A Phylogenetic Analysis of Dioon (Zamiaceae)

Abstract

A phylogenetic analysis of all the intrageneric taxa of the genus Dioon Lindley (Zamiaceae) was undertaken by using chloroplast DNA restriction fragment length polymorphism analysis. Wagner parsimony analysis on a 187 character matrix yielded two equally parsimonious trees, differing only for the position of D. caputoi. The consensus tree has two well‐defined major clades. The first is composed of D. mejiae, D. rzedowskii, and D. spinulosum; the second is composed of D. califanoi, D. caputoi, D. edule var. angustifolium, D. edule var. edule, D. holmgrenii, D. merolae, D. purpusii, D. tomasellii var. sonorense, and D. tomasellii var. tomasellii. A phenetic analysis of the same data showed results broadly congruent with the cladistic analysis. This resulting phylogeny is partially congruent with morphological data and is also compatible with the biogeography of the genus. Modem species of Dioon may have evolved as a consequence of a very fast succession of vicariance events that mainly occurred during the early Cenozoic. The short time between each of these events may not have allowed the accumulation of a large number of morphological synapomorphies for the groups of species.

Conservation genetics of an endangered cycad, Dioon sonorense (Zamiaceae): implications from variation of chloroplast DNA

“…It is thought that the center of diversifi cation of the current Dioon species was in southern Mexico (Moretti et al, 1993;Moynihan, 2008), and very recent migration events have been proposed as a result of successful seed dispersal during interglacial periods of the Pleistocene (Gregory and Chemnick, 2004). This idea seems to be supported by the paleoclimatic characterization of Toledo (1982), and suggests that the Sierra Madre mountain chains have played an important role in the migration of communities that are currently distributed within areas considered as Pleistocene refugia (Sauer, 1988;Contreras-Medina and Luna-Vega, 2007).…”

“…Although D. sonorense is commonly shown as sister species to D. tomasellii, the phylogenetic relationships among the other Dioon species still remain unresolved due to low levels of interspecifi c differentiation and low number of analyzed samples per species in previous phylogenetic studies (Moretti et al, 1993;Moynihan, 2008). Sampling schemes that consider different intraspecifi c groups might provide a better resolution in the understanding of the evolution of this genus.…”

A new species of Leptocycas (Zamiaceae) from the Upper Triassic sediments of Liaoning Province, China

“…These characteristics are more similar to those of the female cone of extant Dioon (Whitelock, 2002). (Moretti et al, 1993;Whitelock, 2002). The new fossil plant has a straight leaflet that is <15 mm wide with entire margins and triangular megasporophylls (Figs.…”

Regionalización biogeográfica de la mastofauna de los bosques tropicales perennifolios de Mesoamérica

“…Trabajos realizados sobre las relaciones de ancestría común, así como morfométricos y cariotípicos para algunos de estos taxones muestran una conformación geográfica marcada de ambos clados (Engstrom et al 1987, Schmidt et al 1989, Audet et al 1993, Genoways & Baker 1996, Silva-Lópes et al 1996, Madeiros et al 1997, Medellín et al 1998, Collins & Dubach 2000a, b, 2001, Cortés-Ortiz et al 2003, Collins 2004) indicando una separación relativamente antigua de estas mastofaunas. Patrones similares se han detectado en plantas (Moretti et al 1993, Novick et al 2003, peces dulceacuícolas (Lydeard et al 1995, Concheiro-Pérez et al 2007, anfibios (Hillis 1988, Parra-Olea et al 2004, reptiles (Wüster et al 2005) y aves (Hackett 1993, Marks et al 2002. incluso en algunos trabajos se ha documentado que la Falla PolochicMotagua no solo demarca al grupo Yucatán y Pantanos de Centla* del grupo TehuantepecPanamá*, sino que además muchas distribuciones complementarias se extienden hasta aquí (e.g.…”