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identified, as far as possible, by the
parasites thereon. A rodent, possibly a
hutia, was recognized by fur parasites
(Poinar, 1988b). A few bones of an
insectivore have also been found
(MacPhee and Grimaldi, 1996).
Hispaniolan caves, so they are possible
contenders too. Bats are very likely to have
been there; as flying mammals, they had a
greater chance of reaching Hispaniola
even when it became an island. There is
evidence for ungulates from Jamaica, and
carnivores are possible too. No doubt birds
were much more plentiful than their
meager fossil remains in amber indicate.
While we can speculate on the
constituents of the amber forest ecosystem
beyond the evidence to hand, the data we
do have are interesting in other ways. For
instance, most of the fauna and flora have
close relatives in Central and South
America yet some, like the
Mastotermes
termites and
Leptomyrmex
ants, now only
occur far away in tropical Australasia. The
closest relative of the amber algarrobo,
Hymenaea protera
, is an East African
species. It is also clear from a number of
examples that some species present in the
amber no longer occur in Hispaniola:
none of the tropical bees in the amber
now still exist on the island, for example.
So part of the Dominican amber biota was
lost, some retreated back to Central or
South America, others to Australasia. The
cause of this could have been climatic: the
Earth saw a gradual, and then a more
dramatic, cooling going through the
Neogene and into the Pleistocene. The ice
ages which affected polar regions did have
some climatic effects in the tropics too.
P
ALEOECOLOGY OF
D
OMINICAN
AMBER
Poinar and Poinar (1996) discussed the
reconstruction of the Dominican amber
forest. While there are tens of thousands of
specimens of plants and animals to help
with this, it must be remembered that the
amber only takes a sample of the habitat, so
what it preserves is only a small, biased
selection of the biota present at the time.
We have seen that the canopy trees are likely
to have included algarrobo (
Hymenaea
),
nazareno (
Peltogyne
), cativo (
Prioria
), and
caoba (
Swietenia
). Understorey trees would
have included palms (e.g.
Roystonea
) and
fig (
Ficus
). The shrub layer would have had
a number of leguminous plants (mimosas,
acacias, locusts), and other types. There
would have been plenty of vines, lianas,
strangler figs, and epiphytes such as
bromeliads, mosses, and lichens. The
invertebrate life of the forest is quite well
known from the amber inclusions described
already, but vertebrates are poorly sampled
by the resin. Smaller tree frogs and lizards
have some representation, but for the
remainder we need to look to mammals,
birds and larger reptiles present today in the
Greater Antilles.
One mammal present today on
Hispaniola which is a possible contender
for a resident of the amber forest is the
Solenodon. Only two species exist, one on
Hispaniola and one on Cuba, and although
no fossils exist, it is thought that they are
relicts from a former much wider
distribution. Solenodons are the only
insectivore in the West Indies; they are
nocturnal and grub around for small
animals using their long, flexible snouts.
Other animals which might have existed in
the amber forest include sloths, of which
fossils are known from the Miocene of
Cuba; monkey bones have been found in
C
OMPARISON OF
D
OMINICAN
AMBER WITH OTHER
A
MBERS
Schlüter (1990) compared the Baltic
amber fauna with that of the Dominican
Republic, the only other amber to have
produced sufficient inclusions to make
quantitative comparisons with Baltic
amber, with informative results. Diptera
account for some 50% of inclusions in the
Baltic amber, less than 40% in Dominican.
In Dominican amber, Hymenoptera
(mainly ants) are second only to Diptera
(also nearly 40%) in abundance, but ants
account for only about 5% of the Baltic
amber fauna. The reason for this is that
ants make up a disproportionate
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