systematics of snakes of the dipsas oreas complex - BioOne

Dipsas oreas Complex in Ecuador and Peru • Cadle 75
tifications in some older literature (e.g.,
Boulenger, 1896), has led to considerable
uncertainty concerning differential characteristics
of these nominal taxa and their
respective distributions.
Peters’ (1960a) confusion of two Ecuadorian
species under the name Dipsas ellipsifera
affected his assessment of variation
within this species. For example, his
ventral and subcaudal counts for males
and females of ‘‘Dipsas ellipsifera’’ (Peters,
1960a: 87) are exceptionally broad for a
species of snake having a small range in
western Ecuador. Nonetheless, Peters
(1960a: 91) recognized a distinctive geographic
pattern to the variation within his
concept of D. ellipsifera:
The material available can be divided into two
groups as to provenance, the first coming from the
Río Mira drainage and referred to as the ‘‘typical
population,’’ and the other from the western slopes
of the Andes in Ecuador, to the south of the Río
Mira.... Although the indicated differences between
these two populations suggest subspecific
status, I am not assigning them a name, because
no satisfactory holotype is available.... The most
striking differences between the two populations
are in counts involving body segments.
Peters goes on to detail differences between
the Río Mira specimens and the
others when samples are segregated by
sex. However, he did not make the conceptual
leap to recognizing distinct species
on the basis of these populational differences.
Nor did he recognize that the ‘‘other’’
population from the western slopes of
the Andes represented Dipsas elegans, believing
as he did that D. elegans was a
Mexican species.
Kofron (1982) clarified much of the
confusion engendered by the uncertain origin
of the holotype of Dipsas elegans. He
summarized evidence that the holotype of
D. elegans came from western Ecuador on
the basis of the known travels and contacts
of Adolphe Boucard, who sold the specimen
to the British Museum (Kofron, 1982:
47). Kofron also reviewed the erroneous
association of the name of the collector,
François Sumichrast, who collected in the
vicinity of the Isthmus of Tehuantepec,
with the type of D. elegans. The error was
promulgated by Günther (1885–1902:
141) and continued in checklists and faunal
works (e.g., Peters, 1960a: 86; Smith
and Taylor, 1945) until Kofron discovered
the mistake. The unfortunate association
of Sumichrast’s name with the specimen
that ultimately became the holotype of D.
elegans resulted in it being considered a
Mexican species by Peters (1960a) and
others (e.g., Smith and Taylor, 1945).
Kofron’s (1982) conclusion that the holotype
of Dipsas elegans most likely came
from Ecuador was a major step toward resolving
the systematics of these snakes.
Nonetheless, because the type specimens
of D. ellipsifera and D. elegans have nearly
identical color patterns, Kofron (1982: 48)
synonymized D. ellipsifera with D. elegans,
which is the earlier name. He did not thoroughly
consider other character variation
in available samples of these snakes, particularly
in the context of geographic origin
and sex, even though some of these patterns
had already been elucidated by Peters
(1960a; see previous quotation).
Despite having examined much of the
same material as Peters, Kofron (1982)
used Peters’ (1960a) data when comparing
the scale counts of the holotype of Dipsas
elegans with D. ellipsifera, apparently failing
to realize that Peters had confused the
two species under the name ‘‘Dipsas ellipsifera’’
and overlooking Peters’ more detailed
discussion of geographic variation
within his concept of D. ellipsifera: ‘‘The
ventral and subcaudal counts of [the holotype
of] D. elegans (183, 95) are within
the ranges of 155–187 ventrals and 72–105
subcaudals reported for D. ellipsifera by
Peters (1960)’’ (Kofron, 1982: 47). Thus,
Kofron (1982) accepted Peters’ (1960a)
characterization of ‘‘Dipsas ellipsifera,’’
which included specimens of D. elegans;
not surprisingly, characteristics of the holotype
of D. elegans conformed well to this
composite taxon. Kofron did not reexamine
the meristic data of specimens segregated
by sex and locality and failed to no-