Biology Reference
In-Depth Information
are beautifully preserved, and a new methodology is providing remarkable
photographs with striking detail. Previously, x-ray CT-scans gave photo-
graphic sections that could be assembled into 3-D images. A new instrument
called a synchrotron—for example, at the ESRF (European Synchrontron
Radiation Facility, Grenoble, France)—uses subatomic particles (electrons)
to generate more powerful x-rays that in combination with new 3-D print-
ers produce images of exquisitely fi ne detail without having to section the
specimens (“An Insight into Amber,” 2008; “Seeing the Light,” 2008). In
addition to insects, the instrument has been used to examine fossil plants in
amber from France dating to 100 Ma, as well as fossils from elsewhere. The
different organisms represented in amber are important for establishing
lineage histories (bacteria, fungi, bees, arachnids, bryophytes, ferns, fl ow-
ers of
Acacia
,
Hymenaea
, and others), and the number identifi ed from the
Dominican amber is rapidly increasing and soon will be suffi cient to recon-
struct ecosystems in combination with ancillary and context information.
The new method is only one example of advances in technology yielding
an ever more precise record of life in the past. One of the many interesting
revelations of the Dominican amber is that one infrared spectrophotometry
pattern, rather than being like the local
Hymenaea courbaril
, is most similar
to the African
H. verrucosa
(Hueber and Langenheim 1986). There are a
number of other examples of Antillean plants with African affi nities, and
their presence will be considered further in chapter 9.
There is another fl ora that reveals Antillean vegetation and environment
at a specifi c time and place, but without others in the vicinity, it is not pos-
sible to trace the plant communities through Neogene time. The Artibonite
fl ora of Haiti at 7-5 Ma (Bowin 1975) is located just north of Mirebal-
ais and consists of plant macrofossils studied in the early twentieth cen-
tury (Berry 1923), along with microfossils studied more recently (Graham
1990). There is no pollen of
Pelliceria
or
Rhizophora
, so the organic-rich
sediments were deposited in an inland to upland bog or swamp located be-
yond the infl uence of marine waters (fi g. 7.3). The vegetation was a lower to
upper montane broad-leaved forest including some plants that now grow in
the cloud forest, which has a lower limit of about 1400 m. The present high
elevations average around 1800 m (the highest is around 2900 m), so there
has been some uplift since Mio-Pliocene time. Pollen of
Pinus
reaches
16 percent in one sample, indicating a montane coniferous forest associa-
tion; spores of ferns make up 36 percent of the assemblage, suggesting a
freshwater herbaceous bog/marsh/swamp formation; and there is pollen
of the aquatic
Hygrophila
. The MAT is estimated at 23°C-26°C. Consider-
ing that the midelevation communities represented in the San Sebastian
