systematics of snakes of the dipsas oreas complex - BioOne

120 Bulletin Museum of Comparative Zoology, Vol. 158, No. 3
arboreal seclusion also occurs within Dipsas.
Porto and Fernandes (1996) reported
an inactive D. neivai found within a bromeliad
on a tree branch close to the
ground, and I collected an inactive D. vermiculata
(MVZ 163259) from a bromeliad
2 m from the ground during the day. Parker
(1926) reported that the type of D. variegata
trinitatis was obtained from a bromeliad
on a fallen tree. Charles W. Myers
collected several inactive D. temporalis
from bromeliads on the sides of trees 1.2–
3 m aboveground during the day (Cadle
and Myers, 2003: 36).
Eggs and Hatchlings. Cadle and Chuna
(1995: 32–34) reported communal egg-laying
in Dipsas oreas (21 total eggs), which
in that instance was coincident with a large
number of communally laid eggs of the
gymnophthalmid lizard, Macropholidus
ruthveni. The eggs, discovered 17 June
1987 at the lower edge of the humid forest
(1,490 m) at the Río Zaña Study Site, were
underground in a moist crevice within a
road embankment. The eggs were 20–30
cm from the entrance to the crevice and
15 cm beneath the surface of the soil (the
crevice ran somewhat parallel to the soil
surface); dimensions of the Dipsas eggs
were 28–30 20 mm. On the basis of
their clustering within the crevice, the
snake eggs probably represented three
clutches of eight, seven, and six eggs. One
egg was opened at the time from each of
the two deepest clutches and contained
advanced embryos of slightly different
stages. Five of the eggs were transported
in plastic bags containing moist paper towels
back to an air-conditioned office, where
they were kept in similar fashion on a table.
These eggs hatched between 23 September
and 1 October. Hatchlings
(FMNH 232570–72, MUSM 16751–52)
were 214–225 mm total length (172–176
mm SVL) and 2.8–3.2 g. A hatchling from
this clutch is illustrated in Figure 17, and
another was illustrated by Cadle and Myers
(2003: fig. 11).
Two hatchlings or near-hatchlings of
Dipsas oreas (MUSM 5530, 5532; total
lengths 230–243 mm) were collected 13–
15 January 1989 near the site where the
above eggs were discovered. It seems likely
that these hatchlings derived from eggs
laid the previous dry season, as indicated
by the eggs discovered in June and their
slightly larger size than the above series of
hatchlings.
Two other females of Dipsas oreas from
Ecuador were gravid, and clutch sizes
were estimated by palpation through the
ventral body wall. ANSP 18117 (421 mm
SVL) contained four eggs. BMNH
60.6.16.56 (566 mm SVL) contained about
8 eggs. No collection dates are available
for these specimens.
Aggregation Behavior in Dipsas oreas
A peculiar aggregation of Dipsas oreas
was discovered on 25 January 1989 at
1,800 m at the Río Zaña Study Site. At 10:
15 a.m., a field assistant found a ball of
four snakes on the surface of the leaf litter
adjacent to a small log (10–15 cm diameter,
2.5 m long) in a somewhat disturbed
patch of cloud forest; all of these snakes
were intertwined in a tight ball. Another
individual was on the leaf litter surface
about 20 cm from the ball. After alerting
me to the discovery we returned to the site
and found another snake hidden under the
leaf litter (15–20 cm deep) where the initial
ball was found. At the opposite end of
the log (2.5 m from the ball), another individual
was hidden under the leaf litter.
A search of the immediate area (surface
and under logs, litter, etc.) turned up no
more snakes. The night before finding the
aggregation included a light drizzle for
several hours; on the morning of the encounter,
the leaf litter was wet and the day
was overcast. Temperature at 11:00 a.m.
was 15 C.
All snakes were quiescent and loosely or
tightly coiled. The four snakes in the initial
ball were completely and tightly intertwined,
and consisted of an adult female
and three adult males. The three individuals
not associated directly with the ball
were adult males. The female is ANSP