Stenocereus huastecorum H. Alvarado-Sizzo, H. J. Arreola-Nava, and T. Terrazas. 2018, sp. nov.
Creators: name: Alvarado-Sizzo, Hernán
name: Casas, Alejandro
name: Parra, Fabiola
name: Arreola-Nava, Hilda Julieta
name: Terrazas, Teresa
name: Sánchez, Cristian
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Caryophyllales
Cactaceae
Stenocereus
Stenocereus huastecorum

description: Stenocereus huastecorum H. Alvarado-Sizzo, H. J. Arreola-Nava, and T. Terrazas. sp. nov.
[urn:lsid:ipni.org:names: 77173956–1]. Holotype: México, Estado de Guanajuato, Puerto las Tinajas, terracería entre Puerto de Palmas y Álamos de Martínez. 100˚06’10.35” W, 21˚28’42.33” N, 15 de Junio de 2016, Hernán Alvarado-Sizzo 350 con I. Torres-García y F. Paz-Guerrero. (MEXU 140542).
Isotype: Hernán Alvarado-Sizzo 350 con I. Torres-García y F. Paz-Guerrero (MEXU 140543).
Additional observed specimens: Table B in S 3 Appendix.
Candelabraform tree, up to 9 m tall; trunk 30–60 cm tall and 20–25 cm width (Fig 7A); many branches, ascending to spreading, up to 6 m long and about 15 cm width, slightly constrained every 20–30 cm, grayish green to glaucous; rarely second order branching; mucilage cavities not evident in transverse branch section; ribs 6 to 8 (Fig 7D), acute in transverse section, slightly sinuated in longitudinal section, 19–35 mm tall by 19–34 mm wide at the base, protrusion between areolas within the same rib (Fig 7B); areolas 11–26 mm apart each, round to obovate (scutelliform), 5.6–11.9 mm long and 8.5–10.2 mm wide, with light-colored trichomes; radial spines 7–9, subulated, divergent, 7.5–23 mm long, white when young, grayish when mature; 3 central spines, rarely 4 (when upper central one is present), subulated, robust, 8.7–36.5 mm long, white with a reddish base when young, grayish at maturity (Fig 7C); subapical flowers, night anthesis remaining opened during the next day, infundibuliform, 5.7–7.3 cm long and 4.2–5.2 cm wide in anthesis (Fig 8A); pericarpel oblate to very wide ovate, deep red, 11.8–15.8 mm wide, covered with slightly prominent podaria, imbricated, with triangular scales about 2.4–3.4 mm long by 2.7–3.9 mm wide at the base, deep red, presenting ocher trichomes; receptacular tube 33–45 mm long, podaria with decurrent scales, narrow oblong to lorate, apex acute to obtuse, about 4–8 mm wide; outer perianth segments narrow oblong to lorate, apex acute to obtuse, 20–30 mm long and 9–11 mm wide, deep red with yellowish imbrication margins; inner segments oblong, entire margin, up to 2.5 cm long and 1 cm wide, yellowish with a central reddish line (Fig 8B); stamina included, numerous, arranged in verticillate series; basifix anthers, yellowish, style 43–50 mm long and 2–2.4 mm wide, yellowish white; stigma lobules 8–10, 4–7 mm long, yellowish white; nectar chamber semi-closed by the lower filaments curvature, 12–15 mm long and 7.6–8 mm wide, striated (Fig 8C); ovary about 6 mm long and 6–7 mm wide; fruit ovoid, up to 10 per reproductive branch apex (Fig 9B), dehiscent when ripe, 57–58 mm in polar diameter by 50–56 mm in equatorial diameter, dark red, covered by areolas with numerous setose spines, about 7–13 mm long, yellowish white with dark tip, deciduous at maturity, sweet flesh, red or orange (Fig 9A); widely ovoid, black seeds 2.5–2.6 mm long by 1.7 mm wide (Fig 9C and 9D).
Common name: "candelabro", "órgano", "pitayo", "pitayo de mayo", and "pitaya" (fruit).
Phenology: flowers and fruits are produced most of the year (except during the winter), but the peak of production lasts from March to July.
Habitat: it inhabits tropical deciduous forest, xerophytic scrubland, thorny scrubland and mezquital, alongside with Prosopis spp., Vachellia spp., Larrea sp., Myrtillocactus geometrizans, and Stenocereus dumortieri. From 200 to 1600 meters above sea level.
Discussion: S. huastecorum populations were considered introduced populations of South American S. griseus by Bravo-Hollis [13]. Moreover, it was also determined as S. pruinosus; genetic, ecological, and morphological differences demonstrate it deserves its own designation. This species can be distinguished by its spination pattern (7–9 radial spines and 3 central spines), pericarpel color (deep red), and restricted distribution to northern Mexico.
Distribution: endemic to Mexico in the states of Guanajuato, Nuevo León, Querétaro, San Luis Potosí, Tamaulipas, and Veracruz.
Etymology: the name S. huastecorum follows the previous designation of the genetic entity described by Parra et al. [16] as "huasteca group", given that its distribution coarsely matches the Huasteca ethnolinguistic region, but we rather use the plural genitive ending to emphasize its belonging as a resource for those human groups.
description: Published as part of Alvarado-Sizzo, Hernán, Casas, Alejandro, Parra, Fabiola, Arreola-Nava, Hilda Julieta, Terrazas, Teresa & Sánchez, Cristian, 2018, Species delimitation in the Stenocereus griseus (Cactaceae) species complex reveals a new species, S. huastecorum, pp. 1-25 in PLoS ONE (e 0190385) (e 0190385) 13 (1) on pages 13-17, DOI: 10.1371/journal.pone.0190385, http://zenodo.org/record/12630726