Biology Reference
In-Depth Information
4.2.6.1 Overview of the Duvernoy's Gland and Associated Dentition of
A. portoricensis
Alsophis cantherigerus
have two posterior enlarged, ungrooved maxillary teeth separated
from the anterior teeth by a diastema (Kardong, personal verbal and written communi-
cation with SAW, June-July 2009). There are few data about the presence or absence
of grooves in other
Alsophis
spp., and available information supports a lack of any
grooves or other significant dentitional modifications. Further study of a large number
of specimens would clarify the specific characteristics of dentition among alsophiines.
Kardong (1980b) detailed the jaw musculature and associated innervation of
Alsophis
cantherigerus brooksi
(
Cubophis cantherigerus schwartzi
Hedges et al., 2009).
The Duvernoy's glands of two
A. portoricensis
specimens (AMNH #1332 and
#28126) both had gland capsules with “heavy thickness” and a mucous supra-
labial gland associated with the serous Duvernoy's gland. However, the Duvernoy's
glands of these two specimens did have some subtle differences in: number of tra-
beculae (#1332
#28126); presence of lumen in tubules (50% in #1332, 90% in
#28126); degree of vascularity (“very high” in #1332, “moderate” in #28126); and
#28126 had very limited storage space, while #1332 had none (Taub, 1967). A speci-
men of
A.
(
Cubophis
Hedges et al., 2009)
vudii
(Bahaman racer; AMNH #34178)
had a Duvernoy's gland with: a heavy, thick capsule; moderate number of trabecu-
lae; absent lumena in tubules; no storage space; a mucous supralabial gland associ-
ated with Duvernoy's gland; and no appreciable gland vascularity (Taub, 1967). The
Duvernoy's glands of all three of the
Alsophis
specimens examined by Taub (1967)
had columnar cells, as well as an absence of mucous cells within the glands. Weldon
and Mackessy (2010) compared the organization of the “venom gland” (Duvernoy's
gland) of
A. portoricensis
to that of
B. irregularis
. They noted a series of lobular sub-
units arranged into secretory tubules lined by serous secretory cells. These secretory
cells were distinguished from those of the supralabial salivary gland by differential
staining with hematoxylin/eosin or periodic acid-Schiff. They also noted an absence
of any storage capacity and a lack of any “venom” (Duvernoy's secretion) in most of
the secretory tubules (Weldon and Mackessy, 2010).
4.2.6.2 Summary of Duvernoy's Secretion Properties and Toxinology of
Alsophis
spp.
Although there is very limited information about the toxinology of the tribe Alsophiini,
there has been some investigation of the Duvernoy's secretions of
A. portoricensis
that shed light on several of its properties and components. In an early investigation,
Hegeman (1961) described hemolytic and proteolytic activities of
A. portoricensis
Duvernoy's secretion, as well as a low level of cholinesterase. An unpublished screen-
ing of direct hemolytic activities in Duvernoy's secretions of several non-front-fanged
colubroids, including
A. vudii
, did not detect any significant activity (Weinstein and
Bernheimer, 1986, unpublished observations). In the most thorough study to date of
A. portoricensis
Duvernoy's secretion, Weldon and Mackessy (2010) found that the
secretion had a protein content of about 89%, high metalloproteinase and gelatinase
