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some pressurization of the system (Fry et al., 2008; Taub, 1966; Weinstein et al., 2010).
The muscle insertion into the venom glands typical of front-fanged snakes exerts a
high-pressure head (often in excess of 30 psi; Kardong, 2009) facilitating rapid deliv-
ery of a significant volume of pre-stored venom bolus through the associated venom
ducts and canaliculate fangs ( Figure 2.1 , Panels D-F) that may be fixed (essentially,
permanently erect, “proteroglyphous,” Plate 2.1A-E ) or erectile with varying mobility (or,
distensibility) according to size or species (“solenoglyphous,” Plate 2.2A ; Kardong,
(A)
(B)
Plate 2.1 (A and B) Fangs of the common Asian cobra ( Naja naja ). The fixed, erected,
canaliculated fangs are representative of the “proteroglyphous” dentition present in the Elapidae.
Many elapid species have short fangs, but some such as the coastal taipan ( Oxyuranus scutellatus )
have long, slightly recurved fangs. Many elapid venoms contain multiple isoforms of postsynaptic
or presynaptic neurotoxins. These venoms may be delivered less deeply than those administered
by the often larger fangs of viperids, but this does not decrease their in vivo lethality.
(A) Profile of fangs of Naja naja , Sri Lanka.
(B) Close-up of fang of Naja naja , North India. Note the elongated oval-shaped bevel
(arrows) that closely resembles that of a hypodermic needle. The canaliculated (hollow or
containing a lumen) morphology facilitates deep injection of venom into the integument of
prey or human victim (see text).
(C) Fangs of the yellow-lipped sea krait ( Laticauda colubrina ), Madang, Papua New
Guinea. Hydrophiine sea snakes and laticaudiines (sea kraits) exhibit the “proteroglyphous”
dentition associated with high-pressure venom glands. Bites from laticaudiines are rare, but
may be life threatening when they occur (see text).
(D) Yellow-lipped sea krait ( Laticauda colubrina ), Madang, Papua New Guinea. While
hydrophiine sea snakes are ovoviviparous, the laticaudiines are oviparous, and come ashore
to lay their eggs in rock crevices. Their venoms contain postsynaptic neurotoxins (e.g.,
erabutoxins), and phospholipases A 2 myotoxins.
(E) Close-up view of fangs of the olive sea snake ( Aipysurus laevis ), Roebuck Bay, Western
Australia. The fixed canaliculated fangs of this hydrophiine sea snake are closely set (arrows),
probably to establish a firm grip on struggling prey and possibly increase the likelihood of effective
venom delivery to the fishes of multiple niches belonging to at least 17 families and six different
morphological types that comprise a major part of the diet of this species (Heatwole and Cogger,
1993). Aipysurus laevis also preys on crustaceans, cephalopods, and fish eggs. Plate 2.1 A, C, and
D, photos copyright to David A. Warrell; Plate 2.1 B, AMNH specimen #64418; and Plate 2.1 E,
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