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IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 247NATURAL HISTORY RESEARCH REPORTS

Pitvipers in the Sea
Envisioning how terrestrial vertebrates
could invade the sea is difficult, and little
is known about the transitional evolu-
tionary processes that produce secondar-
ily marine animals. The utilization of
marine resources in the intertidal zone is
likely to be an important first step 
for invasion. LILLYWHITE ET AL.
(2008. BioScience 58:947–955) described
marine scavenging by the Florida
Cottonmouths (Agkistrodon piscivorus
conanti) that inhabit Gulf Coast islands.
These snakes principally consume dead
fish that are dropped from colonial nest-
ing bird rookeries, but they also scavenge
beaches for intertidal carrion, consuming
dead fish and marine plants, and occa-
sionally enter seawater. Thus, allochtho-
nous marine productivity supports 
the insular Cottonmouth population
through two pathways, and one of these
pathways connects the snakes directly to
the sea. The trophic ecology and behav-
iors of this unusual snake population
suggest a requisite evolutionary scenario
for the successful transition of vertebrates
from a terrestrial to a marine existence.

Female Promiscuity Insures 
Against Nest Failure

Female Bibron‘s Toadlets (Pseudophryne
bibronii) distribute their eggs between
the nests of as many as eight different
males. Such sequential polyandry may
have evolved as an insurance mechanism
to reduce the risk of choosing a mate that
is infertile, closely related, genetically
inferior, or genetically incompatible, but
polyandry also might insure against nest
failure in unpredictable environments.

Most animals are oviparous, and in
species where males provide nest sites
with substantial and unpredictable varia-
tions in quality, polyandrous females
might insure offspring success by distrib-
uting their eggs across multiple nests.
BYRNE AND KEOGH (2008. Proceedings of
the Royal Society B Biological Sciences 276:
115–120) tested this hypothesis in a wild
population of an Australian terrestrial
toadlet, a polyandrous species in which
males construct nests and remain with
broods. The authors found that females
partitioned their eggs across the nests of
two to eight males and that more polyan-
drous females gained a significant
increase in mean offspring survivorship.
These results provide evidence for the
most extreme case of sequential
polyandry yet discovered in a vertebrate
and also suggest that insurance against
nest failure might favor the evolution of
polyandry. The authors proposed that
insurance against nest failure might be
widespread among oviparous taxa and
might provide an important explanation
for the prevalence of sequential
polyandry in nature.

A 100-million Year-old Gecko
Preserved in Amber

ARNOLDI AND POINAR (2008. Zootaxa
1847: 62–68) described a new genus and
species of gecko from a posterior lower
limb and foot and a partial tail preserved
in Lower Cretaceous amber from
Myanmar that is 97–110 million years
old. It appears to be the oldest unequiv-
ocal fossil gecko, predating fragmentary
skeletal remains from the Upper
Cretaceous and being 43–56 million
years older than Yanatarogecko from the

Lower Eocene, previously the oldest
known gecko preserved in amber. It also
provides firm evidence that gekkotans
and possibly gekkonids were in Asia at
this time. The Myanmar specimen shows
that the distinctive foot proportions and
sophisticated adhesive mechanism
involving pads on the toes with trans-
verse lamellae, probably bearing numer-
ous hairlike setae found in many modern
geckos, had already evolved around 100
million years ago. The specimen is very
small, even compared with juveniles of
the smallest living geckos. However, the
high numbers of lamellae on its toe pads
suggest it is from a juvenile of a species
with relatively large adult body size.

Chuckwallas in 
Metropolitan Phoenix

Understanding the responses of reptilian
populations to habitat fragmentation and
degradation due to urbanization has gen-
erated considerable interest. SULLIVAN

AND SULLIVAN (2008. Herpetological
Conservation and Biology 3:149–154)
surveyed populations of the Common
Chuckwalla (Sauromalus ater) in pre-
serves of the Phoenix Mountains and
adjacent areas near the Phoenix
Metropolitan region during the spring of
2008. Fecal dropping counts were used
to assess the current populations in rela-
tion to those sampled in 1995. The
results revealed a strong correlation
between estimates gathered in 1995 and
2008. Additionally, one intensively sam-
pled site established that, although esti-
mates could vary somewhat in relation to
the number of individuals conducting

N A T U R A L  H I S T O R Y  R E S E A R C H  R E P O R T S

Female Bibron‘s Toadlets (Pseudophryne
bibronii) distribute their eggs between the
nests of up to eight different males.

W
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An amber fossil, from 97–110 million years
ago in the tropical forests of Myanmar, con-
tained the foot and partial tail of the world’s
oldest known gecko: Cretaceogekko burmae,
named for its age (Cretaceous) and origin
(Burma is the traditional name for
Myanmar). 

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Florida Cottonmouths (Agkistrodon pis-
civorus conanti) on Gulf Coast islands feed
on dead fish dropped from colonial nesting
bird rookeries and scavenged intertidal car-
rion, and occasionally enter seawater.

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the survey, they were stable over a 13-
year period. The survey results suggest
that Common Chuckwalla populations
are stable in these island preserves in a sea
of urban development.

Hurricane Katrina and 
Mississippi Turtles

The Yellow-blotched Sawback
(Graptemys flavimaculata) is a riverine
turtle that is endemic to the Pascagoula
River system of southern Mississippi.
Population declines led to Federal listing
as a threatened species in 1991, with the
most robust population inhabiting the
Lower Pascagoula River near Vancleave

(~24 river km from the Pascagoula River
mouth). SELMANI AND QUALLS (2008.
Herpetological Conservation and Biology
3:224–230) conducted a mark-resight
survey of this population during the
spring and summer of 2005–2006. On
29 August 2005, Hurricane Katrina
entered the Mississippi Gulf Coast, the
location of their study site. On 13
October 2005, they conducted a one-
hour preliminary visual survey by boat
through the study area and identified
eight individuals that had been marked
prior to Katrina’s landfall, demonstrating
that at least some of the 49 previously
marked individuals remained in the
study area. In October 2005–2006, the

authors conducted more extensive mark-
resight surveys within the same section
of river. The population estimate for
2006 was significantly lower than the
2005 population estimate for the same
stretch of river, suggesting that numbers
substantially decreased during the year
following the hurricane. Of the plausible
explanations for this pattern, the avail-
able evidence most strongly supports a
real decline in population, presumably
due to the long-term impact of
Hurricane Katrina. Possible reasons for
such a long-term effect include hurri-
cane induced saltwater intrusion and
low levels of dissolved oxygen with direct
effects on individuals or indirect effects
on the prey populations (e.g., gastropods
and other aquatic macroinvertebrates).

248 IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 NATURAL HISTORY RESEARCH REPORTS

California Tiger Salamander 
Moves Closer to Protection

The California state appeals court ruled
that the California Fish and Game
Commission must consider a petition to
list the California Tiger Salamander
(Ambystoma californiense) as an endan-
gered species under the California
Endangered Species Act. In a decision
with potential implications for other
poorly monitored species, the court ruled
that the Fish and Game Commission
must consider a listing petition if the
information would “lead a reasonable
person to conclude there is a substantial
possibility” that the species could be
listed. “The Fish and Game Commission
ignored the multitude of known threats
to the Tiger Salamander and dismissed
the petition, falsely claiming it did not
contain all of the data necessary to prove

the salamander population may deserve
protection,” said Brian Nowicki of the
Center for Biological Diversity. “Today’s
ruling should set the listing process back
on the right track and ultimately result in
the Tiger Salamander getting the state-
protected status it deserves.”

The California Tiger Salamander is
now set to advance to the status of can-
didate for state listing. The Santa
Barbara County salamander population
has been listed as Endangered under the
federal Endangered Species Act since
2000, as has the Sonoma County popu-
lation since 2003. The central California
population has been federally listed as
Threatened since 2004. The California
Tiger Salamander depends on ephemeral
vernal pools for breeding, but in recent
decades, 95% of California’s vernal pools
have already been lost, and at least 75%
of the salamander’s habitat throughout
the state has been eliminated. In
Sonoma County, 95% of the frag-
mented and minimal remaining sala-
mander habitat is threatened by develop-
ment; the Santa Barbara population also
is on the verge of extinction.

N E W S B R I E F S

Common Chuckwalla (Sauromalus ater) populations appear to be stable in islands of suitable
habitat in a “sea” of urban development. 

Population sizes of Yellow-blotched Sawbacks
(Graptemys flavimaculata) dropped during
the year following Hurricane Katrina, prob-
ably due to saltwater intrusions and low dis-
solved oxygen levels affecting turtles directly
or their prey.

B
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The California state appeals court ruled that
the California Fish and Game Commission
must consider a petition to list the California
Tiger Salamander (Ambystoma californiense)
as an endangered species under the California
Endangered Species Act. 

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