Cryosophileae is atribe ofpalms in thesubfamilyCoryphoideae.[1][2] The tribe ranges from southernSouth America, throughCentral America, intoMexico and theCaribbean. It includesNew World genera formerly included in the tribeThrinacinae, which was split after molecularphylogenetic studies showed thatOld World and New World members of the tribe were not closely related.[3]
Members of the tribe are palms withfan shaped (or palmate) leaves and arepleonanthic—they flower repeatedly over the course of their lifespan. They are usuallyhermaphroditic (male and female sex organs are present together in flowers), but some species arepolygamodioecious, in which some plants have both male and hermaphroditic flowers, while others have a mixture of female and hermaphroditic flowers.[3]
| Simplified phylogeny of the New World thatch palms based on fournuclear genes and thematK plastid gene.[4] |
The Cryosophileae is one of eight tribes within subfamily Coryphoideae.[3] Within the subfamily, it is asister taxon to theSabaleae[5] (which includes just a single genus,Sabal).[3] Together these are sometimes referred to as the New Worldthatch palmclade.[5]
In the first edition ofGenera Palmarum (1987),Natalie Uhl andJohn Dransfield placed a variety of New World and Old World genera in thesubtribeThrinacinae.[6] Subsequent phylogenetic analysis showed that theOld World andNew World members of the Thrinacinae were not closely related. As a consequence of this, Dransfield and colleagues split the subtribe, and placed the New World species in a new tribe, the Cryosophileae, while the Old World species were placed in the subtribeRhapidinae, which was transferred to the tribeLivistoneae.[3] A new genus and species,Sabinaria magnifica, was described in 2013 and placed in this tribe.[7]
Andrew Henderson and colleagues considered thedistribution of the tribe to suggest that its origins lay in the southern hemisphere.[8] However, the discovery of fossil remains ofTrithrinax inCaribbean amber from theTertiary indicates that this genus, now the southernmost member of the Cryosophileae, once existed further to the north. This, coupled with the presence ofThrinax fossils from the Tertiary in Europe, andCryosophila-like fossil pollen from Central America in the same time period, led Stine Bjorholm and colleagues to conclude that the current distribution of these palms represents northern hemisphere origin and a north-to-south migration, instead of the reverse.[9] Cryosophileae are found in France duringOligocene (Rupelian) andMiocene (Tortonian).[10]
The members of the Cryosophileae form a sequence of species that extends from southern South America through Central America and into Mexico and the Caribbean. The southernmost genus,Trithrinax, is found in subtropical parts ofArgentina,Bolivia,Brazil,Paraguay andUruguay, and includes some of the most cold-tolerant palms in the Americas.Chelyocarpus andItaya are next in the sequence;Chelyocarpus andItaya are found in the westernAmazon basin—inPeru, Brazil andEcuador—with one species ofChelyocarpus extending into the Pacific lowlands ofColombia.Sabinaria is restricted to the Colombia/Panama border.[7]Cryosophila ranges from northern Colombia, through Central America into Mexico.Schippia is found inBelize and a small area ofGuatemala.Thrinax,Coccothrinax andLeucothrinax are widespread in the northern Caribbean;Zombia is restricted the island ofHispaniola andHemithrinax toCuba.[8][11]
