Qualitative and quantitative morphological evidence for recognition of a new species within Ceratozamia (Zamiaceae) from Mexico

Abstract

Several Ceratozamia populations from the “Carso Huasteco” region in Mexico have a controversial circumscription and have been historically identified as Ceratozamia fuscoviridis. In this paper, we present a review of the taxonomic history of this species and provide taxa circumscriptions based on analyses of herbarium specimens from this region and supplemented with fieldwork. For this, we have studied qualitative and quantitative morphological variation at population level. We recognize two species in this group: C. fuscoviridis and a new species, C. chamberlainii. Here, we provide two lines of qualitative and quantitative morphological evidence showing that plants of C. chamberlainii from southern San Luis Potosí to northern Hidalgo are distinct from C. fuscoviridis of central Hidalgo east of Veracruz. These species can be identified by leaflet form, leaf emergence color, color of the ovulate strobilus, and form of the megasporophyll, along with a combination of quantitative morphological characters.

Disentangling the identity of Zamia from Mexican Pacific seaboard, with a description of a new species

“…Species diagnoses in Zamia have traditionally been based on vegetative characteristics (Stevenson 1981, 2001, Nicolalde-Morejón et al 2008, Martínez-Domínguez et al 2017a, b, 2018, due to the absence of reproductive structures in herbarium specimens. However, some characters states of these structures are crucial for identification, and Zamia is no exception (Stevenson 2004).…”

Monograph of Ceratozamia (Zamiaceae, Cycadales): an endangered genus

“…Criteria to delimit species. The taxonomic treatment presented here is partly based on our previously published work on species complexes, considered from an integrative taxonomy perspective for corroboration or refutation of taxonomic hypotheses and employing the “taxonomic circle” sensu DeSalle et al (2005) , in which multiple data sources are analyzed independently for hypotheses testing ( Martínez-Domínguez et al 2016 ; 2017a , b , 2018a , 2020 , 2022a , b ). For taxa we have not treated previously, species were recognized by a unique combination of morphological characters evaluated at the population level, considering their biogeographic distribution patterns as an additional source of evidence.…”

“…Etymology. The specific epithet is in honor of Charles Joseph Chamberlain in recognition of his remarkable contributions to knowledge of the biology of the cycads and his fieldwork on Mexican Cycads (Martínez-Domínguez et al 2017a).…”

“…Nevertheless, the taxonomy of Ceratozamia has been mainly characterized by rearrangements of infrageneric taxa, treatments in floristic works and species-level treatments of species complexes ( Vovides et al 1983 ; Stevenson et al 1986 ; Pérez-Farrera et al 1999 ; Avendaño et al 2003 ; Pérez-Farrera et al 2009 ; Vovides et al 2012 ; Martínez-Domínguez et al 2016 , 2017c ). Recent taxonomic efforts based on analyses of quantitative and qualitative morphological variation, phenology as well as DNA sequences of nuclear, plastid and mitochondrial genomes have produced new insights on the circumscription of species complexes and the most comprehensive taxonomic reviews of Ceratozamia to date ( Martínez-Domínguez et al 2016 , 2017a , b , 2018a , 2022a ). In addition, work focusing on the morphometric variation of vegetative characters and anatomical features have contributed to the clarification of some species ( Pérez-Farrera et al 2014 ; Vovides et al 2016 ; Medina-Villarreal et al 2019 ; Gutiérrez-Ortega et al 2021 ).…”

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

“…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). Other characters commonly used are the direction, form and texture of leaflets and the formation of prickles (Pérez-Farrera et al 2001; Vovides et al 2003).…”