Amphitecna loreae Ortiz-Rodr. & Burelo, 2016

Ortiz-Rodriguez, Andres Ernesto, Burelo Ramos, Carlos Manuel & Gomez-Dominguez, Hector, 2016, A new species of Amphitecna (Bignoniaceae) endemic to Chiapas, Mexico, PhytoKeys 65, pp. 15-23 : 17-20

Amphitecna loreae Ortiz-Rodr. & Burelo sp. nov. Figures 1 , 3

Type.

Mexico. Chiapas, Municipio de Berriozábal, zona sujeta a protección ecológica "La Pera", predio “Peña Flor" camino Berriozábal- Vista Hermosa-El Cairo , km. 12 desvío al Pozo Turipache , 1068 m, 16°51'50.6"N, 93°19'51.7"W, 05 March 2012 (fl, fr) Ortiz-Rodríguez A. E 0178 (holotype HEM; isotypes: UJAT, XAL) .

Diagnosis.

Amphitecna loreae is distinguishable from the other species of Amphitecna by a combination of its cauliflorous inflorescences, large flowers, buds rounded at apex, and broadly elliptical to spherical rather than acuminate fruits. Amphitecna tuxtlensis , Amphitecna montana and Amphitecna latifolia , also distributed in Mexico, have affinities with Amphitecna loreae and share the cauliflorous inflorescences and leaves less than 50 cm long. However, Amphitecna tuxtlensis differs in having the flower buds pointed at the apex and fruits elliptic, acute to acuminate at apex, and Amphitecna montana differs in having larger leaves, long pedicellate flowers and elliptical fruits shortly pointed at the tip, while Amphitecna latifolia differs in having obovate to widely elliptic leaves, rounded to mucronate at apex with poorly defined petioles (Figure 1 ).

Description.

Trees, 15-25 m and 15-50 cm DBH, the secondary branches terete. Leaves, alternate-verticillate, clustered near the apex of the branches, olive-green when dry, glabrous, 10-20 cm long, 2-5 cm wide, oblanceolate to narrowly elliptic, acuminate, subcoriaceous, acute to attenuate basis, midrib slightly raised on the upper surface, prominent on the lower surface; secondary veins 11-14 on a side, slightly raised above, prominent below; petiole short, to 2 cm long, merging with attenuate leaf base. Inflorescences, groups of two or three flowers, with an unpleasant odor, which are borne on leafless portions of old branches and along the main trunk (cauliflory). Flower buds, rounded at apex. Flowers pendant, pedicel 35-60 mm long; calyx campanulate, 28-38 mm long, more or less coriaceous, evenly 2 to 3-labiate to below the middle, circumscissile; corolla radially symmetric, pale green, tubular-infundibuliform, 48-60 mm long, 30-40 mm wide at the mouth of the tube, the basal part of the corolla a straight tube, 15-25 mm long, the lobes fused in to frilly-margined rim; stamens included, inserted 18-28 mm from base of the tube, the anther thecae divergent, 4-7 mm long, the filaments 18-30 mm long; the staminode, when present, less than 20 mm long, inserted 10-20 mm from base of the tube, sometimes well developed (with one or two small thecae) to give the impression of being a fifth stamen; ovary, up to 3 mm long and 2.5 mm wide, broadly elliptical, glandular-papillose; pistil 40-60 mm long with the stigma bifurcate; disc annular-pulvinate, about 6 mm in diameter; flowers are often found with signs of herbivory, in which the ovule and disc are not present. Fruits broadly elliptical to spherical, 70-100 mm long, 60-80 mm wide.

Habitat and ecology.

The species is only known from Chiapas, Mexico. It is a rare species at the type locality in the ecological reserve La Pera. The species inhabits the karst areas, mainly in the tropical rainforest. It is a canopy tree and coexists with species of Quercus lancifolia Schltdl. & Cham., Quercus corrugata Hook., Calatola costaricensis Standl., Spathacanthus hahnianus Baill, and Quararibea funebris (La Llave) Vischer.

Phenology.

Mature flowers and fruits were collected in March and April; buds, ripe and immature fruits were observed in the same months.

Etymology.

The specific epithet honors Francisco Lorea Hernández, in recognition of his many important contributions to our knowledge of the Mexican flora.

Conservation status.

Currently we lack the necessary information to objectively define the conservation status of Amphitecna loreae . However, according to the criteria established by the IUCN, it is possible to tentatively determine that the species is Critically Endangered [CR B1ab (iii)]. Although the only known population of the species is located within a protected natural area, Amphitecna loreae appears to be rare ecologically and only eight individuals in one hectare of sampling were recorded ( Escobar-Castellanos 2016). The Area of occupancy (AOO) is 12,000 km² and the Extent of occurrence (EOO) is 0.763 km², suggesting a very restricted overall distribution. Furthermore, the tropical rain forest in this region of Chiapas is seriously fragmented and only small remnants persist.

Additional specimens examined.

Mexico. Chiapas, Berriozabal: Rancho "El Retiro", atrás de el rancho "El Zapote". 13 km al N de Berriozábal camino a Joaquin Miguel Gutierrez , 16°52'09.2"N, 93°19'26.4"W, 1114 m., 04 May 2014, M. A. Escobar Castellanos 586 (HEM); same locality, M. A. Escobar Castellanos 675 (HEM); zona sujeta a protección ecológica "La Pera", predio “Peña Flor" camino Berriozábal- Vista Hermosa-El Cairo, km. 12 desvío al Pozo Turipache, 16°51'50.6"N, 93°19'51.7"W, 1100 m, 16 May 2015, Y. Licona-Vera 190 (XAL) .

Discussion.

Amphitecna loreae sp. nov. has a combination of characters that clearly separate it from other species of Amphitecna : its strictly cauliflorous inflorescences distinguish it from those species with terminal inflorescences ( Amphitecna apiculata A.H. Gentry, Amphitecna breedlovei A.H. Gentry, Amphitecna donnell-smithii (Sprague) L.O. Williams, Amphitecna isthmica (A.H. Gentry) A.H. Gentry, Amphitecna molinae L.O. Williams and Amphitecna steyermarkii (A.H. Gentry) A.H. Gentry).

The four cauliferous species discussed in the diagnoses have different distribution ranges with different climatic preferences (Figure 2 ). Amphitecna tuxtlensis has two disjunct populations in Veracruz, one in the area of the Los Tuxtlas and another in the Uxpanapa-Chimalpas region, where it inhabits the tropical rainforest. Amphitecna montana is distributed along the Sierra Madre de Chiapas and inhabits the cloud forest above 1200 m. Amphitecna latifolia is distributed intermittently in areas near to the Atlantic coast of Mexico, where it inhabits mainly in riparian vegetation and mangrove associations. In contrast, Amphitecna loreae is endemic to Chiapas and it is known only from a single locality at the municipality of Berriozabal, Chiapas. The species grows on a karstic zone at approximately 900-1,150 m and it inhabits the tropical rainforest (Table 1 ).

Figures

Figure 1. Amphitecna loreae sp. nov. A cauliflorous flowers with trilabiate calyx. B broadly elliptical to spherical fruits C corolla D buds rounded at apex. Photographs by Andres E. Ortiz-Rodriguez (A and C) and Marcos Escobar (B and D).

Figure 2. Distribution range and climatic preferences of Amphitecna loreae and related species. Amphitecna latifolia (purple circles) Amphitecna montana (green cross), Amphitecna loreae (black dots) and Amphitecna tuxtlensis (blue squares). In colours similar to those of the species the 95 % confidence ellipses produced by PCA analysis.

Figure 3. Leaf variation in Amphitecna loreae and related species. A Amphitecna tuxtlensis (H. Gomez 3710 HEM) B Amphitecna montana (N. Martinez 927 HEM) C Amphitecna loreae (M. Escobar 586 HEM) and D Amphitecna latifolia (E. Ucan E 251 XAL).