Calyptranthes Thomasiana

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Calyptranthes thomasiana

No Common Name

ListedFebruary 18, 1994
FamilyMyrtaceae (Myrtle)
DescriptionEvergreen shrub or tree with shiny, leathery leaves.
HabitatUpland, moist forests of volcanic origin.
ThreatsStochastic extinction; land development.
RangePuerto Rico, U. S. Virgin Islands


Calyptranthes thomasiana is an evergreen shrub or small tree that may reach 29.5 ft (9 m) in height and 5.1 in (13 cm) in diameter. The leaves are opposite, obovate to oblong, 0.8-1.6 in (2-4 cm) long, blunt at the apex, and short pointed at the base. Leaves are also coriaceous, with gland dots, shiny on the upper surface, and dull on the lower surface. Flowers and fruit have not been described.


Both sites are located within the subtropical moist forest life zone. Rainfall in this life zone ranges from 39.4-78.7 in (100-200 cm) per year. On Monte Pirata the species is located at an elevation of approximately 984 ft (300 m). On St. John the species is found in upland moist forest at an elevation of approximately 1,312 ft (400 m). Soils on St. John are volcanic in origin and are well-drained and neutral to basic in reaction. Rainfall in St. John ranges from 35-55 in (89-140 cm) per year.


C. thomasiana was first described in 1855 from specimens collected from St. Thomas, U.S. Virgin Islands. The species was previously thought to be endemic to Puerto Rico and the U.S. Virgin Islands, however, it was recently reported from Virgin Gorda, British Virgin Islands, where it occurs within the National Park. It is currently known from Monte Pirata on Vieques Island in Puerto Rico and from St. John, U.S. Virgin Islands. Some 10-12 individuals of C. thomasiana are known to occur on Monte Pirata, an area currently owned by the U.S. Navy. Approximately 100 mature individuals are known to occur on Bordeaux Mountain in the Virgin Islands National Park, St. John, U.S. Virgin Islands.


Agriculture, grazing, the production of charcoal, and the cutting of wood for construction materials has resulted in extensive deforestation in these areas. The area of Monte Pirata has been severely modified in the past for the construction of Navy facilities and expansion of these facilities may result in the elimination of individuals. Known individuals within the Virgin Island National Park may be affected by park management practices and the presence of feral pigs and donkeys. Because so few individuals are known to occur in a limited area, the risk of extinction is extremely high. In 1989, Hurricane Hugo dramatically affected the Monte Pirata area of Vieques, felling large trees and creating numerous canopy gaps.

Conservation and Recovery

The Monte Pirata area is currently designated by the U. S. Navy as a conservation zone, with C. thomasiana being a species of concern. Management practices which would protect the species from uprooting and trampling by feral pigs and donkeys in the Virgin Island National Park include fencing and elimination of the animals. Little is known about the life history of the species; therefore, studies on aspects of the reproductive biology should be conducted. Propagation for introduction into protected areas should be considered as an additional recovery mechanism.


Regional Office of Endangered Species
U.S. Fish and Wildlife Service
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345

Boqueron Ecological Services Field Office
U.S. Fish and Wildlife Service
P.O. Box 491
Boqueron, Puerto Rico 00622-0491
Telephone: (787) 851-7297
Fax: (787) 851-7440


U.S. Fish and Wildlife Service. 1994. "Determination of endangered status for Myrcia paganii and Calyptranthes thomasiana. Federal Register 59(34): 8138-8141.

Woodbury, R.O. and P.L. Weaver. 1987. "The vegetation of St. John and Hassel Island." U.S. Virgin Islands, U.S. Department of the Interior, National Park Service, Southeast Regional Office, Research/Resources Management Report SER-83. 103 pp.