Recent fieldwork in the Sierra Martín García in southwestern Dominican Republic has yielded a new species of the American clade Castela (Simaroubaceae), Castela senticosa sp. nov., from seasonally dry tropical forest. This species has been collected from two separate localities, including Môle St. Nicolas in northwestern Haiti in 1929, but until now fertile material with both flowers and fruit was unknown. We provide a photographic plate and illustration, place it phylogenetically using plastome data, and compare it morphologically with close relatives. This increases the number of known species of Castela on Hispaniola from one to two, both of which are endemic but from different clades, and yields another species for the Greater Antilles, a known biodiversity hotspot and clear center of diversification for this group of arid-adapted, thorny shrubs. This work emphasizes that seasonally dry tropical forest, although often understudied, house as yet undiscovered biodiversity and deserve far more comprehensive studies.

This dataset was generated from genome skimming raw reads that were mapped to the Ailanthus altissima chloroplast genome (NC_037696.1) in Geneious. All raw reads were trimmed with an error probability limit of 0.05% before being mapped. A majority consensus sequence was then generated, one copy of the inverted repeat was trimmed (IRb), and the sequences were aligned in MAFFT yielding an alignment of 139,323 bp, including gaps.