Delimitación de Neobuxbaumia mezcalaensis y N. multiareolata (Cactaceae) con base en análisis multivariados

Abstract

<em>Neobuxbaumia multiareolata</em> and <em>N. mezcalaensis</em> are taxa poorly defined, despite the second species was described originally as a variety of first. Although several classification proposals indicate that they represent different species, in the most recent cacti classification, both are considered a single species. The working hypothesis is that there are morphological characters that allow to separating <em>N. mezcalaensis</em> and <em>N. multiareolata</em>. Multivariate analyses were performed, with a total of 15 populations, to test if a boundary between <em>N. mezcalaensis</em> and <em>N. multiareolata</em> exists, and to compare the morphological characters with those of <em>N. squamulosa</em> and <em>N. polylopha</em>. The results allowed recognizing that intermediate phenotypes do not exist and that individuals of each analyzed populations were classified in their respective species. The areole size and form, central spine length and distribution pattern of the radial spines, plus four characters mentioned previously by other authors, allowed to differentiate <em>N. mezcalaensis</em> from <em>N. multiareolata</em>. Based on these evidences we propose that they represent independent species.

Clave dicotómica y distribución del complejo de especies de Stenocereus griseus (Cactaceae)

“…6C). Por otra parte, recientemente se han descrito técnicas multivariadas para el análisis de la espinación en cactáceas columnares como Cephalocereus (= Neobuxbaumia) (Arroyo-Cosultchi et al, 2010;Tapia et al, 2016) que prometen una mayor robustez en el análisis de dicha característica.…”

Análisis morfométrico del grupo Selenicereus vagans (Cactaceae: Hylocereeae) con base en la anatomía del tallo

“…Se registraron 60 datos correspondientes a 3 individuos por especie (con excepción de S. murrillii donde se registraron 20 datos), para 19 caracteres anatómicos cuantitativos. Los datos de los caracteres cuantitativos continuos fueron transformados a logaritmo natural, mientras que los datos de los caracteres cuantitativos discretos fueron transformados mediante raíz cuadrada (Arroyo-Cosultchi et al, 2010). Se aplicó un análisis discriminante canónico (ADC) evaluando los caracteres anatómicos cuantitativos por especie, se calcularon las distancias cuadradas de Mahalanobis (D 2 ) y se probó su significancia estadística mediante la prueba de distancias de Fisher (Tapia et al, 2016).…”

“…Por otro lado, los análisis morfométricos aplicados a la sistemática vegetal han permitido reconocer especies con amplia variación morfológica o pertenecientes a complejos de especies en diversas familias de plantas (Arroyo-Cosultchi et al, 2010;Cope et al, 2012). A pesar de que este tipo de trabajos son escasos en Cactaceae, en ellos se ha demostrado que los caracteres morfológicos del tallo tienen valor taxonómico en la delimitación de taxones pertenecientes a complejos de especies en Cephalocereus (Arroyo-Cosultchi et al, 2010), Coryphantha (Baker y Butterworth, 2013), Echinocereus (Baker, 2006a, b;Sánchez et al, 2013), Escobaria (Baker y Johnson, 2000) y Melocactus (Mota-Lambert et al, 2006).…”

Morphological plasticity of an endemic widespread columnar cactus and its congener

“…For example, most studies on cactus concern the morphological variation of wild species using univariate and regression analyses (Felger and Lowe 1967; Racine and Downhower 1974;Rundel 1977;Felker et al 2002) as well as multivariate analyses (Chamberland 1997;Hicks and Mauchamp 2000;Muñoz Urias et al 2008) have focus on species complexes. Multivariate analyses have primarily been applied to answer taxonomical questions at different hierarchical levels (Chamberland 1997;Baker and Johnson 2000;Schmalzel et al 2004;Muñoz Urias et al 2008;Arroyo-Cosultchi et al 2010;Baker and Butterworth 2013;Sánchez et al 2013;Vázquez-Benítez et al 2016). In these studies, the multivariate analyses favor the recognition of few diagnostic morphological characters that allow differentiating species, especially when many variables are analyzed.…”

“…However, Arroyo-Cosultchi et al (2010) and Tapia et al (2016) proposed that they represent independent species based on morphological evidences such as areole size and form, central spine length and distribution pattern of the radial spines, plus four reproductive characters (size of the flower, pericarpel, fruit, and seed) mentioned previously by other authors. These reproductive characters do not overlap between species and are diagnostic for each one (Arroyo-Cosultchi et al 2010). One of the questions that arise was what makes that one of these two species to have a wide distribution and the other to be restricted to a few nearby hills at Tierra Colorada and Acahuizotlá at the Costa Chica-Rio Verde hydrological region?…”