A review of research on the cycad genus Ceratozamia Brongn. (Zamiaceae) in Mexico

Abstract

The genus Ceratozamia contains more than 20 species distributed in eastern and southern Mexico, with extensions into Central America. Morphology, anatomy, and molecular (ITS) data allow resolution of some aspects of species relationships, provide correlations with ecology, and suggest phytogeographic hypotheses. Some species complexes, such as those centered around C. norstogii and C. miqueliana, are restricted to southernwest Mexico, in what are regarded as Pleistocene floristic refugia. The low level of divergence of ITS sequences among taxa to the north of the Trans–Mexican Neovolcanic mountain range suggests a pattern of recent, and perhaps rapid, speciation.

Publishing trends for the Cycadales, the most threatened plant group

“…Few attempts have been made to review portions of the cycad literature (Vovides et al 2003(Vovides et al , 2004(Vovides et al , 2007Terry et al 2012). The immense literature on phylogeny and systematics is in effect reviewed with each update of "The World List of Cycads" that appears in each set of conference proceedings, but a review on how tools and methods have evolved over the years may be warranted.…”

“…Cycads can be traced to the late Carboniferous period and offer unique research opportunities for contemporary scientists (Brenner et al 2003;Donaldson 2003). Nevertheless, the quantity and breadth of accessible published research on this ancient and important group of plants is limited (Dehgan 1983;Sabato & de Luca 1985;Moretti et al 1993;Norstog & Nicholls 1997;Vovides et al 2003Vovides et al , 2004.…”

“…Few attempts have been made to summarize these proceedings and/ or the rest of the primary literature in this field (Terry et al 2012;Vovides et al 2003Vovides et al , 2004Vovides et al , 2007, and to our knowledge there have been no attempts to capture recent trends in cycad biology over the past 30 years. We set out to do this using Google Scholar to access the primary literature coinciding with years in which international conferences of cycad biology were held up to 2008 (the most recently published conference proceedings).…”

Taxonomic review of Ceratozamia (Zamiaceae) in the Sierra Madre Oriental, Mexico

“…This genus is endemic to Mega-Mexico ( sensu Rzedowski 1991), ranging from Mexico to Honduras. Mexico is considered the centre of diversity for Ceratozamia , given that 30 out of 31 recognised species occur in its territory (Vovides et al 2004a; Nicolalde-Morejón et al 2014), 90 percent of which are endemic (Calonje et al 2013-2018). Diversity for this genus is particularly prevalent along the Sierra Madre Oriental and Southwest Mexico, especially in the political states of Veracruz, Oaxaca, Chiapas and Tabasco.…”

“…In recent taxonomic works, quantitative morphological characters such as plant size and leaflet width have been commonly used as a basis for the identification and description of new species because they exhibit variability across the genus (Vovides et al 2004a, c; Whitelock 2004). However, other contemporary studies have shown that these characters can be highly variable between and amongst populations, which limits species diagnosis (Martínez-Domínguez et al 2016; 2017a, b, c).…”