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from the standpoint of both a potential digestive role, and as potential, but unveri-
fied, contributors to the local effects in some victims bitten by this species. McCue
(2005) commented on the higher levels of proteolytic activities of venoms from the
more recently derived crotalines, and this could suggest that the evolution of these
venoms may be influenced by their digestive function. Although some research has
provided evidence of a digestive function for venom of
Crotalus atrox
(Thomas and
Pough, 1979), other investigations have not demonstrated any significant contribution
of venom to the digestive process of
C. atrox
(McCue, 2007). This may reflect indi-
vidual venom properties of snakes included in specific studies, as well as differences
in experimental methods and the complexities of studying a dynamic, multifactorial
physiological process.
Crotalus atrox
venoms have notably marked individual, popula-
tion/geographic, and ontogenetic variability (Minton and Weinstein, 1986). However, it
must be noted that studies such as those briefly outlined earlier are crucial to the clari-
fication of potential fundamental biological roles of venoms and other ophidian oral
secretions.
Considering that there are accumulating field and laboratory observations that
support active use of
A. portoricensis
Duvernoy's secretions in subjugation, and pos-
sibly digestion, of prey, as well as demonstrated toxicity to favored prey species,
the criteria for the formal term “venom” have been met. Therefore, the Duvernoy's
secretions of
A. portoricensis
offer an uncommon example of oral secretions of a
non-front-fanged colubroid species that have been studied from a functional biologi-
cal perspective. This research provides sufficient evidence to consider this secretion
as venom, or, prey-specific venom, as suggested elsewhere in this topic. The putative
medical effects from bites by this species remain of unknown etiology, and, as noted
previously and later, should not in any case influence the biological-functional defi-
nition of venom.
4.2.6.4 Conclusion and Assessment of
Alsophis
spp.
There are only a handful of formally documented cases of bites by alsophiine snakes.
The very limited toxinological information about most species in this group further
complicates objective risk assessment. However,
A. portoricensis
has inflicted sev-
eral medically significant bites that consisted of mild-to-moderate local effects. To
date, there is no evidence of systemic “envenomation” by any of these snakes. Due
to the identification of fibrinogenases and high levels of other proteases in
A. por-
toricensis
venom, handling of these snakes is discouraged, and large specimens may
be capable of inflicting a more clinically significant bite. Field and laboratory obser-
vations/findings support the recognition of
A. portoricensis
Duvernoy's secretions as
venom, independent of any medical risks. There is no evidence supporting any medi-
cal significance for the vast majority of alsophiines, but aside from
A. portoricensis
,
the scant biomedical information about most species in this taxonomically unsettled
group is insufficient for a thorough risk analysis.
Assessment of
Alsophis
(
Borikenophis
)
portoricensis
,
A.
(
Cubophis
)
cantherigerus
,
and
Alsophis
spp. based on available evidence: Hazard Level 3 [
A
. (
Borikenophis
)
portoricensis
] and 3/4 [
A
. (
Cubophis
)
cantherigerus
and
Alsophis
spp.].
