Mandevilla sherlockii L.O. Alvarado & Lozada-Pérez, 2017

Alvarado-Cárdenas, Leonardo O. & Lozada-Pérez, Lucio, 2017, A new species of Mandevilla (Apocynaceae; Apocynoideae) from Mexico, Phytotaxa 319 (1), pp. 93-102 : 94-100

publication ID	https://doi.org/ 10.11646/phytotaxa.319.1.5
persistent identifier	https://treatment.plazi.org/id/038C87C2-FFED-FFED-FF0B-90CD1DCE4151
treatment provided by	Felipe
scientific name	Mandevilla sherlockii L.O. Alvarado & Lozada-Pérez
status	sp. nov.

Treatment

Mandevilla sherlockii L.O. Alvarado & Lozada-Pérez View in CoL , sp. nov. (fig. 1, 2)

M. sherlockii is morphologically similar to M. oaxacana , with glands at the base of the blade and infundibuliform corollas similar in size. Mandevilla sherlockii is differentiated by its longer, subcoriaceous to coriaceous blades 9‒ 14.5 cm long (vs 3‒9.5 cm in M. oaxacana ) and inflorescences with a curved rachis between each flower.

Type: B. Juárez 561 — México. Veracruz: Municipality of Ixtaczoquitlan, Cerro Buenavista, 18°53'40"N, 97°2'15"W, 1260 m (18 Aug 1995), (holotype XAL).

Liana ca. 3 m long with reddish, sparsely pubescent to glabrescent branches with colleters on nodes; leaves opposite; petioles 0.7 ‒ 1 cm long, densely pubescent; blades 9 ‒ 14.5 × 3.8 ‒ 5.8 cm long, ovate ‒ oblong to elliptic, apex acuminate, base subcordate to cordate, subcoriaceous to coriaceous, adaxial surface dark green, glabrous to sparsely pubescent on the midrib, colleters 8 ‒ 10 clustered at the base of the midrib, abaxial surface light green and densely pubescent, secondary veins 12 ‒ 19 pairs, evident, adaxially printed, abaxially raised. Inflorescences racemose, axillary, 6 ‒ 10-flowered, peduncles 1.1 ‒ 3 cm long, sparsely pubescent, rachis conspicuously curved between each flower, with a zigzag appearance, pedicels 0.97 ‒ 1.5 cm long, twisted, sparsely puberulent to glabrous, bracts 2.0 ‒ 2.7 × 1.5 ‒ 2.0 mm, ovate to ovate ‒ lanceolate, scarious, sparsely pubescent; calyx lobes divided almost all the way to the base, equal to subequal, 2.8 ‒ 3.5 × 0.8 ‒ 1.0 mm, ovate to broadly ovate, apex acute, sometimes shortly mucronate, scarious, apparently persistent in the fruit, erect, sparsely puberulent to glabrous abaxially, margin shortly ciliated, with 5 ‒ 7 colleters opposite to each lobe on its adaxial side; corolla infundibuliform, yellow, glabrous, lower tube 13.0 ‒ 14.0 × 4.0 ‒ 4.5 mm, straight, upper tube 10 ‒ 12 × 9.8 ‒ 11 mm, campanulate, lobes 10 ‒ 15 × 11 ‒ 12 mm, asymmetrically ovate to slightly obovate, apex obtuse to rounded, patent; stamens inserted in the apex of the lower tube, filaments ca. 0.5 mm, pubescent at the base, anthers 5 mm long, base truncated, apex acuminate, connivent and agglutinated at the style head; pistils ca. 1.3 cm long, ovary ca. 1.5 mm long, ovoid, apex puberulent, style 9 ‒ 9.5 mm long, glabrous, style head pentagonal, ca. 3.5 mm long, apex acuminate; nectaries 5, ca. 1.5 mm, joined in the upper half; follicles 17.5 ‒ 18 × 0.3 cm, falcate, subcontinuous, reddish ‒ brown, glabrous; seeds 7 ‒ 8 × 1 mm, linear, flat, truncated, brown, comose at the apex; coma 1 ‒ 1.5 cm, yellowish.

Phenology:—Flowering from April to August and fruiting in August.

Habitat:— Mandevilla sherlockii has been collected in cloud forest, tropical deciduous forest and oak forest, at elevations ranging from 1226 to 1400 m asl.

Distribution:—This new species is endemic to Mexico and is only known in the states of Oaxaca and Veracruz ( Fig. 3 View FIGURE 3 ).

Etymology:—The name is dedicated to the fictional character Sherlock Holmes, the famous English detective created by Sir Arthur I. Conan Doyle (1887). The character reflects much of the work of taxonomists and scientists in general, which is entirely detective work. Additionally, he was conceived as an amateur botanist, mainly interested in plants that can be used as poisons “Knowledge of Botany. - Variable. Well up in belladonna, opium, and poisons generally” (Conan 1887).

Conservation status:—The new species is known in only three locations, two in Veracruz and one in Oaxaca ( Fig. 3 View FIGURE 3 ), with an AOO than 12 km 2 and an EOO of 772 km 2, as well as a restricted altitudinal range. Mandevilla sherlockii seems to tolerate some degree of disturbance as indicated on the collection labels; however, it is found in a very small area of the country and in seriously threatened vegetation types, such as cloud forests ( Williams-Linera et al. 2002). Our observations of the species in some locations corroborate the constant anthropogenic impact on the vegetation cover. In addition, intense grazing activity that takes place in Veracruz can significantly reduce the number of individuals, as well as the known extent of distribution. Therefore, herein we suggest adding Mandevilla sherlockii to the category of critically endangered (CR B2 (bii, iv)), based on the criteria of IUCN ( IUCN 2013).

Remarks:— Mandevilla is the sixth most diverse genus of Apocynaceae in Mexico and the most diverse of Apocynoideae ( Alvarado-Cárdenas & Morales 2014, Juárez-Jaimes et al. 2007). With this new addition, Mandevilla is represented by 24 species in that country, from which 11 are endemic. This number of species allows us to suggest Mexico as the northernmost center of diversity for the genus.

Of all species of Mandevilla with infundibular flowers known in Mexico and Central America ( Table 1, Fig. 4 View FIGURE 4 ) this new taxon is morphologically very similar to M. oaxacana due to the presence of colleters at the base of the blade, sepals with similar size and shape and infundibular corollas of similar size ( Fig. 4 View FIGURE 4 ). Mandevilla sherlockii is recognized by its larger (9 ‒ 14.5 cm long vs 3 ‒ 9.5 cm in M. oaxacana ), coriaceous to sub ‒ coriaceous (vs. membranous in M. oaxacana ) blades and inflorescences with the rachis curved between each flower (vs. straight or not evidently curved, Fig. 4 View FIGURE 4 ); moreover, its inflorescences appear to be erect (vs. pendulous, Fig. 4 View FIGURE 4 ). The species M. convolvulacea (A.DC. 1844:451) Hemsl. (1881:316) and M. exilicaulis (Sessé & Mociño 1893:45) J.K. Williams (2003:144 ‒ 147) are easily differentiated by their smaller corollas, whereas M. hirsuta and M. sagittarii Woodson (1932:72) have colleters along the midrib of the blades, foliaceous sepals and much larger corollas, pubescent and red tonalities. The remaining species, M. veraguasensis (Seemann 1854:168) Hemsl. (1881:317) and M. boliviensis Woodson (1933:716) , are very easy to identify by their white and purple corollas, respectively.

Additional specimens examined (paratypes):— Oaxaca: Municipio de Santa María Chilchota, aproximadamente 6.3 km del Puente de Fierro, por la terracería a Santa María Chilchotla, 18°11’38.8”N, 96°50’43”W, 4 July 2001 (fl), X. Munn-Estrada, R. Nicholson, M. Shemluck, R. Rivera & C. Nicholson 1306 (XAL!). Veracruz: Municipio de Tlaltetela, Barranca de Tlaltetela, bajando de la parada El Pino hacia Guascatela, Puebla, 15 April 1987 (fl), M. Cházaro, L. Robles & P. Hernández 4639 (XAL!).

Another selected species revised:— Mandevilla convolvulacea . Mexico. Oaxaca. Municipio San Juan Chicomezuchitl, Cerca del puente de Río Grande, 1400 m, 17 May 1979, F. Ventura 16093 (MEXU! ENCB!). Municipio San Miguel Tlacotepec, Senda para el tanque de agua de San Miguel Tlacotepec, 1520 m, 19 Jul 1996, J. Calzada 21121 (MEXU! IEB! QMEX!).

Mandevilla exilicaulis . Mexico. Colima. Municipio Manzanillo, 41 km al N de Manzanillo, 3.5 km NW de Los Cedros, road to Huizcolote, Nov. 1981, E. Lott 859 (MEXU! MO!). Jalisco. Municipio Autlán, 1–2 km SSE of Ahuacapan, Feb. 1990, L. Guzmán 910 (WIS!). Zapotitlán de Vadillo, 1000 m, A Sanders 10820 (MO!). Michoacán. Sierra Madres, 1100 m, Nov. 1898, G. Langlassé 597 (G!).

Mandevilla hirsuta . Mexico. Chiapas. Municipio Ocosingo, A 2 km al N de la estación Chajul, 150 m, Sept. 1992, E. Martínez 25450 (XAL!). Oaxaca. Municipio Matías Romero, Col Cuahutémoc, terracería entre Sarabia y La Laguna, 100 m, T. Wendt 3936 (IEB! XAL!). Tabasco. Municipio Huimanguillo, Km 50 de la desviación de Huimanguillo hacía Francisco Rueda, Nov. 1979, C. Cowan 2619 (XAL!).

Mandevilla oaxacana . Mexico. Oaxaca. Municipio Calpulalpan de Méndez, carretera Ixtlán-Capulalpan km 7.69 después del puente, 2020 m, Aug. 2003, S. Figueroa 185 (MEXU!). Noroeste de Calpulalpan de Méndez, camino a la trituradora, 2030 m, 2003, S. Figueroa 537 (MEXU!).

Mandevilla boliviensis . Venezuela. Distrito Federal, Hacienda Puerto la Cruz, Coastal Region, 2300 m, 28 Aug ‒ 4 Sept 1918, H. Pittier 8108 (G!)

Mandevilla sagittarii . Colombia. Bajo Calima, Concesión Pulpapel/Buenaventura, 100m, 18 Nov. 1985, M. Monsalve 914 (F!). Chocó. Between La Oveja and Quibdó, 1 ‒ 2 Apr. 1931, W.A. Archer 1714 ( US!)

Mandevilla veraguasensis . Costa Rica. Provincia de Alajuela, Punta Arenas y Gunacaste, 1400 ‒ 1500 m, 15 Aug. 1976, V.J. Dryer 561 (F [web!]). Venezuela. Mérida, Thickets around hacienda El Joque of Dr. Ricardo above Jají, 2195 m, 20 Apr. 1944, J. Steyermark 55961 (F!).