Four new species of Matelea (Apocynaceae: Asclepiadoideae) endemic to Mexico

Abstract

SummaryFour new species of Matelea, endemic to Mexico, are proposed and described: M. balrog, M. cornuta, M. jaimesiae and M. lokii. These taxa differ from each other and M. gonoloboides, M. medusae and M. porphyrantha (the Matelea gonoloboides species complex) in their corolla shapes and gynostegial corona ornamentation. Descriptions, illustrations, morphological comparisons and geographic distributions of these species, as well as their conservation status, are provided. A lectotypification for the name M. gonoloboides is also included. These discoveries highlight Mexico as a centre of diversity and endemism for the genus, with 69 species currently known from the country, of which 66% are restricted to it.

Systematics of Urostephanus: resurrection of a Mesoamerican taxon of Gonolobinae (Apocynaceae, Asclepiadoideae), with eight new combinations

“…Only M. patalensis, M. porphyrantha, and M. medusae share a cyathiform corona with staminal and interstaminal corona elements; the latter has five bifid and erect lobes, whereas the interstaminal corona of M. araneosa and M. patalensis is made up only of a basal projection, which resembles a stinger denticulated at the base. Four new species were recently described from the specimens previously identified as M. gonoloboides (González-Martínez et al, 2023). This broadens the specific and morphological diversity and the number of species that can potentially be included in the Urostephanus group due to shared characters of taxonomic importance, such as the fusion of the lobes of the interstaminal corona and appendages on the membrane.…”

“…We recorded the states for vegetative, floral (inflorescence type, corolla, staminal and interstaminal corona, gynostegium), and fruit characters consulting the taxonomic literature. We performed a morphological comparison of the groups related to Urostephanus (Robinson and Greenman, 1895;González-Martínez et al, 2023), including Dictyanthus (Stevens, 1988;Endress et al, 2018;González-Martínez et al, 2019), andPolystemma (Stevens, 2001;Lozada Pérez, 2010;McDonnell and Fishbein, 2016;McDonnell et al, 2018;Endress et al, 2018). We complemented the morphological comparison with observations made directly in the field and of floral samples under the stereoscopic microscope (Leica, EZ4 HD, Solms, Germany) to clarify the organization of the corona in the different genera.…”

“…Our species hypothesis follows the cohesion species concept (Templeton, 1989); taxa are suggested based on their phenotypic, ecological, and genetic cohesion. The molecular data of the individuals used in the phylogenetic analyses are associated with the species hypotheses generated in previous studies (González-Martínez et al, 2023).…”

“…We made distribution maps for the clades to represent the distribution patterns. Geographic distribution records were obtained from a previous review of M. balrog, M. cornutus, M. jaimesiae, and M. lokii specimens (González-Martínez et al, 2023), except for M. araneosa, M. medusae, and M. patalensis, which were obtained from public databases available at GBIF (2023). For Dictyanthus species (17/19 species), Polystemma (5/8 species, excluding the Matelea species nested within the clade), geographical records were obtained from GBIF (2023).…”

“…Rob. & Greenm., and morphologically similar species (henceforth Urostephanus) (Stevens and Morales, 2009;González-Martínez et al, 2023).…”