(DRAFT) - Taxonomy
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
TAXONOMY
NAME - BOA, TREE, VIRGIN ISLANDS
OTHER COMMON NAMES - BOA, TREE, VIRGIN ISLANDS; BOA, VIRGIN ISLANDS;BOA, TREE, ST. THOMAS; BOA and TREE
ELEMENT CODE -
CATEGORY - Reptiles
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - REPTILIA,
ORDER AND SUBORDER - SQUAMATA,
FAMILY AND SUBFAMILY - BOIDAE,
GENUS AND SUBGENUS - EPICRATES,
SPECIES AND SSP - MONENSIS, GRANTI
SCIENTIFIC NAME - EPICRATES MONENSIS GRANTI
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Virgin Islands Tree Boa
Epicrates monensis granti Stull, 1933
KINGDOM: Animal GROUP: Reptile
PHYLUM: Chordata CLASS: Reptilia
ORDER: Squamata FAMILY: Boidae
The Virgin Islands boa is a moderate size species of Epicrates.
In the series from St. Thomas (05), males are about 770 mm, females
about 470 mm in snout-vent length. In a larger series from Cayo
Diablo (01) females were larger, measuring up to 792 mm and males to
602 mm. As a subspecies of E. monensis, it is characterized by the
combination of 5 post intersupraocular scales, high number of dorsal
scale rows (41-47) at mid-body, usually two supralabials entering the
eye, and a high number of body (61-73) and tail (20-22) blotches (05).
In most pattern details the subspecies (E. m. granti) resembles
the nominate subspecies, E. m. monensis. The only major pattern
features that differentiate the two subspecies are the much reduced
head pattern and more often complete occipital "U" in E. m. granti
(05). The taxa are easily distinguishable in scuttelation and blotch
counts. The Tortola Island holotype shows some variation in several
scale counts (i.e., ventral, neck and mid-body scales posterior dorsal
Taxonomy - 1 (DRAFT) - Taxonomy
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
scale rows, and intersupraocular bordering scales) (05).
The taxon was erroneously believed to be a subspecies of E.
inornatus (01). It was later demonstrated that affinities were more
like E. monensis (01,05). Thus, the literature reveals several
synonyms for the species: Epicrates inornatus granti Stull, 1933;
Epicrates monensis granti Stull, 1933; and Epicrates monensis granti
Sheplan and Schwartz, 1974 (05,06,07). This subspecies is also known
by the common names Virgin Islands boa, St. Thomas tree boa and tree
boa.
The holotype (MCZ 33847) of E. m. granti is located at the Museum
of Comparative Zoology, Harvard University, Cambridge, MA (06). Other
type specimens (ASFS V 8070, ASFS V 3640, VINP 1484) remain in the
collections of Albert Schwartz (Field Series), Miami-Dade Community
College North, Miami, FL; and in the Virgin Islands National Park, St.
John, VI. The most recent information on the largest series of
specimens examined is held by the Curator of Amphibians and Reptiles
of the Toledo Zoological Society in Toledo, OH.
Taxonomy - 2 (DRAFT) - Status
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
STATUS
Coded Status
Puerto Rico; Federal Endangered
Puerto Rico; State Listed
Virgin Islands; Federal Endangered
E: Federal Endangered
Game (Consumptive Recreational)
Ceremonial/Cultural
Medicinal
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Virgin Islands tree boa (Epicrates monensis granti) has been
designated an Endangered species pursuant to the Endangered Species
Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C.
1531-1540), as amended. The subspecies has this status wherever found
including the the U.S. and British Virgin Islands.
This subspecies is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild animal
(alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Commonwealth of Puerto Rico
DESIGNATED STATUS: Threatened
Status - 1 (DRAFT) - Status
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
ADMINISTRATIVE AGENCY: Department of Natural Resources
STATE STATUTE: Regulation to Govern the Management of the
Threatened and Endangered Species in the
Commonwealth of Puerto Rico, 1985. (Listed as
species Epicrates monensis which also includes
the Mona boa.
STATE: Virgin Islands
DESIGNATED STATUS: None.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
Epicrates monensis is listed in Appendix I of the Convention on
International Trade in Endangered Species of Wild Fauna and Flora
(CITES). CITES does not distinguish between subspecies for this
species, therefore, E. monensis granti receives full Appendix I
protection under CITES.
ECONOMIC STATUSES:
It was historically and is presently used for medicinals and
spiritual products (illegal). Probably some use as pets and food.
70/10/13:35 FR 16047/ - Listing
77/02/22:42 FR 10462/10488 - Implementation of CITES
79/12/07:44 FR 70677/ - Name change
85/07/22:50 FR 29901/29909 - Five year review
Status - 2 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
LAND USE -
Shrub and Brush Rangeland
Evergreen Forest Land
COMMENTS ON HABITAT ASSOCIATIONS -
Detailed descriptions of the habitats where the species has been
collected or observed are scarce in the literature. Ecological data
is virtually non-existent outside that provided by Nellis, et.al. (04)
and Tolson and Pinero (01). The species has been described to be
adapted to xeric habitats (04) and to occupy dry savanna-like habitats
on the islets off the eastern coast of Puerto Rico (01). Others have
remarked of their presence in moderately mesic woodlands of St. Thomas
(05) or just inhabiting rocky cliffs on Tortola and Guana Island (08).
Nonetheless, the only detailed habitat description is for Cayo Diablo
(01), representing the largest series of individuals examined up to
date.
The prominent vegetation on Cayo Diablo includes a tall open
stand of sea grape, Coccoloba uvifera; significant stands of
Tournefortia gnaphaloces, Suriana maritima, and Thespesia populnea,
around the perimeter of the islet; several coconut palms (Cocos
nucifera); the succulent Sesuvium portulacastum and Cyperus sp. on the
beach; a viney tangle of creepers that include Ipomoea pes-caprae,
Canavalia maritima, and Vigna marina interwoven into a mat over
stunted, thorny Mimosa bahamensis and Opuntia repens, and covering
mainly the interior of the islet (01). The general vegetation
characterization for these sites indicates the presence of an
evergreen littoral hedge in a subtropical zone (13,14). The snakes
were found in all types of vegetation except for the succulents on the
beach (01). In summary, the species occupied groves of sea grapes,
open mixed scrub, tangled-vegetation and cocos palms (01). At night
the boas were encountered crawling on vegetation. During the day
several were found resting beneath loose sections of termite nests, in
palm axils, and under debris (01).
Specific environmental parameters required by the species
throughout their range are unknown. Some information is available on
body temperatures but only for the sample from Cayo Diablo. Data
recorded showed that resting snakes (i.e. during daylight hours) had
considerably higher body temperatures (32.3 degrees C) than active
snakes (27.2 degrees C, during the night) (01). It was "invariably
found that those snakes found during the day, had body temperatures
considerably lower than ambient temperatures outside the refugia where
the snakes were hidden" (01). At night the reverse was true with
active snakes often having body temperatures considerably above
ambient (01).
Habitat Associations - 1 (DRAFT) - Food Habits
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
LIFESTAGE FOOD FOOD PART
General Reptilia
General Aves
General Mammalia
Food Habits - 1 (DRAFT) - Environment Associations
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Coastal Features: Vegetated offshore islands
G Terrestrial Features: Cliffs/ledges
G Terrestrial Features: Hills
Environment Associations - 1 (DRAFT) - Life History
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Information on the food habits of the Virgin Islands boa is
largely inferential. Apart from a stomach analysis reported in the
literature (05), prey items are suggested by general knowledge of the
genus Epicrates, and the specific situation of the boa in areas of
occurrence. In Cayo Diablo the species is believed to depend on
Anolis cristatellus (01). Although other suitable prey items exist,
their different microhabitat and habits considerably reduce the chance
of them being encountered by a hunting boa (01). Thus, it seems
likely that A. cristatellus constitutes the bulk of the diet, as
suggested by an observed pursuit of an Anolis by a small boa (01). A
tail of an Anolis cristatellus (=A. monensis) was found in the stomach
of a preserved specimen of E. m. monensis (09). A mouse was found in
the stomach of a preserved specimen of E. m. granti collected in St.
Thomas (05).
Avian prey could also represent a portion of the diet of this
boa. Epicrates are known to feed on small species of birds if given
the opportunity. In Cayo Diablo birds would represent only a minor
portion of the diet because of the paucity of resident bird species on
the islet (01). However, the situation could be different in other
islands within the species range.
Preferred food types cannot be designated for the species based
on data available. It is unknown whether the abundance of the food
item, the size, or even the ease of capture, determines food
preference.
HOME RANGE/TERRITORY:
No information is available for this species.
PERIODICITY:
The Virgin Islands boa, like other species of Epicrates, is
decidedly nocturnal or crepuscular (01). Hunting for snakes in Cayo
Diablo was most productive at night, when the boas were usually
discovered crawling on vegetation (01). The earliest time that a
snake was active was 19:20 hours and the latest time one was found
active was at 05:15 hours (01).
MIGRATION PATTERNS:
Many aspects of the species biology are still unknown. Based on
general characteristics of the group (i.e., Epicrates) in the West
Indies, the species should be considered non-migratory in the broad
sense of the term. However, movements of E. m. granti throughout its
range from microhabitat to microhabitat is unknown.
COVER/SHELTER REQUIREMENTS:
Specific cover/shelter requirements (i.e., retreat dimensions)
are not possible with the information available. Nevertheless,
shelter availability seems to be an important habitat requirement.
Being nocturnal (or crepuscular), the individuals must conceal
themselves during the day while inactive. Shelters used by the
species include loose sections of termite nests, Cocos palm leaf
Life History - 1 (DRAFT) - Life History
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
axils, and debris (e.g., sheets of cardboard).
REPRODUCTIVE SITE REQUIREMENTS:
No information is available on the reproductive site requirements
of this species.
REPRODUCTIVE CHARACTERISTICS:
Details of reproduction in the species are unknown. Based on
data of specimens examined in Cayo Diablo the following is suggested:
snakes over 500 mm in snout-vent length and 30 g in weight are
considered to be sexually mature, (E. fordii, the sister species to
E. monensis, is sexually mature at this size); the four main size
classes found indicate the species reaches reproductive maturity in
as little as three years (01,10); and the discovery that every adult
female E. m. granti encountered during the 1980 reproductive season
was gravid indicated the species may reproduce every year (01), and
not biennially as most Epicrates are believed to reproduce (11:
in 01). Most of the species of Epicrates in the West Indies mate from
February through April; parturition is usually in September or
October; and of three possible reproductive strategies within the
genus, a reproductive strategy of small females producing small
litters of small young exists for this subspecies (12).
PARENTAL CARE:
There is no direct evidence of this behavior in the species.
POPULATION BIOLOGY:
No information is available for the species at this point. Some
facts are suggested by preliminary studies conducted in Cayo Diablo
but are not broad enough to cover all aspects of the subject. An
intensive population study has been proposed and should begin in 1986.
During a study on Cayo Diablo 104 individuals were captured,
30 of these at night.
SPECIES INTERRELATIONSHIPS:
Although data on this subject is not abundant, some available
evidence suggests the species is threatened by feral mammal
populations in some islands within its range. Predation by house cats
has been documented for the Virgin Islands boa in St. Thomas (01).
Indirect pressure could also occur through competition as some of
these feral mammals could be depleting the food source on which the
snake depends (01).
OTHER LIFE HISTORY DESCRIPTORS:
No other parameters can be discussed with the information that is
available on the species at this time.
Life History - 2 (DRAFT) - Management Practices
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Controlling/Restricting Off-Road Vehicles
Beneficial Restricting/regulating human disturbance of populations
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Transplanting wild animals
Beneficial Restricting Poaching
Beneficial Controlling/Removing Feral Animals
Beneficial Controlling/Removing Domestic Animals
Adverse Harassment/Vandalism/Indiscriminate Killing
Existing Harassment/Vandalism/Indiscriminate Killing
Adverse Climate Alteration
Existing Climate Alteration
Adverse Predation
Existing Predation
Adverse Competition
Existing Competition
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse Forest Alteration
Existing Forest Alteration
Adverse Harvesting
Existing Harvesting
COMMENTS ON MANAGEMENT PRACTICES -
The species current status has been a function of its rareness
rather than of verified population decline through the years. The
species has rarely been encountered since its description (01), a fact
that explains the lack of knowledge on population levels and trends.
Thus, we can only talk about factors that may have been detrimental to
the species through the years.
The Virgin Islands boa is said to be a xeric-adapted species
(04). It is unknown how broad the range of the boa was or how
extensive the preferred habitat was in the past. If both the range
and habitat were indeed wider, ancient populations could have then
occupied areas that were lost as a result of climatic shifts. Such
could be explained by the widespread extinctions of xeric-adapted
herpetofauna on Puerto Rico during the Pleistocene (02).
Feral populations of introduced mammals (i.e., cats, mongoose)
are yet another factor to consider. These mammals could have either
preyed directly on the boa or been competitors for food, depleting the
food source (i.e., Anolis lizards) on which the snake depends (01).
It is suggested that cats prey on the Mona boa (03). House cat
predation has been documented for the Virgin Islands boa (01). The
status of mongoose predation on this boid remains unclear (01). The
presence of the mongoose (Herpestes auropunctatus) has been documented
in some cays within the species range (01).
The presence of man in this archipelago caused, as the islands
Management Practices - 1 (DRAFT) - Management Practices
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
became inhabited, alteration or destruction of the habitat by clearing
or altering the forest, and direct harassment also may have been
detrimental to the boa. This and the presence of introduced mammals
could still be exerting considerable pressure today.
Any manifestation of factors discussed previously could signify
future threats to the species. Heavy collection (i.e., commercial)
of the boa in sites where high densities occur, and severe hurricanes
on low elevation cays and islands of occurrence, could also be fatal
(01).
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1986. Recovery Plan for the Virgin
Islands Tree Boa (Epicrates monensis granti). U.S. Fish and Wildlife
Service, Atlanta, GA.
Actions recommended for the recovery of the Virgin Islands tree
boa include:
1. Controlling domestic animals.
2. Controlling and/or removing exotic vertebrates.
3. Restricting poaching.
4. Transplanting wild individuals.
5. Controlling and/or restricting development.
6. Land acquisition.
7. Land use zoning.
8. Limiting human access.
9. Controlling and/or restricting off-road vehicles.
On-going development of a recovery plan and Section 7
consultations are the only currently occuring recovery activities.
Management Practices - 2 (DRAFT) - References
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Tolson, P.J. and J.L. Pinero. 1985. A field report on the status
of the Virgin Islands Boa, Epicrates monensis granti, on Cayo
Diablo, Puerto Rico. Report to Department of Natural Resources,
Scientific Research Area, San Juan, PR. 13 pp.
02 Pregill, G.K. and S.L. Olson. 1981. Zoogeography of West Indian
land vertebrates in relation to Pleistocene climatic cycles. Ann.
Rev. Ecol. Syst. 12:75-98.
03 U.S. Fish and Wildlife Service. 1984. Mona Boa Recovery Plan.
U.S. Fish and Wildlife Service, Atlanta, GA. 14 pp.
04 Nellis, D.W., R.L. Norton, and W.P. MacLean. 1983. On the
biogeography of the Virgin Islands boa, Epicrates monensis granti.
J. Herpetol. 17(4):413-417.
05 Sheplan, B.R. and A. Schwartz. 1974. Hispaniolan boas of the
genus Epicrates (Serpentes:Boidae) and ther Antillean
relationships. Ann. Carnegie Mus 45(5):57-143.
06 Schwartz, A. and R. Thomas. 1975. A checklist of West Indian
amphibians and reptiles. Carnegie Mus. Natur. Hist., Spec. Publ.
1:1-216.
07 Stull, O.H. 1933. Two new species of the family Boidae. Occ.
Pap. Mus. Zool., Univ. Michigan. 267:14.
08 Grant, C. 1932. Herpetology of Tortola; notes on Anegada and
Virgin Gorda, British Virgin Islands. J. Dept. Agric. Puerto Rico.
16:327-329.
09 Schmidt, K.P. 1926. The amphibians and reptiles of Mona Island,
West Indies. Field Mus. Nat. Hist. Pub. 12(12):149-163.
10 Tolson, P.J. In press. Phylogenetics of the boid snake genus
Epicrates and Caribbean vicariance theory.
11 Huff, T.A. 1977. Captive propagation and husbandry of Epicrates
at the Reptile Breeding Foundation. Proc. 2nd Ann. Reptile Symp.
Thurmont, MD. Pages:103-112.
12 Tolson, P.J. 1984. The ecology of the boid genus Epicrates in the
West Indies. Abstract. Fifth Ecology Symposium. Universidad del
Turabo, Departamento Ciencias y Techologia.
13 Ewel, J.J. and J.L. Whitmore. 1973. The ecological life zones of
Puerto Rico and the U.S. Virgin Islands. U.S. Forest Serv. Res.
Pap. ITF - 18:1-72.
14 Beard, J.S. 1955. The classification of Tropical-American
vegetation types. Ecology 36(1):89-100.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Schwartz, A. and R. Thomas. 1975. A checklist of West Indian
amphibians and reptiles. Carnegie Mus. Natur. Hist., Spec. Publ.
1:1-216.
02 Tolson, P.J. and J.L. Pinero. 1985. A field report on the status
of the Virgin Islands Boa, Epicrates monensis granti, on Cayo
Diablo, Puerto Rico. Report to Department of Natural Resources,
Scientific Research Area, San Juan, PR. 13 pp.
References - 1 (DRAFT) - References
Species BOA, TREE, VIRGIN ISLANDS
Species Id ESIS154002
Date 14 MAR 96
03 Philibosian R. and J. Yntema. 1977. Annotated checklist of the
birds, mammals, reptiles and amphibians of the Virgin Islands and
Puerto Rico. Information Services, St. Croix, VI. 48 pp.
04 Grant, C. 1932. Herpetology of Tortola; notes on Anegada and
Virgin Gorda, British Virgin Islands. J. Dept. Agric. Puerto Rico.
16:327-329.
05 Nellis, D.W., R.L. Norton, and W.P. MacLean. 1983. On the
biogeography of the Virgin Islands boa, Epicrates monensis granti.
J. Herpetol. 17(4):413-417.
06 Stull, O.H. 1933. Two new species of the family Boidae. Occ.
Pap. Mus. Zool., Univ. Michigan. 267:14.
07 Lazell, J.D., Jr. 1980. Report: British Virgin Islands. The
Nature Conservancy. Washington, D.C. 105 pp.
08 Pregill, G.K. and S.L. Olson. 1981. Zoogeography of West Indian
land vertebrates in relation to Pleistocene climatic cycles. Ann.
Rev. Ecol. Syst. 12:75-98.
09 U.S. Fish and Wildlife Service. 1985. St. Thomas Tree Boa
Recovery Plan (draft). U.S. Fish and Wildlife Service. Atlanta,
GA. 11 pp.
10 Sheplan, B.R. and A. Schwartz. 1974. Hispaniolan boas of the
genus Epicrates (Serpentes:Boidae) and ther Antillean
relationships. Ann. Carnegie Mus 45(5):57-143.
References - 2