systematics of snakes of the dipsas oreas complex - BioOne

Dipsas oreas Complex in Ecuador and Peru • Cadle 125
TABLE 4. CONTINUED.
Dipsas gracilis
Ecuador
MUSM 17589
male
MUSM 2701
male
MUSM 2700
male
Tertiary temporals 4/3 3/3 — 0 (N 2)
3(N 14)
4(N 2)
Supralabials (touching eye) 11 (5–7)/11 (5–7) 10 (4–6)/11 (4–7) — 8 (3–5) N 1
9 (3–5) N 3
9 (4–5) N 4
9 (4–6) N 2
10 (3–5) N 1
10 (4–6) N 7
Infralabials 13/13 13/13 — 10 (N 1)
11 (N 3)
12 (N 8)
13 (N 4)
Number of infralabials in
1 pair 2 pairs 1 pair 1 pair (N 9)
contact behind mental
Number of bands or blotches
on body
24 21 22 13–19 (N 9)
uadorian border. The general region is arid
in lower reaches of the valley to the west
and subhumid toward the east. Relictual
patches of humid forest still existed in the
1990s at higher elevations in montane regions
in the eastern part of the valley (personal
observations; see above notes on
habitats of D. oreas in northern Peru).
Dipsas gracilis is otherwise known only
from the lowlands (1,000 m), whereas
the only parts of the Río Quiroz valley
presently having humid forest habitats are
at higher elevations in the eastern part of
the river system (2,000 m).
The pattern elements visible in MUSM
2700–01 are similar to other specimens of
Dipsas gracilis. The dorsal pattern consists
of a series of dorsal blotches or bands,
which, when viewed in lateral aspect, are
oval on the anterior body and round posteriorly.
The anterior bands nearly meet
midventrally; posterior ones encroach onto
the outer edges of ventrals. The top of the
head is mainly dark blackish with light
patches and flecks (more light patches are
present in the smaller specimen, MUSM
2701). The vertebral scale row is greatly
expanded (1.5–2 the width of the paravertebral
rows).
The three Peruvian specimens referred
to Dipsas gracilis conform generally to
other males of D. gracilis I examined, but
there are differences from Ecuadorian
specimens as well (Table 4). The Peruvian
specimens have lower ventral (187–192)
and subcaudal (94–109) counts than males
from Ecuador (ventrals 199–210, subcaudals
114–128). MUSM 2700–01 have
shorter tails and a different loreal pattern
from Ecuadorian specimens. In D. gracilis
from Ecuador, all the dorsal bands are
complete across the venter (anterior body)
or encroach very broadly onto the ventral
scutes, nearly meeting midventrally (posterior
body). This is the case in MUSM
17589, but in MUSM 2700–01, the posterior
bands end on the outer edges of the
ventral scutes.
Although some scutellation characteristics
of the three Peruvian specimens re-