Saturday, December 16, 2023

[Botany • 2023] Casearia isthmica (Salicaceae) • A New Species from Central Panama and insights into its Phylogenetic Position within the Genus


Casearia isthmica de Mestier & O. Ortiz, 

in de Mestier, Pineda, Fonseca et Ortiz, 2023.

Abstract
We describe here a new species of Casearia from Panama based on both morphological and molecular data. Casearia isthmica sp. nov. is restricted to the mid-elevation cloud forests of Central Panama and presents morphological similarities with two more widespread species, C. sanchezii from high elevation areas of El Salvador and Mexico and C. tremula from the Caribbean, Central America, and Northern South America. Casearia isthmica differs in presenting pedunculated and congested inflorescences with up to 20 flowers, as well as flowers with 12 stamens and a pubescent style. Phylogenetic analysis based on selected plastid (petD, trnK-matK, rpl16 and rps4-trnLF) and nuclear (GBSSI and ITS) markers shows that the new species belongs to subclade B3 of Casearia, a lineage that encompasses species from Central America, Mexico and the Caribbean. Results of the morphological and molecular analysis were congruent and allowed a broader understanding of this new taxon, especially regarding its relationships to other Casearia.

Key words: Molecular phylogeny, Neotropics, new species, Samydeae

Casearia isthmica de Mestier & O. Ortiz
A flowering branch B inflorescence C flowers at anthesis D fruiting branch E leaves F ripe fruit G bark.

Photos A, C, E (back side of the leaf) by Carmen Galdames (Galdames 6153). Photos D, E (front side of the leaf) by Carmen Galdames (Galdames 6642). Photo B by Ernesto Campos (Sumich 151).
 Photos G, E by Ernesto Campos Plate by Marco Cedeño-Fonseca.  
 
Casearia isthmica de Mestier & O. Ortiz 
A branches B twig and stipules C trunk base and roots D lenticellate bark. Photos A, B by Carmen Galdames (Galdames 6642). Photo C by Ernesto Campos (Campos 1087). Photo D by Ernesto Campos. Plate by Marco Cedeño-Fonseca.

 Casearia isthmica de Mestier & O.Ortiz, sp. nov.

Etymology: The specific epithet refers to the geographic distribution of the new species, which is restricted to the Isthmus of Panama.


Astrid de Mestier, Ernesto Campos Pineda, Marco Cedeño Fonseca and Orlando O. Ortiz. 2023. A New Species of Casearia Jacq. (Salicaceae) from Central Panama and insights into its Phylogenetic Position within the Genus. PhytoKeys. 236: 97-112. DOI: 10.3897/phytokeys.236.108651