyclobasis T.S. Jaram. & Balslev from Ecuador. They all have relatively small leaf blades of similar shape and thin petioles, and usually lack vernation lines (Figs 5 , 6 ); staminate flowers with short perianth and small anthers; and similarly sized fruit with thin pericarp (Fig. 5 ). The four species can be distinguished by the characteristics in Table 2 .

As mentioned in the introduction, Otoba scottmorii was confused with the Mesoamerican species O. acuminata , which we now consider to be endemic to the Caribbean slope of Costa Rica and Panama. The specimens referred to as O. acuminata from Colombia in recent floras or checklists (e.g., Cogollo et al. 2007; Cogollo 2011; Ulloa Ulloa et al. 2017; Jaramillo-Vivanco and Balslev 2020) correspond to O. scottmorii . The confusion between these two species is likely driven by the similar morphology of the leaf blades (i.e., size and shape, usually without vernation lines, and thin petioles). However, O. scottmorii differs from O. acuminata in having narrower leaf blades (Fig. 5B, A respectively), staminate flowers with short perianth and narrow perianth lobes, a longer column of filaments, and fruits with a smooth surface and thin pericarp (Table 2 ). Although we have not observed the pistillate flowers of O. scottmorii , it is likely that the ovary is glabrous as the fruits do not have traces of trichomes, while in O. acuminata the ovary is pubescent; see for example: A. Rodríguez et al. 1559 (CR-2 sheets, MO); A. Estrada et al. 4829 (CR); B. Hammel & M. Grayum 14288 (CR, INPA [digital image], MEXU [digital image], MO). For a list of specimens that correspond to O. acuminata , see Santamaría-Aguilar et al. (2019).

Notes.

The type specimen of Otoba scottmorii and other collections here mentioned have been previously identified in herbaria and cited in literature as O. acuminata and O. gracilipes , and duplicates may have been distributed under these names.

Specimens examined.

Colombia. Antioquia: Mutatá, Sitio Rio Surambay , 12 km N de Mutata, 07°20'N, 076°30'W, 30-80 m, 21 Nov. 1987 (♂ fl), R. Callejas et al. 5752 (INPA digital image, MO, NY); ibid, 21 Nov. 1987 (fr), R. Callejas et al. 5789 (INPA digital image, MO, NY); Turbo, Carretera Tapon del Darien , Sector Rio Leon-Lomas Aisladas , km 37, [07°39'11"N, 076°58'02"W], 20 m, 29 Nov. 1993 (fr), J. Brand & M. Narváez 682 (COL [n.v.], JAUM digital image, MO); rio Cianura , Paso de la Reina, 730 m, 13 Mar 1986 (fr), E. Renteria et al. 4680 (JAUM digital image); Tarazá, Corregimiento El 12, 210 kms, NE de Medellín, vía El 12-Barroblanco, km 3, 07°30'N, 075°20'W, [450 m], 09 Nov. 1987 (♂ fl), R. Callejas et al. 5509 (INPA digital image, NY); Valdivia, corregimiento Puerto Valdivia, km 5 de Puerto Valdivia hacia "El 12", colecciones a lo largo del Rio Pescado , 07°20'N, 075°20'W, 410 m, 14 May. 1987 (♂ fl), R. Callejas et al. 3440 (MO-2 sheets, NY) .

Figures

Figure 3. Otoba scottmorii A staminate flowering branch, with detail of leaf surface (detail below left) B leaf base, petiole and basal portion of inflorescence C detail of staminate inflorescence D flower bud E staminate flowers, entire (above right) and with one perianth lobe removed, showing the androecium (below center) and perianth lobe (above left) F androecium G stem with infructescence, including an immature, opening fruit H view of dehisced fruit (left, below G) showing the seed and aril (right) Otoba cyclobasis I staminate flowering branch showing leaves with brochidodromous venation, including detail of marginal vein J staminate flower with one perianth lobe removed, showing the androecium and perianth lobe (above left) K androecium. Illustration by Bobbi Angell, W. W. Thomas & C. J. Castano 5501 (NY) (A-F), J. Brand & M. Narvaez 682 (MO) (G, H), E. Narvaez et al. 1072 (MO- 2468293) (I-K).

Figure 4. Geographic distribution of Otoba scottmorii (black circle) and O. squamosa (black triangle). The shaded map area corresponds to the department of Antioquia.

Figure 5. Comparison of leaf blades and fruits of O. acuminata (A L. Poveda et al. 3793, MO A 1 from H. W. Churchill & G. C. de Nevers 4976 MO; immature fruit) O. scottmorii (B R. Callejas et al. 3440 MO B 1 - B 2 from R. Callejas et al. 5789, MO) O. cyclobasis (C E. Narvaez et al. 1072, MO C 1 - C 2 from W. A. Palacios & M. Tirado 11318 MO) and O. vespertilio (D G. McPherson 13597, MO, juvenile leaf, D 1 G. McPherson 12543, MO). Scale bars: leaves: 2 cm; fruits: 0.75 cm.

Figure 6. Comparations of herbarium specimens of Otoba acuminata (A L. Poveda et al. 3793, MO) O. cyclobasis (B P. Mendez et al. 156, MO) O. scottmorii (C W. W. Thomas & C. J. Castano 5501, NY), and O. vespertilio (D R. Aguilar et al. 5024, MO).