Biology Reference
In-Depth Information
(A)
(B)
Plate 4.83
(A and B) Maxilla of the African (Congolese) large-eyed green tree snake or
nataymankeema (
Rhamnophis aethiopissa ituriensis
), Niapu, Belgian Congo.
Another
little-known member of the Dispholidini,
R. a. ituriensis
has enlarged posterior maxillary teeth
that are recurved, and the posteriormost tooth is notably larger than the anterior preceding
teeth (
Plate 4.83A
, arrows). The suggestion of a groove in the second to last posterior
maxillary tooth in this specimen is likely an artifact/defect of age. AMNH #12500, photos
copyright to Arie Lev.
Although effects of most bites by non-front-fanged colubroid snakes cannot easily
be explained by the toxins known to be present in their secretions, there is clear cor-
relation between the pharmacology of toxins of Dispholidini studied to date and the
pathophysiological effects observed in envenomated patients. Kornalik and Taborska
(1978) described the similarity between hemorrhage in mice injected with
T. kirtlandii
venom and that caused by venom of
Bothrops jararaca
(jararaca). Similarly, Weinstein
and Smith (1993) compared hemorrhagic effects in mice succumbing to i.p. injections
of either
D. typus
or
T. capensis
venoms with those resulting from injection of
C. atrox
(western diamondback rattlesnake) venom.
Several investigators have described the prothrombin-activating activity of venoms
from
D. typus
(Bradlow et al., 1980; Guillin et al., 1978) and
T. kirtlandii
(Kornalik
and Taborska, 1978; Kornalik et al., 1978). Bradlow et al. (1980) also reported that
D. typus
venom could activate Factor X and possibly Factor IX. The prothrombin-
activator was identified as a 58-kDa species that generated fragments 1, 2, and
α-thrombin in the absence of Ca
2
and phospholipid. The mechanism involved the
intermediate formation of meizothrombin in the presence of hirudin and therefore
functioned similarly to that of ecarin from venom of the Indian saw-scaled viper,
Echis
carinatus
(Gullin et al., 1978).
Thelotornis kirtlandii
venom exhibited strong
in vivo
