Spathelia belizensis, a new species and first record for the genus in Central America (tribe Spathelieae, Rutaceae)

Abstract Spathelia L. as currently circumscribed is endemic to the western portion of the West Indies, and contains nine species, one endemic to the Bahamas, three endemic to Jamaica and five endemic to Cuba. The discovery of a new species in Belize brings the total number of species in Spathelia to ten and expands its known distribution beyond the West Indies. Spathelia belizensis sp. nov. is herein described, illustrated and contrasted to its most morphologically similar congener. A key to the species of Spathelia is provided.


Introduction
Th e genus Spathelia L. (tribe Spathelieae, Rutaceae) is characterized by palm-like trees with unbranched, slender trunks, and a distal crown of spirally arranged, compound leaves. Th e trees are reported as monocarpic, i.e., producing a distal massive infl orescence after six to eight years and dying right after fruiting. As currently circumscribed, Spathelia is considered endemic to the western portion of the West Indies and closely related to Dictyoloma and Sohnreyia, two monospecifi c South American genera (Appelhans et al. 2011, Pirani andGroppo 2015).
While carrying out ecological surveys in the Golden Stream Corridor Preserve in Belize, the junior author discovered a population of trees that refers to an undescribed species of Spathelia. Th is discovery documents for the fi rst time the occurrence of Spathelia s.s. outside the West Indies, i.e., the northern, eastern tip of Central America. Previous reports of Spathelia (i.e., S. rhoifolia DC.) from Mexico are referred to the anacardiaceous genus Pseudosmodingium.
Th e study of this novel collection from Belize reveals a new species which seems to be closely related to S. brittonii P. Wilson due to morphological similarities. Th e new species, Spathelia belizensis is herein described, illustrated and contrasted to S. brittonii its putative closely related species. A key to the species of Spathelia is presented to facilitate the identifi cation of the species.

Material and methods
Th e description of the new species is based on a single collection, fi eld notes and photographs obtained by the junior author. Th e study is based on a morphological comparative study of the species of Spathelia as recognized by Beurton (2008) and indicates that the Belizean collection is an undescribed species in the genus. A key to the species is based on various fl oristic treatments of the Antilles (Marie-Victorin 1948, Adams 1972, Correll and Correll 1982, Beurton 2008 and the examination of specimens when necessary. Th e type specimens are composed of two sheets, one bearing leaf material and the other bearing portions of the fruiting infl orescence. Th e holotype is deposited in US herbarium, and the isotypes were distributed to K and NY herbaria (acronyms follow Index Herbariorum; http://sweetgum.nybg.org/science/ih/).
Distribution and ecology. Known only from the northern portion of the Golden Stream Corridor Preserve and adjacent portions of the Columbia River Forest Reserve in Belize; on steep slopes of Cretaceous limestone hills at elevations of c. 80-250 m.
Specimens examined. Only the type collection was studied. Etymology. Th e specifi c epithet refers to the country where the new species is known to occur.

Conservation status
Spathelia belizensis appears to be limited to the Golden Stream Corridor Preserve in Belize where several individuals have been spotted by the junior author. However, in the absence of precise information about its frequency the species can only be treated as DD (Data defi cient) within IUCN guidelines.
Th e type specimens of Spathelia belizensis contained only 6-merous fl owers, a feature that departs from other species of Spathelia as they are known to have only 5-merous fl owers. Because this collection only had few fl owers, it is premature to regard the presence of 6-merous fl owers as a distinctive character of the new species. Future collections may show it also to have 5-merous fl owers.