US ISSN: 0025-4231

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DEPARTMENT OF HERPETOLOGY

THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.

MdHS . A FOUNDER MEMBER OF THE

Eastern Seaboard Herpetological League

30 MARCH 1998

VOLUME 34 NUMBER 1

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 34 Number 1

March 1998

CONTENTS

Thermal Tolerance of Five Species of Lizard from Mexico and the South¬
western USA

Royce E. Ballinger, Julio A. Lemos-Espinal, and

Geoffrey R. Smith . . . . . . . . . ..1

Hypocalcemia in Iguanas
Thomas Ryan .

15

Status of Chorus Frogs (Genus Pseudacris) in Southeastern Colorado
Lauren J. Livo, Geoffrey A. Hammerson, Hobart M. Smith

David Chiszar and Stephen F. Mackessy . . . . . .22

A Comparison of the Feeding Behavior of two Pipids, Xenopus laevis and
Hymeno chirus boettgeri with Emphasis on the Use of the Forelimbs

Malcolm L. McCullum . . . 29

Field Observations on the Behavior of Chihuahuan Spotted Whiptail
Lizards (Cnemidophorus exsanguis)

Hobart M. Smith, David Chiszar, Clint Henke, Julio A. Lemos-
Espinal and Frank van Breukelen . . . ...34

BULLETIN OF THE

Volume 34 Number 1

March 1998

The Maryland Herpetological Soceity
Department of Herpetology, Natural History Society of Maryland, Inc.

President Tim Hoen

Executive Editor Herbert S. Harris, Jr.

StegriDgjCommittee

Frank Groves Jerry D. Hardy, Jr.

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

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evenings at the NHSM at 8:00 p.m.

THERMAL TOLERANCE OF FIVE SPECIES
OF LIZARD FROM MEXICO AND
THE SOUTHWESTERN USA

Royce E. Ballinger, Julio A. Lemos-Espinal, and Geoffrey R. Smith

In ectotherms, the ability of an organism to maintain the
appropriate internal environment is often dependent on the ability of the
organism to use its external environment to maintain the proper body
temperature (Huey and Stevenson 1979). Extremes in environmental
temperatures are therefore challenges to an ecto therm's physiological
well being. The response of lizards to thermal extremes has revealed
apparently adaptive responses to cold, even sub-freezing temperatures
(Lemos-Espinal and Ballinger 1992; Costanzo et al. 1993, 1995);
however, at extremely high temperatures almost all reptiles lose the
ability to coordinate their actions (i.e., they reach their critical thermal
maximum; Pough and Cans 1982). Therefore, an important aspect of a
reptile's thermal biology is its tolerance of high temperatures.

In this paper, we report on the thermal tolerances of five species
of lizard from Mexico and the southwestern USA. The thermal biology of
the Mexican species (Phty nosoma asio and Sceloporus mucronatus) has not
been well studied. Indeed, only rudimentary knowledge of field body
temperatures is available for P. asio (Lemos-Espinal, Smith, and
Ballinger unpubl.), and only a slightly more detailed analysis for S.
mucronatus is available (Lemos-Espinal et al. in press). In addition, we
investigate the influence of time of year, as well as sex on the thermal
tolerance of Sceloporus virgatus, S. scalaris, and S. jarravi from the
Quricahua Mountains of southeastern Arizona, USA. More is known
about the thermal biology of these species, and the specific populations
of these species than for the Mexican species (see Smith et al. 1993;
Smith and Ballinger 1994a, b). We also compare the thermal tolerance of
two populations of S. jarravi , one at high elevation and one at low
elevation.

Materials and Methods

Sceloporus virgatus and S. jarravi were collected in the vicinity of
the Southwestern Research Station (1646 m) near Portal, Cochise
County, Arizona. The habitat in this area is primarily pine-oak

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March 1998

woodland and has been previously described by Vinegar (1975).
Sceloporus virgatus and S. jarravi were collected in the vicinity of Rustler's
Park (2500-2600 m). The habitat in this area is primarily wooded with
talus slopes interspersed and has been described previously by Ballinger
(1979), Smith et al. (1993). Lizards were collected and tested throughout
1974 and 1975. Phrynosoma asio were collected in the Canon del Zopilote,
north of Chilpancingo, Guerrero, Mexico (600 m elevation), 14 km south
of Mexcala, a small town on the Rio Balsas. The area is situated in arid
tropical scrub (the most xeric portion of the Bosque Tropical Caducifolio
of Rzedowski 1988). Sceloporus mucronatus were collected near Sierra del
Ajusco, Mexico (3400 m elevation) at km 19 on the Ajusco-
Tinaguistenco highway (Mexico Highway 892) in an open area with
basaltic rocks and lava interspersed with grassy patches ( Festuca
amolissima) and surrounded by a Pinus hartwegii forest.

Lizards were not allowed to acclimate to laboratory temperature
before testing, and were tested within a few hours of capture. Thirty-one
P. asio, 16 S. mucronatus, 81 S. virgatus, 99 S. scalaris, and 190 S. jarrovi
were tested. Lizards were tethered on aluminum foil (to prevent
substrate heating) under a heat lamp which caused lizards to heat up
relatively rapidly. Tests were concentrated in the morning hours. Body
temperatures were taken at the onset of muscle spasms, indicating they
would no longer be able to escape from temperature conditions that
would result in death, also known as the critical thermal maximum
(CTM). Lizards were removed from the heat source and allowed to
recover (individuals not immediately recovering were excluded from the
analysis). Means are given ± one standard error.

Results

Phrynosoma asio. - Mean SVL of the lizards used in this study was
90.1 ± 2.2 mm (N = 31, range = 72 - 120 mm), and Mean BM was 39.0 ±
2.7 g (N = 31, range = 18 - 68 g). Mean indices of thermal tolerance are
given in Table 1. Critical Thermal maximum and Gaping Temperature
were not related to either measure of body size (SVL or BM) (P > 0.15 in
all cases). The temperature at which continuous escape occurred was
negatively correlated with body mass, but not SVL (SVL: N 31, R2 =
0.10, P - 0.08; BM: N - 31, R2 = 0.21, P - 0.0009; y - 39.6 + 0.055x).
Initial Escape Temperature also decreased with body size (SVL: N = 31,
R2 = 0.12, P = 0.053; y = 40.1 - 0.054x; BM: N - 31, R2 - 0.17, P - 0.02; y
= 37.3 - 0.053x).

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March 1998

Initial escape temperature did not differ between males and
females (Table 2; df = 29, t = -0.5, P = 0.62). Critical thermal maximum
also did not differ between males and females (Table 2; df = 29, t = 0.17,
P ~ 0.87). Males did not differ from females in their continuous escape
temperatures (Table 2; df = 29, t = -0.19, P = 0.85), nor in their gaping
temperatures (Table 2; df = 29, t - 0.64, P = 0.52).

Sceloporus mucronatus. - Mean SVL of the lizards used in this
study was 81.7 ± 2.6 mm (N = 16, range = 65 - 95 mm), and Mean BM
was 24.7 ± 2.4 g (N = 16, range =11-39 g). Mean indices of thermal
tolerance are given in Table 1. Initial Escape Temperature and Gaping
Temperature were not related to either measure of body size (SVL or BM
(P > 0.70 in all cases). The temperature at which continuous escape
occurred was positively correlated with body size (SVL: N = 16, R2 =
0.38, P = 0.011; y = 33.1 + 0.085x; BM: N = 16, R2 = 0.33, P = 0.019; y =
37.0 + 0.087x). Critical Thermal Maximum also increased with body size
(SVL: N * 16, R2 = 0.43, P = 0.006; y = 39.5 + 0.035x; BM: N = 16, R2 =
0.35, P = 0.015; y = 41.5 + 0.035x).

Initial escape temperature did not differ between males and
females (Table 2; df = 14, t = -0.96, P = 0.36). Critical thermal maximum
also did not differ between males and females (Table 2; df = 14, t = 0.82,
P = 0.43). Males had slightly, but statistically significantly higher
continuous escape temperatures (Table 2; df = 14, t = 2.23, P = 0.04).
Females had higher gaping temperatures on average than males (Table 2;
df = 14, t = -2.50, P = 0.026).

Sceloporus virgatus. - Sceloporus virgatus used in this study had a
mean SVL of 47.7 ±1.2 mm (N = 82, range = 26 - 66 mm), and mean
BM was 3.8 ± 0.3 g (N = 63, range = 0.6 - 8.8 g). Mean indices of thermal
tolerance are given in Table 3. The temperature at which initial escape
occurred was not significantly related to either SVL or BM (P = 0.10 and
0.09, respectively). Continuous escape temperature increased with SVL
(N = 79, R2 = 0.28, P < 0.0001; y = 30.0 + 0.14x) and BM (N = 61, R2 =
0.23, P = 0.0001; y = 33.7 + 0.69x). The temperature at which S. virgatus
began to open their mouths was significantly and positively related to
their SVL (N = 59, R2 = 0.36, P < 0.0001; y = 32.3 + 0.14x) and BM (N =
51, R2 * 0.24, P = 0.0003; y = 36.4 + 0.53x). Critical thermal maximum
also positively correlated with SVL (N = 82, R2 = 0.52, P < 0.0001; y =
33.4 + 0.17x) and BM (N = 63, R2 = 0.51, P< 0.0001; y = 37.6 + 0.89x).

Sceloporus virgatus males and females did not have different mean
initial escape temperatures (df = 80; t = -0.07, P = 0.94), continuous

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escape temperatures (df = 78; t = -0.75, P = 0.46), gaping temperatures
(df = 57; t - -0.77, P - 0.44), and CTMs (df = 81; t = 0.20, P - 0.84) (see
Table 4). Monthly variation in CTM in S. virgatus was significant (Fig. 1;
Kruskal-WalMs: df = 7; H = 32.3, P < 0.0001).

Sceloporus scakris - The lizards used in this study had a mean SVL
of 45.5 ±1.0 mm (N = 99, range - 27 - 60 mm), and Mean BM was 3.0 ±
0.2 g (N = 87, range = 0.5 - 7.9 g). Mean indices of thermal tolerance are
given in Table 3. The temperature at which initial escape occurred was
positively correlated with SVL (N = 98, R2 = 0.35, P < 0.0001; y = 29.5 +
0.12x) and BM (N = 86, R2 = 0.19, P < 0.0001; y = 33.5 + 0.47x).
Continuous escape temperature increased as SVL (N = 99, R2 = 0.41, p <
0.0001; y = 34.2 + 0.09x) and BM (N = 87, R2 = 0.29, P < 0.0001; y -
37.0 + 0.41x) increased. The temperature at which S. scakris began to
open their mouths was positively related to their SVL (N = 64, R2 = 0.10,
P = 0.009; y = 35.5 + 0.08x) and BM (N = 87, R2 = 0.48, P < 0.0001; y =
40.3 + 0.062x).

Male and female S. scakris did not differ in initial escape
temperature (df = 83, t = 1.3, P = 0.19), continuous escape temperatures
(df = 84, t = -1.0, P = 0.30), gaping (df = 57, t = -0.56, P = 0.57), and
CTM (df = 84, t = .37, P = 0.71) (see Table 4). There was significant
monthly variation in CTM for these S. scakris (Fig. 1; Kruskal- Wallis; df
-7, H - 66.2, P < 0.0001).

Sceloporus jarravi - Mean SVL in this study was 67.2 ±1.0 mm (N
= 188, range = 42 -96 mm), and mean BM as 11.5 ± 0.6 g (N =130, range
= 2.0 - 28.1 g). Mean indices of thermal tolerance are given in Table 3. No
measures of thermal tolerance were significantly related to SVL (P > 0.08
in all cases). The temperature at which initial escape occurred was
positively correlated with BM (N = 128, R2 = 0.04, P = 0.02; y = 29.9 ±
0.08x). Critical Thermal Maximum also increased with BM (N = 130, R2
= 0.04, P = 0.02; y = 40.6 + 0.052x). Very little variation in these indices
in S. jarravi was explained however. There was no significant relationship
between the other two thermal tolerance indices and BM (P > 0.10 in both
cases).

Male and female S. jarravi did not differ in initial escape (df =
183, t = -0.9, P = 0.36), gaping temperature (df = 131, t = -0.0004, P =
1.00), and CTM (df = 189, t = 0.015, P = 0.99( (see Table 4). Females
had slightly higher mean continuous escape temperatures (df = 184, t = -
2.58, P = 0.0110 (see Table 4). Mean CTM varied from month-to-month
(Fig. 1; Kruskal- W allis : df = 7, H = 40.2, P < 0.0001). Individuals in the

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high-elevation population did not have a significantly different mean
CTM than individuals from the low-elevation population (41.5 ± 0.17 C
(N - 104) vs 41.4 ± 0.16 C (N = 83); df = 185, t = -0.45, p = 0.66).

Discussion and Conclusions

The mean CTMs of the five species used in this study ranged
from 41.4 C in S. virgatus and S. jarrovi to 44.1 C in P. asio. If only the
Sceloporus species are considered, the range is even smaller, with the
highest mean being S. scalaris at 42.3 C. Thus there appears to be little
difference in field-acclimated CTMs within the four species of Sceloporus.
However, the same could be said about the range of field active body
temperatures of these four species: S . virgatus 33.4 C (Smith and
Ballinger 1994a), S. scalaris 32.6 - 32.9 C (Smith et al. 1993), S. jarrovi
31.1 - 32.5 C (Smith and Ballinger 1994b), and S. mucronatus 31. 5 C
(Lemos-Espinal et al in press). Phrynosoma asio , on the other hand,
appears to have a higher CTM than any of the Sceloporus considered here.
The higher CTM may be a result of phylogenetic trends: Phrynosoma in
general may have higher thermal tolerances than Sceloporus. Indeed, a
study on P. cornu turn found a relatively high CTM after acclimation
(Ballinger and Schrank, 1970). Phrynosoma asio also has a higher mean
active body temperature than any of the Sceloporus (except S. virgatus)
studied here (33.0 C; Lemos-Espinal, Smith, and Ballinger, unpubl.).

In S. mucronatus , S. virgatus and S. scalaris , there were significant
positive regressions of CTM on body size. At least some of the other
indices of thermal tolerance in all five species were correlated with body
size (negatively in the case of P. asio, but positively in the other species).
These results suggest the possibility of ontogenetic changes in thermal
tolerance in these species. They also suggest a continuous shift in
tolerance rather than an abrupt switch at some threshold size. We found
a very weak relationship between CTM and body size in 5. jarrovi .
Biologically the relationships observed probably do not reflect a shift in
thermal tolerance during the life of S. jarrovi , since the amount of
variation in thermal tolerance explained by measures of body size is very
small. Other studies have failed to find significant differences in thermal
tolerance due to size (SpelLerberg 1972; Art and Claussen 1982) or age
(i.e., adult vs. juvenile, Paulissen 1988).

Thermal tolerances may vary from month to month or season to
season, just as preferred or activity body temperatures can (e.g.,
Patterson and Davies 1978; Smith et al. 1993; Smith and Ballinger

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1994a; Lemos-Espinal et al., 1997). For example, Larson (1961) found
that the critical thermal maximum (CTM) for Sceloporus occidentalis
differed between winter and summer. SpeUerberg (1972) found the same
to be true in many Australian lizards. Similarly, Heatwole and Firth
(1982) found that the voluntary maximum temperature of Amphibolurus
muricatus differed between fall and spring/ summer. For all three species
for which data were available, CTM varied throughout the year. Several
other studies have demonstrated similar trends in other species of
lizards (Larson 1961; Spellerberg 1972; Heatwole and Firth 1982).
Differences in thermal tolerances observed here may result from
differences in acclimation because of seasonal change in temperatures
experienced (individuals were not test at a single acclimation
temperature, but at field acclimated temperatures). Acclimation has
been shown to influence CTM in several species of lizards (Lowe and
Vance 1955; Larson 1961; Ballinger and Schrank 1970; Com 1971; Art
and Clauseen 1982), but Kour and Hutchison (1970) found no
acclimation effect in Sceloporus occidentalis. In addition to changes in
temperature, changes in photoperiod may also influence the thermal
tolerance of lizards (Lashbrook and Livezey 1970; but see Ballinger et al.
1969), suggesting seasonal changes in photoperiod may be influencing
the thermal tolerance of these three species, and resulting in the variation
observed in our study. Interestingly, S. virgatus maintain the same body
temperature in winter and summer (Smith and Ballinger 1994b), whereas
S. scalaris and S. jarrovi maintain higher body temperatures in summer
than in winter (Smith et al. 1993; Smith and Ballinger 1994a).

Over its elevational range in the Chiricahua Mountains, S. jarrovi
exhibits differences in life history characters, physiology, and thermal
ecology (Vinegar and Hillyard 1972; Ballinger and Newlin 1975; Ballinger
1979; Middendorf and Simon 1988; Smith and Ballinger 1994a, c; Smith
et al. 1994; Ballinger et al 1996), however in this study we did not
observe any differences between the CTMs of high and low elevation
populations of S. jarrovi. This is in contrast to the studies of Hertz and
his colleagues studying Anolis along an elevational gradient in Puerto
Rico (Hertz et al. 1979; Hertz 1981), and the study of Lemos-Espinal
and Ballinger (1995) on Sceloporus grammicus from 3700 m and 4600 m in
Mexico. These studied found that CTM tended to decrease with
increasing elevation.

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Acknowledgments

S. Sanoja and M. and S. Newlin assisted in collecting the data.
Comments on various versions of the manuscript by anonymous
reviewers have improved it. Fieldwork by REB was supported by NSF
Grants GB-35490 and BMS 72-022902A01. Data analysis and
manuscript preparation by GRS was supported by a Frank and Marie T.
Wheeler Fellowship from UNL, and by some logistic support from the
Kellogg Biological Station, Michigan State University.

Table 1. Indices of thermal tolerance for Phrynosoma asio and Sceloporus
mucronatus from Mexico. See text for abbreviations. N is given in
parentheses.

Phrynosoma asio

Sceloporus mucronatus

INTT

35.3 ± 0.3 C (31)

37.3 ± 0.3 C (16)

CONT

37.3 ± 0.3 C (31)

40.0 ± 0.4 C (16)

GAPE

40.5 ± 0.3 C (31)

38.6 ± 0.2 C (16)

cm

44.1 ± 0.2 C (31)

42.3 ± 0.6 C (16)

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Table 2. Indices of thermal tolerance for male and female Phrynosoma asio and
Sceloporus mucronatus from Mexico. See text for abbreviations. N is
given in parentheses.

Males

Females

Phrynosoma asio

ini r

35.1 ± 0.4 C (15)

35.4 ± 0.5 C (16)

CONT

37.2 ± 0.5 C (15)

37.4 ± 0.4 C (16)

GAPE

40.8 ± 0.5 C (15)

40.3 ± 0.4 C (16)

CTM

44.2 ± 0.5 C (15)

44.1 ± 0.2 C (16)

Sceloporus mucronatus

INK

37.1 ± 0.5 C (9)

37.7 ± 0.5 C (7)

CONT

40.6 ± 0.1 C (9)

39.2 ± 0.7 C (7)

GAPE

38.2 ± 0.2 C (9)

39.1 ± 0.3 C (7)

CTM

42.4 ± 0.1 C (9)

42.2 ± 0.3 C (7)

Table 3.

Indices of thermal tolerance for Sceloporus virgatus, S. scalaris, and S.
jarrovi from the Chiricahua Mountains of southeastern Arizona, USA.
See text for abbreviations. N is given in parentheses.

S. virgatus

S. scalaris

S. jarrovi

INK

31.3 ± 0.2 C (82)

34.9 ± 0.2 C (98)

30.8 ± 0.2 C (185)

CONT

36.6 ± 0.3 C (80)

38.3 ± 0.2 C (99)

38.4 ± 0.2 C (186)

GAPE

38.6 ± 0.3 C (59)

39.1 ± 0.3 C (64)

36.1 ± 0.2 C (133)

CTM

41.4 ± 0.3 C (83)

42.3 ± 0.2 C (99)

41.4 ± 0.1 C (191)

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Table 4. Indices of thermal tolerance for male and female Sceloporus virgatus, S.

scalaris, and S. jarrovi from the Chiricahua Mountains of southeastern
Arizona, USA. See text for abbreviations. N is given in parentheses.

Males Females

Sceloporus virgatus

INTT

31.3 ± 0.2 C (54)

31.3 ± 0.3 C (28)

CONT

36.4 ± 0.4 C (52)

36.9 ± 0.5 C (28)

GAPE

38.4 ± 0.4 C (37)

38.9 ± 0.4 C (22)

cm

41.5 ± 0.4 C (55)

41.4 ± 0.3 C (55)

Sceloporus scalaris

INK

35.0 ± 0.4 C (23)

35.5 ± 0.2 C (62)

CONT

38.4 ± 0.2 C (23)

38.4 ± 0.2 C (63)

GAPE

38.9 ± 0.4 C (17)

39.3 ± 0.4 C (42)

CTM

42.8 ± 0.2 C (23)

42.7 ± 0.2 C (63)

Sceloporus jarrovi

INK

30.7 ± 0.2 C (101)

31.0 ± 0.2 C (84)

CONT

38.0 ± 0.2 C (103)

38.8 ± 0.2 C (83)

GAPE

36.1 ± 0.3 C (69)

36.1 ± 0.3 C (64)

CTM

41.4 ± 0.2 C (105)

41.4 ± 0.1 C (86)

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Figure 1. Variations in CTM as a function of month in Sceloporusxnrgatris (open
circles), S. scalaris (closed circles), and S. jarrovi (closed rectangles)
from the Chiricahua Mountains of southeastern Arizona. Bars are ±
1SE.

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March 1998

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1982. The rate of thermal acclimation in the lizard, Anolis
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Heatwole, H. and B. T. Firth.

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_____ , and Jarabia, and G. R. Smith.

MS. Thermal ecology of the lizard Sceloporus mucronatus
mucronatus in Sierra del Ajusco, Mexico. Southwest. Nat.
In press.

_____ , G. R. Smith, and R. E. Ballinger.

1997. Thermal ecology of the lizard, Sceloporus gadoviae, from
an arid tropical scrub forest. J. Arid Environ. 35: in press.

Lowe, C. H., and V. J. Vance.

1955. Acclimation of the critical thermal maximum of the
reptile Urosaurus omatus . Science 122: 73-74.

Middendorf, G. A., and C. A. Simon.

1988. Thermoregulation in the iguardd lizard Sceloporus jarrovi:
the influences of age, time, and light conditions on body
temperature and thermoregulatory behaviors. Southwest.
Nat. 33: 347-356.

Patterson, J. W., and P. M. C. Davies.

1978. Preferred body temperature: seasonal and sexual
differences in the lizard Lacerta vivipara. J. Therm. Biol. 3:
39-41.

Paulis sen, M. A.

1988. Ontogenetic comparison of body temperature selection
and thermal tolerance of Cnemidophorus sexllineatus. J.
Herpetol. 22: 473-476.

Pough, F. H. and C. Cans.

1982. The vocabulary of reptilian thermoregulation. In C. Cans
and F. H. Pough (eds.) Biology of the Reptilia, Vol. 12:
Physiology c. pp. 17-23. Academic Press, New York.

Smith, G. R. and R. E. Ballinger.

1994a. Temperature relationships in the high-altitude viviparous
lizard, Sceloporus jarrovi. Am. Midi. Nat. 131: 181-189.

1994b. Thermal ecology of Sceloporus virgatus from southeastern
Arizorda, with comparison to Urosaurus omatus . J.
Herpetol. 28: 65-69.

1994c. Temporal and spatial variation in individual growth in
the spiny lizard, Sceloporus jarrovi. Copeia 1994: 1007-
1013.

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_ , and J. D. Congdon.

1993. Thermal ecology of the high-altitude bunch grass lizard,
Sceloporus scalaris. Can. J. Zool. 71: 2152-2155.

_ _ , and J. W. Nietfeldt.

1994. Elevational variation in growth rates in neonate Sceloporus
jarrovi: an experimental evaluation. Funct. Ecol. 8: 215-
218.

Spellerberg, I. F.

1972. Temperature tolerances of southeast Australian reptiles
examined in relation to reptile thermoregulatory behavior
and distribution. Oecologia 9: 23-46.

Vinegar, A., and S. D. Hillyard.

1972. The effects of altitude on oxygen-binding parameters of
the blood of the iguanid lizards, Sceloporus jarrovi and
Sceloporus occidentals. Comp. Biochem. Physiol. 43A: 317-
320.

Vinegar, M. B.

1975. Demography of the striped plateau lizard, Sceloporus
virgatus. Ecology 56: 172-182.

School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588,
USA (REB); Labor atorio de Investigacion en Conservacion , Universidad
Nacional Autonoma de Mexico , Campus Iztacala, Apartado Postal 314,
Tlalnepantla, Edo. de Mexico, Mexico ( JAL-E ); Department of Biology,
William Jewell College, Liberty, Missouri 64068, USA (GRS; correspondence

author)

Received: 18 March 1997
Accepted: 27 April 1997

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HYPOCALCEMIA IN IGUANAS

Thirty-nine iguanas under one year of age were evaluated
over a three-month period in order to determine their calcium
levels as part of their routine physical examinations or for other
medical purposes. The iguanas were brought to the clinic for
one or more of the following reasons: new pet, anorexia, lack of
movement, swollen jaws or legs, kyphoscoliosis and weakness.
For a variety of reasons, not all iguanas seen in this time period
were tested. Blood calcium levels ranged from 3.0 to 14.5 with
an average of 7.6 (normal 8.0 - 15.0). Low calcium was detected
in 55% of the animals (21 out of 38) with the largest distribution
of calcium levels in the 5.0 - 6.9 range. In iguanas with low
blood calcium, the most common findings included improper
diet, improper environmental temperature and lack of full
spectrum lighting in the animals' habitats. Many of the iguanas
experienced concurrent problems such as bacterial infections,
endo- and exoparasites, starvation and trauma.

Iguanas are becoming increasingly popular as pets. They are
offered for sale at prices as low as $15.99. Most, however, are never seen
by a veterinarian. A three-month study was undertaken at our facility in
order to determine the incidence of hypocalcemia in iguanas under one
year of age. In this time period, approximately seventy-five iguanas were
examined for a variety of reasons. The study was limited to subjects
under one year of age, since these are the animals most commonly sold
through pet stores. Many people had purchased the iguanas on impulse
and had no idea what to feed them or how to care for them. Most
iguanas (approximately 90%) were kept at suboptimal temperatures.
Ninety-five percent of the animals had endoparasites (pinworms). Full
spectrum lighting was absent or used improperly in 85% of the cases.
Blood calcium levels were determined in 38 individuals. Blood was
drawn from the ventral tail vein into red top tubes and was spun and
separated. Blood calcium levels were determined by commercial
laboratories. The levels ranged from 3.0 to 14.5 with an average of 7.6
(normal 8.0 - 15.0). Low calcium was detected in 55% of the subjects (21
of 38) with the largest distribution of levels in the 5.0 - 6.9 range (Fig. 1).
Eighty-four percent of the animals (32 of 38) showed evidence of
metabolic bone disease (MBD). MBD usually results from a low calcium
diet, but it may also be caused by lack of vitamin Ds, excessive dietary
phosphorus and, in rare cases, kidney, parathyroid, thyroid or liver
disease (Boyer, 1991). Signs of MBD include flexible mandible (rubber

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jaw - usually the first sign), round skull, failure to grow, long bone
fractures, inability to move rapidly or raise the body off the ground,
anorexia, twitching of the toes and limbs, scoliosis and kyphosis.
Diagnosis of MBD is based upon clinical signs, blood calcium levels and
radiographs.

Low blood calcium appears to be a frequently-encountered
problem. Eighty-four percent of the iguanas under study displayed
evidence of MBD. Hypocalcemia was detected in 55% of the iguanas
through blood (serum) determination. The difference (29%) between the
individuals who showed evidence of MBD and those detected via blood
determination results from the fact that in individuals with early cases of
MBD, the blood calcium levels have not yet dropped, and the body is
maintaining normal serum calcium levels by drawing upon tone
reserves. Causes of low blood calcium include low amounts of calcium
in the diet (most common cause), vitamin D3 deficiency,
hypomagnesium, metabolic acidosis, hypoparathroidism, excess urinary
loss, steatorrhea, glucose and other rapidly-metabolized foods and
excessive phosphorus (Lindman, 1967; Shils, 1970; Levy et al, 1974;
Lewis, Morris, Hand, 1989; Boyer, 1991). The diets that were fed to the
iguanas were lacking not only in calcium but in most other nutrients as
well. Most of the iguanas were offered lettuce, strawberries, melon,
crickets and meal worms. The tody of knowledge regarding the dietary
requirements of iguanas is still in its infancy. It is currently
recommended for growing animals up to two years of age that the diet
be 80% plant-based and 20% protein-based (Boyer, 1991). Plant-based
foods offered should be predominantly high-fibrous, calcium-rich foods
(collard greens, turnip greens, mustard greens, alfalfa, dandelions). If
fed excessively, broccoli, kale, bok-choy, cabbage and related vegetables
may be goiter genic. Fibrous greens should comprise 50% of the diet;
thirty percent of the diet can consist of string beans, carrots, peppers,
spinach, squash, bean sprouts, hibiscus flowers, nasturtiums and
mulberry leaves. Fruits should be regarded as treats, fed to the iguana as
one would feed a biscuit or a piece of rawhide to a dog. When compared
with vegetables, fruits prove to be poor in nutritional value, and the
sugar/ starch content may induce abnormal hindgut fermentation. In the
wild, green iguanas are folivores and at all ages of their life do not
consume insects, arachnids, eggs or meat (Barbour, 1997; Iverson, 1980,
1982; Round et al, 1990). Animal protein based diets and high protein
fat diets should not be fed (Barbour, 1997; Iverson, 1980, 1982; Rand et
al., 1990).

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Full spectrum lighting is required in order to maintain health.
Ultraviolet light can be divided into UVA (blackKght, longwave,
nearwave), UVB (middlewave, erythermal) and UVC (farwave,
shortwave, germicidal) (Alberts, 1992) (Fig. 2). UVA and UVB are
essential for good health (Gehrman, 1994). UVA results in brighter, more
vibrant color and increase in appetite and reproductive behavior. UVB
induces a chemical reaction in the skin for the production of vitamin Ds
(Alberts, 1994; Bernard, 1991; Barbour, 1997), Research has shown that
iguanas fed a diet that was rich in calcium and vitamin Ds and iguanas
injected with supplemental vitamin D3 fared poorly compared to
individuals that were exposed daily to ultraviolet light (Bernard, 1991).
When using the more frequently-sold lights, the distance from the light to
the reptile should be no more than 18 inches; any questions should be
directed to the manufacturer. Artificial lights, however, are not a
substitute for sunlight and direct sunlight should be used whenever
possible.

The correct environment temperature for iguanas should range
from approximately 95° to 105° during the day with a slight decrease at
night. At this temperature, appetite and activity are improved. In
addition, this temperature allows for proper hindgut fermentation.
Lower temperatures result in incomplete or partial
digestion/fermentation and may alter bacterial flora.

To summarize, iguanas are becoming more popular as pets
because of their low initial cost. Most iguanas, however, are never
presented to veterinarians for physical examinations. Many people object
to spending money on health care for a reptile for which they only paid
$15.00 or $20.00. As a result, most iguanas die within a relatively short
period of time. The majority of iguanas present to veterinarians show
signs of illness. Unless proper nutritional needs, environmental
temperature and lighting requirements are met, most can be expected to
perish.

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Figure 1. Calcium levels of green iguanas seen during a three month period in
private veterninary practice.

Calcium level (mg/dl)
3.0 - 3.9
4.0 -4.9
5.0 - 5.9
6.0 - 6.9
7.0 - 7.9
8.0 - 8.9
9.0 - 9.9
10.0 - 10.9
11.0 - 11.9
12.0 and up

Number of iguanas
3 ”

3

6

7

3

2

5

5

3

2

39

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Literature Cited

Alberts, A. C.

1994. Ultraviolet visual sensitivity in desert iguanas:
implications for pheromone detection. Arum. Behav, 38:
129-137.

Barbour, T.

1997. About Iguanas. Copeia, 1932.

Bernard, J. S. et al.

1991. The response of vitamin D deficient iguanas (Iguana

Boyer, T.

1991.

iguana) to artificial ultraviolet light. Proc. Am. Assoc.
Zoo Vet.: 147-150.

Common Problems and Treatment of Green Iguanas.
AARV, vol. 1, no. 1.

Gehrman, W. H.

1994. Spectral Characteristic of Lamps commonly Used in

Herpetoculture. Vivarium 5(5): 16-21.

Iverson, J. B.
1980.

Colic Modifications in Iguanine Lizards. J. Morphol, 163:
79- 93.

1982.

Adaptations to herbivory in Iguanine lizards, in G. M.
Burghardt and A. S. Rand (editors) Iguanas of the
World: Their behavior, ecology, and conservation. Noyes
Publishers, Park Ridge, NJ, pp 320-341.

Levy, J. et al
1974.

Hypocalcemia in Mg Depleted Dogs. Metabolism, 23:
323.

Lewis, L. D., M. L. Morris, and M. S. Hand.

1989. Small Animal Clinical Nutritions. 3rd Edition, Mark
Morris Assoc.

Lindman, R. D.

1967. Influence of Various Nutrients on Urinary Divalent
Cation Excretion. J La B Clin Med, 70: 236.

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Rand et al.

1990. The diet of generalized folivore: Iguana iguana. ]. Herpt,
24: 211-214.

Shils, M. E.

1970. Experimental Human Mg Deficiency. J. Clia, Invest, 49:
1619.

— Thomas Ryan , DVM, Feathers, Scales and Tails Vet. Hospital, 330 One
Forty Village Road, Westminister, MD 21157.

Received: May 6, 1997
Accepted: June 1, 1997

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March 1998

STATUS OF CHORUS FROGS (GENUS PSEUDACRIS)
IN SOUTHEASTERN COLORADO

Lauren J. Livo, Geoffrey A. Hammerson, Hobart M. Smith, David
Chiszar, and Stephen P. Mackessy

A gap exists in the distribution of chorus frogs in
southeastern Colorado. New locality records extend the known
range of chorus frogs in this area. The factors responsible for
this distributional hiatus remain unknown, as does the specific
identity of chorus frogs from this part of the range of the genus
Pseudacris.

Chorus frogs ( Pseudacris triseriata) are abundant and widespread
in many areas of North America. However, existing information suggests
that only a few widely scattered populations exist in the western Great
Plains region south of the Platte River drainage (Conant and Collins
1991). A large distributional hiatus extends across southeastern
Colorado (Hammerson 1982) and southwestern Kansas (Collins 1993).
Herein we report several new records from southeastern Colorado,
extending the known range of Pseudacris eastward approximately 20 to
60 km in the Colorado portion of the distributional gap.

The area bounded by latitudes 37° and 39° North and longitudes
105° and 102° West encompasses the southeastern portion of Colorado
as well as a very narrow strip of extreme western Kansas. Within this
area, almost all of which is in the Arkansas River drainage, only five
Pseudacris localities were mapped by Hammerson (1982) and none by
Collins (1993). Since the publication of Hammerson (1982), several new
county records have been documented in southeastern Colorado,
including Crowley (Bergman et al. 1996), Huerfano and Las Animas
(Livo et al. 1995), and Kiowa (Mackessy et al. 1996) comities. Platz
(1989) provided an additional published record for Lincoln County.
Figure 1 shows these published localities as well as several previously
unpublished localities. Localities are listed alphabetically by county in
the appendix.

These records more than triple the number of known Pseudacris
localities from the lower Arkansas drainage in southeastern Colorado.
The new localities also help to fill in a major distributional gap between a

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single record of Pseudacris collected in 1963 along the Cimarron River in
extreme southeastern Colorado (UCM 32682) and the nearest localities
to the north and northwest (Hammer son 1982:35). Similar gaps exist
between die Cimarron River locality and localities to the east and south
in Kansas, Oklahoma, and to a lesser extent. New Mexico (see range
maps in Black and Sievert 1989, Collins 1993, Stebbins 1985, and
Degenhardt et al. 1996).

Suitable habitat for Pseudacris exists within the distributional
hiatus, mid there are no abrupt changes in vegetation, soils, or land
forms between occupied and apparently unoccupied areas (Kiichler
1966, Hammond 1980, Hunt 1979). Additional field work is warranted,
especially during the calling season, to determine whether the remaining
distributional gap for Pseudacris is real or simply an artifact of the cryptic
behavior of these small frogs outside of their calling season.

In addition, the specific identity of the chorus frogs in
southeastern Colorado remains a matter to be determined. The chorus
frog present in Colorado and throughout western North America
generally has been regarded to be Pseudacris triseriata. Recently, Platz
(1989) examined call and morphological attributes of three Pseudacris
populations in Colorado and suggested that two species (P. triseriata
and P. maculata) are present, with both occurring in the region from
which our new records derive. Detailed analysis is required to
differentiate between these two taxa. Hence, precise boundaries and
possible areas of sympatry for these taxa remain to be elucidated in
eastern Colorado.

Further, chorus frogs in Colorado exhibit a wide range in
morphological and ecological variation (Pettus and Spencer 1964; Pettus
and Angle ton 1967; Miller 1977), including in large areas not sampled by
Platz (1989). This leads to the possibility of additional, undescribed
taxa. Until more detailed studies of genetic, morphological, and call
variations are made, we feel that the species-level taxonomic status of
Pseudacris in Colorado should be regarded as unresolved.

Acknowledgments

Several students participated in observations of chorus frogs in
southeastern Colorado, including Enoch Bergman, Ron Donoho, Justin
Hobert, Chad Montgomery, and Kevin Waldron. We also appreciate the
constructive comments of an anonymous reviewer.

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Figure 1. Distribution of Pseudacris in southeastern Colorado (Closed circles-
Localities mapped in Hammerson (1982); Closed rectangles - Locality
reported by Plate (1989); Closed triangles » Localiti.es reported in this
paper, also including Bergman et al. (1996), Livo et al. (1995), and
Mackessy et al. (1996), Some adjacent localities are represented by a
single symbol.

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March 1998

Literature Cited

Bergman, Enoch, Scott Boback, Ben Hill, Justin Hobert, Chad
Montgomery, and Stephen P. Mackessy.

1996. Geographic distribution: Pseudacris triseriata metadata.
Herp. Rev. 27(4):209.

Black, Jeffrey H,. and Gregory Sievert.

1989. A field guide to amphibians of Oklahoma. Oklahoma
City: Oklahoma Department of Wildlife Conservation.

Collins, Joseph T.

1993. Amphibians and reptiles in Kansas, 3rd ed. Univ.
Kansas, Mus. Nat. Hist., Publ. Ed. Ser. No. 13.

Conant, Roger, and Joseph T. Collins.

1991. A field guide to reptiles and amphibians: Eastern and
central North America, 3rd ed. Boston: Houghton Mifflin
Co.

Degenhardt, William G., Charles W. Painter, and Andrew H. Price.

1996. Amphibians and reptiles of New Mexico. Albuquerque;
University of New Mexico Press.

Hammerson, Geoffrey A.

1982. Amphibians and reptiles in Colorado. Denver: Colorado
Division of Wildlife, Publ. No. DOW-M-I-3-82.

Hammond, Edwin H.

1980. Classes of land-surface form [map]. U. S. Geological
Survey, Reston VA, 22092, sheet no. 62.

Hunt, Charles B.

1979. Surficial Geology [map]. U. S. Geological Survey, Reston
VA, NAC-P-0204-75M-0.

Kiichler, A. W.

1966. Potential Natural Vegetation [map]. U. S. Geological
Survey, Reston VA, 38077-AH-NA-07M-00.

Livo, Lauren J., David Chiszar, and Hobart M. Smith.

1995. Geographic distribution: Pseudacris triseriata. Herp. Rev.
26(4) :208.

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Mackessy, Stephen P., Ron Donoho, Justin Hobert, Chad Montgomery,

and Kevin Waldron.

1996. Geographic distribution: Pseudacris triseriata maculata.
Herp. Rev. 27(1):30.

Miller, Paul H.

1977. A demographic study of die chorus frog, Pseudacris
triseriata. M. S. thesis, Colorado State University, Fort
Collins, Colorado.

Platz, James E.

1989. Speciation within the chorus frogs Pseudacris triseriata :
Morphometric and mating call analyses of the boreal and
western subspecies. Copeia 1989:704-712.

Pettus, David, and George M. Angleton.

1967. Comparative reproductive biology of montane and
piedmont chorus frogs. Evolution 21:500-507.

Pettus, David, and Albert W. Spencer.

1964. Size and metabolic differences in Pseudacris triseriata
(Anura) from different elevations. Southwest. Nat. 9:20-
26.

Stebbins, Robert C.

1985. A field guide to western reptiles and amphibians, 2nd
ed. Boston: Houghton Mifflin Co.

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Appendix

Cheyenne: Ca. 50 frogs observed by S. P. Mackessy and students at
pond on Co. Rd. 9 0.8 mi Sjct Co. Rd. T (30 July 1996).

Crowley: Specimen collected (UNC-MNH #278) by S. P. Mackessy
and students at pond on Co. Rd. 27 4.2 mi Sjct Lincoln Co. Rd. D (4 June
1996) (Bergman et al. 1996); 4 adult frogs observed by S. P. Mackessy and
students at pond on Co. Rd. BB 0.5 mi E jet Hwy 71 (4 June 1996).

Huerfano: Two specimens collected (UCM 57333-4) by L. J. Livo,
D. Chiszar, andH. M. Smith on 19 May 1995 at 1.1 km east, 0.1 km south
junction of Cucharas River with Walsen Arroyo (T27S, R65W, SE 1/4
Section 30) (Livo et al., 1995) and a chorus heard on 19 May 1995 by L. J.
Livo, D. Chiszar, and H. M. Smith from wetlands at south end of Maria
Reservoir (T27S, R65W, W 1/2 Section 28).

Kiowa: W side County Hwy 109, 0.1 mi S jet county road T
(Mackessy et al., 1996); 2 frogs and numerous tadpoles observed at roadside
pond on Co. Rd. 2 4.1 mi S Lincoln Co. line (5 June 1996); chorus heard at
pond on Hwy 96 2.7 mi E jet Co. Rd. 3 (20 June 1996).

Las Animas: Chorus heard by L. J. Livo on 24 May 1995 at junction
of Apishapa River and Trujillo Creek (T3 IS, R65W, Section 18) southwest of
Aguilar (Livo et al., 1995). Choruses heard by G. A. Hammer son on 17 June
1993 from four localities ranging from 2.4 to 9.6 km east of Beshoar in
T32S, R62W. Probable sections were 25, 22 or 27, 23 or 26, and 30.

Lincoln Co: Platz (1989) reported chorus frogs from Lincoln Co., 3
km west Aroya. S. P. Mackessy and students have observed chorus frogs from
the following additional localities: 200 m W of county road 43, 1 .0 mi N jet
county road U; on S side of county road N ca. 0.3 mi E jet county road 31; 4
frogs observed Co. Rd. M 1.0 mi E jet Co. Rd 22 (20 August 1996); ca. 50
tadpoles (3 July 1996) and 50 froglets (13 August 1996) observed pond NE
comer jet Co. Rd. M and Co. Rd. 22; 25 frogs, including 5 amplexing pairs,
observed ca. 0.5 mi W of Co. Rd. 43, 1.3 mi Sjct Hwy. 94 (1 June 1996); 2
frogs observed at pond on S side of Hwy 94 0.1 mi E jet Co. Rd. 32 (10 June
1996); 4 frogs observed and ca. 15 heard calling at pond on Co. Rd. 32 0.5 mi
N jet Co. Rd. F (10 June 1996); 3 adult frogs and numerous tadpoles observed
at pond on Co. Rd. 43 4.7 mi S jet Hwy 94 (5 June 1996); 1 adult and 3
tadpoles (regurgitated by Thamnophis radix) observed at pond on Co. Rd. 43
0.4 mi S jct Co. Rd. U (5 June 1996); 1 frog observed in ditch pond on Co.
Rd. 32 0.4 mi Sjct Co. Rd. F (5 June 1996); chorus heard at pond on Co. Rd.
32 at jet Co. Rd. N (14 June 19%); chorus heard at pond on Co. Rd. 32 0.8
mi N jet Co. Rd. W (21 June 1996); choms heard at pond on Co. Rd. 32 1.3
mi S. jet Hwy 94 (21 June 1996); chorus heard at pond on Hwy 94 0.6 mi W

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jet Co. Rd. 32 (21 June 1996); pond on Co. Rd. G 1.9 miles west of
Cheyenne/Kiowa County lines (5 August 1996).

Otero: Chorus heard on 10 June 1988 by G. A. Hammerson east of
Fowler (T22S, R59W, Section 1 5 or 22).

Pueblo: Chorus heard on 29 May 1995 by L. J. Livo from a marshy
area 5 km west and 2 km south Boone along U. S. Highway 50 (T21S, R62 W?
S 1/2 Section 10).

Department ofEPO Biology ; University of Colorado, Boulder ; Colorado ,
80309-0334 USA (LJL, HMS); The Nature Conservancy ; 201 Devonshire St v
Boston , Massachusetts 02110 USA (GAH); Department of Psychology,
University of Colorado, Boulder, Colorado 80309-0345 (DC); Department of
Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639

(SPMf

Received: May 6, 1997

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A COMPARISON OF THE FEEDING BEHAVIOR OF
TWO PIPIDS, XENOPUS LAEVIS, AND
HYMENOCHIRUS BOETTGERI WITH EMPHASIS ON
THE USE OF THE FORELIMBS

Typical pipid feeding behavior consists of shoveling food
into the mouth by use of the forelimbs. Xenopus laevis displays
this behavior. Hymenochirus boettgeri does not use its hands in
the typical pipid mode as the webbing between the toes of the
forelimbs may make this behavior maladaptive due to potential
reduced respiratory capacity, increased susceptibility to
predation, and reduced foraging efficiency. Both species utilize
the claws on the hind feet to assist in feeding.

Introduction

Anurans of the family Pipidae are well adapted to a thoroughly
aquatic existence. Their broad flattened bodies, retention of larval lateral
line systems, and loss of a tongue and eyelids have resulted in behaviors
unique to this primitive Aglossid family. One of these behaviors involves
the use of the forelimbs while feeding and foraging (Halliday and Adler,
1987; Wagner, 1955). Most anurans utilize their pectoral limbs to some
extent while feeding. Xenopus laevis (African clawed frog), like most
Pipids, use their "hands" extensively to shovel food into their mouth
(Wagner, 1955). Hymenochirus boettgeri (dwarf African clawed frog),
though, has webbing between the digits of its forelimbs. (Terent'ev,
1965). This fact makes feeding with its forelimbs in typical pipid fashion
more difficult.

There is a definite paucity of data concerning the behavior of H.
boettgeri except in its breeding (Rabb & Rabb, 1963) while X. laevis has
been more thoroughly studied due to its use in medical research
(Stewart, 1967). My study compares the use of the forelimbs while
feeding in these two species. I also describe some associated feeding and
locomotory behaviors in these two species.

Materials and Methods

Five 2 to 5 cm Xenopus laevis were housed individually in 4 L
squat fish bowls. The fish bowls were 3/4 filled with water without any

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gravel or other amendments. These subjects were fed a varied diet of live
earthworms (large and small). Jive adult guppies, live and dead
arthropods, dry flaked and pelleted fish food, and raw meat.

Three 2 to 3 cm Hymenochirus boettgeri were housed communally
in a 40 L aquarium. The aquarium was filled with water and contained
floating Ceratophyllum sp. for the frogs to rest in, VaUisneria spiralis rooted
in a gravel substrate, and several small stones and pieces of driftwood
for hiding places.

The aquarium was filtered with an air-lift undergravel filter. Two
more H. boettgeri were housed in a 4 L "pickle jar" with a few sprigs of
Cobomba sp. rooted in a gravel substrate, and a few small stones. H.
boettgeri were fed small live earthworms, pieces of large live earthworms,
live baby guppies, live brine shrimp, live freshwater amphipods, and dry
flaked and granular fish food.

Results and Discussion

These two species share some feeding behaviors in common, but
their foraging strategies and methods of handling food items differ
substantially.

Description of Xenopus laevis Feeding Behavior

Xenopus laevis utilizes both a sit-and-wait and an active hunting
approach to foraging. The sit-and-wait approach I observed was similar
to that briefly described by Halliday and Adler (1987). When using a sit-
and-wait strategy X. laevis spends considerable time in shallow water
resting on the claws of the hind feet with only the eyes and nostrils
penetrating the surface film. Their forelimbs are positioned anteriorly,
with the palmar regions held supinate and the elbows flexed slightly in
anticipation of prey capture. These frogs will remain in this position for a
considerable duration if a prey item is suspended in view above the
water surface, but out of reach. If die item drops into the water, X. laevis
immediately lunges at and grabs the prey with its forelimbs. The frog
then forces the victim into its mouth using its forelimbs to "shovel" the
item into its mouth in typical Pipid fashion.

X. laevis also utilizes an active, hunting approach to foraging.
This tactic is used while submerged. The frog swims in a random pattern
along the substrate with both forelimbs positioned as previously

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Volume 34 Number i

described. It will swim two or three strokes with its hind legs, then tilt its
head towards die ground. The frog will reach into crevices between the
gravel with its "hands", and in a circumductive movement of the
forearm sweep detritus into its mouth. Then with a chewing motion, the
frog will spit out inedible portions of this material. If a large item, such
as a 4 or 5 cm earthworm is found, X laevis will hold it between the
fingers. Then with alternating movements of the left and right arm, it will
move the prey into and out of die mouth. The frog continues
manipulating the worm until it is positioned satisfactorily, then
swallows it

If the worm is too large to swallow, X. laevis will reach cranially
with one or both of its hind feet (while holding the worm with both its
jaws and fingers). With the plantar region facing anteriorly, the frog digs
its claws into the top of die prey to tear off the protruding portion. The
portion in its grasp is then swallowed. The use of these claws in feeding
was briefly described by Wagner (1955) and as a facilitator to ecdysis by
Me Callum (1997).

Description of the Feeding Behavior of Hymenochirus boettgeri

The feeding behavior and use of the forelimbs by Hymenochirus
boettgeri differs substantially from X. laevis. The former does not hunt or
feed with its forelimbs in typical Pipid fashion. The forelimbs are not
adducted while swimming as in most frogs, or held forward in typical
Pipid fashion for feeding. Instead, the forelimbs are held pronate and
used actively for swimming. When swimming to the surface for air, H.
boettgeri uses the front limbs in either a breast stroke or dog paddle
motion.

The front limbs are also used during foraging to turn over small
pebbles or pieces of plant material, and to dig in the gravel for small
worms and invertebrates. This species is not a sit-and-wait forager. It
spends its time actively climbing about in vegetation, and scouring the
substrate for prey. When it finds a small prey item, H. boettgeri moves
stealthily towards it. Once dose enough it lunges at the victim, using
both the front and hind legs for propulsion (only the hind limbs are used
for propulsion by X. laevis ). The prey will be grabbed with the mouth
only, and swallowed.

If this prey is large, H. boettgeri first attempts to tear it apart
using its forelimbs by reaching cranially with the palmar region held
pronate and digging the terminal phalanges into the prey. Using an

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abductive movement of the forelimb, the frog attempts to tear off the
protruding portion.

If this tactic is unsuccessful, the grog will use its hind legs as
described in X. laevis . Hymenochirus boettgeri , however, does not hold die
prey with its hands. This species is able to catch small fish fry,
crustaceans, and other animals in this fashion. Undoubtedly the more
binocular position of its eyes, not dorsal as in X. laevis, , aid the
effectiveness of this strategy.

The active foraging displayed by X. laevis would be less effective
with webbed hands. This behavior would not sweep items into the
mouth, but away from it like waving a paper fan at your face on a hot
day. Furthermore, frogs with webbed feet that handle prey in typical
Pipid fashion may damage this webbing, especially if the prey is small
crayfish or other arthropod. Such injuries could subject these individuals
to infection, and the frogs could temporarily lose the ability to swim with
their front limbs. This could impede both prey capture and escape from
predators.

Such damage could also impair the frog's respiratory capacity,
as the well vascularized webbing of some Pipids has been suggested as
an accessory respiratory organ (Wagner, 1955). If title webbing were
damaged, this active hunter could experience reduced endurance while
foraging due to lower oxygen uptake and carbon dioxide dissapation.
The lowered respiratory capacity experienced due to webbing damage
could also result in more frequent trips to die surface to breath. These
frogs could be more frequently susceptible to predation from above
while breathing, and would likely be more frequently susceptible to
aquatic predators during trips from the substrate to die surface. These
factors likely selected against primitive H. boettgeri that used their
forelimbs for feeding.

No other Pipid genera endemic to either South America or Africa
are known to display either webbed front feet, or H. boettgeri' s atypical
Pipid feeding behavior, Hus seems to indicate that these characteristics
have evolved recently in H. boettgeri from a typical Pipid ancestor.
Consequently, tihese are probably advanced, not primitive, characteristics
evolved for an aquatic active forager's lifestyle.

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Literature Cited
Halliday, T. R., and K. Adler.

1987. The Encyclopedia of Reptiles and Amphibians. Equinox,
Oxford.

Me Callum, M.

1997. Use of the claws to facilitate eedysis in the African
clawed frog ( Xenapus laevis). Bull. Chicago Herpet. Soc.
32:28.

Rabb, G. B., and M. S. Rabb.

1963. On the behavior and breeding biology of the African
pipid frog Hymenochirus boettgeri. Z. Tierpsychol. 20: 215-
241.

Stewart, M. M.

1967. Amphibians of Malawi. State University of New York
Press, New York.

Terent'ev, P. V.

1965. Herpetology. Israel Program for Scientific Translations,
Jerusalem.

Wagner, V. A.

1955. The Platanna(Xenopws laevis). African Wildlife Mag. 9:49-

53.

1965. The Frogs of South Africa. Rustica Press, Cape Town.

— Malcolm L. Me Callum , Department of Biology, Health, and Physical
Education, Belleville Area College, 2500 Carlyle Avenue, Belleville,
Illinois 62223 USA.

Received: 9 July 1997
Accepted: 4 August 1997

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March 1998

FIELD OBSERVATIONS ON THE BEHAVIOR OF
CHIHUAHUAN SPOTTED WHIPTAIL LIZARDS
( CNEMIDOPHORUS EXSANGUIS)

Hobart M. Smith, David Chiszar, Clint Henke, Julio A. Lemos-Espinal

and Frank van Breukelen

Burrowing and foraging behavior of two Cnemidophorus
exsanguis in southwestern New Mexico is described. The hind
legs were not used in burrowing, except for locomotion - only
the forelegs, in both excavation and clearance. The elevated
scanning posture, frequently intervening between excavation
and clearance episodes, was assumed with brief initial vertical
vibration of the head, and occasionally accompanied by spastic,
digging-like movements of the free foreleg. The lizards were
wary of large moving objects but unconcerned with stationary
ones.

On June 11, 1997, one of us (HMS) was stationed for a few hours
on the continental divide at 1890 m in the San Luis Mts. of Hidalgo Co.,
southwestern New Mexico, between Barnett and Whitewater canyons, on
the north slope of Lang Peak (2060 m), while others in the party climbed
the peak. The locality is about 2 km north of the new Mexico/ Chihuahua
border.

Between 10:00 and 11:30 a.m., two large adult, apparently
gravid Cnemidophorus exsanguis were observed as they moved about
within a few square meters of the road. The literature on this species is
remarkably extensive (Stuart, 1991) in view of its relatively recent
recognition (Lowe, 1956), but we are aware of no previous description of
several behaviors here recorded.

Of special interest is the burrowing behavior of one of the lizards.
It worked some 45 min on a burrow constructed de novo under a small
stone (about 3x20x6 cm) on top of a mound of earth on one side of the
road, created by a road scraper. The burrow, with two exits as well as
the one entrance, ultimately collapsed after being dug some 20 cm under
the rock.

The burrow was started by swipes of the forelegs, used
alternately two or three times each. As displaced soil accumulated in

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front of the burrow, the lizard would turn around and, holding the soil
between the outstretched forelegs and the fore part of body, would push
the soil away like a miniature, animated bulldozer. After two or three
passes that cleared the displaced soil away, the lizard would turn
around and resume digging, again with the forelegs. The burrow
eventually was deepened enough that the body of the lizard was
completely concealed, only part of the tail visible. At no time were the
hind legs used directly for either excavation or clearance.

Initially the observer stood 2-3 m from the burrowing lizard,
during which time it moved steadily between episodes of excavation and
clearance. When the burrow was deep enough to prevent the lizard from
seeing external movements while excavating, the observer changed to a
sitting position 1.2 m from the burrow. Thereafter, the lizard regularly
stopped still for 10-20 seconds, half-emerged from the burrow,
apparently scanning the vicinity for any threat, before resuming clearing
efforts. So posed, the fore part of body was held up by one or both
forelegs extended vertically, but the body was held still and the head
turned slightly no more than once or twice.

While scanning, the lizard exhibited two remarkable behaviors.
Immediately upon adoption of the scanning stance, the lizard vibrated
die head vertically over a distance of no more than 2-3 mm, for just a
fraction of a second, then held still. The function of the vibration was not
evident, but may well be bathyoptic and stereoscopic (facilitating
distance and depth perception, and three-dimensional vision), as is
apparently one function of the conspicuous push-ups of many
phrynosomatid (and other) lizards (Walls, 1967: 342) - a function that
has been very little explored whereas the social function of "signature
displays" (Ferguson, 1977: 409-411) has dominated the literature on the
subject. Maximum depth-perception could well be achieved by a much
smaller movement arc in active, foraging lizards such as Cnemidophorus
than would be the case in less active, ambushing lizards such as
phrynosomatids (Anderson, 1993: 83).

A second remarkable behavior was the seemingly spasmodic,
uncoordinated, erratic digging movement of whichever foreleg was free
as the lizard held its scanning stance. Usually only one extended foreleg
supported the fore part of the body, and the other foreleg was free. In
that position, the free foreleg exhibited futile digging movements in mid¬
air. We interpret this behavior as representing conflict between two
functional patterns: burrow excavation and antipredation vigilance. The
result was the nonfunctional addition of digging movement to the

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March 1998

scanning pattern, conforming to the process called 'superposition ' by
Eibl-Eibesfeldt (1975: 206).

Although these digging movements were maitunctional with
respect to excavation, they may have been ritualized signals indicating
status or territory ownership, as Carpenter et ai (1970) described very
similar motor patterns ("circumduction" was their name for the
behavior) within the social repertoire of three species of ’'Amphiholums*
(now in three genera, Amphiholums , Ctenephoms and Pogona ).

Otherwise die behavior of die two C exsanguis conformed with
previous reports (e.g., Scudday and Dixon, 1973: 284; Schall and
Pianka, 1980: 561) on foraging and approachabilily. Although both were
almost constantly on the move, and skittishly aware of any extraneous
movement, they showed little or no fear of stationary objects - an
attribute Schall and Pianka (1980: 562) regarded as "temerarious." They
periodically sought shade wherever available, and rested there for a few
seconds. Their antagonism was weak, the larger occasionally chasing the
smaller if it approached too closely, the latter then fleeing rapidly.
Nevertheless, both twice rested together for 10-15 seconds in the shade of
tire observer.

After 11:30 a.m. the two lizards disappeared, presumably
because of the heat (lower 30's C), and were not seen again during our
stay there until 1:30 p.m.

Aclmowledgments

We are much indebted to die Animas Foundation and specifically
to the Gray Ranch personnel (Natalie Runyan and Dr. Ben Brown) for
their hospitality and facilitation of our research in every way; and to Dr.
Charles W. Painter for invaluable counsel

Literature Cited

Anderson, R. A.

1993. An analysis of foraging in the lizard, Cnetnidophoms
tigris . Pp. 83-116 in Wright, J. W. and L. J. Vi it. Biology
of whiptailed lizards (genus Cnetnidophoms ).

Carpenter, C. C, J. A. Badham and B. Kimble.

1970. Behavior patterns of three species of Amphiholums
(Agamidae). Copeia, 1970 (3): 497-505.

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Bulletin of the Maryland Herpetologica! Society

March 1998

Volume 34 Number *

Eibl-Eibesfeldt, I.

1975. Ethology - the biology of behavior. New York, Holt,
Rinehart and Winston.

Ferguson, G. W.

1977 Variation and evolution of stereotyped behavior in
reptiles. Part II. Social displays of reptiles:
communications value, ultimate causes of variation,
taxonomic significance and heritability of population
differences. Pp. 405-554 in Cans, C. and D. W. Tinkle,
Biology of the Reptilia, vol. 7. New York, Academic
Press.

Lowe, C. H., Jr.

1956. A new species and a new subspecies of whiptailed
lizards (genus Cnemidophorus) of the inland Southwest.
Bull. Chicago Acad. Sci., 10: 137-150.

Schall, J. J. and E. R. Piartka.

1980. Evolution of escape behavior diversity. Am. Nat., 115:
551-566.

Scudday, J. F. and J. R. Dixon.

1973. Diet and feeding behavior of teiid lizards from Trans-
Pecos Texas. SW Nat., 18: 279-289.

Stuart, J. N.

1991. Cnemidophorus exsanguis . Cat. Am. Amph. Rept., (516):
1-4.

Walls, G. L.

1967. The vertebrate eye and its adaptive radiation. New York,
Hafner.

University of Colorado Museum, Boulder, Colorado 80309-0334 (HMS, DC,
FVB); 11823 Eaton Way, Westminster, Colorado 80020 (CH); and Lahoratorio
de Consewacion, CyMA, U1CSE , Escuela Nadonal de Estudios Profesionales
Iztacala, UN AM, Apartado Postal 314, Tlalnepantla, Estado de Mexico

(JALE)

Received: 28 July 1997
Accepted: 6 August 1997

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 1

March 1998

Notes:

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Bulletin of the Maryland Herpetological Society

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DEPARTMENT OF HERPETOLOGY

THE NATURAL HISTORY SOCIETY OF MAYLAND, INC.

MdHS . A Founder Members of the Eastern

Seaboad Herpetological League

Comparative Metabolic Rate-Temperature Curves
of Five Species of Snakes of the Families
Viperidae, Colubridae and Leptotyphlopidae

30 JUNE 1998

VOLUME 34 NUMBER 2

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 34 Number 2

June 1998

CONTENTS

Comparative Metabolic Rate-Temperature Curves of Five
Species of Snakes of the Families Viperidae, Colubridae, and
Leptotyphlopidae

Mohamed K. Al-Sadoon and Nasr M. Abdo

39

BULLETIN OF THE

mbl)8

Volume 34 Number 2 June 1 998

The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.

President Tim Hoen

Executive Editor Herbert s. Harris, Jr.

Steering Committee

Frank B. Groves Jerry D. Hardy, Jr.

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

Membership Rates

Membership in the Maryland Herpetological Society is $20.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $30.00 per year. Make all checks payable to the Natural History
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Meetings

The third Wednesday of each month, 7:30 p.m. at the Baltimore Zoo’s
Reptile House (except August and September due to The Mid-Atlantic
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other Wednesday evenings at the NHSM at 8:00 p.m.

COMPARATIVE METABOLIC RATE-TEMPERATURE
CURVES OF FIVE SPECIES OF SNAKES OF THE
FAMILIES VIPERIDAE, COLUBRIDAE, AND
LEPTOTYPHLOPIDAE

Mohamed K. Al-Sadoon and Nasr M. Abdo

Abstract

Five snake species (Viper a russelii, Malpolon monspessulanus
insignitus, Coluber florulentus, Spalerosophis diadema, and subadult and
adult Leptotyphlops microrhynchus) belonging to the families Viperidae,
Colubridae, and Leptotyphlopidae were collected from Pakistan, Egypt,
and Saudi Arabia for the comparative study of their metabolic rate-
temperature (M-T) curves. The resting oxygen consumption (&02) rates
of each species were measured at ambient temperatures of 1 0 to 35°C
in a double-chamber, volumetric closed system. The M-T curves and
the linear regression lines were significantly (P< 0.05) directly propor¬
tional in all species. A significant inverse proportionality of the meta¬
bolic rate weight-specific relationship was noticed in all species, but
was more pronounced in the subadult and adult L. microrhynchus. The
Q10 values though pointing to the thermal dependent shifts and pre¬
ferred body temperature ranges, but the variations and similarities ob¬
served in these parameters could be attributed to geographical and en¬
vironmental factors.

Introduction

Extremes of temperature (Sturbaum, 1982) and water relations of
reptiles are always critical and demanding for life, especially in arid
regions (Cloudsley - Thompson, 1971, 1972, 1991), and the selection and
regulation of a preferred body temperature (PBT) range by such ecto-
therms has been reported to be species-specific and as an important
factor in ecological isolation (Bogert, 1949). Such thermoregulation is
of paramount importance to counter changes in environmental tem¬
perature (Sturbaum, 1982). Several studies have been undertaken on
the behavioral and physiological responses of reptiles to temperature
(Cowles & Bogert, 1944; Bogert, 1959; Dawson and Templeton, 1963;
Licht et al., 1966; Cloudsley- Thompson, 1972; Hutchison, 1979 and Al-
Sadoon, 1986, 1991).

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June 1998

Moreover, oxygen consumption at various temperature levels
could be an indirect measure of oxidative metabolism in ectothermic
animals such as reptiles (Al-Sadoon and Spellerberg, 1985a). The rate
of oxygen consumption is expected to show a steady increase with the
rise in the ambient temperature in a manner according to Van't Hoff s
generalization (Gordon et al, 1982). However, more recent studies (Al-
Sadoon and Spellerberg, 1985b) have shown that such a relationship is
not always linear.

Hence, we carried out allometric investigations on the metabo¬
lism of five snake species from various geographical locations and be¬
longing to three different families, looking for any significant correla¬
tions in the patterns of their metabolic rate-temperature (M-T) curves
and their Q10 values.

Materials and Methods

Experimental animals

All experimental specimens were snakes Vipera russeiii (x w= 54.6 g;
SEM=3.8) is a representative of the family Viperidae that had been col¬
lected from the cultivated lowlands of eastern Pakistan. It is solenoglyp-
hous (i.e., has long hinged erectile front fangs), has very potent venom,
and leads a nocturnal (scarcely diurnal) life. The family Golubridae is rep¬
resented by the weakly-venomous, opisthoglyphous (back-fanged) diur¬
nal snake Malpolon monspessulanus insignitus (x w = 91.2 g; SEM = 4.5),
which was collected from Alexandria, Egypt on the Mediterranean coast.
The other two species of the family Golubridae were Coluber florulentus
and Spalerosophis diadema, were collected from the Central desert regions
of Saudi Arabia. Both are diurnal, non-venomous, aglyphous (without
fangs) colubrids. The family Leptotyphlopidae was represented by sub¬
adults (x w = 0.3 g; SEM 0.036) and adults (x w = 2.3 g; SEM = 0.286) of
Leptotyphlops microrhynchus. These thread-snakes or worm-snakes are bur-
rowers that lead a subterranean nocturnal life. They were collected from
the cultivated areas of Wadi Haniefa near to the city of Riyadh, in the
Central Region of Saudi Arabia.

All experimental animals were kept in the serpentarium of the ani¬
mal facility of the Zoology Department, College of Science, King Saud

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June 1998

University in Riyadh. They were kept in large transparent perspex tanks
(1 00 x 50 x 45 cm) with netwire sliding tops. Each tank was provided with
substratum of sand, to simulate the snakes' natural habitat. An automatic
100-watt lamp was placed overhead inside each tank to give a light pe¬
riod of 9 h per day that provided a thermal gradient of 20 to 40° C. The
animals were fed laboratory-bred mice once every fortnight. The worm-
snakes, were fed mealworms and other small insects. Water was provided
ad libitum. In order to achieve a post-absorptive state, the animals were
not fed for 5 days prior to experimentation.

Resting metabolic rate (RMR)

The resting metabolic rate of the snakes was measured in terms of
resting v 02 rate (ml/ g/ h) using the double chamber, volumetric closed
system of Al-Sadoon (1983) and Al-Sadoon and Spellerberg (1985a; 1987)
at temperatures ranging from 10 - 35° C, with 5° C intervals. Seay sowething
about time at each temperature.

Statistical analyses and figure drawings were carried out according
to the model of Biosoft (1991). Two-tail t-test was employed for compari¬
sons of the x 02 of the different groups. All tests were considered signifi¬
cant at a < 0.05.

Results

Metabolic rate-temperature (M-T) curves

Resting v 02 ( RMR) of the five snakes and the X v 02 of each one at
the various experimental temperature levels are presented in Figs. 1-4.
The linear regression analysis of the M-T curves clearly demonstrate that
the N02 rate of each species increased directly with the temperature (Table
3.). On the other hand the values for L. microrhynchus subadults which
have a smaller body mass (x w 0.3g), were significantly (P<0.01) higher
than the adults (x w = 2.3g). The observed /predicted (O/P) v 02 of all
species is around unity, but was very much reduced in the case of adult L.
microrhynchus (Table 1). The M-T curve shapes are variable. Those of 5.
diadema, and of both the subadult and adult of L. microrhynchus are tripha¬
sic (Figs. 3 and 4). Those of V. russelii and M. m. insignitus depict a steady
increase without any middle phase or plateau (Figs. 1 and 2). On the other

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June 1998

0 5 10 15 20 25 30 35 40

Temperature (#C)

Fig. 1. Relationship between the oxygen consumption rates and the ex¬
perimental temperatures of vipers russelii Each point represents the mean
of different individual snakes. Vertical lines represent standard errors (S.E.)

Fig. 2. Relationship between the oxygen consumption rates and the ex¬
perimental temperatures of Malpolon monspessulanus insignitus. Each point
represents the mean of different individual snakes. Vertical lines repre¬
sent standard errors (S. E.)

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June 1998

Fig. 3. Relationship between the oxygen consumption rates and the ex¬
perimental temperatures of Coluber florulentus ( 0 - 0) and of Spalerosophis

diadema (* - - * ). Each point represents the mean of different individual

snakes. Vertical lines represent standard errors (S.E.)

Fig. 4. Relationship between the oxygen consumption rates and the

experimental temperatures Leptotyphlops microrhynchus (0 - 0, subadults)

and (A - A adults). Each point represents the mean of different indi¬

vidual snakes. Vertical lines represent standard errors (S.E.)

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Volume 34 Number 2

June 1998

hand, the M-T curve of C. florulentus shows a decreasing phase between
10°C and 20° C, followed by a steady increase similar to that of V. russelii
and of M. m. insignitus (Figs. 1-3).

Q10 Values

Table 2 shows the Q10 values of L. microrhynchus adults and subadults
with an increasing phase for the subadults (2.4, 1.9 at 10-1 5 and 15-20°C)
followed by a level plateau (1.0 at 20-25°C) then by an increase of 1.4 at 25-
30° C. The adult Ql 0 values show an increase of 7.4 at 10-15° C followed by
a decrease of 0.9 at 15-20 and of 1.0 at 20-25°C, then an increase of 1.6 at
25-30° C. The Q10 values of S. diadema have shown a rising phase of 11.6 at
15-20° C followed by a declining one of 1.3, 1.3 at 20-25°C and 25-30°C,
respectively then followed by an increasing one of 2.0 at 30-35°C (Table 2).

The Q10 values of V. russelii and M. m. insignitus have shown a very narrow
plateau of a slight variation in thermal dependence. Those of M. m.
insignitus depict a rising value of 1.8 at 15-20° C which becomes stationary
at 1.8 at 20-25° C, then a slight increase of 1.9 at 25-30°C. Those of V. russeiii
reach 2.1 at 15-20° C, then drop lightly to 1.9 at 20-25°C, before rising
sharply to 4.4 at 25-30° C. On the other hand the Q10 values of C. florulentus
decrease to 0.8 and 0.6, respectively at 10-1 5 and 15-20° C, before rising
sharply to 4.0 at 20-25° C. However, the overall Q10 value for all species
was around 2.0, but was only 1.2 for L. microrhynuchus subadult (Table 2).

Discussion

The RMR of the five snake species to varied according to species.
However, the M-T curves and the Q10 parameters were similarities among
the species. Both of the Q10 values and the shape of the M-T curves of
subadult and adult L. microrhynchus were biphasic in. This burrowing,
nocturnal species has cooler microhabitats in cultivated areas where it
was been collected. Nevertheless, this cooler microhabitat can reach high
temperature levels in summer, together with the whole desert area of the
Central Region of Saudi Arabia. Hence this species is capable of surviv¬
ing wide ranges of temperature within that habitat. This is also somewhat
true for the diurnal snake S. diadema, which also inhabits the same desert
habitat of the Central Region of Saudi Arabia. What could, however, refer
to the range of its voluntary body temperature (VBT), which has been

Bulletin of the Maryland Herpetological Society

page 45

Table 2. The thermal dependence (Qio values) of resting oxygen consumption of the
five snake species.

Volume 34 Number 2

June 1998

page 46

Bulletin of the Maryland Herpetological Society

Volume 34 Number 2

June 1998

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considered by Bennet and Dawson (1976) as a mechanism of metabolic
homeostasis. On the other hand the M-T curves of the nocturnal viper, V.
russelii and the diurnal colubrid M. m. insignitus have shown some degree
of similarity in the steady increase as well as in the narrow range of low
thermal dependence. This might indicate the damp habitats of both spe¬
cies. The former is collected from the damp cultivated areas of eastern
Pakistan and the latter from the damp Mediterranean coast of Alexandria
in northern Egypt. Similar observations of the effect of climate on the
metabolic rate of various reptiles have been made by several research
workers (Dawson and Templeton, 1963; Davies and Bennet, 1981; Al-
Sadoon, 1983; Wheeler, 1984; Hailey and Davies, 1986; Zari, 1987 and
Patterson and Davies, 1989).

An interesting feature was observed in the M-T curve of C.florulentus,
where the Q10 values were low (decreasing) at the temperature range of
10-20°C. This has only been observed in cool, temperate snakes such as
Thamnophis sirtalis , and has been interpreted by Aleksiuk (1971) as a mecha¬
nism of instantaneous temperature dependence shift. However, such a
feature has never been observed before in any tropical or subtropical snake
species. This low phase is, however, immediately followed by a sharp
rising phase at 20-25° C. At higher temperatures (30-35° C), however, a
low Q10 phase was observed that could be attributed to a physiological
thermoregulation at high temperature by this diurnal desert snake.

Several researchers are of the opinion that the Q10 values are indicative of
the three phase-shaped M-T curves of the majority of the tested snakes
(Avery, 1976; Bennet and Dawson, 1976; Patterson and Davies, 1978, 1984,
1989; Andrews and Pough, 1985; Gatten Jr., 1985; and Zari, 1991). With
the exception of L. microrhynchus the present results demonstrate that the
O/P V02 values of all the snakes are around the value of a unit, which is a
clear indication of their close similarity to the predictions of Bennet and
Dawson (1976) and of Bennet (1982). The variable ratios attained by the
subadult and adult L. microrhynchus could be attributed to the fact that
the regression equations derived by Bennet and Dawson (1 976) depict
the interspecific relationships of large reptiles, while L. microrhynchus is of
a very small body mass. Similar results were obtained by Al-Sadoon (1
986), Al-Sadoon and Spellerberg (1 987) and by Al-Sadoon and Abdo (1988,
1989, 1991).

page 48

Bulletin of the Maryland Herpetological Society

Volume 34 Number 2

June 1998

The highest RMR was that of L. microrhynchus (subadults) which is of the
lightest body mass of the snakes tested in the present study. This could be
attributed to the mass-specific metabolism which is inversely proportional
to the body mass. This feature is, however, also apparent, but with some
minor anomalies in the position of the M-T curves worked out in the
present study for all of the snakes tested. The most anomalous of those
was that of the adult L. microrhynchus and it could well explain that
anomaly. On the other hand, the Q10 values of the relatively heavier snakes
were higher than those of the lighter ones. This is in good agreement with
previous studies (Rao and Bullock, 1954; and Bennet and Dawson, 1976)
and could be attributed to many factors, salient among which are climatic
and environmental ones. More inter and intra-specific studies, especially
those related to geographical barriers, are however needed for the better
understanding of the ecophysiology of these reptiles.

Literature Cited

Aleksiuk M.

1971. Temperature-dependent shifts in the metabolism of
a cool temperate reptile, Thamnophis sirtalis parietalis.
Comp. Bioch. and Physiol 39 A, 495- 503.

Al-Sadoon M.K.
1983.

Al-Sadoon M.K.
1986.

Al-Sadoon M.K.
1991.

The role and the nature of the metabolic rate-tem¬
perature curves in lizards from different climatic re¬
gions. A thesis submitted to the University of
Southampton, U.K., in candidature for the degree of
Philosophiae Doctor.

Influence of a broad temperature range on the oxy¬
gen consumption rates of three desert lizard species.
Comp. Bioch. and Physiol. 84A (2): 339-344.

Metabolic rate-temperature curves on the horned vi¬
per, Cerastes cerastes gasperetti, the moila snake,
Malpolon moilensis, and the adder, Vipera berus. Comp.
Bioch. and Physiol. 99 A (1/2), 119-122.

Bulletin of the Maryland Herpetological Society

page 49

Volume 34 Number 2

June 1998

Al-Sadoon M.K. & Abdo N.M.

1988. A comparative study on the metabolic rates of five
species of lizards belonging to three different fami¬
lies. Bull, of Maryland Herpetol. Soc. 24 (4), 85-98.

Al-Sadoon M.K. & Abdo N.M.

1989. Temperature effects on oxygen consumption of two
nocturnal geckos, Ptyodactylus hasselquistii (Donndorff)
and Bunopus tuberculatus (Blanford) (Reptilia:
Gekkonidae) in Saudi Arabia. J Comp. Physiol. B
159,1-4.

Al-Sadoon M.K. & Abdo, N.M.

1991 . Temperature and body mass effects on the metabolic

rate of Acanthodactylus schmidti Weigmann (Reptilia:
Lacertidae). J. Atid Environ. 21, 352-361.

Al-Sadoon M.K. & Spellerberg, I.F.

1985a. Comparison of thermal acclimation effects on the
metabolism of Chalcides ocellatus (desert lizard) and
Lacerta vivipara (Cool-temperate lizard). Comp. Bioch.
Physiol. 81A, 939-942.

Al-Sadoon, M.K. & Spellerberg, I.F.

1985b. Effect of temperature on the oxygen consumption of
lizards from different climatic regions. Amphibia-Rep-
tilia. 6, 241-258.

Al-Sadoon, M.K. & Spellerberg, I.F.

1987. Metabolism of the lizard Chalcides ocellatus (Forskall)
from Egypt. J Arid Environ. 12, 159-168.

Andrews, R. M. & Pough, F. H.

1985. Metabolism of squamate reptiles: allometric and eco¬

logical relationships. Physiol. Zoo. 58, 241-231.

Avery R. A.

1976. Thermoregulation, metabolism and social behaviour
in lacertidae. In Morphology and Biology of Reptiles (Ed¬
ited by Bellairs A. d'A. & Cox C. B.). Linnean Society

page 50

Bulletin of the Maryland Herpetological Society

Volume 34 Number 2

June 1998

Bennett A. F.

1982.

Symposium Services No. 3, pp. 245-260. Academic
press, London, New York.

The energetics of reptilian activity. In Biology of the
reptilian (Edited by Cans C. & Poush F. H.) 13, 55-199.

Academic Press. London and New York,

Bennett A. F. and Dawson W. R.

1976. Metabolism. In Biology of the Reptilia (Edited by Cans

C. and Dawson W.R.), 5, 127-223. Academic press,
London.

Biosoft

1991.

Fig. P Software Corporation. Cambridge, U.K. and
Ferguson, U.S.A.

Bogert C. M.

1949.

Thermoregulation in reptiles, a factor in evolution.
Evolution. 3, 195-21 1.

Bogert C. M.

1959.

How reptiles regulate their body temperature. In Ver¬
tebrate adaptations readings from Scientific American (Ed¬
ited by Wessells N. K.). pp. 213- 221. Standford Uni-

versify with Freeman and Company. San Francisco.
Cloudsley-Thompson, J. L.

1971 . The Temperature and Water Relations of Reptiles, pp. 159
Waford. England, Merrow.

Cloudsley-Thompson, J. L.

1972. Temperature regulation in desert reptiles. Symp. Zool
Soc . London , 31, 39-59.

Cloudsley-Thompson, J. L.

1991. Ecophysiology of Desert Arthropods and Reptiles. Ber¬
lin , Heidelberg, New York, London: Springer- Verlag.
203 pp.

Bulletin of the Maryland Herpetological Society

page 51

Volume 34 Number 2

June 1998

Cowles, R. B. & Bogert, C. M.

1944. A preliminary study of the thermal requirements of
desert reptiles. Bull. Am. Mus. Nat. Hist. 83, 262-296.

Davies, R M. C. & Bennett, E. L.

1981. Non-acclimatory latitude-dependent adaptation to
temperature in juvenile natricine snakes. Com. Bioch.
Physiol. 65A, 453-457.

Dawson, W. R. & Templeton, J. R.

1963. Physiological response to temperature in the lizard
Crotaphytus collaiis. Physiol. Zool. 36, 219-236.

Gatten Jr., R. E.

1985. Activity metabolism of lizards after thermal acclima¬
tion. J. Therm. Biol. 104,209-215.

Gordon, M.S.,G. A. Bartholomew, A. D. Grinnell, C. B. Jorgensen & White, N.

1982. Anim. Physiol. , 4th Edition. MacMillan Pub. Co. Inc.
New York and London.

Hailey, A. & Davies, P. M. C.

1986. Lifestyle, latitude and activity metabolism of natricine
snakes. J. Zoo. Lon. 209 A, 461-476.

Hutchison, V. H.

1979. Thermoregulation. In, Turtles (Edited by Harless, M.

& Morlock, H.). Perspectives and Research, pp. 207-
228. John Wiley and Sons, Inc.

Licht P. Dawson W. R. Shoemaker V. H. & Main A. R.

1966. Observations on the thermal relations of Western Aus¬
tralian Lizards. Copeia. 1966, 97-1 1 0.

Patterson J. W. and Davies P.M. C.

1978. Predatory body, temperature seasonal and sexual dif¬
ferences in the lizard Lacerta vivipara. J. Therm. Bio. 3,

39-41.

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Bulletin of the Maryland Herpetological Society

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June 1998

Patterson J. W. and Davies M. C.

1982. Predatory behavior and temperature relations in the
snake Natrix maura Copeia. 472-474.

Patterson J. W. and Davies P. M. C.

1984. The influence of temperature, sexual condition, and
season on the metabolic rate of the lizard Psammo-
dromus hispanicus. J Comp. Physio. 154, 311-316.

Patterson J. W. and Davies M. C.

1989. A possible effect of climate on resting metabolic rate
in lizards. Copeia. 719- 723.

Rao, K.P.& Bullock, T.H.

1954. Q10 as a function of size and habitat temperature in

poikilotherms. Am. Nat, 88, 33-44.

Sturbaum B. A.

1982. Temperature regulation in turtles. Comp. Biochem .
Physiol. 72A (4), 615-620.

Wheeler, P. E.

1984. An investigation of some aspects of the transition
from ectothermic to endothermic metabolism in ver¬
tebrates. Ph.D. Thesis, University of Durham.

Zari, T. A.

1987. The energetics and thermal physiology of the
Wiegmann's skink, Mabuya brevicollis. Ph.D. Thesis,
University of Nottingham.

Zari, T. A.

1991 . Effect of temperature on resting metabolic rate of the
spiny tailed lizard, Uromastyx aegyptius microlepis. J
Eygpt & Ger. Soc. Zool. 4, 9-18.

— Zoology Department, College of Science, P. O. Box 2455, Riyadh 11451,
Saudi Arabia.

Received: 5 April 1997
Accepted: 6 July 1997

Bulletin of the Maryland Herpetological Society

page 53

Volume 34 Number 2

June 1998

News and Notes:

Sponsored by the MARS Preservation Fund, Inc.

Mu-

^EPTMLE
5HO

We believe in education
and the protection of
ci ideal habitats.

Maryland State Fairgrounds 4-H Hall (Daily Show and Workshops)

Days Hotel Timonium (Host Hotel & Lectures Saturday Evening)

• Captive bom reptiles & amphibians for display and sale • Equipment, books & supplies
• Book signings each day • Educational exhibits • Door Pnzes • Raffles • Silent Auction
• Display & photographs of Costa Rican rainforest area purchased by M.A. R.S. • Pre-show social gathenng
• “ Reptiles & Rainforests " art collection • Seminars throughout the show • “Critter Contacf hands-on animal display
Professional Lecture Series Saturday Evening Will Feature:

Paul Freed, Supervisor of Herpetology, Houston Zoological Gardens (gecko husbandry)

I'.ert Langerwerf, President, Agama International (Argentine giant tegu lizards)

Rod Mast, Vice President, Conservation International (amphibian decline and biodiversity)

Dr. Peter Pritchard, Veterinarian, Audubon Society (turtles of Madagascar)

“Fabulous Fotos” presentation by Warren Krupsaw, Wildlife Photographer

Show proceeds are donated to The Center for Ecosystem Survival for the
purchase of rainforest. THE MID-ATLANTIC REPTILE SHOW, now in its
sixth year, has purchased 2,077.5 acres of critical habitat to date.

ADMISSION: Weekend Pass (includes show both days and lectures) $13 Adults, One day Pass
(Sat. or Sun.) $7 Adults. Children 6-12 and Seniors over 65 - $6 (for one day or weekend pass),

Children under 5 are free.

FOR ADBDTDONAl INFORMATION, CONTACT:

Tim Hoen, Show Coordinator • P.O. Box 201, Jarrettsville, MD 21084 • (410) 557-6879
Holli Fnedland, Program Director (410) 602-0828 or check the web (http://www.reptileinfo.com)
Only registered vendors may display or sell on the premises.

Please leave your pet animals home! They will not be admitted to the show. Thank you.

page 54

Bulletin of the Maryland Herpetological Society

Volume 34 Number 2

June 1998

News and Notes:

Bulletin of the Maryland Herpetological Society

page 55

Volume 34 Number 2

News and Notes:

June 1998

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The Maryland Herpetological Society
Department of Herpetology
Natural History Society of Maryland, Inc .

2643 North Charles Street
Baltimore , Maryland 21218

US ISSN: 0025-4231

■(S-eP'T

■ ULLtTIN Of THE

flftarylanb

Hecpetological

0onety

DEPARTMENT OF HERPETOLOGY
THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.

MdHS . A Founder Member of the Eastern

Seaboard Herpetological League

30 SEPTEMBER 1998

VOLUME 34 NUMBER 3

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 34 Number 3

September 1998

CONTENTS

Osteology of Leptodactylus latinasus (Anura: Leptodactylidae) and the Va¬
lidity of its Subspecies

Maria L. Ponssa and E. O. Lavilla . . . 57

Differential Survivorship of Larval Leopard Frogs (Rana Pipiens) Exposed

to Temporary and Permanent Reduced pH Conditions

Kellie A. Watkins-Colwell and Gregory J.

Watkins-Colwell . 64

Sceloporus Poinsetti: Its Taxonomic Affinity With Mucronatus

R. Earl Olson . . . . . . 76

Cannibalism in Bothrops Asper

Felipe Correa Sanchez, Amaya Gonzalez Ruiz and

Enrique Godinez Cano . 83

Book Review: T, rex and the Crater of Doom

Jeffrey V. Yule . . 87

Book Review: Amphibians and Reptile of the Great Lakes Region

Harlan D. Walley . 94

BULLETIN OF THE

mM)8

Volume 34 Number 3 September 1 998

The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.

President Tim Hoen

Executive Editor Herbert S. Harris, Jr.

Steering Committee

Frank B. Groves Jerry D. Hardy, Jr.

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

Membership Rates

Membership in the Maryland Herpetological Society is $20.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $30.00 per year. Make all checks payable to the Natural History
Society of Maryland, Inc.

Meetings

The third Wednesday of each month, 7:30 p.m. at the Baltimore Zoo's
Reptile House (except August and September due to The Mid-Atlantic
Reptile Show). The Department of Herpetology meets informally on all
other Wednesday evenings at the NHSM at 8:00 p.m.

OSTEOLOGY OF LEPTODACTYLUS LATINASUS
(ANURA: LEPTODACTYLIDAE) AND THE VALIDITY
OF ITS SUBSPECIES

Maria L. Ponssa and E. O. Lavilla
Abstract

The controversy on the validity of the subspecies of Leptodactylus
latinasus is analyzed from an osteological point of view. The coincidence
of diverse characters states of the skull, hyoid and pectoral girdle indi¬
cates that it is a monotypic species, in spite of some morphological differ¬
ences (especially in the snout), observed among diverse populations.

Introduction

After its description by Jimenez de la Espada (1875), the name
Leptodactylus latinasus, was apparently overlooked, and was inadvertently
replaced by Leptodactylus prognathus Boulenger (1888).

In 1964, Gallardo considered that this taxon was actually composed
of two species, L. prognathus, inhabiting the eastern regions of Uruguay,
Paraguay, Brazil and Argentina, and a new one, L. anceps, restricted to the
dry, chacoan areas.

Since then, two antagonic opinions arose: one supporting the exist¬
ence of only one species with polymorphic populations, and the other
that gave subspecific status to these differences. Among the contributions
the following are the most relevant:

Barrio (1965) studied the nuptial call of L. prognathus and L. anceps,
and due to their overall similarities, considered that they could be co¬
specific, and that the latter would be a chacoan subspecies of L. prognathus.

Heyer (1969) revalidated Leptodactylus latinasus, and later (Heyer
1978) considered L. anceps as a junior synonym of Jimenez de la Espada
primarily based on Barrio's (op. cit.) results and some morphological over¬
lap, but pointing out that chacoan populations could be differentiated
from the coastal ones.

In the meantime. Timeses, Vignes and Tio (1972) showed some struc¬
tural similarity in tongue structure and in the number of teeth of the pre¬
maxilla and maxilla in both entities.

Bulletin of the Maryland Herpetological Society

page 57

Volume 34 Number 3

September 1998

Later authors (i.a. Cei, 1980, 1987; Gallardo, 1987; Gallardo and
Varela, 1992; Lavilla, 1992), agreed with Barrio (1965) and considered
Leptodactylus latinasus as a polytypic species, formed by the nominal sub¬
species and L. latinasus anceps .

In short, while nuptial call, some anatomical characters and some
morphometric data showed similarities, diverse morphological and dis¬
tributional characters showed differences, and due to the diversity of opin¬
ions available, we focused on the osteological analysis to contribute addi¬
tional evidence to help solve the controversy.

Material and Methods

Two groups of Leptodactylus latinasus (sensu lato) were analyzed,
including:

(a) Chacoan populations: Six individuals (three males and three
females) from El Cadillal (Tucuman, Argentina), housed at
Fundacion Miguel Lillo collection (FML) as FML 02410/1-3,
FML 02410/5, FML 02410/7 and FML 02410/9-10. The sample
was assigned to "Tucuman", type locality of Gallardo's L.
anceps.

(b) Eastern populations: Six individuals (three males and three fe¬
males) from Caseros (Prov. Buenos Aires, Argentina), housed
at Museo Argentine de Ciencias Naturales Bernardino
Rivadavia as MACN 6280-6285; this sample was considered
by Gallardo (1964) as Leptodactylus prognathus, and was em¬
ployed as a part of the comparative material in the original
description of L. anceps.

Skeletons were prepared following Wassersug (1976) technique for
stained and cleared vertebrates, and the analysis followed classical con¬
siderations employing the nomenclature proposed by Trueb (1993).

Results and Discussion

The osteological analysis was focused on skull, hyobranchial skel¬
eton, and pectoral girdle, and the following are common characters to the
oriental (Leptodactylus latinasus latinasus) and chacoan (Leptodactylus
latinasus anceps) populations:

page 58

Bulletin of the Maryland Herpetological Society

Volume 34 Number 3

September 1998

Skull:

The frontoparietals, deeply forked, are usually fused to each other in
the rear portion of the parietal region. They run from the posterior end of
the foramen magnum to the posterior portion of the sphenethmoid, over¬
lapping with it. The margins of the occipital region are fused to prootics
and exoccipitals, and the frontoparietal fontanella is irregular and thin.

The nasals are sub triangular, in medial contact each other and with
the sphenethmoid. The dorsal surface of each bone is sculptured, and are
not in contact with the pars facialis of the maxilla, nor with the frontoparietals.

The quadrato-jugals, completely ossified and stick-like, are in con¬
tact with the squamosal and overlaps the maxilla.

The squamosals show the zygomatic ramus of each bone
subtriangular, directed slightly outwards and not in contact with maxilla.
The otic ramus do not contact the frontoparietals. The otic plate is
subquadrangular, not reaching the crista parotica. The descendent ramus
is grooved and in contact with the quadrato-jugals.

The cultriform process of the parasphenoid is lanceolate and with
irregular tip, reaching the area between neopalatines. The bone covers
the sphenethmoid up to the neopalatine level, but is not in contact with
them. The alae are partially fused to prootics and exoccipitals.

The neopalatines are included in a cartilaginous matrix, and contact
the sphenethmoid, vomers and the pars palatina of the maxilla.

In the pterygoids, the anterior ramus of each bone doesn't reach the
neopalatines and are separated from the maxilla by a cartilaginous sheet.
The medial ramus has not contact with parasphenoid alae. The posterior
ramus is laminar, curved and joints the complex quadrato-jugal - squamosal.

The vomers of each side are in medial contact and superposed to
the sphenethmoid. The alae are irregular and indented, forming the ante¬
rior and inner sides of choanae; the dentigerous process bears 11-14 teeth.

The prootics are dorsally sculptured, and fused to exoccipitals and
with the posterior region of frontoparietals and parasphenoid.

The exoccipitals show widely separated occipital condyles, and a

Bulletin of the Maryland Herpetological Society

page 59

Volume 34 Number 3

September 1998

cartilaginous and mineralized crista parotica.

The premaxillae are juxtaposed to the maxilla, and the dentigerous
processes have 9-11 teeth. The allary process of each bone is quadrangu¬
lar, perpendicular to the axial axis and directed dorsally or posterodorsally.
The pars palatina is laminar, while the palatine process is variable, notched
or entire.

The maxillae have 39-45 teeth that go beyond the pterygoid level,
and the pars palatina and facialis are laminar. Of the three typical pro¬
cesses, the preorbital is blunt, the postorbital vestigial, and the pterygoid
is absent. The maxillary arch is complete.

The sphenethmoid is tubular, ossified, and dorsally approaching the
premaxilla.

Pectoral Girdle:

Sternal architecture shows a cartilaginous and mineralized omoster-
num, with the proximal end slightly expanded; the mesosternum is ossi¬
fied, showing the proximal region with convergent, and distal region with
subparallel sides; the xiphisternum is cartilaginous, mineralized and ex¬
panded, and the epicoracoids are cartilaginous and mineralized; in ven¬
tral view the right overlaps the left.

The clavicles are arched and fused to scapulae. The scapulae bear
the pars glenoidalis smaller than pars acromialis, and the union with su-
prascapulae and with coracoids are cartilaginous. The glenoid cavity is
surrounded by cartilage. Finally, the cleithrum show cartilaginous, min¬
eralized tip.

Hyoid:

The hyoid plate is cartilaginous, mineralized and with parallel mar¬
gins. Of its processes, the anterolaterals are perpendicular to the axial axis,
the hials are thin, long and expanded shortly after the curvature, and the
tirohvals are ossified and with cartilaginous tip.

The cricoid is a complete, cartilaginous and not mineralized ring,
where the esophagic process is differentiated, as a triangular structure,
with regular sides. The bronchial process is thin.

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September 1998

The arithenoids are not mineralized, and show triangular shape in
lateral view.

Among the analyzed structures, only three characters showed dif¬
ferences between the so called Leptodactylus latinasus latinasus and
Leptodactylus latinasus anceps, and includes:

The cartilaginous episternum is rounded, rhomboidal or chordiform
in L. I latinasus, and rounded in L. I anceps.

The anterolateral processes of the hyoid are not distally expanded
in L. I latinasus, but show a distal expansion in L. 1. anceps.

Finally, the posterolateral processes of the hyoid are thin, not dis¬
tally expanded in L. I latinasus, but some individuals of L. 1. anceps may
show an expanded tip.

The osteological analysis presented herein show an immense num¬
ber of similarities between populations considered as different subspe¬
cies, and among the few differences, all of them show variable conditions
in one or other set of examined skeletons.

In conclusion, the skeletal evidence indicates that Leptodactylus
latinasus is a monotypic species with the following synonymy:

Leptodactylus latinasus Jimenez de la Espada, 1875

1875. L. latinasus Jimenez de la Espada. Vert. Viaje Pacif.:40.

1888. L. prognathus Boulenger. Ann. Mag. Nat. Hist. (6) 1 (3): 187.

1964. L. anceps Gallardo. Rev. Mus. Arg. Cs. Nat. (zool.), 9 (5): 100

1980. L. latinasus latinasus Cei. Amph. Argentina: 325.

1980. L. latinasus anceps Cei. Amph. Argentina: 329.

Literature Cited:

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 3

September 1998

BARRIO, A.

1965. Afinidades del canto nupcial de las especies cavicolas
del genero Leptodactylus (Anura, Leptodactylidae).
Physis (Bs. As), 25 (70): 401 410.

BOULENGER, G.A.

1888. Description of new Brazilian batrachians. Ann. Mag. Nat.
Hist. (6) 1 (3): 187 189. CEI, J.M. 1980. Amphibians of Ar¬
gentina. Monitore Zool. Ital., N.S., Monogr. 2: i-xii + 1 -
609.

CEI, J.M.

1987. Additional notes to "Amphibians of Argentina": An up¬
date, 1980 - 1986. Monitore Zool. Ital. (N.S.), 21: 209 - 272.

GALLARDO, J.M..

1964. Leptodactylus prognathus Boul. y L. mystacinus (Burm.)
con sus respectivas especies aliadas (Amphibia, Lepto¬
dactylidae del grupo cavicola). Rev. Mus. Argent. Cienc.
Nat. Bernardino Rivadavia. Zool. 9 (5): 91 121.

GALLARDO, J.M.

1987. Anfibios argentinos. Guia para su identificacion.
Biblioteca Mosaico, Bs. As.: 1 - 98.

GALLARDO, J.M. & E.V. DE OLMEDO.

1992. Anfibios de la Republica Argentina: Ecologia y
comportamiento. Fauna de Agua Dulce de la Republica
Argentina, 41 (1): 1 - 116.

HEYER, W.R.

1969. Studies on frogs of the genus Leptodactylus (Amphibia,
Leptodactylidae). V. Taxonomic notes on L. latinasus,
rhodonotus, romani and wuchereri. Herpetologica, 25 (1):
1-8.

HEYER. W.R.

1978. Systematics of the fuscus group of the frog genus
Leptodactylus (Amphibia: Leptodactylidae). Sci. Bull.
Nat. His. Mus. Los Angeles Co. 29: 1 - 85.

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Bulletin of the Maryland Herpetological Society

Volume 34 Number 3

September 1998

JIMENEZ DE LA ESPADA, M.

1875. Vertebrados del viaje al Pacifico, verificado de 1862 a 1865
por una comision de naturalistas enviada por el gobierno
espanol. Batracios. Imp. A. Miguel Ginesta, Madrid: 1 -
208.

LAVILLA, E.O.

1992. Tipos portadores de nombre y localidades tipo de anfibios
de Argentina. Acta zool. Lilloana, 42 (1): 61 - 100.

LIMESES, C.E., I. VIGNES & M. TTO.

1972. Las especies argentinas del genero Leptodactylus (Anura,
Leptodactylidae). Algunos aspectos anatomicos de
posible signification taxonomica. II. Physis (Bs. As.), 31
(83): 631 - 652.

TRUEB, L.

1993. Patterns of cranial diversity among the Lissamphibia. In
J. Hanken and B.K. Hall (eds.). The Skull, 2: 255 - 343.

WASSERSUG, R.J.

1976. A procedure for differential staining of cartilage and bone
in whole formalin fixed vertebrates. Stain. Tech., 51: 131
-134.

Instituto de Herpetologia , Fundacidn Miguel Lillo.
Miguel Lillo 251, 4000 Tucuman, Argentina

Received: 20 February 1998
Accepted: 30 March 1998

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September 1998

DIFFERENTIAL SURVIVORSHIP OF LARVAL
LEOPARD FROGS ( RANA PIPIENS) EXPOSED
TO TEMPORARY AND PERMANENT REDUCED
pH CONDITIONS

Kellie A. Watkins-Colzvell and Gregory ]. Watkins-Colwell

Abstract:

The effect of pH in breeding environments on amphibian's repro¬
ductive success may be directly linked to the current environmental prob¬
lems of acid rain and amphibian population decline. In this study eggs
obtained following hormonally induced ovulation were fertilized artifi¬
cially at pH 6.2 and raised to the free swimming stage at seven pH levels
between 3.5 and 8.1. In addition the effects of short-term exposure to acidic
conditions were investigated by placing developing eggs at different stages
into pH 4.5 for 24 hours and noting visible deformities and survivorship.
Prolonged exposure to pH <4 was lethal. Exposure to pH < 5.6 for more
than 24 hours resulted in high embryo mortality (75-100%). Short-term
exposure to pH 4.5 yielded no significant decrease in embryonic survival.
Prolonged exposure to reduced pH yielded developmental abnormalities
with a higher frequency than 24 hour exposure. Abnormalities observed
include caudal curling, failure to retract yolk plug, and thoracic swelling;
these tadpoles exhibited 100% mortality.

Introduction

Acid precipitation is a very common problem in the United States.
The pH of ponds and lakes can be altered on either a short-term basis or
sometimes even permanently. Because these are breeding sites for many
amphibians, the effect of pH on amphibian development has received some
study (Dunson et al., 1992). Whereas Pough and Wilson (1977) report that
pH does not affect the rate of amphibian development, other investiga¬
tors note that amphibian development does not occur below pH 4.5 and
that various developmental abnormalities occur at higher pH levels (Bee-
bee, 1986; Beebee et al., 1990; Beebee and Griffin, 1977; Pough and Wilson,
1977; Freda and Dunson, 1985b). The majority of recent work focuses on

Key words: Anura ; Rana pipiens; Acid Rain; Larval Survivorship

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September 1998

correlating population studies with environmental chemistry (see Dunson
et al., 1992). This type of study is clearly important and applicable to con¬
servation biologists. However, in spite of published records of lethal pH
(LC50) for several species (Freda and Taylor, 1992; Corn and Vertucci, 1992)
the need still exists for controlled laboratory studies of embryonic devel¬
opment and survivorship over a range of pH levels.

We hypothesized that reduced pH would reduce embryo survi¬
vorship in Rana pipiens significantly even greater than that of the LC50
level. We addressed two specific questions in this study. First, what pH
would be fatal to developing R. pipiens ? Second, what is the critical stage
of development at which a fluctuation in pH would be harmful? R.
pipiens, was used for two reasons both of which relate to its ecology.
First, the species tends to breed in permanent ponds rather than ephem¬
eral ponds such as those utilized by Rana sylvatica and many Bufonids
and Ambystomatids (Dickerson, 1913; Clark and Hall, 1983; Cook, 1983;
Pierce et al, 1984; Freda and Dunson, 1985b). Species that breed in ephem¬
eral ponds are often more tolerant of low pH than are other species (Freda
and Taylor, 1992). Therefore understanding the effect of reduced pH on
a species that does not typically breed in ephemeral ponds should re¬
veal more about the impact acid precipitation has on amphibian popu¬
lations. Second, this species is one of many amphibian species whose
populations are thought to be declining due to acid precipitation (Mar¬
tin, 1990; Milstein, 1990).

Materials and Methods

Acquisition ofEggs

Adult male and female R. pipiens were purchased from a commer¬
cial supplier (Kons Inc.). Consequently, collection locality and subspecies
are unknown. All frogs were refrigerated at 11° C to stimulate brumation
until they were needed with an average time in brumation of 10 days.

Ovulation of gravid female frogs was induced by the injection of
female anterior pituitary glands (Hamburger 1960) and progesterone into
the abdominal cavity. Eggs were artificially fertilized using conventional
methods (Hamburger, 1960; Pierce and Sikand, 1984). Specifically, testes

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from two males were macerated in reconstituted soft water. Females were
stripped of eggs and the sperm solution was delivered by pipette.

Water pH and Buffer System

To investigate pH effects, an artificial buffer system was used. The
buffer system contained 1L of distilled water, 30mg MgS04, 30mg CaS04x
2H20, 2 mg KC1 (Pierce et ah, 1987), 81 mg Na2HP04, and 128mg
NaH2P04x H20. This yields a pH=6.3. The pH was lowered by addition
of dilute sulfuric acid. The control group was maintained in pH 8.1 pond
water. Solutions were changed daily to ensure minimal temporal varia¬
tion in pH.

Short-term Exposure to Reduced pH

To establish if there was a critical point in development at which a
pH shift would be fatal, eggs were fertilized as above and then raised in
pond water at pH 8.1 until they were temporarily exposed to acidic con¬
ditions. Approximately 150 eggs were placed into a pH 4.5 buffered solu¬
tion at each of four developmental stages: (1) fertilization; (2) 24 h or gas-
trula; (3) 48 h or neurula; and (4) 72 h or tail bud. After 24 h exposure the
eggs were returned to pond water at pH 8.1. These egg batches were
kept separated until feeding began.

Three replicates of this experiment were run, each using eggs from a
new female and two new males. The final stage of development reached
was recorded and any deformities were noted. Data on the percentage of
tadpoles that hatched after short-term exposure to reduced pH were ana¬
lyzed using a one way Anova.

Extended Exposure to Reduced pH

To determine a critical lower limit of pH on development approxi¬
mately 200 eggs obtained in the above manner were placed in each of
seven separate dishes pH 3.5, 4.0, 5.0, 5.6, 6.3, and a control of pond water
of pH 8.1 one hour after fertilization. The experiment was replicated once
with eggs from two different females. The pH levels were maintained
until feeding was initiated in free swimming tadpoles, approximately 1
week after hatching. Each day, solutions were changed and any eggs which
stopped developing were removed to ensure that bacteria did not begin

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September 1998

to grow. The final stage of development reached was recorded and any
visible deformities were noted. Data on the percentage of tadpoles that
hatched in conditions of extended exposure to reduced pH were also ana¬
lyzed using a one way Anova followed by a Duncan multi-range test.

The number surviving in both the short-term and extended expo¬
sure experiments were compared and analyzed using a two-way t-test.

Results

Short-term Exposure to Reduced pH

There was no significant difference (F=4.024, p=0.08) in the percent
of tadpoles surviving to free swimming following short-term exposure to
reduced pH at the different developmental stages; 80% to 98% survived
in all cases.

Some developmental anomalies were noted. These anomalies include
swelling of the thoracic region in which the embryo appears bloated
around the pectoral girdle. Caudal curling, or a dramatic bend in the tail,
was also noted and appeared not only in embryos in the egg, but also in
free-swimming larva. All abnormal embryos died either before hatching
or within the first week of hatching.

Extended Exposure to Reduced pH

Percentage survival differed significantly with pH in the extended
exposure experiment (F=81.901, p<0.01). The data indicate that a pH less
than 4.0 is lethal (Fig. 1). Bacterial infection ( Pseudomonas fluorescens) , in¬
hibition of yolk plug retraction, thoracic swelling and caudal curling oc¬
cur at a pH less than 6.3.

Some eggs died of causes not visibly related to the study. These
deaths occurred throughout the test period and showed no specific trend
nor were they limited to any specific developmental stage. No deformi¬
ties were visible in these individuals.

Mortality occurred most often at yolk plug retraction. Prior to this
stage, development seemed normal. However, yolk plug retraction did
not occur prior to neurulation as it should. This deformity was always
fatal in the early stages of neurulation.

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September 1998

Fig. 1 Percent survival under extended pH stress.
Numbers represent standard error.

3.5 4.0 5.0 5.6 6.3

pH

Two other visible deformities of tadpoles were thoracic swelling
and caudal curling. Hatching success was significantly different (p<0.05)
between pH 5.6 and pH 5.0 as was the percent surviving to free swim¬
ming stage.

Survival under conditions of extended exposure was significantly
lower than short-term exposure conditions (T= -10.265, p< 0.01), as illus¬
trated in Fig. 2.

Discussion

The lethal effects of low pH have been noted by several authors.
Dunson and Connell (1982) reported that Xenopus laevis failed to hatch at
pH 4.3. Gosner and Black (1957) listed critical pH ranges for eleven spe¬
cies, including Rana pipiens (pH 3.9-4.1) and Rana sylvatica (pH 3.S-3.9).
Grant and Licht (1993) found the critical pH of R . sylvatica (pH 4.0-4.5), R.
catesbeiana (pH 4.0-4.5), and H. versicolor (pH 3.5-3. 8). Freda and Taylor
(1992) reported the LC50for R. pipiens (pH 4.06), R. clamitans (pH 3.36) and
R. sylvatica (pH 3.71). Similarly, Corn and Vertucci (1992) reported the LC50
of Ambystoma tigrinum (pH 5.3), Bufo boreas (pH 4.5), Pseudacris triseriata
(pH 4.8), R. pipiens (pH 4.5) and R. sylvatica (pH 4.3). Pierce and Mont-

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September 1998

Fig 2. Percent survival to free swimming
as a function of testing environment.

100-1

Short-term Exposure Extended Exposure

Testing Environment

gomery (1989) found that B. valliceps, B. woodhousei and Xenopus laevis
embryos exposed to pH 4.0 for three days showed no permanent effects.
In the present study we found that fewer than 50% of R. pipiens larva
survive prolonged exposure to pH < 5.6 Prolonged exposure to pH 3.5
was 100% lethal. However, we found no significant increase in mortality
when exposed to pH 4.5 for 24 h. The difference in survival rate between
prolonged exposure and short-term exposure to reduced pH was signifi¬
cant. This indicates that brief exposures to reduced pH, even to the LC50
for a species, is significantly less lethal than prolonged exposure to the
same pH.

The reason that a pH of 3.5 was lethal in this study may be corre¬
lated with the increase in development of bacteria (Pseudomonas fluorescens)
which is known to inhabit low pH areas (Bergan, 1981; Jeter and Ingraham,
1981). High mortality in low pH could also be due to physiological fac¬
tors. Dunson and Connell (1982) attributed the poor hatching success of
Xenopus laevis eggs incubated in reduced pH to the blockage of some physi¬
ological process necessary for hatching. Salthe (1965) found that the
amount of perivitelline fluid in R. pipiens eggs did not increase normally
when the eggs were incubated in low pH. High mortality for R. sylvatica
incubated at a pH of 3.5 has been attributed to sodium (Na) imbalance
(Freda and Dunson, 1985b).

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September 1998

Reports of developmental anomalies and deformities are rather com¬
mon in the literature. The deformities found in the current study, inability
to retract the yolk plug, caudal curling of free swimming tadpoles, and
the swelling of the thoracic region have been previously noted for other
amphibian species (Pough and Wilson 1977; Pough, 1976; Pough and Wil¬
son, 1977; Beattie and Tyler-Jones, 1992). Freda and Dunson (1985a) noted
that embryos of other amphibian species exhibit curling within the egg
when maintained at pH < 4.5. Bradford et al. (1992) reported a reduction
in body size for embryonic R. muscosa acidic conditions. In addition, Gosner
and Black (1957) noted deformities for frogs reared in low pH, but no
description of these deformities was given.

Amphibian species are affected differently by pH. Pough and Wil¬
son (1977) found significant pH tolerance differences in two species of
salamanders, Ambystoma jeffersonianum and A. maculatum. Freda and
Dunson (1985b) noted that R. sylvatica can breed in virtually all available
ponds due to a high tolerance to low pH. Conversely, B. calamita will not
reproduce successfully in acidic ponds, and Bufo woodhousei is absent from
acidic ponds in Pennsylvania (Freda and Dunson 1986). Freda and Taylor
(1992) reported that the R. pipiens and B. americanus tadpoles were more
sensitive to acidic conditions than R. clamitans, R. sylvatica and P. crucifer
and their tadpoles will actively avoid acidic conditions. R. pipiens are not
as tolerant to reduced pH as other anuran species.

In the current study, prolonged exposure to low pH reduced sur¬
vival whereas short-term exposure did not. This contradicts what Leftwich
and Lilly (1992) found for Bufo americanus. They report that short-term
exposure to reduced pH significantly hindered survival of embryos. How¬
ever, they did not use a buffer system, nor did they monitor the pH
throughout the study. Also, they only used eggs from one clutch from a
single pair. Consequently, the results they achieved could be an artifact of
the genotype of the parents as there is evidence to suggest a genetic or at
least a maternal-factor basis for acid tolerance (Pierce and Sikand, 1985;
Pierce and Wooten, 1992). At face value, however, their results suggest
that Bufo may be more sensitive to brief exposure to low pH than R. pipiens.

Pierce and Montgomery (1989) assert that temporary reductions in
pH occur more commonly in nature than does prolonged exposure to re¬
duced pH. This would explain why certain areas of the North Eastern

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September 1998

United States, which have been permanently damaged by acid rain, have
diminished amphibian populations or changing populations while those
with only occasional acidic events may show less of a decline.

The natural mortality in normal conditions for developing R. pipiens
is high. Merrell (1977) estimated the highest mortality for a population of
R. pipiens in Minnesota to occur in the larval stage with nearly 95% of the
larva failing to metamorphose. If our data are any indication of natural
survival in fluctuating pH, it seems unlikely that temporary exposure to
low pH could significantly affect a population. However, prolonged ex¬
posure to reduced pH could be detrimental to the population, even caus¬
ing local extinctions.

Ackno wled gment s

We would like to thank A. Fry for his assistance during the study.
We thank K. Lance for his assistance with the buffer, and G. Goldstein for
helping to identify the bacteria species. We also thank B. Palmer and A. J.
Gatz for helpful comments on earlier drafts of this manuscript.

Literature Cited

Beattie, R. C. and R. Tyler-Jones.

1992. The effects of low pH and aluminum on breeding success
in the frog Rana temporaria. J. Herpetol. 26(4):353-360.

Beebee, T.C.

1986. Acid tolerance of Natterjack Toad ( Bufo calamita ) devel¬
opment. Herpetol. J. 1:78-81.

. and J. Griffin.

1977. A preliminary investigation into Natterjack Toad ( Bufo
calamita) breeding site characteristics in Britain. J. Zook,
London 181:341-350.

Bergan, T.

1981. Human- and animal-pathogenic members of the genus
Pseudomonas . pp. 666-700. In: Starr M. P., H. Stolp, H. G.
Truper, A. Balows, H. G. Schlegel (eds.). The prokary¬
otes: A handbook on habitats, isolation, and identifica¬
tion of bacteria. Springer- Verlag, New York.

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 3

September 1998

Clark, K. L. and R. J. Hall.

1985. Effects of elevated hydrogen ion and aluminum concen¬
trations on the survival of amphibian embryos and lar¬
vae. Can. J. Zool. 63:116-123.

Collins, J. R and H. M. Wilbur.

1979. Breeding habits and habitats of the amphibians of the
Edwin S. George Reserve, Michigan, with notes on the
local distribution of fishes. Occasional Papers of the Uni¬
versity of Michigan Museum of Zoology 686:1-34.

Cook, R. P.

1983. Effects of acid precipitation on the embryonic mortality
of Amby stoma salamanders in the Connecticut valley of
Massachusetts. Bio. Conserv. 27 (1983):77-88.

Dickerson, Mary C.

1913. The frog book: North American toads and frogs with a
study of the habits and life histories of those of the north¬
eastern states. Doubleday, Page and Company, New York.

Dunson, W. A., and J. Connell.

1982. Specific inhibition of hatching in amphibian embryos by
low pH. J. Herpetol. 16(3):314-316.

, R. L. Wyman, E. S. Corbett.

1992. A symposium on amphibian declines and habitat acidi¬
fication. J. Herpetol. 26(4):349-352.

Freda, J., and W. A. Dunson.

1985a. The influence of external cation concentration on the
hatching of amphibian embryos in water of low pH. Can.
J. Zool. 63:2649-2656.

1985b Field and laboratory studies of ion balance and growth
rates of ranid tadpoles chronically exposed to low pH.
Copeia 1985 (2):414-423.

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September 1998

1986. Effects of low pH and other chemical variables on the
local distribution of amphibians. Copeia 1986 (2):454-466.

Gosner, K. L. and I. H. Black.

1957. The effects of acidity on the development and hatching

of New Jersey frogs. Ecol. 38:256-262.

Grant, K. P. and L. E. Licht.

1993. Acid tolerance of anuran embryos and larvae from cen¬
tral Ontario. J. Herpetol. 27(l):l-6.

Hamburger, V.

1960. A manual of experimental embryology, pp 28-32. The
University of Chicago Press, Chicago.

Jeter, R. M. and J. L. Ingraham.

1981. The denitrifying prokaryotes, pp. 913-925. In: Starr M. P,
H. Stolp, H. G. Truper, A. Balows, H. G. Schlegel (eds.).
The prokaryotes: A handbook on habitats, isolation, and
identification of bacteria. Springer- Verlag, New York.

Karns, D. R.

1992. Effects of acidic bog habitats on amphibian reproduc¬
tion in a northern Minnesota peatland. J. Herpetol.
26(4):401-412.

Leftwich, Kevin N. and P D. Lilly.

1992. The effects of duration of exposure to acidic conditions
on survival of Bufo americanus embryos. J. Herpetol. 26
(1):70-71.

Martin, Glen.

1990. Froggy bottom. Discover Magazine May: 36-37.

Merrell, David J.

1977. Life history of the leopard frog, Rana pipiens, in Minne¬
sota. Occasional Papers of the University of Minnesota
Bell Museum of Natural History 15:1-23.

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September 1998

Milstein, Michael.

1990. Unlikely harbingers: the sudden, worldwide disappear¬
ance of amphibians alerts scientists to ecological break¬
down. National Parks July/August: 19-24.

Pierce, B. A.

1985. Acid tolerance in amphibians. BioSci. 34:239-243.

, J. B. Hoskin, and E. Epstein.

1984. Acid tolerance in Connecticut wood frogs (Ram sylvatica).
J. HerpetoL 18 (2):159-167.

. and J. M. Harvey

1987. Geographic variation in acid tolerance of Connecticut
wood frogs. Copeia 1987 (1):94-103.

, M. A. Margolis and L. J. Nirtaut.

1987. The relationship between egg size and acid tolerance in
Rana sylvatia. J. HerpetoL 21(3):178-184.

, and Montgomery

1989. Effects of short-term acidification on growth rates of tad¬
poles. J. HerpetoL 23(2):97-102.

, and N. Sikand.

1985. Variation in acid tolerance of Connecticut wood frogs:
genetic and maternal effects. Can. J. Zool. 63:1647-1651.

. and D. K. Wooten.

1992. Genetic variation in tolerance of amphibians to low pH.
J. HerpetoL 26(4):422-429.

Pough, E H.

1976. Add precipitation and embryonic mortality of spotted
salamanders, Ambystoma maculatum. Science 192:68-72.

, and R. E. Wilson.

1977. Acid precipitation and reproductive success of Ambystoma
Salamanders. Water, Air, and Soil Pollution 7:307-316.

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September 1998

Sadinski, W. J. and W. A. Dunson.

1992. A multilevel study of effects of low pH on amphibians of
temporary ponds. J. Herpetol. 26(4):413-422.

Salthe, S. N.

1965. Increase in volume of the perivitelline chamber during
development of Ram pipiens Schreber. Phisiol. Zool.
38:80-98.

Wissinger, S. A. and H. H. Whiteman.

1992. Fluctuation in a Rocky Mountain population of sala¬
manders: anthropogenic acidification or natural varia¬
tion? J. Herpetol. 26(4):377-391.

FrimMed, 698 Brooklawn, Bridgeport , CT 06604.

Department of Biology Sacred Heart University, Fairfield,
Connecticut 06432, USA. zvatkinsg@sacredheart.edu

Received: 22 April 1998

Accepted: 27 May 1998

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 3

September 1998

SCELOPORUS POINSETTI: ITS TAXONOMIC
AFFINITY WITH MUCRONATUS

R. Earl Olson

Populations of Sceloporus poinsetti and of Sceloporus mucronatus have
not been reported to approach each other geographically, so that observa¬
tions of a population near Huichapan, Hidalgo, Mexico exhibiting char¬
acters of both taxa is of interest. Specimens from nearby areas have con¬
sistently been referred to S. mucronatus. Yet 2 of 4 individuals from the
Huichapan locality are identical with individuals of S. poinsetti poinsetti in
most characters, whereas in certain characters of pattern 2 others are in¬
definite of identity, resembling, in certain features, some specimens of
S. mucronatus from Veracruz. Review of examples from the region has
helped to clarify the issue, a study from which this paper results.

Sceloporus poinsetti was described by Baird and Girard in 1854, S.
mucronatus by Cope in 1885. The taxa have retained species status during
more than a century following, with the exception that Boulenger referred
to both as subspecies of S. torquatus (1885, 1897), he accepting the number
of dorsal scales, length of the fourth toe and the tibia as diagnostic.

Diagnostic Characters

Striking differences between these taxa have been given as those of
pattern, particularly the caudal banding — distinct, broad, alternating dark
and light bands, most distinct toward tip of tail in S. poinsetti , absent or
not of equal width, incomplete near tip in — and the broad white margins
of the nuchal collar and a broad light band behind occiput in poinsetti
with narrow white collar borders in S. mucronatus, but no postocciptal
light band.

Regarding Boulenger 's consideration of these taxa as subspecies of S.
torquatus, it is to be noted that throughout almost the entire range of S. torquatus
the dorsal pattern alone is far different from and without tendency toward
that of the S. poinsetti-mucronatus complex where the ranges approach each
other. Furthermore, habitat of S. torquatus is at much higher elevation than
that observed for most populations of S. poinsetti (Olson, 1990).

*Send requests to MSA Laboratories, 133 S. Cleveland Cambridge, MN 55008 U.S.A.

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Figure 1. Anterior dorsal patterns of examples of Sceloporus. Upper left:
#5863, 6.7 mi. SW Huichapan, Hidalgo, Mexico. Upper right: #5864, same
locality as above. Lower left: #1223, W. Acultzingo, Veracruz, Mexico.
Lower right: #5966, Ramirez, Veracruz.

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Population Comparisons

Samples of Sceloporus poinsetti from various portions of its range in
Mexico give indication of individuality of expression of each population.
Some of these were compared with specimens from northern Mexico, Texas
and New Mexico.

In all samples except Durango specimens (central and Western Texas,
central New Mexico, southern Zacatecas, and Hidalgo) the nuchal collar
is narrow (3 scales broad), the collar borders broad (2 or more scales), and
there is a post-occipital light bar, almost as if an additional light collar
border. Specimens from west of cd. Durango have broad, deep set nuchal
collars (5 scales broad) broad borders (not distinctly so broad, however,
because of the breadth of the collar itself), and a post-occipital light bar
which often becomes indistinct in mature individuals. Thus S. p. macrolepis
is quite distinct from other populations by virtue of pattern alone.

The pattern in most populations involves, to some degree, a series
of 3 or 4 dark dorsal cross-bars. These tend to be indistinct in Zacatecas
animals, and somewhat so in specimens from Hidalgo. Zacatecas speci¬
mens, especially larger examples, tend to be tan or dusky dorsally, in con¬
trast to the gray to blue-gray of most populations, with barred dorsum
mentioned above. (Zacatecas populations were often found to inhabit
open, dry soil situations with elaborate burrow systems in the soil, unlike
the usual saxicolous habitats.)

Males in northerly populations have medium to dark blue belly
patches with heavy, black borders medially, these either contacting medi¬
ally or not. I do not find these features in more southerly populations.
Rather, the belly patches are medium to light blue, lack much of a border
and are separated along the midline by a light area 6 or more scales across.

A specimen (REO 5864) from 6.7 mi. SW Huichapan, Hgo. is taken
to be anomalous in pattern. This specimen is 54 mm svl. with well-de¬
fined throat bars. The dorsum is olive with paravertebrally arranged,
cream-colored chevrons. The nuchal collar is olive-brown, the borders of
which are cream-colored, broken medially. Caudal bars are moderately
distinct. In this it closely resembles a juvenile of S. mucronatus (#1227)
from near Puerto del Aire, Veracruz. Many specimens of S. mucronatus
have alternating olive and black caudal bars; those from hilly areas above

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Acultzingo, Veracruz often have sharply black-and-white barred tails.
Adults from the Hidalgo locality bear weakly-barred tails, and two (5862
& 5863) have continuous dark dorsal blotches rather than crossbars,
whereas a third (5874) is nearly plain. The nuchal collars and borders re¬
semble, in other respects, those of S. poinsetti elsewhere. It is to be noted
that the collar borders are usually broader (ca. 11/2 scales) in specimens
of S. mucronatus from Las Vigas and La Joya, Veracruz, and especially
from Oaxaca, where the distinct caudal barring is again observed.

Nearby

Examples from two other localities show influences of S. poinsetti.
Two from Amealco, 15 km. SE Huichapan exhibit strong tendencies, MZFC
3461(a) having faint but equal-width tail bands, narrow collar (3-3 1/2
scales), with broad borders (1 1/2 scales), another, MZFC 3461(b), having
broad black (3) and narrow white (1) tail bands, postoccipital bar, and
medium (1-1 1/2) collar borders. Of 14 others from Ajacubo, 35 mi. SE
Huichapan, 8 have distinct, equal or nearly equal width tail bands (3 of 14
have incomplete tails), 5 have a complete 1-2 scale broad postoccipital
band, and 8 have broad collar borders. But two from 6 mi W Huichapan
(UTEP), are not so similar as above (Table 1.).

Table 1. Scalation.

Femoral

N

Dorsals

Ventrals

Pores

Preoculars

HIDALGO

6.7 mi. SW Huichapan (REO)

4

32-39

44-50

10.9 (9-12)

1 (all)

8.5 mi. NE Pachuca (REO)

1

31

42

13-14

1

Ajacuba (MZFC)

14

28-39

39-51

13.0 (10-15)

1-2 (1.6)

Amealco (MZFC)

2

31.5

46

12-13

1

TLAXCALA

4.5 mi. N Taxco (REO)

3

28-31

41-48

20 mi. N Apizaco (REO)

5

28-31

41-48

12.6 (11-15)

1-2 (1.2)

VERACRUZ

2 mi. ESE Las Vigas (REO)

5

26-30

39-43

12.2 (10-14)

1-2 (1.4)

0.6 mi. S Perote (REO)

2

29

— -

11 (8-14)

1-2 (1.5)

1.2 mi. WNWLaJoya (REO)

6

27-31

42-43

11.7(10-14)

1-2 (1.1)

2-3.5 mi. WSW Acultzingo (REO) 4

33-38

44-50

15.0 (11-18)

1.0 (all)

ENE Puerto del Aire (REO)

2

36-37

47-49

15.0 (14-16)

1.0 (all)

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Fui ther by comparison, features of the taxa are similar or identical.
Belly patches in adult males do not differ significantly And the parallel
medial lines on the throat in females are shared, as is the blue spot on the
shoulders in the nuchal collar field. Supraoculars are in a double row in
both, and scale counts are in agreement. Dentition features are so similar
between the taxa (Figure 2.) as to be indistinguishable (Olson et al. 1986,
1987). Alvarez and Huerta (1973) show similar data.

Figure 2 Dentition examples.

Left: lingual view of teeth 15-17 on left dentary. #11469, 3.8 mi. SE
Arenal, Zacatecas, Mex.

Right: lingual view of teeth 13-15, left dentary. #11466, above Puerto
del Aire, Veracruz, Mex.

Discussion

The considerable overlap and intergrading of characters through¬
out the population complex, and features observed in the Hidalgo locali¬
ties rendering many examples non-definitive as to classification lead to
the conclusion that a single species is involved, and that the Huichapan
area examples are intergrades. Since the name S. poinsetti appears some

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30 years prior to mucronatus , the assemblage is to appear under the name
Scdoporus poinsetti .

Acknowledgments

Thanks are due Dr. Hobart M. Smith for advice and support during
this work, to Dr. Adrian Nieto Montes de Oca of Museo de Zoologia,
Mexico (MZFC), Dr. Robert G. Webb, Univ. Texas El Paso (UTEP), and Dr.
William E. Duellman, Univ. Kansas Mus. Nat. Hist, for loan of specimens,
and to Dr. Duellman and John Simmons for helpfulness during work at
the museum.

I deeply appreciate the financial assistance from The Canada Re¬
search Fund and Walker Van Riper Fellowship. Time and facilities from
the Organization of Tropical Research were very helpful.

Literature Cited

Alvarez, T. and P. Huerta.

1973. Notas Sobre Scelopoms mucronatus (Reptilia: Tguanidae).
An. Esc. Nac. Cienc. Biol, Mex. 20:177-184.

Baird, R.G., and C. Girard.

1854. Characteristics of some New Reptiles in the Museum of
the Smithsonian Institution. Proc. Philadelphia Acad. Sci.
6:125-129. Boulenger, G. A. 1885. Catalogue of the Lizards
in the British Museum (Natural History). Vol. L xii, 436pp.

1897. A Revision of the Lizards of the Genus Scelopoms. Proc.
Zook Soc. London (Til). 474-522.

Cope, E. D.

1885. A Contribution to the Herpetology of Mexico. Proc. Ameri¬
can Philos. Soc. 22:379-404.

Olson, R. E.

1990. Scelopoms torquatus: Its Variation and Zoogeography. Bull.
Chicago Herp. Soc. 25(7); 117-127.

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___ , B. Marx and R. Rome.

1986. Descriptive Dentition Morphology of Lizards of Middle
and North America, I: Scincidae, Teiidae, and
Helodermatidae. Bull Maryland N. Hist. Soc. 22(3): 97-124.

1987. Descriptive Dentition Morphology of Lizards of Middle
and North America, Iguanidae. Bull. Maryland Nat. Hist.
Soc. 23(1): 12-34.

American University of the Caribbean , Les Cayes , Haiti

Received: 8 July 1998
Accepted: 26 July 1998

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CANNIBALISM IN BOTHROPS ASPEFL

There are numerous records concerning cannibalism in snakes
(Mitchell, 1986), this phenomenon occurs more commonly in captivity
(Kiauber, 1972). Although there are reports of cannibalism in some spe¬
cies of "nauyacas" like Bothrops jararaca, Botriechis nigroviridis , B. schiegeli,
Porthidium nasutum (Mitchell, 1986), and Bothrops atrox (Martins and Gordo,
1993), there is a general lack of information on one of the most common
species of the group B. asper .

The "Laboratorio de Herpetologia Vivario de la UNAM Campus
Iztacala," located in Mexico City has successfully maintained this species
since 1986. On July 14th, 1993; a 7 year old female bom in captivity and
weighing 3,468 g. gave birth to 52 youngsters (mean SVL = 263 mm; TL =
305 mm; weight = 12 g), 35 of them were alive, 17 dead and in addition
there were 5 infertile eggs found. At the beginning youngsters were raised
in enclosures of wood and plastic construction (32 X 18 X 39 cm); in groups
of 6 organisms. The bottom of the enclosure was covered with newspaper
(with twice per week changes), and water was offered ad libitum in a plas¬
tic dish.

The literature refers that adults of this species feed mostly on small
mammals as wild rats, mice and birds, while the youngsters prefer frogs
and lizards (Mehrtens, 1987; Alvarez del Toro, 1982). In captivity this spe¬
cies, young of adult, easily accept rats or mice as food, so we fed the young¬
sters small mice (Mus muse ulus) once by week.

After three months the animals began to show eye problems due to
bites that they were receiving from their "room mates." For this reason
we separated them in groups of 2 organisms in each enclosure. The morn¬
ing of October 18th, 1993, we found one of the youngsters (SVL = 350 mm;
TL = 418 mm) swallowing up to the half of the body of its companion
(SVL = 315 mm; TL = 365 mm); we carefully moved the snakes causing
regurgitation. When the "prey" was completely released we could see
that it was alive and in perfect condition, without a single sign of wounds.
After this, both youngsters were separated and placed in individual cages,
and no further problems arose.

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Later, on November 12th, 1993; mid-morning, we detected the ab¬
sence of an organism from one of the enclosures. The only youngster still
in the cage (SVL = 298mm; TL = 348 mm) showed it swollen belly (Fig. 1).
palpating the body of the snake, we could confirm that it was full with
another snake.

Figure 1. Youngster Bothrops asper showed swollen belly.

On January 27th, 1994 in the afternoon, another youngster swallowed
its companion. We were waiting for the next day to obtain an x-ray series,
but when we came for the organism, we found that the "prey" was regurgi¬
tated, probably due to its size (quite the same than its own). The regurgi¬
tated organism showed signs of advanced digestion especially on the head.

One of the most interesting observations resulting from this report,
is the face, that one snake swallowed another live snake. In most of canni¬
balism reports, there is a lack of knowledge regarding whether the "prey"
was or was not dead or injured before it was swallowed; generally it is
suggest that the "prey" was intentionally killed before swallowing, as it
has been reported for the boid Candoia carinata swallowing an individual
of Charina b. bottae (Michaels, 1985), or that it is already dead before swal¬
lowing (Mitchell, 1986).

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In the other two cases we have referred regarding B. asper it is pos¬
sible that the case was similar to the first related here, but we can not be
assure because we did not observed the real ingestion process. It is also
possible that they were attacked and injured or even killed previously to
the ingestion, as it is known to occur in other species of "nauya :as" where
the slightest movement provokes an attack.

The real causes of cannibalism are not well known in snakes; al¬
though many theories have been proposed (Mitchell, 1986), more infor¬
mation is needed to substantiate them. This prolific and relatively easy-
to-maintain species can greatly contribute to the understanding of the
phenomena.

Literature Cited

Alvarez del Toro.

1982. Los reptiles de Chiapas. Pub. Inst. Hist. Nat. Tuxtla
Gutierres, Chiapas. 248 pp.

Klauber, L. M.

1972. Rattlesnakes. Their Habits, Life Histories, and Influence
on mankind. 2”. 2 vol. Univ. California Press*. Berkeley,
1533 pp.

Michaels, S. J.

1985. Candoia carinata (Solomon Island Boa). Ophiophagy. Her-
petological Review 16(2):54.

Mitchell, J. C.

1986. Cannibalism in reptiles a Worldv4de Review, SSAR Herp.
Circ. 15, 37 pp.

Martins, M. and Marcelo Gordo.

1993. B,,throps atrox (Common Lancehead). Diet. Herpetologi-
cal Review 24(4). 151-152

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Mehrtens, J. M,

1987. Living Snakes of World in color. New York, Sterling 480
pp., ill. (color).

Felipe Correa Sanchez , Amaya Gonzalez Ruiz and Enrique Godinez Cano
Lahoratorio de Herpetologia , Jefatura de Biologia , UNAM Campus Macula ,
Apartado Postal 314 , Tlanepantla, Estado de Mexico , Mexico, 54090.

Recieved: 25 November 1997
Accepted: 18 January 1998

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BOOK REVIEW:

T. REX AND THE CRATER OF DOOM . BY WALTER
ALVAREZ. 1997. PRINCETON UNIVERSITY PRESS,
PRINCETON, NEW JERSEY, 185 PP. HARDCOVER.
US $24.95. ISBN 0-691-01630-5. THE GREAT DINO¬
SAUR EXTINCTION CONTROVERSY, 1 BY CHARLES

OFFICER AND JAKE PAGE. 1996. ADDISON-
WESLEY, NEW YORK, 209 PP. HARDCOVER US
$25.00. ISBN 0-201 -48384-X.

Jeffrey V. Yule

Contemporary vertebrate diversity in general and reptilian diver¬
sity in particular are tied to a 65-million-year-old event known as the Cre¬
taceous-Tertiary (K/T) extinction, which eradicated six entire reptilian
orders: two of dinosaurs, three of aquatic reptiles, and one of pterosaurs.
The subsequent diversification of both reptiles and mammals c an only be
fully understood in the context of this incident. Understandably, then, the
K/T extinction has long been a matter of broad scientific interest. In 1980,
an article whose authors included Nobel-laureate physicist Luis Alvarez
and his geologist son Walter initiated an energetic scientific debate by
arguing that a meteorite impact caused the extinction. The evidence pre¬
sented for that claim was the presence of unusually high levels of the
element iridium in the sediments marking the event. Although rare in the
Earth's crust, iridium occurs in higher concentrations in meteorites, and
the authors suggested an impact best explained the anomaly. Seventeen
years later, there is still no consensus as to whether the Alvarez team's
hypothesis is correct Although it has gained many supporters, critics re¬
main, Among the detractors are those who favor traditional,
noncataclysmic explanations for the K/T extinction, such as shifts in cli¬
mate and sea level. Others believe that the extinction — and the iridium
anomaly — resulted from massive volcanism.

Two recent books address the impact vs. volcanism debate. Walter
Alvarez's T. rex and the Crater of Doom sets forth the pro-impact argument,
while Charles Officer's and Jake Page's The Great Dinosaur Extinction Con-

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troversy presents the evidence for volcanism. As is typical of works that
treat unresolved scientific debates, the two books contradict one another's
conclusions at every turn — but not with equal success. T. rex and the
Crater of Doom presents an overview of the pro-impactors' evidence and
discusses how it has been tested. The Great Dinosaur Extinction Contro¬
versy , on the other hand, focuses undue attention on peripheral issues
while giving short shrift to matters of central interest. In particular. Of¬
ficer and Page opt for flawed rhetorical strategies and ignore the difficul¬
ties they face in squaring their interpretations of key evidence with the
conclusions of the broader geological community. Alvarez's discussion of
the impact position suffers from none of these problems.

Although the title T. rex and the Crater of Doom suggests a particular
concern with dinosaurs at the K/T extinction, Alvarez focuses on attempts
to substantiate the impact hypothesis by addressing iridium anomalies
and other geological evidence, including the smoking-gun evidence of
the hypothesized reptile-killing impact: the crater itself. Alvarez presents
a nontechnical account of the search for that key piece of evidence, now
thought to be the Yucatan's Chicxulub (Cheek-shoe-lube) crater. He
contextualizes the search within the broader framework of modern geol¬
ogy, discussing matters from radioactive dating and geological mapping
to the shift of opinion that led geologists to recognize the importance of
catastrophic as well as uniformitarian processes.

Alvarez is particularly successful at explaining just how devastat¬
ing the impact of a 10-kilometer meteorite would have been. He effec¬
tively presents the un familiar in light of the familiar, comparing the object's
diameter to that of modern-day San Francisco and describing its probable
final velocity of 30 km/ sec as 1,000 times faster than a car on the highway.
His ability to provide useful perspective extends to other matters as well,
as when he explains that the impact would have released enough energy
to vaporize the meteorite within a second while producing a hole with a
momentary depth of 40 km. This hole would have almost instantly col¬
lapsed tc form a broader, shallower crater 150-200 km across. Under these
circumstances, Alvarez writes, the "Earth would suffer cataclysmic dam¬
age in less time than it takes to read this sentence." To the author's credit,
he makes that point clearly, briefly but ably covering matters from the
vaporization of bedrock and subsequent atmospheric heating and forest
fires to the effects of a giant tsunami, greenhouse gases, and add rain.

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Despite its strengths, however, Alvarez's account suffers from be¬
ing too reader friendly, general, and nontechnical Although end notes
direct interested readers to a variety of sources for further details, he is at
times more interested in offering marginally significant personal remi¬
nisces than in addressing pertinent scientific matters. For instance, Alvarez
ignores provisional answers that have been offered to some of the ques¬
tions he raises — as when he writes that it is not clear whether the impact¬
ing object was a comet or a meteor and that no one has been able to satis¬
factorily explain why dinosaurs and other organisms went extinct while
turtles, crocodiles, and a host of others did not. Both of these matters have
been addressed in some detail by among others, David Brez Carlisle, who
has gone to especially great lengths to establish the impactor's cometary
origin. Alvarez's failure to mention Carlisle's or other researchers' work
on these and a variety of other matters represents a mild puzzle regard¬
less of whether or not he accepts their conclusions. His account of the
development of the impact hypothesis could only have benefited by ad¬
dressing some of the matters he raises in greater detail. In general, though,
while T. rex and the Crater of Doom does not treat the impact- volcanism
debate comprehensively, it offers a clear and reasonably fair overview.
The same cannot be said of The Great Dinosaur Extinction Controversy .

Officer — who, along with Charles Drake, formulated the explo-
sive-volcanism hypothesis — has long argued for a volcanic cause for the
K/T extinction. The well-publicized polarity of the impact-volcanism de¬
bates notwithstanding, however, the reader has a night to expect that some
attention will be paid to counterarguments. Yet Officer and Page repeat¬
edly downplay or ignore the existence of other reasonable points of view.
Officer's assertion that shocked quartz associated with the K/T bound¬
ary layer was formed during volcanic explosions contradicts accepted
beliefs about its diagnostic value in identifying impact sites, a consider¬
ation raised both in T. rex and the Crater of Doom and elsewhere (Carlisle
96; Glen 68). Although Officer and Neville Carter produced evidence of
shocked quartz crystals associated with volcanic activity, Alvarez explains,
their samples never quite matched the damaged crystals associated with
known impact craters and the K/T boundary laver (97). In writing that
volcanoes are "unquestionably responsible" (112) for iridium anomalies.
Officer and Page similarly ignore opinions at variance with their own. At
times that strategy is so obviously flawed that one wonders how the book

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ever saw print, especially in light of its other problems of consistency
and rhetoric.

For example. Officer and Page twice devote attention to a 1984 opin¬
ion poll showing that a minority of German and British paleontologists,
Soviet geoscientists, and American geophysicists accepted the Alvarez
hypothesis (102-104; 186). This poll, they suggest, was wrongly ignored
in a 1989 Washington Post article written by Richard Kerr. The reader is left
to wonder just how important this supposed oversight might be — after
all, the poll was five years old when Kerr "ignored" it and it is 12 years
old now. Officer and Page invoke the 1984 poll again in attempting to
argue that, as often happens with pathological science, opinion in favor
of erroneous research initially rises towards 50 percent before falling off
to oblivion (186). Here, they suggest that acceptance of the impact hy¬
pothesis is and should be falling off, yet their only evidence for such a
shift in opinion is one outdated poll — a fact that they seek to excuse by
noting that they are unaware of any recent surveys on the matter. Since
graduate students working on theses or dissertations would be expected
to undertake their own polling in such a situation, it is difficult to under¬
stand why these authors do not behave similarly in writing a book.

Among the many factors adversely affecting Officer's and Page's
attempt jo present their position, perhaps the most damaging is another
rhetorical consideration. They give the appearance of trying to make their
case in the style of a shrewd but cynical prosecutor — - by executing a
smear campaign against the defendant. While Alvarez is always civil and
sometimes even gracious to his critics. Officer and Page generally are not.
Alvarez comments that the frustrating ten-year search for the crater was
actually a blessing, noting that "an early discovery of the impact site might
have short-circuited the intense challenge to each bit of evidence that
Chuck Officer compelled us to face." At least occasionally, Alvarez also
notes when other researchers' opinions on key issues differ from his own.
He writes, for example, that members of Officer's so-called Dartmouth
group are among a minority of researchers who don't accept the presence
of small glass particles called microtektites as evidence of an impact —
this despite the fact that pro-impact researchers consider microtektites to
be among their most important evidence. In a refreshing move away from
the either-or thinking often characteristic of the impact volcanism debates.

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Alvarez even concludes by suggesting that volcanism might play a role in
the final explanation of events despite the fact that an impact appears to
have been a more important factor (142-144). By contrast. Officer and Page
attempt to make their case by impugning the integrity of pro-impact re¬
searchers and their work. They write, for instance, that "most of the 'sci¬
ence" performed by the Alvarez camp has been so inexplicably weak, and
the response to it so eagerly accepted by important segments of the scien¬
tific press... that some skeptics have wondered if the entire affair was not,
on the impact side, some kind of scam" (xiii). In what reads as a transpar¬
ent attempt to make that very charge without being required to substanti¬
ate it, they immediately back away from their statement, noting that they
lack the investigative skills necessary to substantiate such an allegation.
Instead, they write, they will limit themselves to the "scientific merits of
the case" (xiii). It is thus with some surprise that the reader later finds
Officer and Page bringing personalities into their analysis.

Their sixth chapter opens by focusing on the late Luis Alvarez's al¬
leged personal shortcomings, in particular arrogance and intolerance of
disagreement. Once again. Officer and Page sound a modest note, writ¬
ing that they lack the necessary skills to determine why a researcher would
behave so poorly; instead, they reiterate, they will focus on the scientific
merits of the case. Inexplicably, they then attempt the very sort of assess¬
ment of Luis Alvarez that they so recently admitted they were incapable
of formulating. Eventually, they offer a brief and not especially convinc¬
ing explanation for doing so. Based on the elder Alvarez's shortcomings,
they finally reveal, it could have been predicted that "he would have had
some trouble getting along with geologists and paleontologists ' (82). Why
this line of evidence would be crucial to making the volcanism argument
is not clear. Moreover, the argumentative strategy employed in the rest of
the book suggests that Officer's and Page's motivation for including their
anti-Luis Alvarez section was to attack the most well-known researcher
associated with the hypothesis in an effort to damage it by association.
Such a strategy would certainly be in keeping with their generally
scattershot approach. One of their main lines of argument is to portray
those who take the opposite view as a wrong-headed group of potential
flimflam artists. If there is any flimflam to be found in The Great Dinosaur
Extinction Controversy , however. Officer and Page are the ones seeking to
perpetrate it.

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Inconsistencies as well as attempts at misdirection abound in their
argument. For instance, they note that the publicity gained by the Alvarez
hypothesis might have done harm to the environment by diverting atten¬
tion from the current global extinction crisis (6) — a consideration which
is neither here nor there insofar as their argument goes but which might
gain them something if a reader were willing to dislike an environmen¬
tally unfriendly hypothesis. Still, they offer no evidence to support their
claim. On the previous page, in fact, they contradict it. There, we find that
the impact hypothesis is potentially ecofriendly since it might have drawn
attention to the spate of extinctions currently being caused by human ac¬
tivities. At times, then, Officer's and Page's prose can best be character¬
ized as muddled. The authors are at their best when they examine the
scientific evidence, as when they outline the problems with the Chicxulub
site as the "smoking-gun" crater (151-157). Unfortunately, these sections
are not as common as they ought to be and even when they do turn up
they tend to be exceedingly one-sided. In discussing the Chicxulub crater,
for instance, they briefly report pro-impact researchers' conclusions only
to summarily dismiss them. By contrast, in discussing the same matter
Alvarez presents the pro-impactors' conclusions, a brief overview of pro¬
volcanists' critiques of those conclusions, and then an outline of the re¬
search pro-impactors undertook to address those critiques. While the pro¬
impact p osition deserves a careful cross-examination. Officer and Page
have not offered one here. If, as they maintain, the public has been hood¬
winked nto accepting a hodgepodge of bad science as the genuine ar¬
ticle, they have set themselves up for the job of debunking it, but they
never fuTy engage that task.

Even among those who accept that an impact took place near the
time of the K/T extinction, there is no agreement that the impact was the
sole or even the most important factor in the extinction. It might turn out,
as the University of Pennsylvania's Peter Dodson has recently suggested,
that the dinosaurs were eliminated not by any one cause but, instead, by
a "symphony of causes" (280), from changing sea level and climactic shifts
to volcanism and mountain building. But more and more lately it appears
that the relevant scientific communities see a connection between iridium
and the extinction event that wiped out a fantastic array of Mesozoic rep¬
tiles. In setting forth its case, T. rex and the Crater of Doom may not thor¬
oughly cover all the reasonable counterarguments, but it does recognize

page 92

Bulletin of the Maryland Herpetological Society

Volume 34 Numbers

September 1998

that they exist. Regrettably, the various shortcomings of The Great Dino¬
saur Extinction Controversy provide little reason to question the impact
hypothesis. While scientists need not necessarily be civil to one another
to maintain their credibility, they must at least rely on argumentative strat¬
egies that play fair. By allowing himself to be associated with a work that
fails to do so. Officer calls into question his entire argument. Thus,
Officer's and Page's characterization of pro-impactors as pathologically
self-deluded should be taken with a grain of salt. Although the pro-volca-
nism school might have a case to make, we will have to wait at least a
while longer to see it in print.

Works Cited

CARLISLE, D. B.

1995. Dinosaurs, Diamonds, and Things from Outer Space: The
Great Extinction. Stanford Univ. Press, Stanford, Califor¬
nia. 241 pp.

DODSON, R

1996. The Horned Dinosaurs. Princeton Univ. Press, Princeton,
New Jersey. 346 pp.

GLEN, W.

1994. "How Science Works in the Mass-Extinction Debates."
W. Glen (ed.). The Mass-Extinction Debates: Etozv Science
Works in a Crisis, pp. 39-91. Stanford Univ. Press, Stanford,
California.

4315 Wiltshire Avenue, Baltimore, Maryland 21206

Reviewed: 9 October 1997

Bulletin of the Maryland Herpetological Society

page 93

Volume 34 Number 3

September 1998

BOOK REVIEW:

AMPHIBIANS AND REPTILES OF THE GREAT
LAKES REGION , BY JAMES H. HARDING, 1997,
UNIVERSITY OF MICHIGAN PRESS, ANN ARBOR,
MICHIGAN, VII-XVI + 1 78 PR 83 PIS. II FIGS., 78
MAPS, ISBN 0-472-09628-1 , CLOTH, $49.50 AND
ISBN 0-472-06628-5, PBK. $19.95.

In this modestly priced volume, Harding certainly achieved his stated
aims to provide a specific reference guide for identification, distribution,
and life history of those herptiles occurring within the Great Lakes Re¬
gion, which includes the following states: Illinois, Indiana, Michigan,
Minnesota, New York, Ohio, Pennsylvania, Wisconsin, as well as the Ca¬
nadian Frovince of Ontario.

The introduction provides guidance on the importance of Amphib¬
ians and Reptiles in our Ecosystem, along with a brief introduction on the
Conservation of the Herpetofauna, and a list of addresses for Govern¬
mental Agencies, which provide current legal information and permit re¬
quirements is given just prior to the Index. The introduction is followed
by a section on definitions, origins, classification and checklist of species
found within the Great Lakes Region.

Three to six pages are devoted to individual species accounts, along
with color range maps for the 75 species and subspecies of Amphibians
and Reptiles recorded from the region. Each species accounts includes
traditional description, remarks on distribution, habitat, ecology, repro¬
duction, growth, status, and Conservation. The author also provides de¬
scriptions for ten additional marginal and questionable species that pos¬
sibly could turn-up in the Great Lakes Region.

The book is attractively laid out, and photo quality is consistently
high throughout. The only drawback appears in the distributional maps,
which can be deceiving, as they reflect the overall distribution, as seen
in the major Field Guides, and not the true present distribution of each
species. A much more accurate format would have been to show spot
localities for museum specimens, literature accounts, or other reliable

page 94

Bulletin of the Maryland Herpetological Society

Volume 34 Number 3

September 1998

observations, with different symbols for each. The author also fails to
provide a key for the identification of the 75 taxa represented, although
this can possibly be explained by the author having mentioned In the
Preface, that the book was designed for non-specialist, although profes¬
sional will find this volume of considerable importance as a reference
for ecological data. The illustrations and maps are placed along with
each species account, and not centrally located as in so many recent her-
petological works. This certainly is a plus for anyone not familiar with
the herpetofauna of their area.

I found no topographical errors in the text, and the book is printed
on acid-free paper, with the font easy-on-the-eyes. Overall the book is
attractively laid out, and the quality and accuracy of the text are excep¬
tional, and should serve as an excellent guide for anyone interested in the
Herpetofauna of northeastern and north-central United States.

Harlan D. Walley , Department of Biology, Northern Illinois
University , DeKalb, Illinois 60115.

Received: 9 February 1998

Bulletin of the Maryland Herpetological Society

page 95

Volume 34 Number 3

September 1998

News and Notes:

Smithsonian Institution Press

470 LENFANT PLAZA, SUITE 7100, WASHINGTON, D.C, 20560

SALAMANDERS OF THE UNITED STATES AND CANADA

TITLE

JAMES PETRANKA

AUTHOR

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ISBN CLOTH
$60.00

ISBN PAPER

PRICE (CLOTH)

SEPTEMBER 11, 1998

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For further information contact: Brenda Tucker
BTUCKER@SIPRESS.SI.EDU

Marketing Department
202/287-3738, ext. 343

Please send two copies of reviews.

Ordering information: Books may be ordered from
Smithsonian Institution Press, P.O. Box 960, Herndon,

VA 20172-0960, 1-800/782-4612. Please include $3.50
postage and handling for the first book and $1.00 for each
additional book.

page 96

Bulletin of the Maryland Herpetological Society

News and Notes :

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.

Volume 34 Number 3

September 1998

, ,,

News and Notes:

V

The archipelago of Indo-Malaya, stretching
from the Andaman and Nicobar Islands,
eastward to Timor, is the large st in the world
(approximately 14,000 islands), and includes
several political entities. Much of the land
area and associated coastal water fall within
the political boundaries of a single nation, that
of the Republic of Indonesia. However,
significant portions are controlled by India,
Myanmar or Burma, Malaysia, and the
Philippines. This work is a comprehensive
bibliography of the scientific papers, magazine
and newspaper articles, books book reviews,
museum catalogues, bibliographies, chapters
from books, and theses that contain references
to any species of amphibians and reptiles in
this region. Both terrestrial and aquatic taxa
are included. Languages in the cited literature
include Bahasa Indonesia, Chinese, Dutch,
English, French, German, Hungarian, Italian,
Japanese, Latin, Polish, Portugese, Russian,
and Spanish.

Dr. Das is currently Associate Professor,
Universiti Malaysia Sarawak.

Orig. Ed. 1998 $22.50 96 pp. ISBN 1-57524-026-2

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The Society also publishes a Newsletter on a somewhat irregular
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Major papers are those over five pages (double spaced, elite type)
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The Maryland Herpetological Society
Department of Herpetology
Natural History Society of Maryland, Inc.

2643 North Charles Street
Baltimore , Maryland 21218

of Maryland

US ISSN: 0025-4231

BULLETIN OF THE

Warylanb

fierpetological

0oriety

DEPARTMENT OF HERPETOLOGY
THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.

MDHS . A Founder Member of the Eastern

Seaboard Herpetological League

30 DECEMBER 1998 VOLUME 34 NUMBER 4

7 ) 5

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 34 Number 4 December 1 998

CONTENTS

Morphological Variation and Relationship of Rhadinaea hogertorum
(Squama (a: Colubridae), an endemic Snake of the Sierra De Juarez, Oaxaca,
Mexico

Aurelio Ramierez-Bautista, Mario Mancilla-Moreno,
Hobert M. Smith, David Chiszar and Frank
VanBreukelen . 99

The Report of the Snake Genus Conophis in South America is Erroneous

David L. Auth, Jean Mariaux, Joel Clary, David
Chiszar, Frank van Breukelen and Hobart M.

Smith . 107

Abundance and Water Volume Effects in Amphibian Larvae

Geoffrey R. Smith . 113

BULLETIN OF THE

Volume 34 Number 4

December 1998

The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.

President
Executive Editor

Tim Hoen

Herbert S. Harris, Jr.

Steering Committee

Jerry D. Hardy, Jr.

Frank B. Groves

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

Membership Rates

Membership in the Maryland Herpetological Society is $20.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $30.00 per year. Make all checks payable to the Natural History
Society of Maryland, Inc.

Meetings

The third Wednesday of each month, 7:30 p.m. at the Baltimore Zoo’s
Reptile House (except August and September due to The Mid-Atlantic
Reptile Show). The Department of Herpetology meets informally on all
other Wednesday evenings at the NHSM at 8:00 p.m.

Volume 34 Number 4

December 1998

MORPHOLOGICAL VARIATION AND RELATIONSHIP
OF Rhadinaea bogertorum (SQUAMATA:
COLUBRIDAE), AN ENDEMIC SNAKE OF THE
SIERRA DE JUAREZ, OAXACA, MEXICO

AURELIO RAMIREZ-BA UTIS TA, MARIO MANCILIA-MORENO,
HOBART M. SMITH , DAVID CHISZAR AND
FRANK VAN BREUKELEN

Twenty-five previously unreported specimens of Rhadinaea
bogertorum, five of R. macdougalli, and three of R. mversi, are described
and compared. They appear to represent a single complex which also in¬
cludes R. marcellae. for which the complex is named. Partial sympatry
occurs between the former two of southern Atlantic slopes; R. mversi is
dichopatric on southern Pacific slopes, and R. marcellae on northern At¬
lantic slopes. Rhadinaea macdougalli exhibits convergence with R.
marcellae in some characters where their ranges are most closely approxi¬
mated.

Rhadinaea bogertorum Myers has been known since its original de¬
scription (Myers, 1974) only from two specimens (AMNH 100906-7). We
here record variation in 25 previously unreported specimens of that spe¬
cies, and compare them with other recently collected material of the simi¬
lar species, R. macdougalli and R. mversi.

All specimens of R. bogertorum are from the Sierra de Juarez, north¬
ern Oaxaca, Mexico. New material we have examined is (museum acro¬
nyms as in Leviton et al., 1985): IBH (Instituto de Biologia, UNAM) 06249
(2), 11.4 km NE Cerro Pelon; IBH 11280, Santiago Comaltepec; KU 187299-
187303, 10.6 km N Cerro Pelon; LACM 130104, 7.2 rd mi SSE Vista
Hermosa; MZFC (Museo de Zoologia, Facultad de Ciencias) 04518,
Santiago Comaltepec, km 80.5 on Tuxtepec-Oaxaca Hwy; MZFC 04520,
Santiago Comaltepec, rd to San Isidro, km 190 on Tuxtepec-Oaxaca Hwy;
UCM 49355-7, 49359, 49361-6, 49367, 49369-70, 52384, Vista Hermosa.

Rhadinaea macdougalli Smith and Langebartel has been known only
from three specimens (Myers, 1974). We here report three additional ones

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 4

December 1998

(UCM 41189, 52493, 52669) from Vista Hermosa, Oaxaca, and two (MZFC
9946, 9947) from San Martin Caballero, Oaxaca.

Rhadinaea mversi Rossman has also been known only from three
specimens (Myers, 1974). We here report three additional animals, two
(UCM 44516, 44518) from Rio Sal, Lachao, Juquila, Oaxaca, and one (UCM
49353) from Santa Rosa, Lachao, Juquila, Oaxaca.

Variation in R. bogertorum. - All specimens have 8-8 supralabials,
except for three hatchlings with 7-8, and one with 7-7. The 4th and 5th
supralabials enter the orbit in all except those with 7 supralabials, in which
either the 3rd and 4th, or the 4th only (one side of UCM 49363, with 7-8)
enter the orbit. The infralabials vary from 9 to 11, the latter number was
found (KU 187303, UCM 49357) on one side only in two specimens; the
modal number is 10, occurring about twice as frequently as 9 (AMNH
100906, UCM 49355). The preoculars vary from 1 to 4, a single scale occur¬
ring on one side only in two specimens (UCM 49362-3), and on both sides
in two others (UCM 49356-7), and four scales occurring on one side in one
snake (UCM 49365); the modal number is two, occurring about twice as
frequently as three. The postoculars are 2-2 in all specimens except two
females (IBH 11280, MZFC 04518) with 1-2, and two males (UCM 49363,
KU 187299) with 1-1. The temporals are 1-2-3 in all except one male (UCM
49366) with 1-2-2 on one side, and two males (KU 187302, UCM 49362)
with 1-2-2 on both sides.

The dorsal scale rows are 17-17-17 in all except one male (KU 187303)
with 17-17-16, one female (UCM 52384) with 16-17-17, a male (UCM 49365)
with 15-17-17, and a male (UCM 49367) with 15-17-15. The ventrals are
160 to 170 in females (X = 165.2, n = 13), 144 to 158 (X = 153.7, n = 14) in
males. The range of variation in males (15) exceeds that in females (11).

The umbilicus is evident in eight hatchlings. It involves one or two
ventrals, usually just one. The anterior or single ventral interrupted var¬
ies from the 118th to the 137th, depending on the number of ventrals: it
varies from 81 to 85 per cent of the total ventral count from the first ven¬
tral (X = 82.9, n = 8), or 15-19% of the total ventral count from the anal
plate (X = 17.1, n = 8). The caudals (including the types) are 62-70 in fe¬
males (X = 65.9, n = 12), 65-80 (X = 72.7, n = 11) in males.

page 100

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

The largest specimen is a female 581 mm TTL (total length), the larg¬
est male 510+ mm (snout-vent length (SVL) = 402 mm and tail length (TL)
= 108 broken + 8 mm). The smallest snake measured 116 mm TTL, 35 mm
TL. However, most of the UCM specimens are hatchlings and so brittle
that they could not be measured. The tail/total length ratio varied from
0.21 to 0.27 (X = 0.24, n = 11) in females, and from 0.25 to 0.30 (X = 0.28, n
= 8) in males.

The color pattern of all specimens corresponds well with the de¬
scription and figures of the species in Myers (1974: figs. 10-11). In the larg¬
est specimen (UCM 49355) no evidence exists of dark lines between the
dark lateral sides; the vertebral dark line typical of the other specimens is
completely lacking throughout the length of the body. Loss of distinct¬
ness of lines appears to be ontogenetic. In hatchlings both vertebral and
dorsolateral dark lines (the latter on the adjacent edges of the 6th and 7th
scale rows) are evident either anteriorly, posteriorly, or both. In larger in¬
dividuals no evidence of the dorsolateral dark line remains.

The pale supraocular line deviates laterally far enough to engage
the rear edge of the posterior supralabial in all specimens except MZFC
4520, although it borders that scale in this specimen and, in several others
(UCM 49355, 49359, 49361) barely encroaches upon it. There is a narrow
break in the same pale line, the length of only one scale, on both sides of
one (UCM 49363) and one side of another specimen (UCM 49367). The
labials, mental and rostral are frequently immaculate white, but the ante¬
rior two or three labials (both upper and lower) bear a few black flecks in
about half the specimens, and in a few specimens similar flecks are also
present on the mental and/or rostral.

Variation in R. macdougalli.- It was somewhat of a surprise to find
that Thomas MacDougall, who collected all of the UCM specimens of the
three species here dealt with, found R. macdougalli sympatric with R.
bogertorum. All of the latter, however, were taken in 1972, whereas his R.
macdougalli were collected in 1967 and 1970. It is therefore likely that the
two species were not found in microsympatry, even though all are la¬
belled "Vista Hermosa". How their habitats differ there remains to be
determined. These specimens extend the known range of the species some
50 km northwestward from Yelagago, Oaxaca (Myers, 1974).

Bulletin of the Maryland Herpetological Society

page 101

Volume 34 Number 4

December 1998

The five specimens we examined appear to conform reasonably well
with those previously recorded (Myers, 1974). The supra labials are 8-8 in
all, 4th and 5th entering the orbit; infralabials 10-10 except in one speci¬
men with 9-10; preoculars 2-2 in two individuals, 2-3 in one, 3-3 in one
snake, and indeterminate in one; postoculars 2-2 except in one specimen
with 1-2; temporals 1-2-3 in all specimen; ventrals 134, 138 and 141 in
three females, 127 and 130 in two males; umbilicus at ventral 110; caudals
63, 73 and 82 in three females, 71 and 76 in two males; scale rows 17-17-17
in all; TTL in one small female is 187 mm and in two adult females 321
and 350 mm, TL 53, 98 and 110 mm; TTL in one male 331 mm, TL 105 mm
(the other male, a hatchling, is too brittle to measure); TL/TTL ratio in the
measurable male is 0.32, in the females 0.28, 0.28 and 0.34. The hemipenial
spines in the single adult male are about 20 in number.

The pale supraocular line is strongly displaced laterally, passing
through the upper posterior part of the last supra labia I, but is interrupted
on both sides in three specimens (UCM 52493, MZFC 9946 - 9947), is com¬
plete on both sides in one specimen (UCM 52669), and is interrupted on
only one side in one (UCM 41189). In the latter, the pale line itself is inter¬
rupted, but its black borders are united and continuous through that in¬
terruption of less than half of a scale length.

There is no dorsolateral dark line. In UCM specimens, the vertebral
scales are dark edged and with slightly lighter centers in some parts of
the dorsum, somewhat as in R. marcellae (Myers, 1974: fig. HE), whereas
in the MZFC specimens, these scales bear a reticulate pattern and are darker
at the edges and center. In one specimen (UCM 52493) there is a black
edged postparietal pale spot on four successive scales of the vertebral
row, widest (1.5 scales) anteriorly; in two others (UCM 52669, MZFC 9947)
there is a faint pale postparietal streak on four vertebral scales. In the
UCM specimens, the scales in the fifth row are distinctly pale-centered,
producing the effect of a pale lateral line, although anteriorly the line is
very distinct and continuous, aligned with the postocular series. Much as
in R. marcellae. in one specimen (UCM 41189) a postparietal spur extends
mediad from the pale lateral line for a distance of two scales on one side,
one scale on the other. The labials are mostly white, but a dark dot on
their lower edge occurs on the anterior six to seven supralabials, and the
anterior four infralabials. One similar black dot is present on each side of
the rostral and mental.

page 1 02

Bulletin of the Maryland Herpetoiogical Society

Volume 34 Number 4

December 1998

This species differs from R. bogertorum most importantly in its lower
number of ventrals (119 to 130 males, 124-141 in females vs 144 to 158 in
males, 160 to 170 in females of R. bogertorum). The position of the umbi¬
licus, at the 110th ventral in the single available hatchling, is lower than
those of hatchlings R. bogertorum (118 - 137), but the difference is merely
a reflection of the lower number of ventrals, because the relative position
is the same, as indicated by its position as expressed in per cent of the
total ventral count from the first ventral (82%) and from the anal plate
(18%). A number of differences in pattern as tentatively suggested by Myers
(1974) are substantiated, including more extensive spotting of the upper
and lower lips in R. macdougalli: the absence of a vertebral dark line,
whose place is taken by dark edging of the vertebral scales, the centers of
which are slightly more pale than the adjacent ground color; the absence
of a dark dorsolateral line, even in hatchlings; the presence of distinct
pale centers of the scales in the 5th row; and the frequent hiatus in the
postocular light line.

Of great interest is the resemblance of the three UCM specimens of
R. macdougalli to R. marcellae in the supposedly partially diagnostic char¬
acteristics of a black-edged pale vertebral line and of postparietal trans¬
verse and median pale lines as figured and described in Nieto-Montes de
Oca and Mendelson (1997). These peculiar similarities suggest that R.
macdougalli might actually be a subspecies of R. marcellae. inasmuch as
their ventral and caudal counts are very similar. However, R. macdougalli
differs sharply from R. marcellae in the involvement of the 8th supralabial
in the pale postocular stripe and in the smaller number of hemipenial
spines (in the low 20's vs about 50), and accordingly we retain them as
separate species. Material from the area between their present known range
limits will be critical in verifying their species status.

Variation in R. mversi.- In the three previously unreported speci¬
mens, the supralabials are 8-8, with the 4th and 5th entering the orbit in
all specimens; infralabials 10-10 in two specimens (UCM 49353, 44516), 9-
9 in one (UCM 44518); preoculars 2-2 in two (UCM 44518, 44516), 3-3 in
one (UCM 49353); postoculars 2-2 in all specimens; temporals 1-2-2 on
one side of one (UCM 44518), 1-2-3 in others (UCM 44518, 49353); scale
rows 17-17-17 in all snakes; ventrals 145 in one female (UCM 44516), 136
and 141 in two males (UCM 44518 and 49353 respectively); caudals 68 in

Bulletin of the Maryland Herpetological Society

page 103

Volume 34 Number 4

December 1998

one female (UCM 44516), 84 in one male (UCM 44518); female the long¬
est, 391 mm TTL, 110 mm TL; adult male 309 mm TTL, tail incomplete;
hatchling male 137 mm TTL, 43 mm TL; ratio TL/TTL 0.28 in female, 0.31
in male.

This species is most closely similar to R. bogertorum and R.
macdougalli, although both of the latter are restricted to Atlantic slopes,
R. mversi to Pacific slopes, so far as known. The most salient distinction
of the latter species from the former two is its intermediate number of
ventrals, with only a slight overlap with R. macdougalli. In R. mversi the
ventrals number 139-145 in two females, 132 to 141 in four males (vs 160
to 170 and 144 to 158, respectively, in R. bogertorum: 124 to 141 and 119 to
130, respectively, in R. macdougalli).

The pattern differences pointed out by Myers (1974) remain consis¬
tent in the present series. Most reliable is the more nearly parallel position
of the pale postocular lines, which do not touch the posterior supralabial,
contrary to the condition in both R. bogertorum and R. macdougalli. The
black dorsal border of the lateral brownish zone lies prominently on the
lateral edge of the 5th scale row, less upon the upper edge of the 4th; the
scales of the 5th row are distinctly pale-centered. There is no dorsolateral
dark line even in the hatchling. The vertebral dark line is virtually indis¬
tinguishable; only a little dark edging on the scales of that row distin¬
guish them from adjacent scales. There is a narrow dark brown bar across
the rostral. Spotting on the labials varies; in one specimen spots are present
on most scales, whereas in the hatchling they are not evident at all, and on
the other specimen there are scattered tiny flecks on most scales.

Remarks.- Among the eleven members of the decorata group as rec¬
ognized by Myers (1974: 57), four (bogertorum. macdougalli, marcellae,
mversi) comprise a distinct species complex we here designate the
marcellae complex, inasmuch as R. marcellae Taylor (1949) was the earli¬
est described. All are relatively high elevation species, occurring in cloud
forest or in the pine-oak zone. Each of the last two is isolated in distribu¬
tion, but the first two are partially sympatric at least grossly; it remains to
be determined whether their habitats are similar or not.

page 104

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

Ackno wled gments

We are very grateful to Drs. A. Nieto-Montes de Oca, V. Reynoso, A. De
Queiroz, and R. Humphrey for the privilege of studying specimens un¬
der their care; J. Mendelson III for his constructive comments on the manu¬
script, and to Dr. M. Breed for facilities at the University of Colorado.

Literature Cited

Leviton, A. E., R. H. Gibbs, Jr., E. Heal, and C. E. Dawson.

1985. Standards in herpetology and Ichthyology: Part I. Stan¬
dard symbolic codes for institutional resources collections
in herpetology and ichthyology. Copeia 1985:802-832.

Myers, C. W.

1974. The systematics of Rhadinaea (Colubridae), a genus of
New World snakes. Bulletin of the American Museum of
Natural History, 153:1-262.

Nieto-Montes de Oca, A. and J. R. Mendelson III.

1997. Variation in Rhadinaea marcellae (Squamata:
Colubridae), a poorly known species from the Sierra
Madre Oriental of Mexico. Journal of Herpetology, 31:
124-127.

Taylor, E. H.

1949. A preliminary account of the herpetology of the state of
San Luis Potosi, Mexico. University of Kansas Science
Bulletin, 33:169-215.

Escuela Nacional de Estudios Profesionales Iztacala, Unidad de Biologia ,
Tecnologia y Prototipos (UBIPRO), UNAM. Av. de Los Barrios s/n, Los Reyes
Iztacala , Tlalnepantla, Edo. de Mex. C.P. 54090 , A.P. 314 ( AR-B , MM-M, E-
mail: raurelio@servidor.unam. mx).

Department ofEPO Biology, University of Colorado, Boulder, Colorado,
80309-0334 , USA (HMS, FvB , E-mail: hsmith@spot.colorado.edu).

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 4

December 1998

Department of Psychology, University of Colorado, Boulder, Colorado 80309-
0345, USA (DC, E-mail: chiszar@clipr.colorado.edu).

Received: 8 September 1998

Accepted: 26 November 1998

page 106

Bulletin of the Maryland Herpetological Society

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December 1998

The Report of the Snake Genus Conophis in
South America is Erroneous

David L. Auth, Jean Mariaux, Joel Clary , David Chiszar,

Frank van Breukelen and Hobart M. Smith

Abstract. The report of Conophis lineatus from Colombia, South
America, is erroneous and based on Liophis lineatus. The similarities of
the two genera suggest that they belong to the same tribe or subfamily.

The southern limit of distribution of Conophis has long been regarded
as Costa Rica (Wellman, 1963; Peters and Orejas-Miranda, 1970; Villa et
al., 1988). However, at least two records of C. lineatus are for more south¬
ern localities: Barranquilla, Colombia (Perez-Santos and Moreno, 1988),
and Code, Panama (Auth, 1994a). The latter record was promptly re¬
futed, however (Auth, 1994b), with identification of the snake in question
as Liophis lineatus , a species well known from Panama and northern South
America (Michaud and Dixon, 1987).

The basis for the Colombia record was a specimen cited by Perez-
Santos and Moreno (1988: 129), MHNG 1368.98 (museum acronyms as in
Leviton et al., 1985), which they did not examine, and whose identity has
never been verified. We reexamined the specimen, and found that in real¬
ity it also represents Liophis lineatus , conforming in most details with the
definition of the species in Michaud and Dixon (1987: 5). It is a well-
preserved, adult female In good condition 681 mm TTL, 176 mm TL, taken
between 1966 and 1968 by J. Garzoni for E. Kramer. Its pattern (Fig. 1)
conforms with that of populations west of the Andes (Michaud and Dixon,
1987: 5), and differs from that of populations east of the Andes (Fig. 2).
The body has three dark brown stripes, all extending to tail tip and origi¬
nating on snout, where the median stripe is narrowly separated from the
lateral stripes, which are continuous on rostral; median stripe nearly uni¬
formly dark, with narrow, slightly darker brown edges, occupying three
and two half scale rows on body, narrowing to two half rows on tail; lat¬
eral dark stripe passing posteriorly through eye and upper edges of
supralabials, on neck involving the 5th scale row, adjacent half of the 4th
and lower edge of the 6th; more posteriorly the lateral stripe descends to
the 4th and 5th rows, and descends still farther at the point of scale row
drop to the 3rd and 4th rows; on the tail it occupies the 2nd scale row and

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 4

December 1998

ultimately the 1st. There are no markings whatever between the dark
stripes, or ventral to the lateral dark stripe on head, body or tail.

Fig. 1. Midbody pattern of Liophis lineatus, MHNG 1368.98, Barranquilla,
Colombia, west of the Andes, styled for comparison with figures of the
same species in Michaud and Dixon (1987: 6).

Fig 2. Midbody pattern of Liophis lineatus , MF1NL 42000566, locality un¬
known but presumably east of the Andes.

page 108

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

The supralabials are 8-8, 4th and 5th entering orbit; rostral with a
narrow, transverse, semicircular ventral prelabial concavity, not reaching
even with the lateral edges of mental, and not extending forward more
than a third of the median length of the rostral in ventral view; in neither
dorsal nor lateral view is the rostral at all protuberant; in lateral view it is
much shorter than 1st supralabial, and in dorsal view its posterior edge is
semicircular, not pointed, not extended between internasals; latter nearly
square, much narrower than prefrontals; latter extending slightly below
canthus rostralis, broadly contacting a large, nearly square loreal on each
side; loreal contacting 2nd and 3rd supralabials; nasal large, completely
divided, butterfly-shaped, naris contacting internasal, narrowly separated
from 1st supralabial; preoculars 1-1, half again longer dorsally than ven-
trally, narrowly separated from frontal, contacting 3rd and 4th supralabials;
2-2 postoculars, upper twice size of lower; temporals 1-1-2, 1-2-3.
Infralabials 10-10; anterior chinshields longer than posterior.

Ventrals 169; anal divided; tail complete; 84 subcaudals; 19-19-17
scale rows; scale row reduction at 109th and 110th ventral; scales smooth,
without apical pits.

The left maxilla has 18 prediastemal teeth, increasing in size posteri¬
orly; the postdiastemal teeth (two sockets) are half again as large as the
preceding tooth, and have a flange but no groove.

The occasional confusion of this species with Conophis is due to a
remarkable similarity of pattern, especially of C. vittatus, which is indis¬
tinguishable in pattern from some specimens of L. lineatus. There is also a
remarkable similarity in the occurrence of a unique ventral concavity on
the rostral of L. lineatus and all Conophis; in the latter genus it appears to
be associated with burrowing habits for which the rostral is adapted also
by its protrusion in a somewhat conical shape to varying degrees in dif¬
ferent species. In addition there are fundamental similarities in scalation
(especially scale rows, head scales and number of ventrals), as well as a
clinal conformity in northward reduction in number of subcaudals, num¬
ber of teeth and increase in size and grooving of the fangs.

Of critical importance is the nature of the hemipenis, which on the
basis of a fully everted one on a Conophis vittatus from El Salvador (KU
183865, Ahuachapan: Barra de Santiago) appears to conform with the dis-

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 4

December 1998

tine live structure depicted in Dowling and Duel! man (1978: 112a.4) for
various members of the tribe Xenodontini as of that work. In that speci¬
men the right hemipenis is 14 mm long, the sulcus forks 4 mm from the
base; there are two flat apical discs, centrally indented, in contact with
each other, without a notable depression between; the calyces on the discs
are unornamented; only small spines are present on the sulcate side; large
spines are present on the lateral and sulcate surfaces, extending to near
the apices, where they are small around the edge of the disc.

Although Dowling (1995) was uncertain of the affinities of Conopins
it seems likely that it should be included among the xenodontine genera
Erythrolamprus , Liophis, Lygophis, Lystrophis , Umbrivaga, Waglerophis and
Xenodon (Dixon, 1980; Dowling, 1995), in view of the extensive agreement
with some or all of those genera in critical characters.

Ackno wled gments

We are much indebted to Drs. James R. Dixon, Herndon Dowling
and Enrique La Marca for their counsel; to Dr. Ivan Ineich for initiation of
this study by arranging collaboration with the MHNL; to Chris Sheil and
John Simmons for assistance in studying material in the KU Museum; to
Dr. Alan de Queiroz and Rosanne Humphrey for loan of comparative ma¬
terial from the UCM; to Deborah Aguiar for preparation of the figures;
and to Drs. Michael Breed and Michael Grant for space and facilities for
laboratory study

Literature Cited

Auth, D. L.

1994a. Checklist and bibliography of the amphibians and rep¬
tiles of Panama. Smithsonian Herpetological Information
Service (98): 1-59.

1994b. Corrections and additions I to the checklist and bibliog¬
raphy of the amphibians and reptiles of Panama. Pri¬
vately Printed. 4 pp.

Dixon, J. R.

1980. The Neotropical colubrid snake genus Liaphis: the generic

page 110

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

concept. Milwaukee Public Mus. Contr. Biol. Geol. (31):
1-40.

Dowling, H. G.

1995. Prodromus of a new classification of snakes. Privately
Printed. 59 pp. Talladega, Alabama.

- - and W. E. Duellman.

1978. Systematic herpetology: a synopsis of families and higher
categories. HISS Publ. in Herp., (7): i-vii, l-118(x 2-3), I-
VIII.

Leviton, A. E., R. H. Gibbs, Jr., E. Heal & C. E. Dawson.

1985. Standards in herpetology and ichthyology: part I. Stan¬
dard symbolic codes for institutional resource collections
in herpetology and ichthyology. Copeia 1985: 802-832.

Michaud, E. J. and J. R. Dixon.

1987. Taxonomic revision of the Liophis lineatus complex (Rep-
tilia: Colubridae) of Central and South America. Milwau¬
kee Public Mus. Contr. Biol. Geol. (71): 1-26.

Perez-Santos, C. and A. G. Moreno.

1988. Ofidios de Colombia. Museo Regionale di Scienze Torino
Monografia 6: 1-520.

Peters, J. A. and B. Orejas-Miranda.

1970. Catalogue of the Neotropical Squamata. Part 1. Snakes.
Bull. U. S. Nat. Mus. (297): 1-247.

Villa, J., L. D. Wilson and J. D. Johnson.

1988. Middle American herpetology. Columbia, LJniv. Mis¬
souri. 132 pp.

Wellman, J.

1963. A revision of snakes of the genus Conophis (family
Colubridae), from Middle America. Univ. Kansas Publ.
Mus. Nat. Hist. 1-5: 251-295.

Bulletin of the Maryland Herpetological Society

page 1 1 1

Volume 34 Number 4

December 1998

(DLA) Florida Museum of Natural History, University of Florida, Gainesville,
Florida 32611 ; (JM) Museum d'Histoire Naturelle, Route de Malagnou 1 , case
postale 6434 , CH-1211, Geneve 6, Switzerland; ( JO Museum d'Hisioire
Naturelle , 28 Boulevard des Beiges , 69006 Lyon , France; (DC) Department of
Psychology & Museum, University of Colorado, Boulder, Colorado 80309-
0345; (FvB) Department ofEPO Biology, University of Colorado, Boulder,
Colorado 80309-0334 ; (HMS) Department ofEPO Biology & Museum,
University of Colorado, Boulder, Colorado 80309-0334.

Received: 18 November 1998

Accepted: 28 November 1998

page 112

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

ABUNDANCE AND WATER VOLUME EFFECTS IN
AMPHIBIAN LARVAE

Geoffrey R. Smith

Density is defined as the number of individuals per unit area or
volume. In most studies of intraspecific interactions, the number of indi¬
viduals is manipulated while area or volume is kept constant. For ex¬
ample, in amphibians, increased densities of larvae have been shown to
increase time to metamorphosis, decrease survivorship, decrease size at
metamorphosis, decrease growth rate, increase variability and skew in
body size, and affect post-metamorphic performance (e.g., Wilbur and
Collins, 1973; John-Alder and Morin, 1990; Newman, 1994; Scott, 1994;
Tejedo and Reques, 1994). However, in many of these types of studies,
both density and abundance change, therefore confounding density ef¬
fects with abundance effects. The density of individuals could influence
encounter rates or behavioral interactions among individuals, such as in¬
terference competition, whereas abundance effects could influence food
limitation through exploitative competition.

I conducted a short-term experiment to assess the relative impor¬
tance of abundance and density effects on early growth in bullfrog tad¬
poles (Rana catesbeiana Shaw) by manipulating both the number of tad¬
poles and the volume of water, while maintaining a constant food ration
across treatments. I also conducted an experiment to evaluate the poten¬
tial influence of water-borne agents by manipulating abundance and wa¬
ter change frequency.

Tadpoles were obtained from field-collected egg masses from ponds
in southeastern Michigan in 1995 (Experiment 1) and southwestern Michi¬
gan in 1996 (Experiment 2). Only one egg mass was used per experiment
to control for potential maternal or genetic effects. Eggs were incubated
in aerated pond water, and tadpoles were introduced into the experiment
5 d after hatching. In both experiments, tadpoles were maintained in cy¬
lindrical plastic containers (15 cm diameter, 20 cm tall).

Experiment I was a 2 X 2 factorial design (replicated 4 times) with
two volume treatments (low: 0.5 L, high: 1 L) and two abundance treat¬
ments (low: 3 tadpoles, high: 6 tadpoles). Every 3 d, I changed 3/4 of the

Bulletin of the Maryland Herpetological Society

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December 1998

water in each container using unfiltered pond water, and added equal
portions of food (algal flakes). Food portions were doubled over the ex¬
periment, with the amount of food provided increased when low abun¬
dance tadpole treatments fully consumed their food (initial portion = 0.03
g). Experiment 2 was a 3 x 2 factorial design (replicated 4 times) with three
abundance treatments (low: 1 tadpole; medium: 2 tadpoles; high: 4 tad¬
poles), and two water change frequencies (low: changed every 6 d; high:
changed every 3 d). All other maintenance was the same as in Experiment
1. At the beginning of each experiment, I randomly assigned tadpoles to
treatments, excluding obviously differently sized individuals.

At the end of each experiment (after 30 d), I weighed tadpoles (body
mass after blotting dry; BM) to the nearest 0.0001 g using an electronic
balance. I used standard parametric analysis after assumptions were
checked. Replicate means were used in analyses to avoid
pseudoreplication. Means are given ± 1 SE.

In Experiment 1, tadpoles from low abundance treatments were 2.27
times larger on average than tadpoles from high abundance treatments
(0.356 ± 0.026 g vs. 0.157 ± 0.011 g; Fl12 = 54.7, P < 0.0001). Tadpoles in the
low volume treatment were smaller than tadpoles in the high volume treat¬
ment; however, the difference only approached statistical significance
(0.234 ± 0.040 g vs. 0.280 +.0.043 g; Fl12 = 2.96, P = 0. 1 1). There was no
significant interaction between abundance and volume (Fl12 = 0.48, P =
0.50). A preplanned contrast between the low abundance, low volume
treatment and the high abundance, high volume treatment (i.e., the two
treatments with the same density but different abundances of tadpoles)
showed a significant difference, with the low abundance, low volume treat¬
ment tadpoles being larger than the high abundance, high volume treat¬
ment tadpoles (0. 3 24 + 0.043 g vs. 0. 171 ± 0.013 g; F = 16. 1, P = 0.00 1 7).

In Experiment 2, tadpoles from high abundance treatments (0. 140 ±
0.010 g; N = 8) were smaller on average than tadpoles from low abun¬
dance treatments (0.389 + 0.069 g; N = 8), with tadpoles from the medium
abundance treatments intermediate in BM (0.257 + 0.030 9; N = 8) (F218 =
7.94, P = 0.003). Water change frequency did not significantly affect BM
(low: 0.228 ± 0.034 g vs. high: 0.295 ± 0.055 g; N = 12 in both cases; Fllg =
1.73, P = 0.20). There was no significant interaction between abundance
and water change frequency (F2lg 0.63, P = 0.54).

page 114 Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

The negative effect of abundance on final BM strongly implicates
intraspecific competition. As pointed out above, such a result was not
unexpected, and indeed, is not a surprise given the numerous previous
studies finding density (abundance?)~dependent growth in amphibian
larvae. The lack of water volume effects in this experiment contrasts with
the results of several previous studies manipulating the proximity or
crowding of tadpoles (both conspecifics and heterospecifics) that found
increased physical interaction or increased potential physical interaction
decreased various aspects of amphibian larval performance (e.g., John
and Fenster, 1975; Breden and Kelly, 1982; Griffiths, 1991). However, Smith
(1990) suggested that it may be total space available to tadpoles, and not
per capita space that may be important in tadpole performance.

My results suggest that abundance was relatively more important
than density in this experiment. First, given a constant and equal food
supply among treatments, any increase in absolute numbers of tadpoles
per container decreased the per capita food ration. Second, the distribu¬
tion and nature of the food was such that all tadpoles could have access to
the food at the same time if no active interference was occurring (pers.
observ.). Third, the preplanned contrast between treatments with the same
density (e.g., tadpoles per liter), but different abundances, found that lower
abundance tadpoles grew faster on average than high abundance tad¬
poles. All of these results support the notion that my results reflect an
abundance effect, not a true density effect.

What might be the mechanism of the abundance effect? One possi¬
bility is exploitative competition (i.e., per capita food availability and con¬
sumption was decreased thus resulting in decreased growth). My results
are generally consistent with this hypothesis (see discussion above). A
second possibility is the presence of water-borne agents (see Beebee, 1995;
Griffiths, 1995; Petranka, 1995 for a discussion of water-borne agents in
amphibians). While I cannot preclude the second possibility, I think that,
given the lack of water volume effects in Experiment 1 and the lack of
significant water change frequency effects in Experiment 2, the effect of
water-borne agents was relatively minor in my experiments, at least com¬
pared to the abundance effect due to food limitation. However, the non¬
significant trends in the results are consistent with the expected effect of
water-borne agents.

Bulletin of the Maryland Herpetological Society

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Volume 34 Number 4

December 1998

In conclusion, abundance effects appeared to influence early-stage
bullfrog tadpoles more than true density effects. These preliminary re¬
sults suggest that additional studies investigating the mechanism of am¬
phibian larval competition, beyond those on water-borne agents, could
be very enlightening.

Acknowledgments

I thank J. Chase and M. Leibold for generously providing the tad¬
poles, and the Kellogg Biological Station (especially G. Mittelbach) for
providing space. J. Rettig provided assistance and support, and read and
commented on an early version of the manuscript.

Literature Cited

Beebee, T. J. C.

1995. Tadpole growth: is there an interference effect in nature?.
Herpetol. J. 5: 204-205.

Breden, F. and C. H. Kelly

1982. The effect of conspecific interactions on metamorphosis
in Bufo americanus. Ecology 63: 1682-1689.

Griffiths, R. A.

1991 . Competition between common frog, Rana temporaria, and
natterjack toad, Bufo calamita, tadpoles: the effect of com¬
petitor density and interaction level on tadpole develop¬
ment. Oikos 61: 187-196.

1995. Determining competition mechanisms in tadpole assem¬
blages. Herpetol. J. 5: 208-210.

John, K. R. and D. Fenster, D.

1975. The effects of partitions on the growth rates of crowded
Rana pipiens tadpoles. Am. Midi. Nat. 93: 123-130.

John- Alder, H. B. and P. J. Morin

1990. Effects of larval density on jumping ability and stamina

in newly metamorphosed Bufo woodhousiifowleri. Copeia
1990: 856-860.

page 116

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

Newman, R. A.
1994.

Effects of changing density and food level on metamor-
phosis of a desert amphibian, Scaphiopus couchii. Ecology
75: 1085-1096.

Petranka, J. W.

1995. Interference competition in tadpoles: are multiple agents
involved?. HerpetoL J. 5: 206-207.

Scott, D. E.

1994. The effect of larval density on adult demographic traits
in Ambystoma opacum. Ecology 75: 1383-1396.

Smith, D. C.

1990. Population structure and competition among kin in the
chorus frog (Pseudacris triseriata). Evolution 44: 1529-1541.

Tejedo, M. and R. Reques

1994. Plasticity in metamorphic traits of natterjack tadpoles:
the interactive effects of density and pond duration. Oikos

71: 295304.

Wilbur, H. M. and J. R Collins

1973. Ecological aspects of amphibian metamorphosis. Science
182:1305-1314.

Department of Biology, William Jewell College , Liberty , Missouri 64068 USA

Received: 20 November 1998

Accepted: 28 November 1998

Bulletin of the Maryland Herpetological Society

page 117

Volume 34 Number 4

December 1998

New Book Releases

Smithsonian Institution Press

470 L’ENFANT PLAZA, SUITE 7100, WASHINGTON, D C. 20 560
SALAMANDERS OF THE UNITED STATES AND CANADA

TITLE

JAMES PETRANKA

A’JTHOR

1-56098-828-2

ISBN CLOTH

ISBN PAPER

$60.00

PRICE (CLOTH)

PRICE (PAPER)

SEPTEMBER 11, 1998

publication date

For further information contact: Brenda Tucker
BTUCKTR@SIPRJESS.SI.EDU

Marketing Department
232/287-3738, ext. 343

Ordering information: Books may be ordered from
S.mithsonian Institution Press, P.O. Box 960, Herndon,

VA 20172-0960, 1-800/782-4612. Please include $3.50
postage and handling for the first book and $1.00 for each
additional book.

page 118

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

New Book Releases

Smithsonian Press/

Smithsonian Productions

Smithsonian Institution Press

Feature release For more information, contact:

September 18, 1998 Stacy Zellmann, ph 202-287-3738, ext 355

For use after October 23, 1998 SZellman@sipress.si.edu

Learn to Love Rattlesnakes* Says Author and Photographer

Humans a Greater Danger to Rattlesnakes than the Other Way Around

Washington, D.C. — Rattlesnakes are among the most feared creatures, so much so that drivers go out of
their way to run them over and rattlesnake roundups are organized annually to rid communities of these
supposedly menacing reptiles. The phrase “mean as a rattlesnake” is one of the greatest insults you can hurl
at an enemy, and a “snake oil salesman” is one of the lowest forms of life.

It is Manny Rubio’s avocation to turn fear into fascination, to encourage people to see the beauty of
these majestic creatures and understand their critical role in the ecosystem.

Since his teens, when Rubio lived within walking distance of the Staten Island Zoo and its famed
rattlesnake collection, he has searched for rattlesnakes, studied them, photographed them, and written
about them. Now Rubio has produced Rattlesnake: Portrait of a Predator (Smithsonian, $39.95), a stunning
272-page book illustrated with more than 250 of his own photographs of rattlesnakes. But it is much more
than a picture book: its fourteen chapters are packed with information about rattlesnakes’ evolution,
habitat, biology, reproduction, and feeding habits. In addition, Rubio provides a unique glimpse of a
snakehandling service in a Pentecostal church and a blunt expose of rattlesnake roundups.

A longtime sports photographer whose work has appeared in magazines including Sports Illustrated ,
Time, and Newsweek, Rubio started with the idea of putting together a book of just photographs of
rattlesnakes and gradually became convinced that he should write about the snakes as well. Although he
was a biology major in college, he considers himself a snake “avocationist.” As such, he says that he has
learned a great deal about rattlesnakes because he has had the time to observe them in the field and to read
about them widely. And he wanted to pass that knowledge on.

The book was written not for a scientific audience — although scientists reviewed every chapter — but
for anyone willing to suspend the inborn human dread of snakes and appreciate their beauty and natural
history. It includes a strong message of conservation, because many species of rattlesnakes are endangered.
William S. Brown, a leading herpetologist, writes in his foreword, “Rubio’s message may do more to save
rattlesnakes than anything yet published.”

Bulletin of the Maryland Herpetological Society

page 1 1 9

Volume 34 Number 4

December 1998

New Book Releases

Over a twelve-year period, Rubio photographed almost every one of the approximately 83 living
species and subspecies of rattlesnakes. His book includes photos of unusual hybrid snakes and a never-
before-recorded sequence of a banded rock rattlesnake eating a large poisonous centipede. He has never
been bitten, he says, because he is too aware of the possible danger to take chances, but he has had a few
close calls, each of which has made him more cautious in dealing with snakes.

Rubio treats a rattlesnake bite seriously — he says it must be treated as a medical emergency — and he
offers important emergency procedures to be followed by anyone bitten by a rattlesnake. But he also points
out that most snakebites occur when someone is trying to handle, catch, or kill venomous snakes. On
average, twelve people are killed by rattlesnake bites each year in the United States.

By contrast, at least 5,000 snakes a year are killed at rattlesnake roundups — highly publicized
commercial events that are promoted as a way of controlling rattlesnake populations, ostensibly to prevent
the deaths of catde and people. Snake collectors are paid by the pound for rattlesnakes, so people go so far
as to force-feed them sawdust to raise their weight and therefore their value. Many snakes are caught for
roundups when their dens are fumigated with gasoline or volatile fertilizers. In addition to driving
rattlesnakes above ground, the vapors kill nonvenomous snakes, frogs, toads, lizards, tortoises, and other
small animals occupying the underground tunnel.

Thousands more rattlesnakes are killed by cars each year, and drivers go out of their way to run them
over. In Florida many years ago, a Cadillac directly in front of Rubio suddenly swerved sharply to try to hit
a ratdesnake. When the driver missed, she turned her car full of children around and drove it off the road
in an attempt to kill the snake, but she got stuck in the mud instead.

Part of Rubio’s mission in writing his book is to educate the people who go to such lengths to kill
rattlesnakes. In addition to being beautiful and less harmful than many would like to believe, rattlesnakes
are important predators who keep destructive rodents in check. An adult ratdesnake that consumes
between 12 and 24 rodents per year is forestalling the eventual birth of thousands of rats and mice.

The key to coexistence with ratdesnakes is respect, Rubio says. If you come across a ratdesnake on a
trail, walk on by, giving it a wide berth. If you want to feed birds in your backyard but don’t want snakes to
prey on them, circle your yard with a snakeproof fence. But above all, Rubio would ask us to remember
that “the ratdesnakes were here before us and that they deserve to exist alongside us.”

Rattlesnake is available at bookstores or from the Smithsonian Institution Press.

page 120

Bulletin of the Maryland Herpetological Society

Volume 34 Number 4

December 1998

New Book Releases

Smithsonian Institution Press

470 L’ENFANT PLAZA, SUITE JlOO, WASHINGTON, D C. 20560

RATTLESNAKE: Portrait of a Predator

TITLE

MANNY RUBIO

AUTHOR

1-56098-808-8

ISBN CLOTH

ISBN PAPER

$39.95

PRICE (CLOTH)

PRICE (PAPER)

OCTOBER 23, 1998

PUBLICATION DATE

For further information contact: Brenda Tucker
BTUCKER@SIPRESS.SI.EDU

Marketing Department
202/287-3738, ext. 343

Ordering information: Books may be ordered from
Smithsonian Institution Press, P.O. Box 960, Herndon,

VA 20172-0960, 1-800/782-4612. Please include $3.50
postage and handling for the first book and $1.00 for each
additional book.

Bulletin of the Maryland Herpetological Society

page 121

News and Notes

.

Society Publication

Back issues of the Bulletin of the Maryland Herpetological Society,
where available, may be obtained by writing the Executive Editor. A list
of available issues will be sent upon request. Individual numbers in stock
are $5.00 each, unless otherwise noted.

The Society also publishes a Newsletter on a somewhat irregular
basis. These are distributed to the membership free of charge. Also pub¬
lished are Maryland Herpetofauna Leaflets and these are available at
$. 25/page.

Information for Authors

All correspondence should be addressed to the Executive Editor.
Manuscripts being submitted for publication should be typewritten
(double spaced) on good quality 8 1/2 by 11 inch paper with adequate
margins. Submit original and first carbon, retaining the second carbon. If
entered on a word processor, also submit diskette and note word proces¬
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are to appear in text. Cite all literature used at end in alphabetical order
by author.

Major papers are those over five pages (double spaced, elite type)
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The Maryland Herpetological Society
Department of Herpetology
Natural History Society of Maryland, Inc.

2643 North Charles Street
Baltimore , Maryland 21218

Bulletin of the Maryland Herpetological Society

page 123

Maiylanil
Herpet»lo|ical
.Society

US ISSN: 0025-4231

M 3 9?

.&E£t

or THE

flFtarylanb

f)erpetological

Ooriety

DEPARTMENT OF HERPETOLOGY

THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.

MDHS . A Founder Member of the Eastern

Seaboard Herpetological League

30 MARCH 1999

VOLUME 35 NUMBER 1

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 35 Number 1

March 1 999

CONTENTS

Behavioral Resourcefulness in a Striped Whipsnake, Masticophis
t. taeniatus

Hobart M. Smith, David Chiszar and Kamuran

Tepedelen . . . . . . . . 1

Mudpuppies (Necturus maculosus) and Barrier Falls in Wisconsin

Philip A. Cochran . . . 4

Case Report of an Untreated Human Envenomation by the Western
Massasauga Rattlesnake Sistrurus catenatus tergiminus

Andrew S. Baldwin . . . . . . . . . 14

BULLETIN OF THE

mM)6

Volume 35 Number 1 March 1 999

The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.

President Tim Hoen

Executive Editor Herbert S. Harris, Jr.

Steering Committee

Frank B. Groves Jerry D. Hardy, Jr.

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

Membership Rates

Membership in the Maryland Herpetological Society is $20.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $30.00 per year. Make all checks payable to the Natural History
Society of Maryland, Inc.

Meetings

The third Wednesday of each month, 7:30 p.m. at the Baltimore Zoo’s
Reptile House (except August and September due to The Mid-Atlantic
Reptile Show). The Department of Herpetology meets informally on all
other Wednesday evenings at the NHSM at 8:00 p.m.

Volume 35 Number 1

March 1999

Behavioral Resourcefulness in a Striped Whipsnake,
Masticophis t taeniatus

Hobart M. Smith, David Chiszar and Kamuran Tepedelen

The anecdotal observations here reported provide a glimpse of a
repertoire of ophidian behavior that is almost completely unknown and
that could reward intensive investigation.

On 26 July 1992, DC captured an adult (~1 m) Striped whipsnake
(Masticophis t. taeniatus) on Cross Mountain in Moffat Co., northwestern
Colorado. Inasmuch as this species is a noted visual forager, the specimen
was kept in captivity for a time in order to compare its feeding behavior
with that of the largely ambush-feeding rattlesnakes. It was ultimately
released July 1993, at the mouth of Irish Canyon in the Cold Spring Moun¬
tains of Moffat Co., some 35 airline km from the point of capture, where
the species has frequently been observed and where lizard food (Uta
stansburiana stejnegeri , Sceloporus undulatus elongatus) is reasonably abun¬
dant.

In the meantime the snake was kept in a top-lidded wooden cage,
32 cm x 43 cm x 60 cm, with a glass front, maintained at a temperature
(with an incandescent bulb) of 28 degrees C during the day, 17 degrees C
at night, and provided with a water dish, hide box and a few rock slabs
below the light on a newspaper-covered floor. It was hibernated by KT
from 1 November 1992 to 15 March 1993, under excelsior in a cage with
an ambient temperature of about 10 degrees C, interrupted briefly in Janu¬
ary to permit the snake to drink.

During the 6.5 months of activity in captivity, the snake consumed
56 mostly live lizards, predominantly Sceloporus undulatus elongatus, but
also some S. g. graciosus and Urosaurus omatus - all taxa that are moder¬
ately abundant In the snake's original habitat. Other lizards eaten were S.
u. erythrocheilus and Lepidodactylus lugubris. Eumeces obsoletus (both dead
and alive), neonate Thamnophis radix, young Pituophis catenifer (400 mm
TTL) and neonate rats were also offered but not accepted.

Indeed, the snake seldom ate either dead or immobile live lizards. It
was extremely quick to chase and attack a moving lizard, but often would
crawl right over a stationary live one.

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 1

March 1999

The quantity of food ingested was in sharp contrast with the three
or four mice that rattlesnakes consume in the wild in an active season.
Correlated with that difference is a sharp contrast in behavior of the two
kinds of snakes. Rattlesnakes seldom forage, whereas the whipsnake did
so much of the time. It usually emerged from its hide box shortly after the
heat lamp turned on, warmed itself for a time under the lamp, then for¬
aged around the cage for a while before returning to rest under the heat
source. It would repeat the performance several times a day, and would
retire to its hide box shortly before or after the lamp turned off.

The snake was quite efficient in capturing and eating any sceloporine
lizard that moved, but had considerable trouble catching the much fleeter
geckoes. At times the snake just gave up the attempt when geckoes were
in the cage, although in due time it would try again.

The sceloporine lizards quickly became motionless In the snake's
cage, in apparent self-protection, allowing the snake to tongue-flick them
and crawl right by or even over them. Immobile lizards were rarely at¬
tacked - hence dead lizards were not eaten unless they became entangled
with a live one that was being consumed.

The Sceloporus that feigned death apparently recognized snakes as
predators. Although some lizards exhibited what might be interpreted as
learning in assuming immobility after several minutes of exposure to the
snake, some did so immediately when introduced into the cage; there was
little real "learning" time. That there may be an inherent fear of snakes
was suggested by the behavior of S. u. erythrocheilus observed in the hills
near Boulder, Colorado. When most predators appeared in sight there,
the lizards would simply dive into the nearest crack in adjacent boulders,
where they would be safe from hawks and various mammals. One speci¬
men was observed to spot an approaching racer (Coluber constrictor
flaviventris) several feet away, whereupon it fled far from the scene, as if
aware that a sanctuary in a crevice would be insufficient when faced with
a snake predator.

On May 2 the snake exhibited an extraordinary foraging behavior
of alertly watching its own probing body movements in an apparent at¬
tempt to flush out a lizard that the snake had previously seen but could
not find. The snake had been out foraging as usual, after initial warming

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Bulletin of the Maryland Herpetological Society

Volume 35 Number 1

March 1999

under the lamp. A S. u. elongatus was placed in the cage (quickly, because
the snake often charged the opened lid at once), but it landed behind the
hide box, out of sight. The snake nevertheless was seemingly aware of Its
presence, and rather frantically began searching throughout the cage with¬
out success. It then changed tactics, holding head and fore part of body
perfectly still while watching the rear part of body and tail as they ener¬
getically felt all around the cage. Twice the snake even charged its own,
actively moving tail, before resuming its watch. This behavior continued
for two or three minutes, without disturbing the lizard. The snake then
gave up the effort, and remained quiet for 10 min., after which it again
started foraging, but this time quietly, not frantically as before, interrupted
by brief (10-15 secs) episodes of immobility every 2-3 min. It hadn't found
the lizard by the time observation ceased a half hour later. The lizard was
gone, however, when the cage was checked an hour later.

The body-loop foraging strategy was not observed again. Whether it
would ever be utilized in nature is conjectural. It may be a behavior elic¬
ited by detection of prey in a relatively closed space. Nevertheless it is
indicative of a surprisingly novel attempt to resolve an impasse in feeding.

We encourage others to report observations suggesting comparable
sorts of behavioral plasticity in reptiles and amphibians, as such cases
will provide a view of the possible range of adjustments the animals may
exhibit. Such information can be a source for hypotheses to be tested un¬
der controlled conditions.

(HMS) Museum , University of Colorado, Boulder ; Colorado 80309-0315;

(DC) Department of Psychology, University of Colorado, Boulder, Colorado
80309-0345; (KT) P. O. Box 19096, Boulder, Colorado 80308.

Received 2 January 1999
Accepted 6 January 1999

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 1

March 1999

Mudpuppies (Necturus maculosus) and
Barrier Falls in Wisconsin

Philip A. Cochran

"For zoogeographical purposes Necturus should be considered more
an ichthyological rather than a typical urodelan problem." - Hecht and
Walters (1955)

Since the time of Hecht and Walters (1955), relatively little attention
has been paid to the zoogeography of the mudpuppy (Necturus maculosus)
in the northern part of its range. However, the much greater effort di¬
rected at fishes (e.g., Hocutt and Wiley 1986) provides a basis for unravel¬
ing how the mudpuppy recolonized glaciated regions from southern refu-
gia after the retreat of glacial ice. For example, Cochran (1991) used previ¬
ous analyses of fish dispersal routes to explain how the mudpuppy dis¬
persed through Minnesota from a Mississippi River refugium to inhabit
drainages now physically isolated from that river system.

The mudpuppy was reported from 29 counties in Wisconsin by
Vogt (1981) and has been reported from 22 additional counties since then
(Cochran and Lyons 1986, Casper 1996, Casper 1997). Understandably,
its range sometimes has been depicted as including the entire state
(Bishop 1947, Tyning 1990, Harding 1997), although Conant and Collins
(1991) bucked this trend by reducing the Wisconsin range from that
shown in the previous edition of the same book (Conant 1975). In any
case, examination of distributional data at a finer scale of resolution is
necessary to assess the possibility that mudpuppies failed to colonize at
least some portions of Wisconsin through a lack of physical access at
appropriate times.

Mudpuppies are well known from the Great Lakes bordering Wis¬
consin (e.g., Reigle 1967, Long 1993) and from the lower portions of Great
Lakes tributaries (Gilderhus and Johnson 1980). The Great Lakes drain¬
age in Wisconsin was completely covered by glacial ice during the Pleis¬
tocene Epoch. Subsequent access to the Great Lakes from refugia in the
Mississippi River drainage was available through several routes at vari-

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Bulletin of the Maryland Herpetological Society

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March 1999

ous times. These include, in Wisconsin, connections between the present
day St. Croix (Mississippi drainage) and Brule (Lake Superior) river val¬
leys and between the Wisconsin (Mississippi drainage) and upper Fox
(Lake Michigan) rivers (Greene 1935, Wielert 1980).

Some Great Lakes tributaries pass over falls that are presently barri¬
ers to upstream dispersal. The natural occurrence of fishes above such a
barrier is an indication that they dispersed into the drainage relatively
early, before a combination of isostatic rebound and failing lake levels
brought the barrier into effect (Underhill and Mlyle 1968). Cochran (1991)
pointed to the lack of mudpuppy records from above barrier falls on tribu¬
taries to the north shore of Lake Superior in Minnesota.

Barrier falls occur on tributaries to the south shore of Lake Superior
in Wisconsin. The 22 waterfalls listed by Johannes (1974) range in height
from 1. 5 m to 50 m. Bailey and Smith (1981) suggested that northern pike
(Esox Indus) colonized the south shore tributaries too late to disperse above
their falls, whereas muskellunge (Esox masquinonge) occur naturally above
the falls and apparently colonized earlier. The purpose of this note is to
compare the distribution of mudpuppy records in the Lake Superior drain¬
age of Wisconsin to the position of barrier falls on south shore tributaries.

Methods

In the modern scientific arena, correlations among geographic vari¬
ables are typically examined with a computer-driven geographic infor¬
mation system (GIS). In contrast, I used a "poor man's GIS" to compare
the geographic distributions of mudpuppy collection sites and barrier falls
on Wisconsin's Lake Superior tributaries. The maps supplied by Johannes
(1974) and Vogt (1981) provided localities of waterfalls and mudpuppy
collection sites, respectively. Although additional Wisconsin localities for
mudpuppies subsequent to Vogt (1981) have been documented (see refer¬
ences above), no additional specimens are known from the Lake Superior
drainage (Gary Casper, Milwaukee Public Museum, personal communi¬
cation). An office photocopying machine with a feature permitting speci¬
fication of percentage enlargement or reduction was used to prepare trans¬
parencies of the two maps at equivalent scales. By over laying the trans¬
parencies, it was possible to compare directly the locations of mudpuppies
and waterfalls.

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Volume 35 Number 1

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Results

Comparison of the maps of Johannes (1974) and Vogt (1981) revealed
a single apparent occurrence of a mudpuppy above a barrier fall, a record
plotted by Vogt (1981) in central Ashland County just upstream from Cop¬
per Falls in the Bad River drainage (Figure 1). Unfortunately detailed data
for records in Vogt (1981) are not available. Copper Falls was described
by Johannes (1974) as a 29-foot (8.8 m) drop into a narrow, rock-walled
gorge, but a table in the same article listed Copper Falls as a 40-foot (12.2
m) drop. A barrier of either height would be impassible to mudpuppies
moving upstream.

Figure 1. The Bad River drainage in northern Wisconsin , with the location of
Copper Falls approximated from Johannes (1974) and the location of a
mudpuppy collection site approximated from Vogt (1981).

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March 1999

Discussion

Although Pleistocene fossils of Necturus maculosus have been col¬
lected in a few localities, none are known from the Great Lakes or other
glaciated regions (Holman 1995). According to Holman's (1992,1995,1998)
model of the reoccupation of postglacial Michigan by reptiles and am¬
phibians, the mudpuppy is included among the primary invaders, spe¬
cies whose ecological tolerances include coniferous forests. These spe¬
cies were thought by Holman (1992, 1995,1998) to have invaded
Michigan's Lower Peninsula via Indiana and Ohio approximately 12,000
years ago, but not to have reached the Upper Peninsula via Wisconsin
until at least 9,900 years ago. Unlike the other primary invaders, how¬
ever, the mudpuppy does not have a terrestrial stage, and the timing
and routes of its dispersal were not necessarily congruent with those of
the other species.

The occurrence of a mudpuppy upstream from a barrier on a tribu¬
tary to Lake Superior's south shore indicates that mudpuppies arrived in
the region by the time that Lake Duluth occupied what is now the Lake
Superior basin, when lake levels were high enough for fishes (or
mudpuppies) to colonize Lake Superior tributaries above their falls (Bailey
and Smith 1981). According to Bailey and Smith's (1981) scenario, this
occurred approximately 11,600 to 11,500 years ago (see their Fig. 6), but
Underhill's (1986) interpretation (see his Fig. 4.7), based on more recent
geological studies, would suggest a somewhat later timing (approximately
10,000 years ago). In either case, mudpuppies could have colonized Lake
Duluth directly from the Mississippi River drainage via the St. Croix River
- Brule River connection.

If the scenario just presented is correct, then additional collections
of mudpuppies can be expected above barrier falls on other tributaries to
Lake Superior, including both the north shore streams of Minnesota
(Cochran 1991) and the south shore streams of Wisconsin. However, it
remains possible that mudpuppies are absent above some of these barri¬
ers. First, differences in the heights of barriers, coupled with an east- west
gradient in rate of isostatic rebound (Larsen 1994), make it almost certain
that different barriers came into effect at different times; depending on
just when mudpuppies arrived in the basin, they may have had access to
some tributaries but not to others. Second, any extinctions of upstream

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March 1999

populations subsequent to the establishment of corresponding barriers
could not have been offset by recolonization.

Hecht and Walters (1955) described Necturus as a cold-adapted taxon
and suggested that low water temperatures should not have been a limit¬
ing factor in its northward distribution. On this basis, it might also be
expected that mudpuppies were among the aquatic species that dispersed
back into deglaciated regions relatively early. Early recolonization would
have permitted mudpuppies greater opportunity to take advantage of
temporary routes between drainages and around barriers.

Perhaps, however, mudpuppies are not as cold-adapted as surmised
by Hecht and Walters (1955). Their inference was based on the mudpuppy's
well known tendency to be active during the winter, as evidenced, for
example, by the frequency with which they are caught by anglers fishing
through the ice. Subsequent observations have confirmed that
mudpuppies forage during the winter (see Vogt 1981 and Cochran 1986
for Wisconsin examples), but it is also well known that mudpuppies re¬
produce during the summer (Bishop 1926, Cochran and Lyons 1985,
Cochran 1995). It is probable that successful completion of egg deposition
and embryological development depends on water temperature exceed¬
ing some threshold for a minimum length of time. If so, then northward
range expansion by the mudpuppy might have been delayed until rivers
and lakes shifted from thermal regimes dominated year-round by frigid
glacial meltwater to more temperate cycles responding to moderating lo¬
cal climates. Holman (1998) has assumed that the amphibian species of
several thousand years ago had essentially the same ecological tolerances
and habitat preferences that they do today; if this assumption is valid,
then the seasonal cycles in thermal selection (Hutchison and Spriestersbach
1986) and tolerance (Hutchison and Ritchart 1989) displayed by
mudpuppies from central Wisconsin may indicate that the aquatic habi¬
tats this species invaded in formerly glaciated regions had assumed sea¬
sonal cycles in water temperature.

The available evidence concerning the timing of mudpuppy dispersal
is somewhat equivocal: (1) A single, problematic record is available from
the Mississippi River drainage above St. Anthony Falls (Cochran 1991).
(2) A single record from above a barrier falls on a tributary to Lake
Superior's south shore was revealed during the present study; details about

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March 1999

this record are unavailable. (3) No specimens are known from above bar¬
rier falls along Lake Superior's north shore (Cochran 1991). (4) I am cur¬
rently investigating the fish fauna above a waterfall on the Devils River, a
tributary to the West Twin River in Manitowoc County, Wisconsin (Lake
Michigan drainage). Although I have collected several mudpuppies in
the nearby East Twin River, I have not obtained any in suitable habitat
above the waterfall. A consideration of postglacial drainage changes in
this region (Wielert 1980) suggests that mudpuppies could have first colo¬
nized the area when Glacial Lake Oshkosh drained into the Wisconsin
River valley of the Mississippi River drainage, and this possibility is sub¬
stantiated by the presence of mudpuppies today in Lake Winnebago, a
remnant of Glacial Lake Oshkosh. However, an early presence in Glacial
Lake Oshkosh should have permitted mudpuppies to colonize above the
Devils River waterfall during the subsequent interval when Glacial Lake
Oshkosh drained through the West Twin River valley to Lake Michigan;
during this time, the huge volume of water moving through the West
Twin River valley should have resulted in a water level high enough to
submerge the falls. Alternatively, mudpuppies may first have colonized
Glacial Lake Oshkosh after the West Twin River outlet was abandoned by
using the subsequent Kewaunee or Ahnapee river outlets to invade from
Lake Michigan (see maps in Wielert 1980).

It is hoped that this note will encourage other field personnel in
Wisconsin, including fisheries scientists and other aquatic biologists, to
document and report the occurrence of mudpuppies in their collections.
In light of recent advances in the zoogeography of fishes in other parts of
the Great Lakes basin (Legendre and Legendre 1984, Mandrak and
Crossman 1992, Stephenson and Momot 1994, Momot and Stephenson
1996), it is also hoped that experts in those regions with access to
mudpuppy distributional data will contribute to the analysis of a prob¬
lem that has lingered since the time of Hecht and Walters (1955).

Acknowledgments

I thank Nelson Ham of St. Norbert College for sharing his geologi¬
cal insight and commenting on an earlier draft of this manuscript. Gary
Casper provided information about mudpuppy specimens at the Milwau¬
kee Public Museum. Any errors of interpretation are strictly my own.

Bulletin of the Maryland Herpetological Society

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March 1999

Literature Cited
Bailey, R.M. and G.R. Smith.

1981 . Origin and geography of the fish fauna of the Laurentian

Bishop, S.C.

1947.

Great Lakes basin. Can. J. Fish. Aquat. Sci. 38:1538-1561.

Handbook of salamanders. Comstock Publishing Co.,
Ithaca, New York. 555 pp.

Casper, G.S.

1996.

Geographic distributions of the amphibians and reptiles
of Wisconsin. Milwaukee Public Museum, Milwaukee,
Wisconsin. 87 pp.

Casper, G.S.

1997.

Recent amphibian and reptile distribution records for
Wisconsin. SSAR Herp. Rev. 28: 214-216.

Cochran,P.A.

1986.

Some observations on the herpetofauna of the Univer¬
sity of Wisconsin-Madison Campus. Bull. Chi. Herp. Soc.
21:34-35.

Cochran, P.A.

1991.

Distribution of the mudpuppy, Necturus maculosus , in
Minnesota in relation to postglacial events. Can. Field-
Nat. 105:400-402.

Cochran, P.A.

1995.

Life history notes: Necturus maculosus . Reproduction.

SSAR Herp. Rev. 26:198.

Cochran, RA. and J.D. Lyons.

1985. Life history notes: Necturus maculosus. Juvenile ecology.
SSAR Herp. Rev. 16:53.

Cochran, P.A. and J.D. Lyons.

1986. New distributional records for Wisconsin amphibians
and reptiles Trans. Wise. Acad. Sci. Arts. Lett. 74:138-141.

page 10

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March 1999

Conant, R.

1975. A field guide to reptiles and amphibians of eastern and
central North America, 2nd ed. Houghton Mifflin, Bos¬
ton, Massachusetts. 429 pp.

Conant, R. and J,T. Collins.

1991 . A field guide to reptiles and amphibians: eastern and cen¬
tral North America, 3rd ed. Houghton Mifflin, Boston,
Massachusetts. 450 pp.

Gilderhus, RA. and B.G.H. Johnson.

1980. Effects of sea lamprey (Fetromyzon marinus) control in the
Great Lakes on aquatic plants, invertebrates, and amphib¬
ians. Can. J. Fish. Aquat. Sci. 37:1895-1905.

Greene, C.W.

1935. The distribution of Wisconsin fishes. Wise. Cons. Comm.,
Madison, Wisconsin. 235 pp.

Harding, J.H.

1997. Amphibians and reptiles of the Great Lakes region. Univ.
Mich. Press, Ann Arbor, Michigan. 378 pp.

Hecht, M.K. and V. Walters.

1955. On the northern limits of the salamander Necturus
maculosus . Copeia 1955:251-252.

Hocutt, C.H. and E.O. Wiley (eds.).

1986. The zoogeography of North American freshwater fishes.
John Wiley and Sons, New York, New York. 866 pp.

Holman, J.A.

1992. Patterns of herpetological re-occupation of post-glacial
Michigan: amphibians and reptiles come home. Michi¬
gan Academician 24:453-466.

Holman, J.A.

1995. Pleistocene amphibians and reptiles in North America.
Oxford Univ. Press, New York, New York. 243 pp.

Bulletin of the Maryland Herpetological Society

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March 1999

Holman, J.A.

1998. Amphibian recolonization of midwestern states in the
postglacial Pleistocene. Pp. 9-15 in: Lannoo, M.J. (ed.).
Status and conservation of midwestern amphibians. Uni¬
versity of Iowa Press, Iowa City, Iowa.

Hutchison, V.H. and J.P. Ritchart.

1989. Annual cycle of thermal tolerance in the salamander,
Necturus maculosus. J. Herpetol. 23:73-76.

Hutchison, V.H. and K.K. Spriestersbach.

1986. Diel and seasonal cycles of activity and behavioral ther¬
moregulation in the salamander Necturus maculosus.
Copeia 1986:612-618.

Johannes, S.I.

1974. Our south shore waterfalls. Wise. Cons. Bull. 39:9-1 1.
Larsen, C.E.

1994. Beach ridges as monitors of isostatic uplift in the upper
Great Lakes. J. Great Lakes Res. 20:108-134.

Legendre, P. and V. Legendre.

1984. Postglacial dispersal of freshwater fishes in the Quebec
peninsula. Can. J. Fish. Aquat. Sci. 41:1781-1802.

Long, C.A.

1993. Biogeography of the reptiles and amphibians of the Lake
Michigan isles. Bull. Chi. Herp. Soc. 28:214-218.

Mandrak, N.E. and E.J. Crossman.

1992. Postglacial dispersal of freshwater fishes into Ontario.
Can. J. Zool. 70:2247-2259.

Momot, W.T. and S.A. Stephenson.

1996. Atlas of the distribution of fish within the Canadian tribu¬
taries of Lake Superior. Occasional Paper 19, Center for
Northern Studies, Lakehead University, Thunder Bay,
Ontario.

page 12 Bulletin of the Maryland Herpetological Society

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Reigle, N.J., Jr.

1967. The occurrence of Necturus in the deeper waters of Green
Bay. Herpetologica 23:232-233.

Stephenson, S.A. and W. T. Momot.

1994. Isostatic rebound and its effects on fish colonization and
distribution in the western Lake Superior basin. Can. J.
Zool. 72:78-86.

Tyning, T.F.

1990. A guide to amphibians and reptiles. Little, Brown and
Co., Boston, Massachusetts. 400 pp.

Underhill, J.C.

1986. The fish fauna of the Laurentian Great Lakes, the St.
Lawrence Lowlands, Newfoundland and Labrador. Pp.
105-136 in: C.H. Hocutt and E.O. Wiley (eds.). The zoo¬
geography of North American freshwater fishes. John
Wiley and Sons, New York, New York.

Underhill, J.C. and J.B. Moyle.

1968. The fishes of Minnesota's Lake Superior region. Conser¬
vation Volunteer 31:1-25.

Vogt, R.C.

1981. Natural history of amphibians and reptiles of Wiscon¬
sin. Milwaukee Public Museum, Milwaukee, Wisconsin.
205 pp.

Wielert, J. S.

1980. The late Wisconsinan glacial lakes of the Fox River wa¬
tershed, Wisconsin. Trans. Wise. Acad. Sci. Arts Lett.
68:188-201.

Division of Natural Sciences , St. Norbert College ,

DePere, Wisconsin 54115

Bulletin of the Maryland Herpetological Society

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March 1999

Case Report of an Untreated Human Envenomation
by the Western Massasauga Rattlesnake
Sistrurus catenatus tergiminus

ABSTRACT

Records were kept on the symptoms following a bite by a western
massasauga (S. c. tergiminus). Although symptoms included severe swell¬
ing from the afflicted hand into the chest area, intense pain, temporary
fever and nausea, no medical attention was received. Although docu¬
mented cases of massasauga bites exist for the eastern subspecies S. c.
catenatus , no recent case reports exist for this western subspecies.

INTRODUCTION

Massasauga rattlesnakes occur throughout the state of Texas and
are separated into two subspecies (Gloyd, 1955); the desert massasauga S.
c. edwardsi in the west and southwest and the western massasauga S. c.
tergiminus in the central and northeastern parts of the state. Though wide¬
spread, these snakes are rarely encountered by humans and are typically
only observed crossing roads at night during the months of May and June
(Knopf and Tinkle, 1961). Werler (1963) reports the western massasauga
as docile and reluctant to rattle, but my experience is in agreement with
Greene and Oliver (1965). The individuals encountered have been very
aggressive; continually rattling and striking repeatedly.

However, due to their reclusive nature, human envenomation by
the western massasauga is rare (Tennant, 1998) and well-documented
envenomation case reports for this subspecies are presently unavailable.
The reports provided by Tennant (1998) give no details or symptoms ex¬
cept that bites are "seldom serious" and in the two cases mentioned, re¬
sulted in "no permanent damage." This manuscript describes a different
scenario. Case reports available on massasauga bites are from the eastern
subspecies and most were documented when popular techniques involved
tourniquets and incisions (LaPointe, 1965) which are no longer recom¬
mended as treatment.

page 14

Bulletin of the Maryland Herpetological Society

Volume 35 Number 1

March 1999

REPORT

On September 4, 1997 at 8:45 PM CST, this author (24 years old,
130 lbs., good general health) was bitten by an 43 cm male massasauga
while collecting it in Parker County, Texas, west of the city of Fort Worth.
Both fangs penetrated the middle finger of the left hand with puncture
wounds one centimeter apart. One fang entered on the dorsal side of the
medial knuckle, the other on the proximal side of the same knuckle. There
was an instant intense burning accompanied by strong throbbing in the
bitten finger. Oral suction was immediately applied and continued for
five minutes.

At five minutes after the bite, the swelling and throbbing had in¬
creased in the finger. There was significant bleeding from the puncture
wounds and the finger went numb. At ten minutes, a "tingling" sensation
was felt in all fingers on the left hand, numbness, pain, and throbbing
continued to increase. At 15 minutes, swelling had increased into the hand
and other fingers, lymph nodes in the left armpit became tender, and a
dry metallic taste was noticed in the mouth.

At 30 minutes, swelling had continued in both the palm, the dorsal
side of the hand to the wrist, and fingers became immovable. At 45 min¬
utes, the taste in my mouth was gone, the puncture sites continued to
bleed, swelling had passed my wrist, the pain was almost unbearable and
was extremely sensitive to touch or movement.

After one hour, the swelling was into the forearm. The burning
sensation was less intense (possibly due to Advil® painkillers at 20 min¬
utes) but the throbbing continued and my arm was immovable beyond
the elbow. At 75 minutes, swelling continued toward the elbow, numb¬
ness was going in and out of my arm, and tenderness in my left armpit
was increasing.

At 1:30 PM, nearly five hours after the bite, I returned home from
the field having unadvisedly decided that medical attention would no
longer be useful. At this time, swelling had reached the elbow and the
pain was significant but bearable. Although slower, the wounds contin¬
ued to bleed as I managed to go to sleep. At eight hours after the bite, I
briefly awoke sweating, shaking uncontrollably with chills, with a fever

Bulletin of the Maryland Herpetological Society

page 15

Volume 35 Number 1

March 1999

page 16 Bulletin of the Maryland Herpetological Society

of 38.3 C, mild nausea, and was very "lightheaded." The bleeding of the
bite wound had stopped and the swelling had slightly increased. At 11
hours, I awoke again with all symptoms from earlier in the morning gone
(i.e. my temperature was normal) and took two more Advil for pain. The
swelling had rounded the elbow and the throbbing had increased slightly
from last night (Figure 1 and Figure 2).

Figure 1. Photo of the author eleven hours after the bite of a western massas-
auga rattlesnake. Photo by K. Wray.

At 14 hours, all of the initial "burning" was gone. The pain was now
a dull throbbing ache that I tend to associate with severe bruises. My whole
arm was very sore and extremely sensitive to touch and sunlight. Any
movement of my arm hairs, even due to my own breath, was extremely
painful and the most diffuse sunlight reaching my arm felt like a severe
sunburn. At 20 hours, the swelling had reached the midpoint of my left
triceps, appearing to have progressed up the back of my arm instead of
up the front. The swelling in this area was not tight as in my forearm and
hand, but very heavy and sagging. Fain was still considerable.

Twenty-four hours after the bite, I ate for the first time. The swelling
had reached my armpit and shoulder. For the following 12 hours, the pain
remained unchanged although the swelling progressed through my arm-

Volume 35 Number 1

March 1999

Figure 2. Photo of the author eleven hours after the bite of a western massas-
auga rattlesnake. Photo by K. Wray.

pit, into my chest, and down into the left side of my torso. Lymph nodes
in my groin and in both armpits became increasingly tender and swollen.
At 30 hours, my left wrist measured 24.1 cm in circumference (right wrist
- 20.3) and my left elbow measured 33.0 cm (right elbow = 29.2). Esti¬
mated elbow movement was constrained to no more than 10-15° either
direction of the 130° position.

Between 48-60 hours, swelling in the hand decreased slightly and I
regained some finger mobility. Swelling in the arm, pain, and skin sensi¬
tivity remained the same with the addition of a slight headache. At 60
hours, the lymph nodes in both armpits were visibly swollen and it was
painful to rest my arm next to my body. At 72 hours, the decreased swell¬
ing in the hand and forearm enabled the tip of my thumb to touch the tip
of my fourth finger with limited wrist mobility. The bitten finger was
still immovable.

For the following four days, the swelling that left the hand and fore¬
arm drained into the elbow and shoulder and eventually into my torso.
Lymph nodes remained very tender and heavy discoloration became ap¬
parent in my arm. At one week after the bite, all swelling was gone except

Bulletin of the Maryland Herpetological Society

page 17

Volume 35 Number 1

March 1999

in the bitten finger. All joints and muscles in the left hand, wrist, and fore¬
arm were stiff, weak, and sore. At 10 days, stiffness had decreased al¬
though I could not completely close my hand into a fist. Except for sore¬
ness, the only pain experienced was when contact was made to the arm.
Skin was very dry, cracked, and beginning to slough around the bitten
knuckle. At 14 days, the entire arm up to the elbow had sloughed at least
one layer of skin and discoloration was nearly gone.

At one month, a depression was noticed across each fingernail on
the left hand that had slowly grown out and had been cut off through
trimming. This depression presumably coincided with the time of intense
swelling which had thus affected nail growth.

Seventeen months after the bite, the bitten finger cannot be fully
extended and a dull ache is still present at nearly all times, which I expect
to be a permanent condition. Any activity that requires a strong grip with
my left hand results in increased soreness and even more limited mobil¬
ity for several days following.

In summary, swelling and pain increased through daily activity and
decreased at night during sleep. Bleeding from the puncture wounds con¬
tinued for five hours. I had no appetite for 24 hours following the bite, but
continually drank water. No respiratory or gastrointestinal effects were
noted nor was there ever discoloration in urine. The only systemic effects
occurred five hours after the bite but did not persist. After two weeks, all
visible signs of the snakebite had disappeared. Medical attention was never
received and the only medication used was over-the-counter painkillers.
I now consider this poor judgement on my part. I greatly underestimated
the venom strength of a "pigmy" rattlesnake and an effort should have
been made to seek medical attention.

On a more personal note, when this occurred, I was rightfully very
concerned as to what I should expect regarding symptoms. However, I
could find no literature on a bite from this snake or any Sistrurus bite in
enough detail to satisfy my anxiety.

Regretfully, I do not have such medical knowledge or the proper
equipment available to monitor other attributes (i.e. blood pressure) that
may be useful information. Although most of these symptoms are typical

Bulletin of the Maryland Herpetological Society

page 18

Volume 35 Number 1

March 1999

of pit viper envenomation, should any researcher working with these
snakes be as unfortunate as to endure this same experience, I hope this
will provide some idea as to what to anticipate. However, I should stress
that bites differ in location, amount of venom injected, the reaction by the
victim, and variability demonstrated through the seasons of the year and
age of the snake (Chippaux, et al, 1991).

Literature Cited

Chippaux, J. R, V. Williams, and J. White.

1991. Snake venom variability: methods of study, results and
interpretation. Toxicon 29: 1279-1303.

Gloyd, H. K.

1955. A review of the massasaugas, Sistrurus catenatus, of the
southwestern United States (Serpentes: Crotalidae). Bul¬
letin of the Chicago Academy of Sciences 10: 83-98.

Greene, H.W. and G. V. Oliver, Jr.

1965. Notes on the natural history of the western massasauga.
Herpetologica 21: 225-228.

Knopf, G. N. and D. W. Tinkle.

1961. The distribution and habits of Sistrurus catenatus in north¬
west Texas. Herpetologica 17: 126-13 1.

LaPointe, J.

1953. Case report of a bite from the massasauga, Sistrurus
catenatus catenatus. Copeia 2: 128-129.

Tennant, A. J.

1998. A Field Guide to the Texas Snakes, Second Edition. Gulf
Publishing Company, Houston, Texas, 291 pp.

Werler, J. E.

1963. Poisonous snakes of Texas and first aid treatment for their
bites. Texas Game and Fish Commission, Austin, Bull.
31: 1-3 1.

Bulletin of the Maryland Herpetological Society

page 19

Volume 35 Number 1

March 1999

Andrew S. Baldwin. Department of Biology, Box 19498, The University of
Texas at Arlington, Arlington, Texas 76019. U.S.A.
baldwin@exchange.uta.edu

Received 16 February 1999
Accepted 20 February 1999

Nature Study Day

Sunday, May 23, 1999
ll:OOA.M. to 5:00P.M.

Oregon Ridge Park

Come join the Natural
History Society of Maryland and the
Oregon Ridge Nature Center Council for a day
of learning about nature for the whole family.

You will see live raptors (hawks and owls),
reptiles from Maryland and around the world,
and take nature walks with some of Maryland’s
top naturalists. Information booths from outdoor
education and conservation organizations will be
present. Workshops will be held throughout the day and
food and drink will be available. Bring your family,
friends, and binoculars for an afternoon of nature
activities. There will
be outdoor and indoor
activities, so toss a

raincoat in the car and come rain or shine.

For more information please call the Natural
History Society of Maryland at 410-235-61 16
or visit our website at www.naturalhistory.org.

Admission: adults - $5.00; students 13 and older, and seniors - $3.00;

under 13 - free. Free parking.

Directions to Oregon Ridge Park: From the Baltimore
Beltway (1-695) take 1-83 North to Exit 20-B
Shawan Road West. Make a left at the first light
onto Beaver Dam Road. Follow signs to Oregon
Ridge Park entrance.

Presented by the Natural History Society of Maryland and the Oregon Ridge Nature Center Council

page 20

Bulletin of the Maryland Herpetological Society

Volume 35 Number 1

March 1999

News and Notes

Presented by MARS Preservation Fund, Inc.

Mu-

WMF rV'

^EPTBLE

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?h°w/s(

1999

M JB

Saturday in, eminars:

r y 3./21, . 4.^

Stares 7 ,, J0P

We believe in education,
the promotion of captive
breeding and the protection
of critical habitats.

Sundi

§how/S{

11

m.

Pm.

11

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%Oiy

ettiinars-

5p.

a.m.

m.

LOCATION*

8P.A

Maryland State Fairgrounds 4-H Building (Daily Show and Seminars)

Days Hotel Timonium (Host Hotel & Lectures Saturday Evening)

• Captive bom reptiles & amphibians for display and sale • Equipment, books & supplies
• Book signings each day • Educational exhibits •Door Prizes •Raffles • Silent Auction

• Display & photographs of Costa Rican rainforest area purchased by MARS

• Pre-show social gathering • ! Reptiles & Rainforests” art collection

• Seminars throughout the show • “Critter Contact” hands-on animal display
Professional Lecture Series Saturday evening will feature well-known Dr. Richard Funk

(reptile and amphibian veterinarian), Alan Kardon (herpetologist, reptiles of Mexico), others to
be announced and another uFabulous Fotos” exhibit.

Show proceeds are donated to The Center for Ecosystem Survival for the
purchase of rainforest. THE MID-ATLANTIC REPTILE SHOW, now in its
seventh year, has purchased 2,528.5 acres of critical habitat to date.

Bring your aluminum cans to our recycling bin and help
us purchase and protect more rainforest!

ADMISSION: Weekend Pass (includes show both days and lectures) $13 Adults, One Day Pass (Sat. or Sun.) $7
Adults. Children 6-12 and Seniors over 65 - $6 (for one day or weekend pass). Children under 5 are free.

FOR ADDDTDONAL INFORMATION*

Call the MARS Hotline at 410-580-0250, visit our web site at http://www.reptileinfo.com
or e-mail us at mars@reptileinfo.com
Only registered vendors may display or sell on the premises.

Please leave your pet animals home! They will not be admitted to the show. Thank you.

Bulletin of the Maryland Herpetological Society

page 21

Volume 35 Number 1

March 1999

News and Notes

Help Us Turn

"Trash Into Cash" To Purchase
And Protect Rainforest!

Join the Mid-Atlantic Reptile Show (MARS), MARS Preservation Fund,
Inc. (a non-profit 501(c)(3) organization), International Amphibian Day,
the National Aquarium in Baltimore and other volunteers in our annual
clean-up at Pimlico Racetrack following the Preakness. All the proceeds
from our work and the recycled aluminum cans go directly toward the
purchase and permanent protection of rainforest acreage in Costa Rica.

Over the past 9 years, more than $69,000 was raised to purchase 581
acres of rainforest in Costa Rica’s Talamanca Biosphere Reserve. This
coastal reserve is the home to thousands of species of mammals, birds,
reptiles, amphibians, and numerous other creatures. North American song
birds such as the Baltimore Oriole are known to migrate during the winter
to this region. This reserve also includes important nesting beaches for
endangered leatherback sea turtles and is the home to many tropical
frogs like the red-eyed tree frog and four species of poison dart frogs.

This year’s clean-up will take place on MAY 16, 6:00 A.M. - 12:00
P.M. (please be prompt - we want to finish by noon!) and involves pick¬
ing up aluminum cans and trash from approximately 1/3 the infield (an
amount that will increase as volunteers sign-up). We will once again have
a picnic lunch and door prizes for volunteers following the clean-up. All
volunteers must be 18 YEARS or older to participate.

For further information and to sign-up as a volunteer call 410-
580-0250. Please leave us a message with your name, address and
phone number.

page 22

Bulletin of the Maryland Herpetological Society

Volume 35 Number 1

March 1999

News and Notes

International Amphibian Day

The first event to support captive breeding, conservation and
ethical commerce of amphibians
with the participation of noted breeders, scientists and hobbyists.

October 7th to the 10th

Days Hotel, Timonium, National Aquarium in
Baltimore and other locations in Maryland
• Show and Sale (Oct. 9) • Workshops and lectures •

• Field survey workshop • Benefit auction •

• Visit to the National Aquarium in Baltimore •

All proceeds benefit the Declining Amphibian Population
Task Force and the Center for Ecosystem Survival

International Amphibian Day

241 E. Colonial Hwy. • Hamilton, Virginia 20158
Spaces are limited for some activities, so please call for more information, inscriptions:

(609) 641-4944 or visit our site: http://www.mediasoft.net/olson/iad
Presented by MARS Preservation Fund Inc.

Reptile and
Amphibian Rescue
410-580-0250

We will try to take as many unwanted pet reptiles
and amphibians as we can.

Leave a message with your name and number to
give up an animal for adoption;
or to volunteer to help with our efforts.

WE NEED:

• Cages, Aquariums, Supplies & Food
• Drivers to Transport Animals

• Foster Homes • Adoptive Homes

Bulletin of the Maryland Herpetological Society

page 23

Volume 35 Number 1

March 1999

News and Notes

A New Book from the Society for the Study of Amphibians and Reptiles

The Lizards of Iran

by Steven C. Anderson

CALIFORNIA ACADEMY OF SCIENCES AND UNIVERSITY OF THE PACIFIC

IRAN IS A LARGE AND STRATEGICALLY LOCATED
country, but few synthetic studies of its her-
petofauna have been published. Steven C. Ander¬
son has conducted extensive field work in Iran,
beginning in 1958, and has spent a lifetime
studying its herpetofauna, a subject on which he
is a recognized authority. The lizard fauna of
Iran is quite diverse and includes representa¬
tives of eight families: Agamidae (20 species),

Anguidae (2), Eublepharidae (3), Gekkonidae
(39), Lacertidae (42), Scincidae (14), Uromas-
tycidae (3), and Varanidae (2).

This book is the first monographic treatise
on the lizards of Iran, and contains sections on
the history of herpetological studies in Iran; the
biogeography of Iranian lizards; illustrated keys
to families, genera, and species; an extensive
bibliography of Iranian amphibians and reptiles; and appendices listing specimens examined and a
gazetteer of collecting localities. The detailed species accounts include these sections: synonymy,
diagnosis, color pattern, size, natural history, habitat, distribution, and remarks.

A major feature of this book is an outstanding group of color
portraits of lizards (152 photographs) and their habitats (38). Most of
these have not been published previously and many of the species of
lizards have never been illustrated before. There are also nearly 150
figures in the text plus 1 03 spot distribution maps. This book will become
the standard reference on the lizards of Iran and adjacent regions.

Specifications: About 350 pages, 137 figures, numerous illustrations in keys, 103
distribution maps, 190 color photographs, index, clothbound with dustjacket,
ISBN 0-916984-49-4. To be issued in September 1999.

I S. Anderson: Lizards of Iran • Pre-publication price to SSAR members US$50 • Institutions and non-members US$65
I Other SSAR Books on the Herpetology of Southwest Asia:

• J. Anderson: Herpetology of Arabia (1896, reprint 1984), 160 p., one color plate, clothbound . . . US$25

• Latifi: Snakes of Iran (1991), 167 p., 22 color plates (66 figures), 2 color maps, clothbound . . . . US$22

• Leviton et al.: Middle East Amphibians and Reptiles (1992), 264 p., 32 color plates (220 photos), clothbound ............ US$30

• Szczerbak & Golubev: Gecko Fauna of USSR and Contiguous Regions (1996), 245 p., 24 color photos, clothbound .. US$48

■ Shipping Cost per Book : • USA address, add us$3; non-USA address, add us$6

Send orders to: Dr. Robert D. Aldridge, SSAR Publications Secretary, Department of Biology, Saint Louis
University, 3507 Laclede Avenue, Saint Louis, Missouri 63103-2010, USA ( telephone : area code 314, 977-
3916or -17 \0fax: 3 14, 977-3658; e-mail, ssar@slu.edu). Makechecks payable to “SSAR.” Overseas orders
must be paid in USA funds using a draft drawn on American banks or by International Money Order. Orders
may also be charged to MasterCard or Visa (please provide account number and card expiration date). SSAR
membership details and a complete list of all Society publications can be obtained on request to Dr. Aldridge.

page 24

Bulletin of the Maryland Herpetological Society

Society Publication

Back issues of the Bulletin of the Maryland Herpetological Society
where available, may be obtained by writing the Executive Editor. A list
of available issues will be sent upon request. Individual numbers in stock
are $5.00 each, unless otherwise noted.

The Society also publishes a Newsletter on a somewhat irregular
basis. These are distributed to the membership free of charge. Also pub¬
lished are Maryland Herpetofauna Leaflets and these are available at
$.25 /page.

Information for Authors

All correspondence should be addressed to the Executive Editor.
Manuscripts being submitted for publication should be typewritten
(double spaced) on good quality 8 1/2 by 11 inch paper with adequate
margins. Submit original and first carbon, retaining the second carbon. If
entered on a word processor, also submit diskette and note word proces¬
sor and operating system used. Indicate where illustrations or photographs
are to appear in text. Cite all literature used at end in alphabetical order
by author.

Major papers are those over five pages (double spaced, elite type)
and must include an abstract. The authors name should be centered un¬
der the title, and the address is to follow the Literature Cited. Minor pa¬
pers are those papers with fewer than five pages. Author's name is to be
placed at end of paper (see recent issue). For additional information see
Style Manual for Biological Journals (1964), American Institute of Biological
Sciences, 3900 Wisconsin Avenue, N.W., Washington, D.C. 20016.

Reprints are available at $.07 a page and should be ordered when
manuscripts are submitted or when proofs are returned. Minimum order
is 100 reprints. Either edited manuscript or proof will be returned to au¬
thor for approval or correction. The author will be responsible for all cor¬
rections to proof, and must return proof preferably within seven days.

The Maryland Herpetological Society
Department of Herpetology
Natural History Society of Maryland, Inc.

2643 North Charles Street
Baltimore, Maryland 21218

Bulletin of the Maryland Herpetological Society

page 25

ol Mainland

US ISSN: 0025-4231

640

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BULLETIN

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DEPARTMENT OF HERPETOLOGY
THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.

MDHS . A Founder Member of the Eastern

Seaboard Herpetological League

30 JUNE 1999

VOLUME 35 NUMBER 2

JUL 2 3 1999

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 35 Number 2

June 1999

CONTENTS

Resting Metabolism and Temperature Selection in the Desert Skink,

Sphenops sepsoides (Reptilia: Scincidae)

TalalA. Zari . . . . . . . . . . . . . 27

Emory's Softshell Turtle, Apalone spinifera emoryi, in Mexico

Julio A. Lemos-Espinal, Robert G. Webb, Hobart

M. Smith . . . . . 40

Seasonal Variation in Reporduction in the Red-Eared Slider (Trachemys
scripta elegans)

John K. Tucker

43

BULLETIN OF THE

mM)6

Volume 35 Number 2 June 1 999

The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.

President Tim Hoen

Executive Editor Herbert S. Harris, Jr.

Steering Committee

Frank B. Groves Jerry D. Hardy, Jr.

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

Membership Rates

Membership in the Maryland Herpetological Society is $20.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $30.00 per year. Make all checks payable to the Natural History
Society of Maryland, Inc.

Meetings

The third Wednesday of each month, 7:30 p.m. at the Baltimore Zoo’s
Reptile House (except August and September due to The Mid-Atlantic
Reptile Show). The Department of Herpetology meets informally on all
other Wednesday evenings at the NHSM at 8:00 p.m.

Volume 35 Number 2

June 1999

RESTING METABOLISM AND TEMPERATURE
SELECTION IN THE DESERT SKINK,
SPHENOPS SEPSOIDES (REPTILIA: SCINCIDAE)

Talal A. Zari
Abstract

Resting metabolic rate and temperature selection of the desert skink,
Sphenops sepsoides, were measured during day and night. The resting meta¬
bolic rate was low. No significant metabolic differences were observed
between night and daytime measurements. The mass exponent b values
ranged between 0.52 and 0.71. Thermal sensitivity (Q10) was low at 20-
25°C and 30~35°C Skinks had significantly lower mean selected body tem¬
peratures during late scotophase and midphotophase than other times of
day over the 24 h period. The adaptive significance of these patterns of
metabolism and temperature selection in S. sepsoides was discussed.

Introduction

Oxygen consumption rates of lizards are influenced by many fac¬
tors including temperature, body mass, season, time of day, sex and phy-
logeny (Bennett and Dawson, 1976; Andrews and Pough, 1985; Zari, 1987,
1997). Moreover, strong effects of behavior and ecology were observed on
the metabolic rate-temperature curves of lizards (Al-Sadoon and
Spellerberg, 1985; Zari, 1992, 1996). Behavioral thermoregulation in liz¬
ards has been widely studied (Brattstorm, 1965; Avery, 1982). Many fac¬
tors modify the selected body temperature (preferred body temperature)
of lizards such as time of day, light, season, feeding and sexual condition
(Spellerberg, 1974; Huey, 1982; Tu and Hutchison, 1994; Zari, 1987, 1998).

Until recently, there were no published studies on resting energy
metabolism and temperature selection in S. sepsoides (=Chalcides sepoides)
during day and night. This skink occurs in North Africa, Senegambia,
Arabia and Syria (Khalil and Hussein, 1963; Fuhn, 1975). Do the behavior,
ecology and morphology of this desert species affect its energy metabo-

Key Words: Resting metabolism, temperature selection, skink, Sphenops
sepsoides, body mass, temperature

Bulletin of the Maryland Herpetological Society

page 27

Volume 35 Number 2

June 1999

lism and temperature selection? To answer this question, resting metabo¬
lism and body temperature selection in S. sepsoides were measured dur¬
ing day and night.

Materials and Methods

S. sqjsoides were imported from Egypt. They were kept in 100 x 60 x
60 cm glass aquaria. A 100 W heat lamp was placed 10 cm above the floor
of each aquarium to provide a photothermal gradient. Each heat lamp
was switched on between 09.00 and 19.00 h. Each aquarium contained
sand, stones and vegetation to simulate a natural habitat. The ambient
temperature in the room was around 26°C. Skinks were provided with
food (insects and spiders) and water ad libitum. They were acclimated to
these conditions for at least 2 weeks before any experimental measure¬
ments were made.

The resting metabolic rate (RMR) of skinks was measured at differ¬
ent temperatures (20-35°C) as the rate of oxygen consumption (ml g'1 h*1),
using constant pressure manometric respirometers having both animal
and control chambers as described by Zari (1987). In the morning, the
skinks were weighed and placed in the respirometers. The animal and
control chambers were immersed in a constant temperature water bath
at the test temperature. Measurements of RMR were made on quiescent
and postabsorptive skinks of various body sizes during day and night.
Consequently, they were deprived of food for 3 to 6 days prior to respirom¬
etry.

Body temperature selection by 12 skinks was measured in a linear
thigmothermal gradient over a 24 h period. A 120 cm long x 20 cm wide x
40 cm high trough with an aluminium base was heated from below by a
subsurface heater to produce a linear 15-45°C gradient when in a room at
15°C. Abroad-spectrum fluorescent tube was suspended above the trough
to provide light but not heat between 07.00 and 19.00 h. A skink was placed
in the trough and allowed to settle for 24 h. A YSI thermistor probe was
then inserted about 1.5 cm into the cloaca and taped to the tail. After
about 8 h, body temperature was recorded continuously on a chart re¬
corder for 24 h. Mean selected body temperature (MST) was registered at
10-min intervals. All measurements were carried out during the spring
(March-May).

page 28

Bulletin of the Maryland Herpetological Society

Volume 35 Number 2

June 1999

Regression analyses of log-transformed oxygen consumption rate
and log body mass data were carried out by the method of least squares.
Comparisons of regression lines were made using the analysis of covari¬
ance (ANCOVA). Statistical comparisons of the mean Q10 values and se¬
lected body temperatures were performed using two-tailed f-tests and
analysis of variance (ANOVA). Differences were considered to be statisti¬
cally significant when P < 0.05 (Sokal and Rohlf, 1981).

Results

The relationships between resting oxygen consumption rate and
body mass of S. sepsoides (0.453 - 7.258 g) were investigated at 20, 25, 30
and 35°C Regression lines for each temperature were fitted to the data by
the method of least squares. The relationship between mass-specific RMR
(ml g1 h1) and body mass was expressed by the equation:

log RMR = log a + (b-1) log M
or the allometric form:

RMR = a M (b l)

where log a is the intercept, b-1 is the regression slope (or mass expo¬
nent), and M is the body mass (g). RMR values (ml h1) are obtained by
using b as the regression slope. The values of RMR at night (scotophase)
did not differ significantly than those during day (photophase) (P > 0.05
by ANCOVA); therefore, the data were combined. The values of log a, b-
1, b along with correlation coefficients r and P values are presented in
Table 1. RMR (ml g1 h1) decreases with increasing body mass at each tem¬
perature (20-35°C). Statistical regression analysis indicates that the regres¬
sion slopes b-1 were highly significant for all temperatures tested (P <
0.001) (Table 1).

Analysis of covariance, ANCOVA, was used to determine whether
there are differences in the slopes b-1 and intercepts log a of regression
equations describing the oxygen consumption rates at different tempera¬
tures. There were no significant differences in the slopes of the regres¬
sions among the different temperatures (P > 0.05 by ANCOVA). How¬
ever, log a values were significantly distinct from one another only be¬
tween 25 and 30°C (P < 0.001 by ANCOVA) .

Bulletin of the Maryland Herpetological Society

page 29

Volume 35 Number 2

June 1999

Table 1. Regression statistics and ANCOVA for RMR (ml g1 hr1) of S. sepsoides
as a function of body mass (g) measured at different temperatures (20-35° C)

T(°C)

n

r

log a

b-1

b

P

20

20

-0.91

-0.962

-0.481

0.519

<0.001

25

22

-0.92

-0.902

-0.485

0.515

<0.001

30

20

-0.87

-0.772

-0.291

0.709

<0.001

35

22

-0.89

-0.687

-0.289

0.711

<0.001

The adjusted mean values for RMR of S. sepsoides are shown in Table
2 and Fig. 1. The temperature coefficient (Q10) values were calculated from
these adjusted mean rates of metabolism over the temperature range 20-
35°C (Table 3). The lowest Q10 value was obtained for the temperature
range 20-25°C. The highest Q10 value was found to occur in the tempera¬
ture range of 25-30°C. No significant diel variations existed between the

Fig. 1. The adjusted mean RMR (ml hr1) (ANCOVA) for S. sepsoides at
different temperatures (20-35° C). Each point represents the mean of different
measurements. The vertical lines above and below each mean are standard
deviations of that mean.

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Table 2. Adjust mean RMR (ml h :±SD) (ANCOVA), mean mass-specific

RMR (ml g1 hr1±SD) and body mass (g±SD) of S. sepsoides measured at
different temperatures (20-35° C).

T(°C)

n

Adjusted mean

Mean mass-specific

Mean mass

RMR (ml h'+SD)

RMR (ml g1 h’+SD)

(g+SD)

20

20

0.2597±0.0831

0.0612+0.0296

4.7078+1.9530

25

22

0.2874±0.0509

0.0675+0.0295

4.6961+1.8595

30

20

0.526 1±0. 1522

0.1173+0.0377

4.8744+1.8583

35

22

0.6364+0.1692

0.1445+0.0511

4.6961+1.8595

Table 3. temperature coefficient (Q10) values for the adjusted mean RMR
(ANCOVA) in S. sepsoides within body temperature (T) intervals between 20
and 35° C

T Intervals (°C)

S. sepsoides

20-25

1.22

25-30

3.35

30-35

1.46

Overall

1.82

overall Q10 values over the temperature range 20-35°C (P > 0.05 by
ANOVA). The Q10 values at 25-30°C were significantly higher than those
at 20-25°C or at 30-35°C (P < 0.01 by f-test).

The mean selected body temperature (MST±SD) of the twelve skinks
was 29.7+2.5°C (photophase 29.6±2.3°C, scotophase 29.8±2.7°C). The se¬
lected temperature range was 7.7°C (26.9-34.6°C) during day and 11.7°C
(24.1-35.8°C) at night. Skinks chose their lowest MST (27.92±1.59°C) dur¬
ing late scotophase (02.00 to 05.00 h) over the 24 h period. The MSTs dur¬
ing late photophase (14.00 to 19.00 h), early scotophase (20.00 to 24.00 h)
and early photophase (06.00 to 10.00 h) were significantly higher than

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during late scotophase (02.00 to 05.00 h) and midphotophase (11.00 to
13.00 h) (P < 0.05 by f-test) over the 24 h period (Fig. 2).

Discussion

The present results show an inversely proportional relationship be¬
tween the RMR (ml g1 h1) of S. sepsoides and body mass (g) (Table 1).
Mass exponents of S. sepsoides (b=0.52-0.71) are within the range of values
reported for other lizard species (Bennett and Dawson, 1976; Andrews
and Pough, 1985; Zari, 1993, 1996, 1997). These intraspecific b values are
lower than the interspecific generalized values reported by Bennett and
Dawson (1976), Bennett (1982) and Andrews and Pough (1985). Most mass
exponents for comprisons within species are >und to be lower than the
mass exponent for comparisons among lizard species (Andrews and
Pough, 1985). Several studies have differentiated between multi-species
and ontogenetic b values in animals (Taylor and Davies, 1981; Heusner,
1982; Andrews and Pough, 1985).

The observed values of RMRs of adult S. sepsoides at different tem¬
peratures are lower than the values predicted from the allometric equa¬
tions of Benett and Dawson (1976), Bennett (1982) and Andrews and Pough

Fig. 2. Mean selected body temperature of S. sepsoides over 24 h in a linear
thermal gradient illuminated from 07.00 to 19.00 h. The vertical lines above
and below each mean are standard deviations of that mean.

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June 1999

(1985). Similarly, lower metabolic rates have been reported for other fos-
sorial scincid species, e.g., Acontias mdeagris (Withers, 1981; Brownlie and
Loveridge, 1982) and Chalcides ocellatus (Bakker and Andrews, 1984; Fough
and Andrews, 1984). Andrews and Fough (1985) reported that day-active
predators had higher metabolic rates than fossorial lizards. Behavioral,
ecological and morphological differences among scincid species are re¬
flected in the variations of their resting metabolism (Withers, 1981;
Brownlie and Loveridge, 1982; Al-Sadoon and Spellerberg, 1985; Andrews
and Fough, 1985; Zari, 1987) which have been reported for this group. In
the present study, low RMR in 8. sepsoides inhabiting desert environments
could be explained by its ecology, behavior and morphology. This spe¬
cialized burrowing skink is secretive and adapted for burrowing in sand.
It has reduced limbs and an elongated body (Fuhn 1975). In the eastern
Egyptian desert, the sand-swimming, S. sepsoides is always moving from
under one bush to another, through the highest layer of the sand. This
type of movement produces traces of wavy continuous lines (Khalil and
Hussein, 1963). In addition, reduced metabolic rate in desert lizard spe¬
cies was found to be amongst the adaptive means for living in hot deserts
(Dawson and Templeton, 1966; Cloudsley-Thompson, 1972; Al-Sadoon
and Spellerberg, 1985; Zari, 1996). In the present study, no significant
metabolic differences in S. sepsoides were observed between night and
daytime measurements. This may due to the fact that the values of 02 con¬
sumption were used only if the skinks did not move during measure¬
ments. It is probably that some (and possibly all) of the metabolic differ¬
ences between night and daytime measurements in the lizards are attrib¬
utable to spontaneous activity during day (Beaupre el al. , 1993) or night
(Feder and Feder, 1981). Highest metabolic rates usually occur during
active periods and lowest during inactive periods (Cragg, 1978; Mautz,
1979; Feder and Feder, 1981).

The overall QJ0 value of 5. sepsoides is comparatively low through¬
out the metabolic rate-temperature curve (RT curve) and this is more likely
to be related to both thigmothermic and fossorial behaviors of this spe¬
cies. It seems that the RT curve of 8. sepsoides is rotated to give reduced
temperature sensitivity and elevated RMR at low temperature (Fig. 1).
This temperature dependent shift may enable the lizards to maintain lev¬
els of resting oxygen consumption suitable for activity and locomotion at
low temperatures (Tromp and Avery, 1977; Fough and Busack, 1978; Zari,

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1996, 1997). Moreover, low thermal dependence is found in S. sepsoides at
higher temperatures (30-35°C) occurs at its selected body temperature that
may assist metabolic homeostasis (Cloudsley-Thompson, 1972; Bennett
and Dawson, 1976; Zari, 1993). The MST of S. sepsoides is 29.7°C over the
24 h period. Selected body temperatures of skinks are generally lower
than those of most other groups of lizards (Brattstorm,1965; Licht et al,
1966; Avery, 1982). In addition, mean activity temperatures differ widely
among scincid species and are correlated with their behavior and ecology
(review in Avery, 1982). S. sepsoides was fully active at temperatures be¬
tween 24.4 and 35°C and fully inactive below 18.5°C and above 40°C (Khalil
and Hussein, 1963). In the present study, S. sepsoides displayed diel cycles
of thermal selection. They had significantly lower mean selected body
temperatures during late scotophase and midphotophase than other times
of day over the 24 h period (Fig. 2). It seems that the timing of the incre¬
ments in MSTs coincides with normal activity times of this species (Zari,
unpublished data). Khalil and Hussein (1963) noted that the activity of S.
sepsoides is of the arrhythmic type with a nocturnal major period of activ¬
ity that lies between 19.00 and 23.00 h. Time of day is an important factor
in temperature selection in lizards (Sievert and Hutchison, 1989). The high¬
est body temperatures are selected during activity for both diurnal and
nocturnal lizards (Regal, 1967; Hutchison and Kosh, 1974; Spellerberg,
1974; Huey, 1982; Bennett and John- Alder, 1986; Sievert and Hutchison,
1988, 1989; Zari, 1998). In Australia, the cryptozoic skinks (Eremiascincus
spp. and Hemiergis spp.) have the lowest preferred body temperatures
(PBTs) of all species examined and they show a nocturnal increment in
PBTs. Eremiascincus are active at dusk and in the early evening. Hemiergis
have been observed abroad in the late afternoon and early evening and
are almost never seen during the day (Bennett and John- Alder, 1986).

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Literature Cited

Al-Sadoon, M. K. and Spellerberg, I, F.

1985. Effect of temperature on the oxygen consumption of liz¬
ards from different climatic regions. Amphibia-Reptilia 6:
241-258.

Andrews, R. M. and Pough, F. 11.

1985. Metabolism of squamate reptiles: allometric and ecologi¬
cal relationships. Physiol Zool. 58: 214-231.

Avery R. A.

1982. Field studies on body temperatures and thermoregula¬
tion. In Biology of the Reptilia (Edited by Cans C and
Pough F. I I.), VoL 12, pp. 93-166. Academic Press, Lon¬
don.

Bakker, A. and Andrews, R. M.

1984. Intraspecific variation in metabolic rate of Chalcides
ocellatus. }. Herpetol 18: 85-86.

Beaupre, S. J.; Dunham, A. E. and Overall, K. L.

1993. Metabolism of a desert lizard: the effects of mass, sex,
population of origin, temperature, time of day, and feed¬
ing on oxygen consumption of Sceloporus merriami.
Physiol Zool 66: 128-147.

Bennett, A. F.

1982. The energetics of reptilian activity. In Biology of the Rep¬
tilia (Edited by Cans C. and Pough F. PL), VoL 13, pp.
155-199. Academic Press, London.

Bennett, A. F. and Dawson, W. R.

1976. Metabolism. In Biology of the Reptilia (Edited by Cans C.
and Dawson W. R.), VoL 5, pp. 127-223. Academic Press,
London.

Bennett, A. F. and John- Alder, H. B.

1986. Thermal relations of some Australian skinks (Sauria:
Scincidae). Copeia 1986: 57-64.

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Brattstorm, B. H.

1965. Body temperatures of reptiles. Am. Midi. Nat. 73: 376-422.

Brownlie, S. and Loveridge, J. P.

1982. The oxygen consumption of limbed and limbless Afri¬
can skinks (Sauria: Scincidae): Circadian rhythms and ef¬
fect of temperature. Comp. Biochem. Physiol. 74A: 643-647.

Cloudsley-Thompson, J. L.

1972. Temperature regulation in desert reptiles. Symp. Zool. Soc.
Lond. 31: 39-59.

Cragg, P. A.

1978. Oxygen consumption in the lizard genus lacerta in rela¬
tion to diel variation, maximm activity and body weight.
J. exp. Biol. 77:33-56.

Dawson, W. R. and Templeton, J. R.

1966. Physiological responses to temperature in the alligator
lizard, Gerrhonotus multicarinatus. Ecology 47: 759-765.

Feder, M. E. and Feder, J. H.

1981. Diel variation of oxygen consumption in three species of
Philippine gekkonid lizards. Copeia 1981: 204-209.

Fuhn, I. E.

1975. The skinks. In Grzimek's Animal Live Encyclopedia (Edited
by Grzimek B.). Vol. 6 (Reptiles), pp. 242-264. Van
Nostrand Reinhold Company, New York.

Heusner, A. A.

1982. Energy metabolism and body size. 1. Is the 0.75 mass
exponent of Kleiber's equation a statistical artifact? Respir.
Physiol. 48: 1-12.

Huey, R. B.

1982. Temperature, physiology and the ecology of reptiles. In:
Cans, C. and Pough, F. B. (Eds), Biology of the Reptilia,
Vol. 12, pp. 25-91. Academic Press, London.

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June 1999

Hutchison, V. H. and Kosh, R. J.

1974. Thermoregulation function of the parietal eye in the liz¬
ard Anolis carolinensis. Oecologia 16: 173-177.

Khalil, F. and Hussein, M. F.

1963. Ecological studies in the Egyptian deserts. Ill - Daily and
annual cycles of activity of Uromastyx aegyptia, Agama
pallida and Chalcides sepoides with special reference to tem¬
perature and relative humidity. Proc. Zool Soc. A. R. Egypt
1:93-108.

Licht, R; Dawson, W. R.; Shoemaker, V. H. and Main, A. R.

1966. Observations on the thermal relations of western Aus¬
tralian lizards. Copeia 1966: 97-110.

Mautz, W. J.

1979. The metabolism of reclusive lizards, the Xantusiidae.
Copeia 1979: 577-584.

Pough, F. H. and Andrews, R. M.

1984. Individual and sibling-group variation in metabolism of
lizards: implications for the origin of endothermy. Comp.
Biochem. Physiol. 79 A: 415-419.

Pough, F. H. and Busack, S. D.

1978. Metabolism and activity of the Spanish fringe-toed liz¬
ard (Lacertidae): Acanthodactylus erythrurus.j. therm. Biol.
3: 203-205.

Regal, P. J.

1967. Voluntary hypothermia in reptiles. Science , N. Y. 155: 1551-
1553.

Sievert, L M. and Hutchison, V. H.

1988. Light versus heat: thermoregulatory behavior in a noc¬
turnal lizard (Gekko gecko). Herpetologica 44: 266-273.

Sievert, L M. and Hutchison, V. H.

1989. Influence of season, time of day, light, and sex on the
thermoregulatory behaviour of Crotaphytus collaris. J.
therm Biol. 14: 159-165.

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June 1999

Sokal, R. R. and Rohlf, F. J.

1981. Biometry : the Principles and Practice of Statistics in Biologi¬
cal Research, 2nd edition. W. H. Freeman, San Francisco.

Spellerberg, I. F.

1974. Influence of photo-period and light intensity on lizard
voluntary temperatures. Br. J. Herp. 5: 412-420.

Taylor, B. M. and Davies, R M. C.

1981. Changes in the weight dependence of metabolism dur¬
ing the sloughing cycle of the snake Thamnophis sirtalis
parietalis. Comp. Biochesm Physiol 69 A: 113-119.

Tromp, W. I. and Avery, R. A.

1977. A temperature dependent shift in the metabolism of the
lizard Lacerta vivipara. /. therm. Biol. 2: 53-54.

Tu, M. C. and Hutchison, V. C.

1994. Influence of pregnancy on thermoregulation of water
snakes (Nerodia rhombifera). J. therm. Biol. 19: 255-259.

Withers, P. C.

1981. Physiological correlates of limblessness and fossoriality
in scincid lizards. Copeia 1981: 197-204.

Zari, T. A.

1987. The energetics and thermal physiology of the
Wiegmann's skink, Mabuya brevicollis. Ph. D. Thesis. Uni¬
versity of Nottingham.

Zari, T. A.

1992. Effects of temperature on resting metabolism of two spe¬
cies of juvenile nocturnal Lizards, Hemidactylus turcicus
and Ptyodactylus hasselquistii (Reptilia: Gekkonidae) in
Jeddah, Saudi Arabia. Comp. Biochem. Physiol. 102A: 491-
495.

Zari, T. A.

1993. Effects of body mass and temperature on standard meta¬
bolic rate of the desert chameleon chamaeleo calyptratus.
J. Arid Environ. 24: 75-80.

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June 1999

Zari, T. A.

1996. Seasonal metabolic compensation in the fringe-toed liz¬
ard, Acanthodactylus boskianus (Reptilia: Lacertidae). J.
therm . Biol 21: 145-150.

Zari, T. A.

1997. Effects of body mass, temperature, and season on rest¬
ing metabolism of the nocturnal gecko Hemidactylus
flaviviridis. Zool Middle East 14: 77-85.

Zari, T. A.

1998. Effects of sexual condition on food consumption and tem¬
perature selection in the herbivorous desert lizard,
Uromastyx philbyi. J. Arid Environ. 38: 371-377.

Department of Biological Sciences , Faculty of Science, King Abdul Aziz
University , P. 0. Box 9028 , Jeddah 21413 , Saudi Arabia.

Recieved 20 November 1998

Accepted 27 March 1999

Bulletin of the Maryland Herpetological Society

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June 1999

Emory’s Softshell Turtle,

Apalone spin if era emoryi, in Mexico

Aside from an introduced (since early 1900s), established and wide¬
spread population in the Gila-Colorado River drainage in Arizona,
Emory's Softshell Turtle, Apalone spinifera emoryi , characteristic of the Rio
Grande (and Pecos River) drainage, is recorded from the Mexican states
of Chihuahua, Coahuila, Nuevo Leon, and Tamaulipas. In Tamaulipas
emoryi is also known to occur in the Rio San Fernando and the Rio Soto la
Marina / Purif icacion (Webb, 1962, 1973). Pritchard (1979:633, legend of
fig.) provided a good photograph of a softshell readily identified as emoryi
"from the Rio Verde, San Luis Potosi." Recently, one of us (JAL) acquired
two softshells from the Rio Balsas, far south of the known range in north¬
eastern Mexico. These two turtles are deposited in the Coleccion
Herpetologica, Unidad de Biologfa, Tecnologia, y Prototipos, Universidad
Nacional Autonoma de Mexico, Campus Iztacala, Tlalnepantla, Edo de
Mexico, Mexico.

The two softshells are from about the same place along the Rio Bal¬
sas, Colonia Valerio Trujano, Guerrero, Mexico. One (JLE 2592) is a young
male received from a person working in the river, 15 February 1998; the
other (JLE 2593) is a young female (blotched carapace pattern) from the
edge of the river below the Mezcala bridge, 23 May 1998. Respective mea¬
surements of carapace length and width (curvature) and plastron length
[flexible mm tape] and head width [calipers] of the male and female are
96, 148; 87, 123; 77, 107; and 16.5, 21.2 mm. Both are referable to emoryi in
having (Webb, 1973) the pale rim of the carapace noticeably widened pos¬
teriorly, a straight or slightly curved (may be broken) dark line on the
forehead between the eyes, low rounded tubercles on the anterior edge of
the carapace (female), and the juvenile pattern of white dots confined to
the posterior part of the carapace (male). Pattern features of the two
Guerrero turtles that vary somewhat from the "norm" are (1) the dark
gray carapaces, especially the small male (instead of pale brownish); Webb
(1962:511) previously noted some unusual darker individuals of emoryi ,
(2) the mostly complete pale postocular stripes (black borders partly in¬
terrupted); stripe variable in emoryi (may be complete, UTEP 3385, El Paso),
but often only distinct, short postocular stripe with posterior part obliter¬
ated, and (3) more bold pattern of larger black spots and barlike marks on

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June 1999

dorsal surfaces of the limbs; pattern variable in emoryi but usually reduced
with smaller markings.

Thus, the morphological features of the Rio Balsas softshell turtles
do not suggest any great taxonomic divergence from the known varia¬
tional parameters of emoryi. Further field work is necessary to establish if
the two Guerrero turtles are part of a larger interbreeding population, as
well as to corroborate occurrence in the Rio Verde in San Luis Potosi. Pos¬
sibly, they represent man-transported introductions. However, local resi¬
dents at the Rio Balsas collection site report having seen these turtles for
many years (since about the 1950s). Avise et al. (1992) recognized low
levels of genetic variability and differentiation in turtles (reflected in slow
evolutionary rate of mitochondrial DNA compared to other vertebrates).

Acknowledgments

One of us (JAL) thanks Julio and Sergio Lemos-Sanoja and Susy
Sanoja-Sarabia for field support.

Literature Cited

Avise, J. C, R. W. Bowen, T. Lamb, A. B. Meylan, and E. Bermingham.

1992. Mitochondrial DNA evolution at a turtle's pace: evidence
for low genetic variability and reduced microevolution¬
ary rate in the Testudines. Mol. Biol. Evol. 9(3):457-473.

Pritchard, P. C. H.

1979. Encyclopedia of Turtles. T.F.H. Publ., Inc., Neptune, New

Jersey, 895 pp.

Webb, R. G.

1962. North American recent soft-shelled turtles (Family
Trionychidae). Univ. Kansas Publ. Mus. Nat. Hist.
13(10):429-611, 24 pis.

1973. Trionyx spiniferus. Cat. Amer. Amph. Rept. 140:1-4.

Bulletin of the Maryland Herpetological Society

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June 1999

Julio A. Lemos-Espinal, Laboratorio de Ecologta, Unidad de Biologia,
Tecnologia, y Protitipas , UNAM, Campus Iztacala, Apartado Postal 314 ,
Tlalnepantla, Edo. de Mexico , Mexico; Robert G. Webb , Department of
Biological Sciences , University of Texas at El Paso , El Paso , TX 79968, USA;
Hobart M. Smith, Department ofEPO Biology , University of Colorado,
Boulder, CO 80309, USA.

Received 27 November 1998

Accepted 27 March 1999

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June 1999

SEASONAL VARIATION IN REPRODUCTION IN
THE RED-EARED SLIDER
(TRACHEMYS SCRIPTA ELEGANS)

John K. Tucker i
Abstract

Seasonal variation or systematic variation in reproductive life-his¬
tory traits within a single reproductive seaason was studied among 1,667
female red-eared sliders ( Trachemys scripta elegans) over a four year span
at two sites in west-central Illinois. Statistically significant seasonal varia¬
tion was not found in egg mass, clutch size, clutch mass, or maternal mass.
However, females nesting in the first half of the nesting season tended to
be heavier than those nesting in the second half of the nesting season.
Moreover, females found nesting more than once tended to be heaviest
prior to laying their first clutches but lighter when laying their second
clutches. However, even these differences were slight and were not statis¬
tically significant. Variance in clutch size and egg mass within individu¬
als laying multiple clutches and variance in clutch size and egg mass
among all individuals sampled did not differ even while holding mater¬
nal size constant and removing potential effects of annual and local varia¬
tion. Environmental and microhabitat influences appear to be controlling
factors on reproductive life-history traits.

Introduction

Seasonal variation can be defined as systematic variation in repro¬
ductive life-history traits that occur within a single reproductive season
of a given turtle species (i.e., Frazer and Richardson, 1985a). This varia¬
tion may occur between sequential clutches for species that lay more than
one clutch per nesting season (e.g.. Gibbons et al., 1982; Iverson and Smith,
1993). Similarly, reproductive traits of turtles nesting early or late in the
nesting season may vary (e.g., Frazer and Richardson, 1985a; Rowe, 1994).

The importance of seasonal variation has long been recognized
(Iverson, 1978; Moll, 1979). Nonetheless, most studies of turtle reproduc¬
tion do not examine seasonal variation in detail. Seasonal variation is dif¬
ficult to study because large numbers of females must be examined to

Bulletin of the Maryland Herpetological Society

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June 1999

locate turtles nesting more than once per season (i.e., Iverson and Smith,

1993) . Moreover, females must be collected throughout the nesting sea¬
son (i.e., Frazer and Richardson, 1985a).

An understanding of the magnitude of seasonal variation is needed
to accurately define life-history traits such as reproductive effort espe¬
cially for species known to produce multiple clutches within a single nest¬
ing season. Detailed studies of such species find that clutches can vary
systematically in traits such as egg size and number (i.e.. Gibbons et al.,
1982; Frazer and Richardson, 1985b) or that sequential clutches do not
vary in any predictable way (i.e., Iverson, 1978; Mitchell, 1985a). More¬
over, studies of species such as the painted turtle ( Chrysemys picta) find
variation among successive clutches (i.e., Iverson and Smith, 1993; Rowe,

1994) , but others find no evidence of variation between successive clutches
(i.e.. Gibbons, 1968; Christians and Bider, 1986; Mitchell, 1985b).

Two methods have been used to study seasonal variation. One
method divides the nesting season into two or more parts and then com¬
pares reproductive life-history traits between or among those parts (e.g.,
Frazer and Richardson, 1985a; Bjorndal and Carr, 1989; Hayes et al., 1993;
Rowe, 1994). The other method compares successive clutches from indi¬
vidual females (e.g.. Gibbons, 1968; Mitchell, 1985a, Frazer and Richardson,
1985b; Hays and Speakman, 1992). The first method examines popula¬
tion-wide seasonal variation, whereas the second examines intra-indi¬
vidual variation.

In this study, I use both methods to examine seasonal variation in
reproductive life-history traits for female red-eared sliders (Trachemys
scripta elegans ) collected from two populations in West-Central Illinois
during 1995-98. Reproduction in these populations have been extensively
studied (Tucker et al., 1998a and b), and they are known to show annual
and local variation. I further examine whether these two populations show
similar patterns of seasonal variation in egg size and clutch size. Mean
annual clutch frequency and mean annual fecundity ( sensu Frazer et al.,
1990) will be examined in another study.

Materials and Methods

I caught turtles either crossing roads adjacent to nesting areas or at
nesting areas near Stump Lake in Jersey County and Swan Lake in Calhoun

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June 1999

County, Illinois (see Tucker, 1997). Smaller subsets of the data presented
herein were previously published (Tucker and Moll, 1997; Tucker et al.,
1998a and b). Turtles have been collected at these two sites from 1994 to
1998. The current study concentrates on those collected between 1995 and
1998 because sample sizes in each of those years are robust.

Gravid body mass (nearest 10 g) and straight-line plastron length
(nearest mm) was measured for each female. Eggs were weighed to 0.01
g. Clutch mass was derived by multiplying mean egg mass for a particu¬
lar clutch by the number of eggs in the clutch (method of Tucker et al.,
1998a).

Oxytocin was used to induce oviposition (Ewert and Legler, 1978).
Turtles were uniquely marked by drilling holes in the marginal scutes
and released at the original collecting area. Hatchlings from eggs collected
during this study were released at the collecting sites of their female par¬
ents after being overwintered in captivity.

I used SAS for all statistical analyses (SAS Institute, 1988).
Spearman's rank correlation (Rho) was employed for correlation analy¬
sis. Successive clutches from females laying more than one clutch per nest¬
ing season were compared with Wilcoxon rank sum test (Z). Analysis of
covariance (ANCOVA) with maternal plastron length as the covariate was
employed to compare reproductive data gathered during the first and
second halves of the nesting season for each year from 1995 to 1998. Nest¬
ing seasons were divided into equal halves based on the first and last day
that nesting females were collected. Means given in the text are accompa¬
nied by ± 1 SD.

This study relied on statistical tests, each of which has an overall
0.05 chance of a type I error (Rice, 1989). I used a conservative approach
and employed the sequential Bonferroni procedure to interpret test re¬
sults on a study-wide basis as opposed to a table-wide basis (Rice, 1989;
Amos, 1996). Consequently, I questioned the biological significance of
values of F greater than 0.001.

Results

Roughly equal numbers of turtles were collected in each half of the
nesting season from Stump Lake (Table 1) and Swan Lake (Table 2) in

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each year of the study. Once adjusted for differences in maternal size, few
comparisons between first and second halves of the nesting season in each
of the years examined were statistically different sufficient to exclude type
I errors at 0.05 (Table 3).

However, there is evidence of consistent patterns in maternal mass
and possibly in egg mass, as well. In every instance, maternal mass ad¬
justed for differences in plastron length was greater among turtles col¬
lected in the first half of the nesting season than those collected in the
second half of the nesting season (Table 3). In one of eight instances (Swan
Lake, 1998), the difference was statistically significant. Except for Stump
Lake in 1998, egg mass was greater among eggs collected in the first half
of the season than among those collected in the second half of the season
(Table 3). However, none of the statistical comparisons were significant
and most differences between halves were slight (Table 3).

Because relatively few turtles were found nesting more than once
in a particular year, samples from Swan Lake and Stump Lake were com¬
bined for analysis (Table 4). None of the comparisons of reproductive traits
or maternal mass between sequential clutches were significantly differ¬
ent in any year of the study (Table 4). Nonetheless, maternal mass was
greatest for turtles laying their first clutches of the season compared to
maternal mass for the same turtles laying a subsequent clutch in each
year of the study (Table 4). Clutch size was also greatest in each year among
first clutches compared to subsequent clutches. However, in all of these
instances statistical comparisons in each year were not significant.

Reproductive traits and maternal mass did not differ between
renesting turtles and turtles not found renesting at Stump Lake using
ANCOVA. For instance, least squares mean (LSM) for maternal mass for
those renesting was greater than those not found renesting (1810 g vs.
1770 g, respectively) but the difference was not significant (F1985 = 2.58, P
= 0.1082). Similarly, clutch size LSM (14.0 vs. 14.0 eggs, respectively, F1846
= 0.00, P = 0.9623), clutch mass LSM (148.3 vs. 142.8 g, respectively, F1846 =
1.00, P = 0.3183), and egg mass LSM (10.5 vs. 10.1 g, respectively, F1 870 =
2.14, P = 0.1437) did not differ between turtles found nesting more than
once and turtles not found nesting more than once.

Similarly, Swan Lake turtles found nesting more than once did not

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June 1999

weigh more than those found nesting once (maternal mass LSM 1780 vs.
1820 g, respectively, F1765 = 0.99, P - 0.3190). Reproductive traits including
clutch size LSM (13.5 vs. 12.9 eggs, respectively, F^86 - 0.56, P = 0.4528)
clutch mass LSM (154.7 vs. 140.9 g, respectively, F1586 = 1.85, P = 0.1744),
and egg mass LSM (11.4 vs. 11.9 g, respectively, ¥1 600 = 1.52, P = 0.2187) did
not differ significantly.

Table 2. Descriptive statistics for reproductive life-history traits and measures
of size of red-eared sliders (Trachemys scripta elegans) collected at Stump Lake
in Jersey County , Illinois between 1995 and 1998 with the nesting season divided
into two equal halves . Measures of length are in mm, and measures of mass are in g.

Trait

N

First half nesting season

Mean(SD) / Range

N

Second half nesting season

Mean(SD) / Range

Plastron length

73

Stump Lake-1995

214.5(14.8)/167-240

67

214.5(12.4)/184-236

Clutch mass

64

163.6(45. 2)/52.5-270.0

67

153.9(47.2)/61.6-292.6

Clutch size

64

15.0(3. 61)/6-25

67

14.8(4. 19)/7~26

Egg mass

66

10.86(1.37)/6.41-13.42

67

10.42(1.55)/6. 50-13.45

Maternal mass

66

1945(377.7)/975~2600

67

1 877 (31 0.6) / 1 200-2475

RCM

64

0.092(0.019)/0.044-0.133

67

0.089(0.022)/0.042-0.137

Plastron length

151

Stump Lake-1996

213.6(15. 1)/170-251

133

215.5(13.7)/179-247

Clutch mass

122

134.0(41. 8) /43.0-295.6

128

138.5(38.4)/43.1-221.1

Clutch size

122

13.3(3.22) /6-26

128

13.7(3.24)/6-21

Egg mass

126

10.00(1. 64)/6.25-13.26

128

10.06(1. 34)/6.54-12.87

Maternal mass

123

1854(384.5)/1000-2850

126

1894(369.2) / 1100-2700

RCM

119

0.078(0.017)/0.037-0.140

126

0.079(0.017)/0.037-0.138

Plastron length

79

Stump Lake-1997

216.6(15.4)/181-251

69

209.3(15.4)/167-245

Clutch mass

64

150.6(46.2) /56.9-301. 9

56

143.1 (40.5)/46.9-233.1

Clutch size

64

13.8(3.42)77-26

56

13.7(2.97)/5-20

Egg mass

66

10.76(1.58) /7.11-13.05

58

10.32(1. 76)/6.44-14.04

Maternal mass

64

1902(409.8)/1080-2810

53

1781 (370.0) /1100-2600

RCM

63

0.085(0.018)/0.037-0.128

53

0.089(0.019)/0.032-0.133

Plastron length

231

Stump Lake-1998

209.5(15.8)/169-247

187

210.6(15.7)/172-247

Clutch mass

174

140.9(46.4) /29.S-273.8

149

145.1 (46.2) /53.8-339.3

Clutch size

174

14.1(3.82)/4-29

149

14.2(3.58) /5-30

Egg mass

185

9.82(1 .52)/5.09-13.95

153

10.18(1.51)75.95-14.56

Maternal mass

215

1705(393.0) /950-2730

184

1673(398.8)/700-2660

RCM

165

0.090(0.020)70.022-0.161

147

0.093(0.019)/0.034-0.148

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Table 2. Descriptive statistics for reproductive life-history traits and measures of size of red-eared
sliders (Trachemys scripta elegans) collected at Swan Lake in Jersey County, Illinois between
1995 and 1998 with the nesting season divided into two equal halves. Measures of length are in
mm, and measures of mass are in g.

Trait

N

First half nesting season

Mean(SD) / Range

N

Second half nesting season

Mean(SD) / Range

Plastron length

58

Swan Lake-1995

214.5(11. 4)/190-240

71

208.8(13.3) /181-234

Clutch mass

42

171 .6(30.2) / 98.9-233.8

52

149.3(35.8)/68.4-224.4

Clutch size

42

14.8(2.50)/8-20

52

13.8(2.95) /8-22

Egg mass

42

11.65(0.84)/9.78-13.23

52

10.87(1. 52)/6.91-13.19

Maternal mass

42

1954(268.3)/1300-2550

52

1800(312.1) /1125-2625

RCM

42

0.097(0.013)/0.066-0.123

52

0.091(0.018)/0.047-0.127

Plastron length

46

Swan Lake-1996

212.8(14.1)/172-241

51

222.9(12.5)7193-248

Clutch mass

40

133.1 (28.0)/84.6-219.4

51

153.9(42.4) /64.2-234.S

Clutch size

40

12.1(2.32)/7-16

51

13.7(3.45)/6-23

Egg mass

40

11.08(1.57)/8.35-15.07

51

11.17(1.07)/8.03-13.69

Maternal mass

40

1868(287.8)/1350-2650

51

2058(355.8) / 1 375-2800

RCM

40

0.077(0.013)/0.047-0.106

51

0.081(0.01 8)/0.043-0.123

Plastron length

112

Swan Lake-1997

213.4(13.7)/173~252

167

213.6(13.0)/181-246

Clutch mass

114

133.9(35.2)/61.5-234.5

110

135.9(32.3)/ 63.4-227.4

Clutch size

114

11.9(2.69)/5-18

110

12.6(2.61)/6-19

Egg mass

115

11.16(1.34)/8.27-14.07

115

10.74(1.44)77.12-13.75

Maternal mass

115

1 829(327.4) / 1 000-2670

115

1 791 (346.7) / 1 000-2630

RCM

114

0.079(0.017)/0.033-0.120

110

0.083(0.018) /0.033-0.120

Plastron length

91

Swan Lake-1998

215.3(13.9)/168-250

81

214.6(11. 4)/188-241

Clutch mass

70

144.4(39.7) /48.2-230.3

64

130.6(31 .9) /40.2-224.0

Clutch size

70

13.1(3.11)/ 6-21

64

12.5(2.50)/4-19

Egg mass

78

10.95(1. 31)/7.86-13.

54

66 10.43(1. 18)/7.51-13.03

Maternal mass

90

1 822(342.5) /960-2600

81

1728(279.3)/1220-2460

RCM

70

0.085(0.018)/0.038-0.133

64

0.082(0.015)70.022-0.108

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June 1999

Table 3. Results of analysis of covariance for maternal mass and reproductive life-history traits of
Trachemys scripta elegans collected in west-central Illinois. Measures of mass are in g.

Trait

LSMj

lsm2

DF

F

P

Stump Lake-1995

Clutch mass

164.71

152.89

1, 130

3.72

0.0560

Clutch size

15.1

14.7

1, 130

0.35

0.5570

Egg mass

10.88

10.41

1, 132

5.31

0.0228*

Maternal mass

1952

1870

1, 132

10.46

0.0015*

Stump Lake-1996

Clutch mass

136.1

136.5

1, 249

0.01

0.9278

Clutch size

13.5

13.6

1, 249

0.10

0.7537

Egg mass

10.06

10.00

1, 253

0.16

0.6914

Maternal mass

1877

1872

1,248

0.07

0.7952

Stump Lake-1997

Clutch mass

146.4

147.9

1, 119

0.07

0.7882

Clutch size

13.6

13.9

1, 119

0.41

0.5216

Egg mass

10.59

10.52

1, 123

0.13

0.7216

Maternal mass

1862

1829

1, 116

1.29

0.2575

Stump Lake-1998

Clutch mass

143.2

142.5

1,320

0.05

0.8296

Clutch size

14.3

14.0

1,320

0.40

0.7123

Egg mass

9.89

10.09

1,335

2.30

0.1304

Maternal mass

1712

1664

1,396

10.55

0.0013

Swan Lake-1995

Clutch mass

166.2

153.7

1,93

4.97

0.0283*

Clutch size

14.4

14.0

1, 93

0.53

0.4704

Egg mass

11.53

10.96

1, 93

5.09

0.0265*

Maternal mass

1886

1885

1,93

1.19

0.2777

Swan Lake-1996

Clutch mass

143.0

146.1

1, 90

0.28

0.6007

Clutch size

12.8

13.2

1,90

0.53

0.4674

Egg mass

11.28

11.02

1, 90

0.98

0.3260

Maternal mass

1982

1968

1, 90

0.18

0.6712

Swan Lake-1997

Clutch mass

133.4

136.4

1,223

0.64

0.4233

Clutch size

11.9

12.6

1, 223

4.27

0.0399*

Egg mass

11.15

10.76

1,229

6.15

0.0138*

Maternal mass

1823

1797

1, 229

2.02

0.1566

Swan Lake-1998

Clutch mass 143.6 131.5 1, 131 6.10 0.0148*

Clutch size 13.1 12.6 1, 131 1.19 0.2777
Egg mass 10.92 10.47 1, 141 6.91 0.0095*

Maternal mass 1815 1736 1, 168 11.56 0.0008

LSMj = Least squares mean for first half of nesting season; LSM2 = Least squares mean for
last half of nesting season; *Values of P > 0.0014 should be viewed with caution due to the
number of post hoc comparisons.

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Table 4. Comparison of sequential clutches for Trachemys scripta elegans that were found nest¬
ing twice in a single nesting season in west-central Illinois. Measures of mass are in g.

Trait

First Clutch

Mean(SD) / Range

Subsequent Clutch

Mean(SD) / Range

Wilcoxon rank sum

Z P

1995 (N = 3)

Clutch mass

234.0(6.7)/228.1-241.3

192.3(32.3)/162.9-226.8

1.75

0.0809

Clutch size

19.3(252)/ 17-22

16.0(1.73)715-18

1.33

0.1840

Egg mass

12.21(1.23)/10.97-13.42

11.98(0.97)/10.86-12.60

0.00

0.9999

Maternal mass

2425(1 52. 1 ) / 2325-2600

2317(137.7) / 2225-2475

0.87

0.3827

RCM

0.107(0.01)/0.096-0.116

0.090(0.011)70.079-0.101

1996 (N = 12)

Clutch mass

155.9(19.6)/126. 1-183.8

140.4(25.4)/95.4-179.8

1.33

0.1824

Clutch size

14-1(2-19)711-18

12.8(2.44) /10-18

1.43

0.1519

Egg mass

11.14(0.89)/9.70-12.34

10.96(0 72)79.54-11.92

0.61

0.5443

Maternal mass

2015(190.4)/ 1630-2260

1 988(227.0) / 1 600-2300

0.35

0.7287

RCM

0.082(0.012)/0.059-0.100

0.076(0.013)/0.053-0.104

1997

r (N = 5)

Clutch mass

149.0(27.0)/120.6-193.5

143.5(21.4)7112.0-169.4

0.08

0.9362

Clutch size

1 4.2(1 .92) / 1 2-17

13.4(1. 14)/12-15

0.53

0.5936

Egg mass

10.51(1. 33) /9.25-12.30

10.72(1.52) /9. 33-13.03

0.42

0.6761

Maternal mass

1 818(354. 1 ) / 1280-2130

1794(326.9)/1270-2150

0.08

0.9362

RCM

0.088(0.012)/0.076-0.104

0.088(0.008) /0.078-0.097

1998

(N = 14)

Clutch mass

170.3(48.6) /73.9-273.8

170.4(80.0) /S8.2-339.3

0.00

0.9999

Clutch size

15.2(3.62)/8-24

15.1(6.39)/5-30

0.00

0.9999

Egg mass

ll.ll(1.53)/8.22-13.60

11.38(1.50)/8.80-13.79

0.44

0.6625

Maternal mass

2072(363.8)/ 1350-2550

1987(409.5)/1300-2660

0.69

0.4905

RCM

0.088(0.012)70.076-0.104

0.088(0.008)70.078-0.097

Discussion

The primary finding of this study is that seasonal variation among
reproductive life-history traits in the turtles that I examined was slight.
Turtles nesting early and those nesting late did not differ in any particu¬
lars. Similarly, successive clutches also did not vary significantly. The only
suggestion of a seasonal "trend" was that females nesting early and fe¬
males making their first nesting forays were relatively heavy. The desert
tortoise (Gopher us agassizii) also is heaviest before laying the first clutch of
the season than it is just before laying its second clutch of the season (Turner
et ah, 1984).

Gibbons et al. (1982) suggested that second clutches laid by South
Carolina Trachemys scripta are smaller than their first clutches. Second

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June 1999

dutches from Illinois I. scripta also tended to have fewer eggs like those
from South Carolina but the differences among the Illinois dutches are
not significant. Gibbons et al. (1982) found that first observed dutches
were larger than later dutches in 4 of 12 instances and smaller in 5 of 12
instances. I found that 17 of 36 first dutches of the season were larger than
the following dutch in the same year and that 16 of 36 were smaller. Ap¬
parently T. scripta from Illinois and South Carolina are able to parti¬
tion their reprodutive output evenly during the nesting season.

Gibbons (1982) pointed out the importance of within and among
individual comparisons in the amount of variation in dutch size. If repro¬
ductive life-history traits are strongly controlled genetically then vari¬
ability in reproductive traits should be greater within the population than
within the individual. Gibbons (1982) concluded that for Trachemys scripta
environmental or microhabitat influences upon the individual are con¬
trolling factors. I examined this same problem with the data from Illinois
T. scripta using ANCOVA to remove the effect of body size (Tucker et al.,
1998a) but also accounted for local and annual variation for the years be¬
tween 1995 and 1998. Main effects were location, year, and turtles with
multiple clutch records and the entire sample of turtles. Within individual
variance was not significantly different from within population variance
for dutch size ( ty 1468 = 1.89, P = 0.1689) and egg mass (Fj 1510 = 2.36, P ~
0.1248). The similarity between South Carolina and Illinois turtles is im¬
portant because both data sets are based on long-term studies and sample
size for the Illinois turtles is sufficient to include potential effects of an¬
nual and local variation in the examination.

Although I found little indication of seasonal variation in repro¬
duction in the Trachemys scripta that I studied, seasonal variation is im¬
portant for other turtle species. A number of studies of sea turtles find
that last-laid dutches tend to have fewer eggs or smaller eggs (Hirth, 1980;
Frazer and Richardson, 1985a, b; Hays and Speakman, 1992; Hayes et al.,
1993). Similarly a number of studies of freshwater turtles report seasonal
variation. These studies find that the second or last clutch of the season
tends to have fewer and sometimes smaller eggs for a number of species
(Montevecchi and Burger, 1975; Mitchell, 1985a; Etchberger and Ehrhart,
1987; Iverson and Smith, 1993). Clearly an understanding of the amount
of seasonal variation present is needed before reproductive life-history
traits of any turtle species can be properly studied.

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June 1999

Acknowled gments

I thank N. I. Filoramo, F. J. Janzen, G. L. Paukstis, M. M. Tucker, and
D. A. Warner for assistance in the field. Female turtles, eggs, and hatchlings
were collected under Illinois Department of Natural Resources permit
number A-93.0202 and extensions. This work was partially supported by
the Illinois Natural History Survey and the Upper Mississippi River Sys¬
tem Long Term Resource Monitoring Program.

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Mitchell, J. C.

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1998b. Variation in carapace morphology and reproduction in
the red-eared slider Trachemys scripta elegans. J. Herpetol.
32:294-298.

Turner, F. B., P. M. Medica, and C. L. Lyons.

1984. Reproduction and survival of the desert tortoise
( Scaptochelys agassizii) in Ivanpah Valley, California.
Copeia 1984:811-820.

Illinois Natural History Survey, Great Rivers Field Station
Long Term Resource Monitoring Program-Reach 26
4134 Alby Street, Alton, Illinois 62002, USA

Recieved 26 February 1999

Accepted 29 March 1999

Bulletin of the Maryland Herpetological Society

page 55

Volume 35 Number 2

June 1999

News and Notes

Presented by MARS Preservation Fund, Inc.

^ISPTDILIi
S Ml © W

We believe in education,
the promotion of captive
breeding and the protection
of critical habitats .

Maryland State Fairgrounds 4- II Building (Daily Show and Seminars)
Days Hotel Timonium (Host Hotel & Lectures Saturday Evening)

• Captive bom reptiles & amphibians for display and sale • Equipment, books & supplies
• Book signings each day • Educational exhibits • Door Prizes • Raffles • Silent Auction

• Display & photographs of Costa Rican rainforest area purchased by MARS

• Pre-show social gathering • ‘‘Reptiles & Rainforests ” art collection

• Seminars throughout the show • “Critter Contact” hands-on animal display

Professional Lecture Series Saturday evening will feature well-known Dr. Richard Funk
( reptile and amphibian veterinarian ), Alan Kardon (herpetologist, reptiles of Mexico), others to
be announced and another Fabulous Fotos” exhibit.

Show proceeds are donated to The Center for Ecosystem Survival for the
purchase of rainforest. THE MID- ATLANTIC REPTILE SHOW, now in its
seventh year, has purchased 2,528.5 acres of critical habitat to date.

Bring your aluminum cans to our recycling bin and help
us purchase and protect more rainforest!

ADMISSION: Weekend Pass (includes show both days and lectures) $13 Adults, One Day Pass (Sat. or Sun.) $7
Adults. Children 6-12 and Seniors over 65 - $6 (for one day or weekend pass), Children under 5 are free.

for additional niNiiF©iMAirgoiNi:

Call the MARS Hotline at 410-580-0250, visit our web site at http://www.reptileinfo.com
or e-mail us at mars@reptileinfo.com
Only registered vendors may display or sell on the premises.

Please leave your pet animals home! They will not be admitted to the show. Thank you.

page 56

Bulletin of the Maryland Herpetological Society

Volume 35 Number 2

June 1999

News and Notes

International Amphibian Day

The first event to support captive breeding, conservation and
ethical commerce of amphibians
with the participation of noted breeders, scientists and hobbyists.

October 7th to the 10th

Parkville Armory, Days Hotel [Timoniom], National Aquarium
in Baltimore and other locations in Maryland

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• Field survey workshop • Benefit auction •

• Visit to the National Aquarium in Baltimore •

Ail proceeds benefit the Declining Amphibian Population
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International Amphibian Day

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Spaces are limited for some activities, so please call for more information, inscriptions:

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We will try to take as many unwanted pet reptiles
and amphibians as we can.

Leave a message with your name and number to
\ give up an animal for adoption;

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Bulletin of the Maryland Herpetological Society

page 57

Volume 35 Number 2

June 1999

News and Notes

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The Maryland Herpetological Society
Department of Herpetology
Natural History Society of Maryland, Inc.

2643 North Charles Street
Baltimore , Maryland 21218

Bulletin of the Maryland Herpetological Society

page 59

Maryland
Hcrpeioleiical
.Society

US ISSN: 0025-4231

BULimM or TMC

flFtarylanb

f)erpeto!ogicaI
tePT Ooriety

DEPARTMENT OF HERPETOLOGY
THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.

MDHS . A Founder Member of the Eastern

Seaboard Herpetological League

30 SEPTEMBER 1999

VOLUME 35 NUMBER 3

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 35 Number 3 September 1999

CONTENTS

Reproductive output of Terrapene Carolina, chrysemys picta, and
Sternotherus odoratus from west-central Illinois

John K. Tucker . . . 61

IXODES SCAPULARIS (Acari: Ixodidae) Parasitizing Coal Skink
(Eumeces anthracinus)

Harlan D. Walley . . . . . . . . . 76

A Major Range Extension of the Yucatecan Blind Snake, Typhlops micros -
tomus, (Serpentes, Typhlopidae)

Gonzalo Ferez-Higareda and Hobart M. Smith ........... 79

External Morphological Variation in Hardy's Hooknose Snake Ficimia
hardyi (Squamata: Colubridae)

Aurelio Ramirez-Bautista, Xochitl Hernandez-Ibarra,
Ricardo Torres-Cervantes and Hobart M. Smith .... 81

Strike-induced Chemosensory Searching in the Caucasus Viper (Viper a
kaznakovi) and the Ocellate Mountain Viper (Viper a wagneri)

David Chiszar, Jennifer Brown, Adam Chiszar and
Hobart M. Smith .

85

BULLETIN OF THE

mMjs

Volume 35 Number 3 September 1999

The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.

President Tim Hoen

Executive Editor Herbert S. Harris, Jr.

Steering Committee

Frank B. Groves Jerry D. Hardy, Jr.

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

Membership Rates

Membership in the Maryland Herpetological Society is $20.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $30.00 per year. Make all checks payable to the Natural History
Society of Maryland, Inc.

Meetings

The third Wednesday of each month, 7:30 p.m. at the Baltimore Zoo’s
Reptile House (except August and September due to The Mid-Atlantic
Reptile Show). The Department of Herpetology meets informally on all
other Wednesday evenings at the NHSM at 8:00 p.m.

Volume 35 Number 3

September 1 999

Reproductive output of Terrapene Carolina,
Chrysemys picta, and Sternotherus odoratus
from west-central Illinois

John K. Tucker
Abstract

Reproductive life-history traits including egg mass, egg length, egg
width, clutch size, and clutch mass were studied in Terrapene Carolina ,
Chrysemys picta , and Sternotherus odoratus collected in west-central Illinois.
Clutch size but not egg mass was positively correlated with clutch mass
consistent with optimal egg theory. Generally, larger females of each spe¬
cies laid more eggs per clutch. Egg mass increased with maternal size in
C. picta and S. odoratus. Egg mass of T. Carolina tended to decrease with
increasing clutch size and maternal size because egg length was nega¬
tively associated with clutch size. Overall, eggs of T. Carolina were the heavi¬
est, longest, and widest once the effect of maternal size was removed.
Sternotherus odoratus , the species with the smallest body size, laid more
eggs per clutch than the other two species once clutch size was adjusted
for differences in maternal size. Turtles of all three species from the west-
central Illinois sites laid large clutches and large eggs compared to turtles
of these three species elsewhere in the United States.

Introduction

The study of life-history traits is enhanced when information is avail¬
able for numerous species from many geographic locations (Iverson, 1992;
Iverson et al., 1993). Turtle species in Illinois have been the object of some
early studies (Cahn, 1937; Cagle, 1950; Smith, 1961). Turtles from west-
central Illinois, particularly the red-eared slider (Trachemys scripta elegans)
have also been extensively studied (Thornhill, 1982; Tucker et al., 1998a,
b). Nonetheless, relatively few data have been published on other species
from the Mississippi and Illinois River systems in west-central Illinois. In
the current study, I report data collected from 1994-1998 for the eastern
box turtle (Terrapene Carolina ), the painted turtle (Chrysemys picta), and the
stinkpot (Sternotherus odoratus).

Bulletin of the Maryland Herpetological Society

page 61

Volume 35 Numbers

September 1999

Herein, I also revisit some of the topics important in understanding
turtle reproductive life-history (see Congdon and Gibbons, 1985). Specifi¬
cally, I examine the influence of maternal body size on egg and clutch
size. Moreover, I look at how egg shape varies with respect to maternal
body size in these three species (Tucker and Janzen, 1998). Finally, I put
data gathered in west-central Illinois into context with data from else¬
where on these same species.

Materials and Methods

The methods follow those of Tucker et al. (1998a). Turtles were found
crossing roads in Jersey and Calhoun Counties. Turtles were palpated to
determine their reproductive status. Turtles without oviductal eggs were
uniquely marked, measured, and then released at the collecting location
within 24 h. Gravid turtles had their gravid body mass (nearest 10 g),
straight-line plastron and carapace lengths, maximum carapace height,
and maximum carapace width measured to the nearest 1 mm (Tucker et
al., 1998b). A smaller subset of the data collected on Terrapene Carolina was
reported by Tucker (1995).

Oxytocin was used to induce oviposition (Ewert and Legler, 1978).
Eggs were weighed to 0.01 g with an electronic balance. Egg width and
length were measured with vernier calipers to 0.01 mm. Eggs broken by
the female during oviposition were included in clutch size. Clutch mass
was determined by multiplying mean egg mass for intact eggs by the
total number of eggs laid (Tucker et al., 1998a, b). Spent body mass was
estimated by subtracting clutch mass from the female's gravid body mass
(method of Iverson and Smith, 1993). Relative clutch mass (RCM), rela¬
tive egg mass (REM), and egg elongation ratio (ELO) were calculated us¬
ing the method of Iverson and Smith (1993).

Females were released at the original collecting area 48 h after eggs
were laid (Tucker et al, 1995). Eggs were incubated to hatching. Hatchlings
from eggs collected during this study were released at the collecting sites
of their female parents. Hatchling Chrysemys picta were overwintered in
captivity before being released. Hatchling Terrapene Carolina and
Sternotherus odoratus were released within a month of hatching.

I used SAS for all statistical analyses (SAS Institute, 1996). Spearman's
rank correlation (rho) was employed for correlation analysis and for par-

page 62

Bulletin of the Maryland Herpetological Society

Volume 35 Numbers

September 1 999

tial correlation analysis. I employed the sequential Bonferroni procedure
to identify P-values that do not exclude type I errors at 0.05 (Rice, 1989).

Because measures of reproductive output are often related to mater¬
nal size, I used analysis of covariance (ANCOVA) to compare reproduc¬
tive traits among species. In order to select the measure of maternal size
that explained the maximum amount of variance for all three species, I
first performed stepwise multiple regression to find out which measure
of maternal size best predicted egg mass and clutch size (Table 1). Cara¬
pace width was that measure of maternal size for egg mass, whereas cara¬
pace length was best for clutch size. I selected instead, maternal plastron
length as the covariate for ANCOVA. This maternal variable was best
overall for the two reproductive traits (Table 1). Selection of plastron length
has another advantage in that it is nearly universally used as an index of
maternal size (but see Jackson, 1988; Tucker et al, 1998b). The plastron of
Sternotherus odoratus is reduced in length. Carapace length was substi¬
tuted for plastron length in this species.

Results

Reproductive traits varied extensively among the three species ex¬
amined (Table 2). Correlation among reproductive traits varied among

Table 1. Details from stepwise multiple regression of two measures of reproduc¬
tive output against six measures of maternal size.

Reproductive trait: Egg mass Clutch size

Maternal trait

R*

E

E

R2

F

P

Plastron length

0.25

19.22

0.0001

0.20

14.75

0.0003

Carapace length

0.06

3.50

0.0663

0.38

35.53

0.0001

Carapace height

0.34

31.02

0.0001

0.00

0.05

0.8217

Carapace width

0.57

78.49

0.0001

0.00

0.19

0.6676

Gravid mass

0.32

27.37

0.0001

0.17

12.65

0.0007

Estimated spent mass

0.32

27.95

0.0001

0.15

10.15

0.0023

Bulletin of the Maryland Herpetological Society

page 63

Volume 35 Number 3

September 1 999

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page 64

Bulletin of the Maryland Herpetological Society

Volume 35 Numbers

September 1999

species. For instance, egg length and egg width were positively corre¬
lated in Chrysemys picta (rho = 0. 52, P < 0.0001) . Egg width (rho 0.91, P <
0.0001) and egg length (rho = 0.75, P < 0.0001) were both positively asso¬
ciated with egg mass. Neither linear measure of egg size was significantly
correlated with clutch size or clutch mass (P > 0.05). Clutch size and clutch
mass were also positively correlated (rho 0.80, P < 0.0001), but egg mass
was not significantly correlated with either clutch mass or clutch size (P >
0.05).

Similarly, clutch size and clutch mass of Sternotherus odoratus were
positively correlated (rho = 0.78, P = 0.0027), but egg mass and clutch
mass were not significantly related (P > 0.05). Both egg leng th (rho = 0. 85,
P = 0.0002) and egg width (rho = 0. 74, P = 0.0036) were positively corre¬
lated with egg mass. No other comparisons were significant.

Terrapene Carolina mirrored the other two species in having clutch
size and clutch mass positively associated (rho = 0.92, P < 0.0001) and in
having no significant correlation between egg mass and clutch mass (P >
0.05) . Again, egg width (rho = 0.65, P = 0.0018) and egg length (rho = 0.77,
P < 0. 0001) were both positively correlated with egg mass. Interestingly,
egg length was negatively correlated with clutch size, but the association
only bordered on significance (rho = -0.55, P = 0.0117) given the number
of comparisons.

Clutch mass was positively correlated with plastron length (rho =
0.52, P = 0.0018) , plastron height (rho = 0.66, P < 0. 0001), and gravid mass
(rho = 0.61, P = 0.0002) in Chrysemys picta . Maternal gravid mass was also
positively correlated with egg mass (rho = 0.52, P = 0.0016), egg width
(rho = 0.53, P = 0.0018), and egg length (rho = 0. 53, P = 0. 0017) in C. picta.
Egg width was positively correlated with maternal plastron length (rho =
0.39, P = 0.0239) and maternal carapace height (rho = 0.47, P = 0.0061).
However, the correlations were weak given the number of comparisons
made.

In contrast, only egg mass was positively associated with maternal
gravid mass (rho = 0.87, P = 0.0003) in the smaller sample of Sternotherus
odoratus . None of the other comparisons were statistically significant. Pos¬
sibly, the small sample from a narrow range of maternal sizes (see Figs. 1
and 2) did not allow relationships between maternal size and reproduc¬
tive traits to be shown.

Bulletin of the Maryland Herpetological Society

page 65

Volume 35 Numbers

September 1 999

Reproductive data gathered on Terrapene Carolina also showed few,
correlations with maternal size. Clutch size was positively related to ma¬
ternal plastron length (rho = 0. 67, P = 0.0009) and to maternal gravid
mass (rho = 0.65, P = 0.0014). Clutch size was also positively related to
maternal carapace height (rho = 0.62, P = 0.0063) but the P-value does not
exclude type I error at 0.05 given the number of comparisons. Regardless,
the correlation coefficients suggest that clutch size increases as body size
increases. In contrast, egg size tends to decrease with clutch size as noted
above. Consistent with that observation was the finding that egg mass
(rho = -0.34, P = 0.13) and egg length (rho = -0.51, P = 0.0219) but not egg
width (rho = 0.12, P = 0.62) were negatively associated with maternal plas¬
tron length and other measures of maternal size. Although these associa¬
tions were not statistically significant, they were consistent with the hy¬
pothesis that larger Terrapene Carolina clutches tend to be laid by larger
females and that eggs in those clutches tend to weigh less and be shorter
in length but not width than eggs in smaller clutches of smaller females
(Figs. 1 and 2).

Egg size-clutch size trade-offs were not demonstrated for any of the
three species in partial correlation with the influence of plastron length
held constant in the correlation of egg mass and clutch size. Coefficients
were negative but not statistically significant for Chrysemys picta (rho =
-0.21, P = 0.25), Sternotherus odoratus (rho = -0.29, P = 0.4150), and Terrapene
Carolina (rho = -0.26, P - 0.26).

Because egg mass was predictable from egg width and length, re¬
gression equations were developed for data from each species. The rela¬
tionship for Chrysemys picta (egg mass = 0.65* egg width + 0.24* egg length
- 13. 01, R2 = 0.98) was significant (F231 = 824.68, P < 0.0001) . All param¬
eters were significantly different from 0 (t > 16.5, P < 0.0001). The same
relationship for Sternotherus odoratus (egg mass 0.48*egg width + 0.20*egg
length - 8.79, R2 = 0.97) was also significant (F2 10 = 140.74, P < 0.0001), and
the regression parameters were also significantly different from 0 (t > 1!7 ,
P < 0.0001). Likewise, for Terrapene Carolina the regression equation (egg
mass = 0. 92* egg width + 0. 37*egg length - 22.76, R2 = 0.95) was signifi¬
cant (F2 17 = 150.80, P < 0.0001) and the parameters were statistically differ¬
ent from 0 (t > 11.0, P < 0.0001).

page 66

Bulletin of the Maryland Herpetological Society

Volume 35 Number 3

September 1999

14 -T

□ Sternotherus

+

12-

* Terrapene

+

+

10-

+ Chrysemys

+ +

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A A

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- - - r -

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90 110 130 150 170

Maternal length (mm)

Figure 1. Egg mass as a function of maternal plastron length for Terrapene
Carolina and Chrysemys picta and of carapace length for Sternotherus
odoratus.

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150

170

Maternal length (mm)

Figure 2. Clutch size as a function of maternal plastron length for Terrapene
Carolina and Chrysemys picta and of carapace length for Sternotherus
odoratus.

Bulletin of the Maryland Herpetological Society

page 67

Volume 35 Number 3

September 1 999

Interspecific comparisons of egg mass indepedent of maternal size
using ANCOVA found that LSM for egg mass of Terrapene Carolina (10.37 ±
0.21 g) was greater (P < 0.0001) than LSM for egg mass of Chrysemys picta
(6.93 ± 0.27 g) and Sternotherus odoratus (4.59 ± 0.58 g). The latter two spe¬
cies also differed significantly (P = 0.0045). Slopes for egg mass regressed
on maternal size for these three species did not differ significantly (F. ,, =
3.03, P = 0.0555).

Eggs of Terrapene Carolina were also relatively wide when the effect
of maternal size was factored out with ANCOVA. Egg width LSM for T.
Carolina (21.8 ± 0.19 mm) was significantly greater (P < 0.0001) than egg
width for either Chrysemys picta (18.3 ± 0.24 mm) or Sternotherus odoratus
(16.9 ± 0.51 mm). Egg width LSM for the latter two species did not differ
significantly (P = 0.0623). Slopes of egg, width regressed on maternal size
did not differ significantly among the three species (F2 60 = 0.41, P = 0.6658).

Slopes varied slightly but significantly among species for egg length
regressed on maternal size (F260 = 4.73, P = 0.0123). An ANCOVA model
for heterogeneous slopes was used to compare egg length among species
without the effect of maternal size. All three species differed from each
other. Terrapene Carolina had the longest egg length LSM (35.9 ± 0.43 mm, P
< 0.0001), egg length LSM for Chrysemys picta (32.5 ± 0.56 mm) as shorter
(P < 0.0001) than T. Carolina but longer (P = 0.0004) than egg length LSM
for Sternotherus odoratus (26.4 ± 1.17 mm).

Slopes for clutch size regressed on maternal size were homogeneous
(F260 = 0.61, P = 0.5449). In this instance clutch size LSM for Sternotherus
odoratus (8.8 ± 0.94 eggs) independent of maternal size was greater (P =
0.0002) than clutch size LSM for Terrapene Carolina (5.2 ± 0.33 eggs). Clutch
size LSM for Chrysemys picta (6.8 ± 0.43 eggs) was greater (P = 0.0095) than
clutch size LSM for T. Carolina. These relationships are particularly well
shown in Fig. 2.

Slopes for clutch mass regressed on maternal size did not differ sig¬
nificantly (F2 m = 0.28, P = 0.7570). Clutch mass LSM for Sternotherus odoratus
(53.92 6.78 gj, for Terrapene Carolina (52.98 ± 2.39 g), and for Chrysemys picta
(43.92 ± 3.08 g) did not differ significantly in any pairwise t-tests.

Overall, eggs of Terrapene Carolina were heaviest, longest, and wid¬
est when effects of maternal body size were removed. In contrast, clutch

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September 1 999

size was smallest relative to maternal body size for T. Carolina suggesting
that egg size and dutch size are being traded-off in this interspecific com¬
parison. Sternotherus odoratus , the species with the smallest body size, was
the species that produced the largest dutch mass and clutch size relative
to body size.

Discussion

Congdon and Gibbons (1985) studied reproduction in a number of
South Carolina turtle species including the three species that I examined
from Illinois. Thus, comparisons of their findings to mine are particularly
appropriate. They found that clutch size and dutch mass was positively
correlated with maternal size (plastron length) except for Terrapene Carolina
(Congdon and Gibbons, 1985). My findings only agree with theirs with
respect to Chrysemys picta . I found no relationship between maternal size
and egg size in Sternotherus odoratus . This finding may reflect the small
sample size from a limited range of maternal sizes available to me.

The differences between my findings on Terrapene Carolina and those
of Congdon and Gibbons (1985) are more important. I found a statisti¬
cally significant positive relationship between clutch size and maternal
size in T. Carolina , whereas this relationship was not detected among the
South Carolina T. Carolina . Moreover, my findings suggest that larger fe¬
males while laying larger dutches tend to lay lighter and shorter eggs in
those dutches. Other studies of T. Carolina (Allard, 1935) and T. ornata
(Legler, 1960) also found the largest eggs in the smallest dutches. Reduced
egg size in larger clutches that I studied appears to be due to reduction in
egg length but not egg width. Judd and Rose (1989) also found that aver¬
age egg length decreased with increasing dutch size in Gopherus berlandieri ,
another terrestrial turtle but one not closely related to T. Carolina.

Consistent with optinal egg theories, egg mass was not significantly
related to dutch size or dutch mass in any of the three species that I ex¬
amined. Congdon and Gibbons (1985) made identical findings for South
Carolina turtles of these same species. However, a significant negative
partial correlation between egg mass and clutch size with maternal size
as the partial variable could not be demonstrated for any of the Illinois or
South Carolina turtle species. Apparently any egg size-clutch size trade¬
off Is not strong enough to detect given the sample sizes and range of

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sizes for the turtles that we each examined (Tucker et al., 1998a).

Nonetheless, large female Terrapene Carolina from Illinois seem to be
trading increased fecundity (i.e., larger clutch size) for smaller eggs and
presumably smaller hatchlings (i.e., Packard et al, 1985). This is a remark¬
able finding given the suspected importance of supplying hatchlings with
maximal energy reserves so that they can successfully cope with patchy
terrestrial habitats (Wilbur and Morin, 1988; Congdon and Gibbons, 1990).
Egg, and thus, hatchling size were actually smallest among the larger box
turtles that I studied (Fig. 1).

My findings for these species collected in larger river habitats are
consistent with previously published studies of turtles from lakes and
ponds in Illinois. Mean clutch size for Chrysemys picta from central Illinois
was 8.7 eggs in one study (Moll, 1973) and ranged between 5.89 and 9.86
for turtles studied by Tucker (1978). The mean clutch size that I observed
(8 eggs) is what would be expected. Mean egg mass unadjusted for ma¬
ternal body size (7.16 g) is somewhat higher among Illinois C. picta than
means previously reported from South Carolina (6.17 g, Congdon and
Gibbons, 1985), Nebraska (means ranged from 5.4 to 6.66 g, Iverson and
Smith, 1993; Rowe, 1994), and Virginia (means ranged from 4.69 to 5.50 g,
Mitchell, 1985, 1994).

The Illinois Sternotherus odoratus that I observed had larger mean
clutch size (5.8 eggs) unadjusted for maternal size than reported for any
other population of the species. This value exceeded mean clutch size of
4.6 eggs for northern S. odoratus (Tinkle, 1961). Relatively large clutch size
for Illinois S. odoratus is consistent with the geographic trend for clutch
size to increase from north to south (Tinkle, 1961; Fitch, 1985). Mean egg
mass (4.03 g) for the Illinois S. odoratus that I studied is relatively high and
compares to egg sizes for the species from South Carolina (4.04 g, Congdon
and Gibbons, 1985) and Alabama (4.2 g, McPherson and Marion, 1981).
Findings for Illinois turtles agree with Fitch (1985) who found no evi¬
dence of consistent north to south trends in egg size in S. odoratus.

Clutch size in Terrapene Carolina is known to decrease from north to
south (Fitch, 1985). Mean clutch size (4.9 eggs) for Illinois T. Carolina was
similar to mean clutch sizes reported from Washington D.C. (4.2, eggs
Allard, 1935) and Virginia (4.1 eggs, Mitchell, 1994) even though these

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September 1999

locations are at slightly lower latitudes than the Illinois sites. Mean egg
mass (10.31 g) that I observed was greater than egg mass reported for the
species from South Carolina (9.02 g, Congdon and Gibbons, 1985) and
from Virginia (9.8 g, Mitchell, 1994).

Although I made interspecific statistical comparisons of reproduc¬
tive life-history traits, I hesitate to statistically compare the ratios that I
derived (RCM, REM, and ELO). The geographic and interspecific varia¬
tion in these was discussed in detail by Iverson (1992) and Iverson et al.
(1993). The values I derived for the species that I studied (Table 2) are
similar to those listed by Iverson (1992) and Iverson et al. (1993). I do
think it is noteworthy that all three of these species lay eggs that have
about the same ELO (Table 2). However, REM for Chrysemys picta (0.013)
was considerably lower than REM for either Terrapene Carolina (0.022) or
Sternotherus odoratus (0.023).

Acknowledgments

I thank N. I. Filoramo, F. J. Janzen, G. L. Faukstis, M. M. Tucker, and
D. A. Warner for assistance in the field. Female turtles, eggs, and hatchlings
were collected under Illinois Department of Natural Resources permit
number A-93.0202 and extensions. This work was partially supported by
the Illinois Natural History Survey and the Upper Mississippi River Sys¬
tem Long Term Resource Monitoring Program.

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September 1 999

Literature Cited

Allard, H. A.

1935. The natural history of the box turtle. Sci. Monthly 41:325
338.

Cagle, F. R.

1950. The life history of the slider turtle, Pseudemys scripta
troostii (Holbrook). Ecol. Monogr. 20:31-54.

Cahn, A. R.

1937. The turtles of Illinois. Illinois Biol. Monogr. 35:1-218.

Congdon, J. D., and J. W. Gibbons.

1985. Egg components and reproductive characteristics of
turtles: relationships to body size. Herpetologica 41:194-
205.

Congdon, J. D., and J. W. Gibbons.

1990. Turtle eggs: their ecology and evolution, pp. 109-123. In:
Gibbons, J. W. (ed.). Life History and Ecology of the Slider
Turtle. Smithsonian Institution Press, Washington, D.C.

Ewert, M. A., and J. M. Legler.

1978. Hormonal induction of oviposition in turtles.
Herpetologica 34:314-318.

Fitch, H. S.

1985. Variation in clutch and litter size in New World reptiles.
Misc. Publ. Univ. Kans. Mus. Nat. Hist. 76:1-76.

Iverson, J. B.

1992. Correlates of reproductive output in turtles (Order
Testudines). Herpetol. Monogr. 6:25-42.

Iverson, J.B., and G.R. Smith.

1993. Reproductive ecology of the painted turtle (Chrysemys
picta) in the Nebraska Sandhills and across its range.
Copeia 1993:1-21.

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September 1999

Iverson, J. B., C. P. Balgooyen, K. K. Byrd, and K. K. Lyddan.

1993. Latitudinal variation in egg and clutch size in turtles. Can.
J. Zool. 71:2448-2461.

Jackson, D. R.

1988. Reproductive strategies of sympatric emydid turtles in
northern peninsular Florida. Bull. Florida State Mus., Biol.
Sci. 33:113-158.

Judd, F. W., and F. L. Rose.

1989. Egg production by the Texas tortoise, Gopherus berlandieri,
in southern Texas. Copeia 1989:588-596.

Legler, J. M.

1960. Natural history of the ornate box turtle, Terrapene ornata
ornata Agassiz. Publ. Mus. Nat. Hist. Univ. Kansas
11:527-669.

McPherson, R. J., and K. R. Marion.

1981. The reproductive biology of female Sternotherus odoratus
in an Alabama population. J. Herpetol. 15:389-396.

Mitchell, J. C.

1985. Female reproductive cycle and life history attributes in a
Virginia population of painted turtles, Chrysemys picta. J.
Herpetol. 19:218-226.

Mitchell, J. C.

1994. The reptiles of Virginia. Smithsonian Institution Press,
Washington, D. C.

Moll, E. 0.

1973. Latitudinal and interspecific variation in reproduction of
the painted turtle, Chrysemys picta. Herpetologica
29:307318.

Packard, G. C, M. J. Packard, and W. H. N. Gutzke.

1985. Influence of hydration on the environment on eggs and
embryos of the terrestrial turtle Terrapene ornata. Physiol.
Zool. 58:564-575.

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September 1 999

Rice, W. R.

1989. Analyzing tables of statistical tests. Evolution 43:223-225.

Rowe, J.W.

1994. Egg size and shape variation within and among Nebras¬
kan painted turtle (Chrysemys picta bellii) populations: re¬
lationships to clutch and maternal body size. Copeia
1994:1034-1040.

SAS Institute, Inc.

1996. SAS/STAT user's guide. Statistical Analysis Systems In¬
stitute, Inc., Cary, North Carolina.

Smith, P. W.

1961 . The amphibians and reptiles of Illinois. Ill. Nat. Hist. Surv.
Bull. 28:1-298.

Thornhill, G. M.

1982. Comparative reproduction of the turtle, Chrysemys
scripta elegans, in heated and natural lakes. J. Herpetol.
16:347-353.

Tinkle, D. W.

1961 . Geographic variation in reproduction, size, sex ratio and
maturity of Sternothaerus odoratus (Testudinata:
Chelydridae). Ecology 42:68-76.

Tucker, J. K.

1978. Variation in reproductive potential and growth in
Chrysemys picta within a single body of water. Bull. Mary¬
land Herpetol. Soc. 14:223-232.

Tucker, J. K.

1995. Notes on three clutches of the box turtle, Terrapene Carolina.
Bull. Chicago Herpetol. Soc. 30:41-43.

Tucker, J. K., and F. J. Janzen.

1998. Order of oviposition and egg size in the red-eared slider
turtle (Trachemys scripta elegans). Can. J. Zool. 76:377-380.

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September 1 999

Tucker, J. K., F. J. Janzen, and G. L. Paukstis.

1995. Oxytocin induced nesting behavior in females of the
redeared turtle, Trachemys scripta elegans, without oviduc-
tal eggs. Herpetol. Rev. 26:138.

Tucker, J. K., G. L. Paukstis, and F. J. Janzen.

1998a. Annual and local variation in reproduction in the red-eared
slider, Trachemys scripta elegans. J. Herpetol. 32:515-526.

Tucker, /. K., F. J. Janzen, and G. L. Paukstis.

1998b. Variation in carapace morphology and reproduction in
the red-eared slider Trachemys scripta elegans. J. Herpetol.
32:294-298.

Wilbur, H. M., and P. J. Morin.

1988. Life history evolution in turtles, pp. 387-439. In: Gans, C.
and R. B. Huey (eds.). Biology of the Reptilia, Vol. 16.
Alan R. Liss, New York.

Illinois Natural History Survey

Great Rivers Field Station Long Term Resource Monitoring Program-Reach 26

8450 Montclaire Avenue , Brighton , Illinois , 62012 , USA.

Received 18 March 1999

Accepted 21 March 1999

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IXODES SCAPULARIS
(Acari: Ixodidae) Parasitizing
Coal Skink ( Eumeces anthracinus)

While Ixodes scapularis is known from nearly 125 host species of
vetebrates, with Mammalian and Avian hosts being the most common, it
has only been recorded from a handful of reptilian species in Southeast¬
ern United States. Keirans, et al. (1996) felt that this phenomenon was
rare or absent in the Northeast and Mid-west states where the same spe¬
cies of lizards occurred. Studies by Rogers (1953), Oliver, et al. (1996),
Apperson, et al. (1993), Durden & Oliver (1996), and Levine, Apperson,
Howard, Washburn and Braswell (1998) have shown that various species
of skinks, belonging to the genus Eumeces and Ophisaurus are the most
common reptilian host in the Southeast. In Florida, the ground skink
(Scincella lateralis) has been reported as a host, along with heavy infesta¬
tions also noted on Broadhead skinks (Eumeces laticeps). A single speci¬
men of E. laticeps harbored no less than 394 immature ticks, Rogers (1953)
and Apperson, et al. (1993). Eads (1949) reported an engorged nymph
from a specimens of Ophisaurus ventralis in Texas.

In recent years Ixodes scapularis has been noted as a primary vector
of the spirochete of Lyme Disease ( Borrelia burgdorferi), and while examin¬
ing over 300 specimens of Eumeces anthracinus from throughout its range
four specimens of Eumeces anthracinus pluvialis from Arkansas and Mis¬
souri harbored larval ticks of I. Scapularis behind the forelimb axilla re¬
gion. This number could possibly be underestimated, as I was concerned
with meristic data, and little emphases was giving parasites. MPMC 20812-
3 were collected from 3 mi. N. Pickens Chapel, Cleburne County, and 5
miles W. Searcy, White County, Arkansas, while MPMC 15080 was taken
from 5 mi. W. Smackover, Union County, Arkansas. Another specimen
UK 176549 from Carry Mt. Wildlife Management area, Ozark County,
Missouri also harbored ticks. It is noteworthy that all four specimens har¬
boring ticks were collected in the Spring, between April 3 and April 29.

This is the first record for Eumeces anthracinus as a host for the Ixo¬
didae mentioned above.

I wish to thank Dr. J.R. Levine for verifying the identity of Ixodes
scapularis.

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September 1 999

LITERATURE CITED

Apperson, C.S., J.F. Levine, T.L. Evans, A. Braswell , and J. Heler.

1993. Relative utilization of reptiles and rodents as hosts by
immature Ixodes scapularis (Acari: Ixodidae) in the coastal
plain of North Carolina. Exp. Appl. Acarol. 17:719-731.

Durden, L.A., G.N. Vogel, and J.H. Oliver, Jr.

1996. Noctural questing by adult black-legged ticks, Ixodes
scapularis (Acari: Ixodidae). J. Parasitol. 82:174-175.

Eads, Richard B.

1949. Notes on Ixodes scapularis Say with an additional lizard
host. Entomol. News 60(9):238-240.

Galbe, Jordi and James H. Oliver, Jr.

1992. Immune response of lizards and rodents to larval Ixodes
scapularis (Acari: Ixodidae). Jour. Med. Entomol.
29(3):774-783.

Keirans, James E., H.J. Hutcheson, L.A. Durden and J.S.H. Klompen.

1996. Ixodes ( ixodes ) scapularis (Acari: Ixodidae): Redescription
of all active stages, distribution, hosts. Geographical
variation, and medical and veterinary importance. Jour.
Med. Entomol. 33(3):297-318.

Lavender, David R. and James H. Oliver, Jr.

1996. Ticks (Acari: Ixodidae) in Bulloch County Georgia. Jour.
Med. Entomol. 33(2):224-231.

Levin, Michael, J.F. Levine, S. Yang, P. Howard and C.S. Apperson.

1996. Reservoir competence of the southeastern Five-lined
skink (Eumeces inexpectatus) and the Green Anole ( Anolis
carolinensis) for Borrelia burgdorferi . Am. J. Trop. Med. Hyg.
54(l):92-97.

Levine, Jay F., Charles E. Apperson, Peter Howard, Michelle Washburn
and Alvin L. Braswell.

1998. Lizards as host for immature Ixodes scapularis (Acari: Ixo¬
didae) in North Carolina. J. Med. Entomol. 34(6)594-598.

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 3

September 1999

Oliver, James H., Jr., G.A. Cummins and M.S. Joiner.

1993. Immature Ixodes scapularis (Acari: Ixodidae) parasitizing liz¬
ards from the southeastern U.S.A. J. Parasitol. 79:684-68.

Rogers, Andrew J.

1953. A study of the Ixodid ticks of Northern Florida, including
the biology and life history of (Ixodidae: Acarina). PhD
Thesis, Univ. Maryland i-xvi + 183pp.

Harlan D. Walley , Department of Biology, Northern Illinois University ,

DeKalb, Illinois 60115

Received
Accepted

17 March 1999
20 March 1999

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September 1 999

A Major Range Extension of the
Yucatecan Blind Snake, Typhlops microstomus ,
(Serpentes, Typhlopidae)

Although the blind snakes of the family Leptotyphlopidae are rea¬
sonably common in many parts of Mexico, quite the opposite is true of
members of the family Typhlopidae. Concomitantly, whereas five species
and 18 species and subspecies of Leptotyphlops are known from Mexico,
only three species of Typhlopidae are known (Liner, 1994).

Until recently, the only typhlopid known from the state of Veracruz
was Typhlops tenuis , a species known only from scattered localities along
Atlantic slopes from central Veracruz to Honduras, excluding the Penin¬
sula of Yucatan (Dixon and Hendricks, 1979: 17). Ramphotyphlops braminus
has been known for many years from Pacific slopes of Mexico, Baja Cali¬
fornia to Guerrero, and was first reported on Atlantic slopes in 1975
(Minton de Cervantes and Minton, 1975), in Queretaro, Queretaro. It was
for the first time recorded from south-central Veracruz by Mendoza et
al., 1993).

The third Mexican species of typhlopid, Typhlops microstomus, has
long been been assumed to be limited to the Yucatan Peninsula, where
records exist for the states of Yucatan, Quintana Roo and Campeche, as
well as for Belize and Peten, Guatemala (Lee, 1996: 280). It was thus with
considerable surprise that a specimen was taken by GPH shortly after a
heavy rain at El Farallon (near Laguna Verde), municipality of Actopan,
Veracruz, in March, 1998.

That specimen, UNAM-LT 3501, is 290 mm in total length; scale rows
18-18-18; subocular present; nasal suture complete, contacting rostral.
Color pink in life; body scales immaculate, not pigmented.

The present record extends the known range of the species some
600 km northward from previous records in Campeche, and constitutes
an addition to the known ophidiofauna of the state of Veracruz. All three
species of the typhlopid snakes of Mexico are now known from the state;
no other state is known to harbor more than one.

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September 1 999

Whether the apparent discontinuous distribution of the species, with
a group of recorded localities in the northern part of the Yucatan Penin¬
sula, another in the southern part of that Peninsula, and a third in central
Veracruz, is a sampling artifact or a reality remains to be determined. As
secretive as these snakes are they could well have a continuous distribu¬
tion over the entire area.

Literature Cited

Dixon, James R. and Fred S. Hendricks.

1979. The wormsnakes (family Typhlopidae) of the neotropics,
exclusive of the Antilles. Zoologische Verhandelingen,
(173): 1-39.

Lee, Julian C.

1996. The amphibians and reptiles of the Yucatan Peninsula.
Ithaca, New York, Comstock, xii, 500 pages.

Liner, Ernest A.

1994. Scientific and common names for the amphibians and
reptiles of Mexico in English and Spanish. Soc. Study
Amph. Rept. Herp. Circular, (23): i-iii, 1-113.

Mendoza-Quijano, Fernando, Mario Mancilla Moreno and Alejandra
Rendon Rojas.

1993. Geographic distribution: Ramphotyphlops braminus. Herp.
Rev., 24: 110.

Minton de Cervantes, Brooks and Sherman A. Minton.

1975. Geographic distribution: Typhlops braminus. Herp. Rev.,
6:117.

Gonzalo Perez-Higareda and Hobart M. Smith
Estacion de Biologia " Los Tuxtlas," Apartado Postal 51, Catemaco,
Veracruz , Mexico (GPH); and Department of Environmental, Population and
Organismic Biology and Museum , University of Colorado, Boulder, Colorado

80309-0334 , USA (HMS).

Received 15 March 1999

Accepted 3 April 1999

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September 1 999

External Morphological Variation
in Hardy's Hooknose Snake Ficimia hardyi
(Squamata: Colubridae)

Ficimia hardyi was described by Mendoza-Quijano and Smith (1993)
from four specimens from the Sierra de Zacualtipan, northern Hidalgo.
Three additional specimens (Hernandez-Ibarra et al., submitted) are from
Guadalcazar, San Luis Potosi. Those three include two adult females, one
(XR 559, field number of the second and third authors) from San Jose de
las Flores (22° 40' 46" N 100° 24’ 52” W) and the other (XR 775) from El
Realejo (22° 32' 55" N 100° 27’ 46” W), and a hatchling male (XR 767) from
San Jose de los Cervantes (22° 32' 55” N 100° 27' 46” W) . They extended
the known range of the species about 290 km to the north.

F. hardyi occurs in the state of Hidalgo, Mexico, along with its conge¬
ners F. streckeri, F. publia and F. olivacea (Hardy, 1990, Mendoza-Quijano
and Smith, 1993). Only F. streckeri and F. olivacea were known from the
state of San Luis Potosi (Hardy, 1975, 1990) until F. hardyi was reported
(Hernandez-Ibarra et al., submitted).

Because of the rarity of the species we here report the external mor¬
phological variation of all of its seven known specimens. In addition to
data from the new material cited above, we include data on the speci¬
mens reported by Mendoza-Quijano and Smith (1993), all in the Museo
de Zoologia, Facultad de Ciencias, Universidad Nacional Autonoma de
Mexico (MZFC 4876-8, 5328, the first a female, all others males).

The supralabials are 7-7 except for two with 6-6, 3rd and 4th enter¬
ing the orbit, 2nd and 3rd in contact with the single preocular (except for
XR 767, only with the 3rd), 2nd with the prefrontal, 1st and 2nd with the
nasal. Temporals 1-2, anterior contacting 5th and 6th supralabials, lower
secondary the 6th and 7th. Two postoculars, lower contacting 5th and 6th
supralabials. No internasals. Dorsals contacting right and left parietals 5-
4 in XR 775, 5-5 in XR 559 and MZFC 5328, and 4-4 in XR 767 and MZFC
4878. Infralabials 6-7 in two, 6-6 in three, 7-? in one. Posterior chinshields
separated by only one scale in two (XR 539, XR 767), by two scales in one
(XR 775), but in contact in all from Hidalgo except MZFC 4878. Scale rows
17-17-17 in all except XR 559 with 17-17-16 and MZFC 5328 with 17-17-15.

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September 1999

Ventrals 140 in all three females, 129-136 in males. Subcaudals 33-40 in
three females, 38-46 in four males. Anal divided in all except one with an
entire anal (XR 775).

In XR 559 the SVL was 276 mm, tail 43.4 mm; in XR 775, 207.7 mm
and 38.5 mm, and in XR 767, 100.8 and 20.4 mm, respectively. Ratios of
head measurements are as follows: naris-snout length/eye-snout distance
0.889 in XR 559, 0.0778 in XR 775, 0.667 in XR 767; eye-lip distance/eye
diameter 0.714 in XR 559, 0.667 in XR 767, XR 775; rostral length/width,
3.5 in XR 559, 1.4 in XR 775, 0.857 in XR 767, and 1.4 in all Hidalgo speci¬
mens except MZFC 5328 with 1.08; rostral length /rostral suture length,
0.875 in XR 559, 1.2 in XR 767, 1.75 in XR 775, 2.77 in MZFC 4876, 2.75 in
MZFC 4878, and 2.0 in MZFC 4877; rostral-frontal suture length /frontal
length, 1.6 in XR 559, 1.25 in XR 767, 0.364 in XR 775, 0.44 in MZFC 4877,
0.58 in MZFC 4878, and 0.22 in MZFC 5328; frontal width/frontal length
0.8 in XR 559, 0.5 in XR 767, 0.636 in XR 775, 0.823 in MZFC 4877, 0.69 in
MZFC 4878, and 0.892 in MZFC 5328; interparietal suture length /frontal
length 0.4 in XR 559, 1.5 in XR 767, 0.636 in XR 775, 0.855 in MZFC 4877,
0.677 in MZFC 4978, and 0.75 in MZFC 5328.

Dorsal ground color gray-brown in all specimens; transverse dark
blotches on body 47 (XR 775), 49 (XR 559) and 45 (XR 767), but in speci¬
mens from Hidalgo 43 in two (MZFC 4876, 4878), 44 (MZFC 4877) and 47
(MZFC 5328); caudal blotches 15 in two (XR 775, MZFC 4878), 17 in three
(XR 559, 767, MZFC 4877), 19 in one (MZFC 5328) and 22 in one (MZFC
4876). Width and length (relative to body) of 1st dorsal blotch, 8 and 3
scales respectively (XR 539), 9 and 4 (XR 767), and 7 and 4 (XR 775), whereas
the length was 4 scales in all specimens from Hidalgo. The nuchal blotch
is separated from the parietals by one scale row in one (XR 767), by two in
three (XR 559, 775, MZFC 4878), and by four in one (MZFC 5328).

The most unexpected variation observed was the single anal scale
in one specimen. Hardy (1975) recorded an undivided anal scale in only
one specimen of the some 155 examined. That one exception was on the
lectotype of F. publia, of which he saw more specimens (69) than of any
other species. It is probably coincidental that F. publia is the closest rela¬
tive of F. hardyi.

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Bulletin of the Maryland Herpetological Society

Volume 35 Numbers

September 1999

The new material from San Luis Potosi conforms well with the dif¬
ferential criteria of the species as deduced from the series from Hidalgo
and discussed in Mendoza-Quijano and Smith (1993). Especially signifi¬
cant is agreement of the San Luis Potosi material with that from Hidalgo
in having one preocular, two postoculars, no intemasals, and 45-49 trans¬
verse, light-edged dark blotches on body, each blotch separated on each
side by a distinct light space from a small dark spot (as in Fig. 1, Mendoza-
Quijano and Smith, 1993).

The species' closest relationship remains apparently with F. publia.
On the other hand, a number of differences between the Hidalgo and
San Luis Potosi samples is apparent. There is but a slight difference in
mean number of dorsal blotches (44.3 vs 47), but categorical differences
in contact vs separation of the posterior chinshields, and in number of
subcaudals (40-46 vs 33-38). The samples are not large enough however
to justify generalizations, and the differences are not of such magnitude
that further material would be unlikely to bridge them. The variation in
the San Luis Potosi sample does not tend toward the variational pattern
of F. publia; the differences from the latter are somewhat greater than in
the Hidalgo sample.

All specimens from Hidalgo were collected in a habitat at 1200-1885
m dominated by xerophytic bush or maguey (Agave), and submontane
bush (Juniperus), whereas the habitat where specimens were taken in San
Luis Potosi at 1585-2160 m was in chaparral (Quercus) and grassland.

Acknowledgments

This work was conducted as part of a study of the herpetofauna of
San Luis Potosi, supported by CONABIO project No. R045/98 and
CONACYT project No. 27618-N. We are indebted to Dr. H. Hernandez
for his help and for introducing us (ARB, XHI, RTC) to the region of
Guadalcazar; and to M. Espinoza and the authorities of Guadalcazar for
their invaluable logistic support.

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 3

September 1999

Literature Cited

Hardy, L. M.

1975. A systematic revision of the colubrid snake genus Ficimia.
J. Herp. 9: 133-168.

1990. Ficimia. Cat. Am. Amph. Rept. 47: 1-5.

Hernandez-Ibarra, X., A. Ramirez-Bautista, R. Torres-Cervantes, and H.
Hernandez-Macias.

1999. Geographical distribution: Ficimia hardyi. Herp. Rev. (sub¬
mitted).

Mendoza-Quijano, F. and H. M. Smith.

1993. A new species of Hooknose snake, Ficimia (Reptilia,
Serpentes). J. Herp. 27: 406-410.

Aurelio Ramirez-Bautista , Xochitl Hernandez-Ibarra,

Ricardo Torres-Cervantes and Hobart M. Smith
Laboratorio de Ecologia , Unidad de Biologia, Tecnologia y Frototipos , Escuela
Nacional de Estudios Profesionales Iztacala, UNAM, A. P. 314, Av. de los
Barrios s/n. Los Reyes Iztacala, Tlalnepantla, Edo. de Mexico, 54090 Mexico
(ARB, email raurelio@servidor.unam.mx ; XHI, e-mail
xrgithic@servidor.unam.mx ; RTC, e-mail rjtcxh@servidor.unam.mx);
Department ofEPO Biology and Museum, University of Colorado,
Boulder, Colorado 80309-0334 (HMS, email hsmith@spot.colorado.edu).

Received 31 March 1999

Accepted 3 April 1999

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Bulletin of the Maryland Herpetological Society

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September 1999

Strike-induced Chemosensory Searching
in the Caucasus Viper (Vipera kaznakovi ) and
the Oceliate Mountain Viper (Vipera wagneri)

Abstract

Three specimens of the Oceliate Mountain Viper ( Vipera wagneri) and
one specimen of the Caucasus Viper ( V. kaznakovi) were observed after
striking rodent (Mus musculus) prey and after no-strike presentations of
M. musculus. Rate of tongue flicking did not rise after no-strike presenta¬
tions, but exhibited a 10-fold elevation after strikes were delivered. Hence,
strike-induced chemosensory searching occurred in these snakes.

Rattlesnakes typically strike and release adult rodent prey, allowing
the envenomated animal to wander from the site of attack until venom
takes effect (Estep et al, 1981; Kardong, 1986; Hayes & Galusha, 1984).
The snakes then exhibit searching movements coupled with a pronounced
elevation in the rate of tongue flicking, collectively called strike-induced
chemosensory searching (SICS), which facilitates finding and following
the chemical trail left by wounded prey (Diller, 1990; Dullemeijer, 1961;
Golan et al., 1982). While most recent work on SICS has concentrated on
rattlesnakes, there have been a few demonstrations of its presence in non-
venomous snakes (Burghardt & Chmura, 1993; Cooper, McDowell, &
Raffer, 1989) and a substantial volume of work documenting similar phe¬
nomena in lizards (Cooper, 1989, 1994). The only recent paper on Old
World vipers showed that SICS occurred in Vipera ammodytes, V. latifii, V.
raddei and V. xanthina (Chiszar et al, 1982; see Burghardt, 1970, for a re¬
view of earlier literature on V. aspis and V. berus). Hence, it is clear that
SICS is a widespread phenomenon, not confined to vipers and pit vipers,
but most highly developed in these animals, especially those terrestrial
species that ambush rodents using the strike-release strategy (see Halpern
1992, for a review of chemical perception in reptiles).

We now add two relatively rare species of vipers to the list of taxa ex¬
hibiting SICS. The Caucasus viper (Vipera kaznakovi Nikolsky, 1909) and the
Oceliate Mountain viper (V. wagneri Nilson & Andren, 1984) are rare in the
United States, with only a few zoos exhibiting them. Indeed, when we did
our comparative studies of SICS in the 1980's, no specimens of either species
were available in American zoos or in any of the western European zoos

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 3

September 1999

with which we were in contact. Consequently, it was with great interest that
we studied the present individuals at the Rio Grande Zoo.

Method

Three adult specimens of V zvagneri and one of V. kaznakovi in the
collection of Rio Grande Zoo were each observed twice during April, 1994.
All snakes were maintained in individual glass terreria (51 x 27 x 30 cm).
Both observations involved a 10-min baseline period followed by presen¬
tation of a mouse (Mus musculus, 12-15g) and a 30-min post-presentation
period. During each min of observation, we recorded all tongue flicks
using hand-held counters. On one trial a freshly euthanized mouse was
suspended by forceps into the snake's cage, but held for 3 sec just out of
striking range, approximately 15 cm directly in front of the snake's face.
The mouse was then removed. This was the no-strike condition (NS). The
strike condition (S) was exactly like the NS procedure except that after the
3 sec suspension period, the mouse was moved into striking range. All
snakes struck and released the prey, which was then removed.

Temperature was maintained at 26°C and the light cycle was 12:12,
centered at noon. All snakes were long-term captives, well acclimated to
their current conditions, and accustomed to a feeding schedule that of¬
fered one M. musculus , freshly euthanized, each fortnight. Cages contained
paper substrate, ad libitum water, and a plastic hiding box. Observations
were conducted when snakes were 14-days hungry.

Results

Figure 1 presents the mean rate of tongue flicking over baseline and
post-mouse-presentation periods for both NS and S observations. Baseline
rates of tongue flicking were low and did not differ significantly between
the NS and S trials (F = 0.35, df = 1,3, p > 0.05), indicating that snakes were
quiescent prior to mouse presentations. Following NS presentations, the
mean rate of tongue flicking did not rise above baseline rate, and it even¬
tually dropped to zero. After S presentations, however, the rate of tongue
flicking rose considerably above the baseline rate, and it remained high
during the 30 min period. The post-presentation rates of tongue flicking
were, therefore, significantly different in the NS and S observations (F =
63.24, df = 1,3, p < 0.05). Repeated-measures analysis of variance showed,
in addition, that the interaction between baseline versus post-presenta-

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Bulletin of the Maryland Herpetological Society

Figure 2. Mean rate of tongue flicking over successive minutes following no-strike (NS) and strike ($) presentations of
rodent prey.

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September 1 999

Bulletin of the Maryland Herpetological Society

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Successive Minutes

Volume 35 Number 3

September 1999

tion x NS versus S was significant (F = 38.98, df = 1,3, p < 0.05), indicating
that the elevation in rate of tongue flicking beyond baseline was signifi¬
cantly higher after S than after NS presentations. In fact, this interaction
accounted for 37% of the variance observed in this experiment. The main
effect of NS versus S accounted for 28% of the variance. These two factors,
therefore, explain 65% of the variance.

Discussion

There is no question that SICS occurred in the present eastern spe¬
cies of the genus Vipera, agreeing with previous experiments involving
mostly western species of that genus (Burghardt, 1970; Chiszar et al., 1982).
Hence, we may be reasonably confident that SICS is characteristic of Vipera
as it is of Crotalus and Sistrurus. Furthermore, it appears as though SICS is
as well developed in Vipera as it is in the rattlesnakes, since the post-strike
rate of tongue flicking is very high and long lasting in both groups. This
leads to the interesting evolutionary issue of whether SICS developed in¬
dependently in these two groups of solenoglyphs or if SICS was acquired
by each through descent from a common ancestor. Our hypothesis is that
the latter thought is correct, and we propose that this hypothesis can be
tested by studying SICS in relatively primitive viperid genera such as
Agkistrodon, Azemiops, and Causus (Liem et al., 1971).

While colubrid snakes and numerous species of lizards exhibit SICS-
like behavior, in none of these species does the phenomenon last more
than a few minutes. Accordingly, it is unreasonable to hold that Crotalus ,
Sistrurus and Vipera acquired their highly developed form of SICS directly
from saurian or colubrid ancestors. Rather, we think a more likely sce¬
nario is that from a colubrid ancestor arose protovipers who evolved a
more elaborate form of SICS that was retained by their subsequent de¬
scendants, including taxa that are today seen as primitive viperids as well
as taxa that represent advanced viperids.

Acknowledgements

We thank Mr. Dale Belcher, Curator of Amphibians and Reptiles at
the Rio Grande Zoo for permission to work on these animals during the
spring of 1994. Several members of the staff provided help: Ralph Jack-
son, Glenn Riordan and Paul Thompson. We also appreciate the interest
in this project expressed by employees of numerous zoos in the US and

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Bulletin of the Maryland Herpetological Society

Volume 35 Numbers

September 1999

abroad, as without their cooperation our growing database on the evo¬
lution and distribution of SICS in venomous snakes could never have
been built.

Literature Cited

Burghardt, G. M.

1970. Chemical perception in reptiles. Pp 241-308 in J. W.
Johnson, Jr., D. G. Moulton and A. Turk (eds.). Commu¬
nication by chemical signals. New York: Appleton-Cen-
tury-Crofts.

Burghardt, G. M. and P. J. Chmura.

1993. Strike-induce chemosensory searching by ingestively na¬
ive garter snakes ( Thamnophis sirtalis). Journal of Com¬
parative Psychology 107:116-120.

Chiszar, D., C. Andren, G. Nilson, B. O'Connell, J. S. Mestas, Jr., H. M.
Smith, and C. W. Radcliffe.

1982. Strike-induced chemosensory searching in Old World Vi¬
pers and New World pit vipers. Animal Learning and
Behavior 10:121-125.

Cooper, W. E., Jr.

1989. Strike-induced chemosensory searching occurs in lizards.
Tournal of Chemical Ecology 15:1311-1320.

Cooper, W. E., Jr.

1994. Chemical discrimination by tongue-flicking in lizards. A
review with hypotheses on its origin and its ecological
and phylogenetic relationships. Tournal of Chemical Ecol¬
ogy 20:439-487.

Cooper, W. E., Jr., S. G. McDowell, and J. Raffer.

1989. Strike-induced chemosensory searching in the colubrid
snakes Elapheg. guttata and Thamnophis sirtalis. Ethology
81:19-28.

Diller, L.

1990. A field observation on the feeding behavior of Crotalus
viridis lutosus. Tournal of Herpetology 24:95-97.

Bulletin of the Maryland Herpetological Society

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September 1 999

Dullemeijer, P.

1961. Some remarks on the feeding behavior of rattlesnakes.
Kon. Ned. Acad. Wetenschap.. Series C 64:383-396.

Estep, K., T. Poole, C. W. Radcliffe, B. O'Connell, and D. Chiszar.

1981. Distance traveled by mice ( Mus musculus) after enveno-
mation by prairie rattlesnakes (Crotalus viridis). Bulletin
of the Psvchonomic Society 18:108-110.

Golan, L., C. W. Radcliffe, T. Miller, B. O'Connell, and D. Chiszar.

1982. Trailing behavior in prairie rattlesnakes ( Crotalus viridis).
Toumal of Herpetology 16:287-293.

Halpern, M.

1992. Nasal chemical senses in reptiles: Structure and function.
Pp 423-523 in C. Gans and D. Crews (eds.). Biology of
the Reptilia, Vol. 18. New York: Academic Press.

Hayes, W. K. and G. Galusha.

1984. Effects of rattlesnake ( Crotalus viridis oreganus) enveno-
mation upon mobility of male wild and laboratory mice
(Mus musculus). Bulletin of the Maryland Herpetological
Society 20:135-144.

Kardong, K. V.

1986. Predatory strike behavior of the rattlesnake, Crotalus
viridis oreganus. Tournal of Comparative Psychology
100:304-314.

Liem, K. F., H. Marx, and G. B. Rabb.

1971. The viperid snake Azemiops: Its comparative cephalic
anatomy and phylogenetic position in relation to
viperinae and crotalinae. Fieldiana Zoology 59:65-126.

David Chiszar ; Jennifer Brown , Adam Chiszar and Hobart M. Smith

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Bulletin of the Maryland Herpetological Society

Volume 35 Numbers

September 1 999

David Chiszar, Department of Psychology, CB 345 , University of Colorado,
Boulder, CO 80309, Phone: (303) 492-4283, E-mail :
chiszar@clipr. Colorado. eduDepartment of Psychology, University of Colorado,
Boulder, CO 80309-0345 (DC, e-mail: chiszar@clipr.colorado.edu); Albuquer¬
que Biological Park, Albuquerque, NM 87105 and Department of Biology,
University of New Mexico, Albuquerque, NM 87131 (JB, e-mail:
jeliza@unm.edu); Centennial Middle School, Boulder, CO 80304 (AC); and
Department ofEPO Biology, University of Colorado, Boulder, CO 80309-0334
(HMS, e-mail: hsmith@spot.colorado.edu).

Received 3 April 1999

Accepted 26 April 1999

Bulletin of the Maryland Herpetological Society

page 91

Volume 35 Number 3

September 1999

page 92

Bulletin of the Maryland Herpetological Society

Volume 35 Number 3

September 1 999

News and Notes

Presented by MARS Preservation Fund, Inc.

SHOW

os save ra«*°^

We believe in education ,
the promotion of captive
breeding and the protection
of critical habitats.

M

Lecturi

a.m.

•es7.

Show/s,

11

4:30

Pm.

Pm.

wyii

eminars-

PR£.

a.m.

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LOCATION:

Maryland State Fairgrounds 4-H Building (Daily Show and Seminars)

Days Hotel Timonium (Host Hotel & Lectures Saturday Evening)

• Captive bom reptiles & amphibians for display and sale • Equipment, books & supplies
• Book signings each day • Educational exhibits • Door Prizes • Raffles • Silent Auction
• Display & photographs of Costa Rican rainforest area purchased by MARS
• Pre-show social gathering • “Reptiles & Rainforests" art collection
» Seminars throughout the show • “Critter Contact ’’ hands-on animal display

Professional Lecture Series Saturday evening will feature well-known Dr. Richard Funk ( reptile &
amphibian veterinarian), Alan Kardon (herpetologist, reptiles of Mexico), Frank Retes (herpetologist,
monitors) and another “ Fabulous Fotos” exhibit by Jim Merli (breeder and photographer)

Show proceeds are donated to The Center for Ecosystem Survival for the
purchase of rainforest. THE MID-ATLANTIC REPTILE SHOW, now in its
seventh year, has protected 2,528.5 acres of critical habitat to date.

Bring your aluminum cans to our recycling bin
and help us protect more rainforest!

ADMISSION: Weekend Pass (includes show both days and lectures) $13 Adults, One Day Pass (Sat. or Sun.) $7
Adults. Children 6 - 12 and Seniors over 65 - $6 (for one day or weekend pass), Children under 5 are free.

FOR ADDITIONAL INFORMATION:

Call the MARS Hotline at 410-580-0250, visit our web site at http://www.reptileinfo.com
or e-mail us at mars@reptileinfo.com
Only registered vendors may display or sell on the premises.

Please leave your pet animals home! They will not be admitted to the show. Thank you.

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 3

September 1999

News and Notes

International Amphibian Day

The first event to support captive breeding, conservation and
ethical commerce of amphibians
with the participation of noted breeders, scientists and hobbyists.

October 7th to the 10th

Parkville Armory, Days Hotel [Timonium], National Aquarium
in Baltimore and other locations in Maryland

• Show and Sale (Oct. 9-10) • Workshops and lectures •
• Field survey workshop • Benefit auction •

• Visit to the National Aquarium in Baltimore •

All proceeds benefit the Declining Amphibian Population
Task Force and the Center for Ecosystem Survival

International Amphibian Day

241 E. Colonial Hwy. • Hamilton, Virginia 20158
Spaces are limited for some activities, so please call for more information, inscriptions:

(609) 641-4944 or visit our site: http://www.medfasoft.net/olson/iad
Presented by MARS Preservation Fund, Inc.

Reptile and
Amphibian Rescue
410-580-0250

We will try to take as many unwanted pet reptiles
and amphibians as we can.

Leave a message with your name and number to
give up an animal for adoption;
or to volunteer to help with our efforts.

WE NEED:

1 Cages, Lights, Other Equipment & Food
• Drivers to Transport Animals
• Foster Homes • Adoptive Homes

page 94

Bulletin of the Maryland Herpetological Society

Volume 35 Numbers

September 1 999

News and Notes

Bulletin of the Maryland Herpetological Society

page 95

Society Publication

Back issues of the Bulletin of the Maryland Herpetological Society,
where available, may be obtained by writing the Executive Editor. A list
of available issues will be sent upon request. Individual numbers in stock
are $5.00 each, unless otherwise noted.

The Society also publishes a Newsletter on a somewhat irregular
basis. These are distributed to the membership free of charge. Also pub¬
lished are Maryland Herpetofauna Leaflets and these are available at
$.25/page.

Information for Authors

All correspondence should be addressed to the Executive Editor.
Manuscripts being submitted for publication should be typewritten
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Major papers are those over five pages (double spaced, elite type)
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The Maryland Herpetological Society
Department of Herpetology
Natural History Society of Maryland, Inc.

2643 North Charles Street
Baltimore , Maryland 21218

page 96

Bulletin of the Maryland Herpetological Society

US ISSN: 0025-4231

BULLETIN Or THE

flf-tarylanb

f)Ecpctological

Oociety

DEPARTMENT OF HERPETOLOGY
THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.

MDHS . A Founder Member of the Eastern

Seaboard Herpetological League

31 December 1999

Volume 35 Number 4

BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY

Volume 35 Number 4

December 1999

CONTENTS

Amphibia and Reptilia of the high grasslands of the Sierra de
Comechingones, Cordoba, Argentina.

L. J. Avila, M. Morando and J. W. Priotto . . . 97

Removal of an Evolutionarily-Reduced Color Signal, and Resotration of
the Signal to the Ancestral State, Influence Male-Male Interactions in the
Striped Plateau Lizards, Sciloporus Virgatus

Allison J. Abell . . . . . 115

The Challenge of the Plateau and Prairie Lizards (Sceloporus undulatus)
of New Mexico

Hobart M. Smith, David Chiszar and Frank van

Breukelen . . . . . . . 143

The Known Distribution in 1998 of the Members of the undulatus
Group of the Lizard Genus Sceloporus in Chihuahua, Mexico

Julio A. Lemos-Espinal, David Chiszar, Hobart M.

Smith and Clint Henke . . . . . . 152

BULLETIN OF THE

Volume 35 Number 4

December 1999

The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.

Tim Hoen

Herbert S. Harris, Jr.

President
Executive Editor

Steering Committee

Frank B. Groves

Jerry D. Hardy, Jr.

Herbert S. Harris, Jr. Tim Hoen

Library of Congress Catalog Card Number: 76-93458

Membership Rates

Membership in the Maryland Herpetological Society is $20.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $30.00 per year. Make all checks payable to the Natural History
Society of Maryland, Inc.

Meetings

The third Wednesday of each month, 7:30 p.m. at the Baltimore Zoo’s
Reptile House (except August and September due to The Mid-Atlantic
Reptile Show). The Department of Herpetology meets informally on all
other Wednesday evenings at the NHSM at 8:00 p.m.

Volume 35 Number 4

December 1999

Amphibia and Reptilia of the high grasslands of the
Sierra de Comechingones, Cordoba, Argentina.

L. f. Avila , M. Morando and }. W. Priotto
Abstract

Amphibian and reptile fauna of high grassland of Sierra de
Comechingones Mountains, the southernmost part of Sierra de Cordoba
Mountains, in central Argentina is studied. Distributional data and con¬
servation issues about this fauna is provided.

Introduction

The present biodiversity crisis, with its quick increase of species ex¬
tinction rate and accelerated destruction of natural ecosystems, needs
immediate biological inventories in such areas as contain an important
biodiversity of little-known organisms. These studies are needed to give
information, whether for systematic or biogeographic studies or for bio-
ecological projects tending to establish proper conservationist measures
or sustentable use of natural resources.

The central area of Argentina, more particularly the areas within the
province-lines of San Luis and La Pampa provinces, as well as the south
of Cordoba province, has a wide variety of environments with a scarcely
known diversity of amphibians and reptiles. Studies of this fauna are usu¬
ally limited to ecological aspects or else are restricted to small geographic
areas. In the mountain and hillfoot ("serrana and periserrana") areas in
southern Cordoba, the more recent herpetological list based on material
deposited in collections is the one made by Martori & Aun (1994), and it is
the only one that presents any information on the herpetofauna on the
hillfoots of the Sierra de Comechingones; particular data may be found in
the descriptions of Liolaemus saxatilis (Avila cl al 1992) and Cnemidophorus
serranus (Cei & Martori, 1991), as well as in specific geographic or ecologi¬
cal records (Avila 1994, Avila & Priotto 1995a, b, c, Avila 1997, Avila &
Morando 1998).

The highest segment of the Sierra Grande of Cordoba, occupied by
high grasslands, called "pastizales de altura," has remained out of reach
for herpetologic studies, with the single exception of Pampa de Achala, a

Bulletin of the Maryland Herpetological Society

page 97

Volume 35 Number 4

December 1999

high mountain environment placed about 100 km. north of Sierra Grande,
and considered for many years a "faunistic island" (Ringuelet 1961, Di
Tada et al 1980 , Di Tada et al 1984, Polop 1989, 1991).

The object of the present paper is to record the herpetofauna found
in the high grasslands of the central area of the Sierra de Comechingones,
and to contribute with some observations on the biology of the species
concerned.

Materials and methods

The survey tasks were performed between 1991 and 1996, in the
working stations known as "Cerro de Oro" (1) and "Puesto Gonzalez"
(2), situated 2,000 m above sea level on the Sierra de Comechingones, Rio
Cuarto Department, Cordoba Province, Argentina. The survey was made
on these sites, on the area within 2-3 km around, and on the ingress and
egress paths. The trips, each one 2 to 5 days in length, were performed
during April and June (Fall) 1993, February and March (late Summer)
1994, January and February (Summer) 1995 and January 1996. During these
trips, both collecting and observations were performed. Six further trips
were made during the Fall and Winter from 1993 to 1994, in which only
observations were made. In sundry months of the years 1991 to 1996, 8
trips one to two days in length were made to other areas of the Sierra de
Comechingones, affording some sporadic survey of the following tracts:
1) Villa Larca (San Luis) - Quebrada del Tala - Alpa Corral (Cordoba), 2)
Villa del Carmen (San Luis) - El Chacay (Cordoba), 3) La Cruz - Quebrada
del Rayo - La Cruz (Cordoba), 4) La Cruz (Cordoba) - Cerro Aspero -
Carpinteria (San Luis) and 5) San Javier (Cordoba) - Champaqui - Villa
Alpina (Cordoba). Each trip was undertaken by a group of two or three
persons, not always the same, who made captures and observations total¬
ing about 350 man-hours of fieldwork. This afforded data on the presence
of species, hours of activity, microambients which they take up and gen¬
eral biological information. Representative series of all the species found
were collected (except for Mabuya dorsivittata) and deposited in the Her-
petological Collection of the Vertebrate Zoology Area (Orientacion
Zoologia de Vertebrados), at the Departamento de Ciencias Naturales,
Facultad de Ciencias Exactas, Fisico-Quimicas y Naturales, LJniversidad
Nacional de Rio Cuarto, Rio Cuarto (Cordoba) (ZV-UNRC) and also in
the Herpetological Collection of the Instituto de Herpetologia, Fundacion

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Miguel Lillo, Tucuman (FML).

Description of the research area:

Sierra de Comechingones is the denomination given to the moun¬
tain chain south of the Cerro (Peak) Champaqui (2790 m.a.s.l.) (32°00,S,
64,58'W), in Calamuchita Department, and which runs approximately up
to the locality of Achiras (Cerro La Buena Yerba, 1116 m.a.s.l.) (33°10,S, 64-
59' W) in Rio Cuarto Department (Map 1). Its north-south length is about
130 km and its width varies, being about 25-30 km at the research area.
While the oriental slopes are relatively gentle, the occidental ones are
abrupt and cliff-like.

The relief of the research area, restricted to high grasslands, is that
of a high mountain plain, or "pampa de altura", remarkable for the mo¬
saic of large rock outcrops and a soil of variable thickness which covers
horizontal and depressed areas. Many streams and temporary or perma¬
nent watercourses are found all over the area, and these may swell to
great spate during rainy spells.

Biogeographically, this area is comprised within the hill-lands
steppes (estepas serranas) of the Hilly Chaco District (Distrito Chaquefio
Serrano), Chaco Province (Provincia Chaquefia), Chaco Domain (Dominio
Chaquefio) (Cabrera & Willink 1973). The physiognomy of the area is de¬
scribed by Bianco et al. (1987) as a Gramineae Steppe, "estepa graminosa"
with predominance of "pajas" and "pastes punas", the dominant species
being Festuca hieronymi, together with other species of the genera Stipa
and Aristida. In wet spots, the so-called "lawns"("cespedes") appear, domi¬
nating species being "sheep's weed" ("yerba de la oveja"), Alchemilla
pinnata, Azorella biloba , Eryngium agavifolium , Stipa flexibarbata, and stretches
of Poa stuckerti and Blechnum penna-marina. The rock outcrops are bare on
parts open to wind or water, but as a rule they are densely colonized by
different species of lichens or covered by Selaginella peruviana. In fissures,
rock cracks and incipient soils, as well as on the creeks, small valleys and
sheltered places, generally on slopes with a southern exposition, grow
several species of ferns of the genera Folystichum, Ctenopteris,
Hymenophyllum and Lycopodium , and also "tabaquillo," Polylepis australis ,
more frequent in the Occidental slopes (among those having a southern
exposition). Very remarkable are the "moss mattresses" on very humid

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Map I: Study area : Squares: working stations , black dots: collection sites ,
white area: land below 1500 m, more dense dotted: land above 2000 m, black
lines: creeks or rivers , Villa Larca: nearest town to study site . South America
map: black rectangle is the approximate position of Sierra de Comechingones .

32°20'

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and very sheltered spots, where sometimes different species of amphib¬
ians and reptiles are found. As a rule, vegetation is considerably reduced
on spots accessible to cattle, and strong erosive processes are observed as
a consequence of overpasturing, of grass burning and of the passing of
bovine and equine cattle, which are continued by hydric and/or aeolic
activity.

The climate of the research area is a cold-temperate mountain cli¬
mate, with low temperatures in Winter, wide temperature range and strong
winds. Maximal absolute temperatures may attain 30° C and minimal ab¬
solute may be as low as -15° C. Precipitations begin in Spring and are
more abundant in Summer, and almost nonexistent in Winter, when there
are only sporadic falls of snow. Mean annual precipitation is about 750
mm; mean relative humidity about 75 %; frosts have been recorded on 9-
10 months out of 12. See table I for some observations of amphibians in
these areas.

Table I: Some ecological characters observed in the amphibian fauna of the
high grasslands of Sierra de Comenchingones.

The four types of environment predominating in the study area are indi¬
cated. P = present; r = amphibians in reproductive activity. Time of activity for
each species: D = diurnal , C = crepuscular, N = nocturnal. *Only juveniles.

ACTIVITY

ENVIRONMENTS

SPECIES

Rock

Outcrop

Scattered

Rocky

stretches

Grassland

Matresses

Periaquatic

area

0. achalensis

C

P

Pr

R kriegi

C

P

Pr

H. pulchella

DCN

Pr

B. achalensis

C

P

Pr

M. s. steizneri

D

P

Pr

P. achalensis

D

P

P*

M. dorsivittata

D

P

L vanzolini

D

P

B.

ammodytoides

D

P

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Results

Results of the survey allow to confirm the presence of 4 species of
Reptilia (one Polychrotidae, one Scincidae, one Viperidae, one Colubridae)
and 5 species of Amphibia (one Hylidae, two Leptodactylidae and two
Bufonidae), as detailed in the following commented systematic list:

Class Amphibia
Order Anura

Family Leptodactylidae Werner 1896

Odontophrynus achalensis Di Tada et al. 1985.

Reference material:ZV-UNRC 1691 to 1695, 2377, 2988 to 2993, 3196,

3516 to 3522.

Presence detected through song and by capture of specimens in sev¬
eral instances. This is the most frequent amphibian species after H. pulchella
cordobae and B. achalensis. Its large tadpoles are found at the bed of the
shallower streams, a difference with those of H. pulchella cordobae , which
are also found at the bed, but in deeper pools. The tadpoles O. achalensis
also may be found in small temporary courses. Tadpoles were observed
along the whole year, but in Winter they seek shelter under stones, or stay
motionless in the slime of the bed of permanent streams.

Pleurodema kriegi (Muller 1826).

Reference material: ZV-UNRC 2981, ZV-UNRC 3514-3515.

Although its song was heard several times, specimens could be cap¬
tured only in two instances. In one case, two males were taken while per¬
forming the mating song from a small artificial well, in which they floated
with the help of their swollen gular sacks. The manner of egg-laying is
not known with precision (Di Tada et al. 1980), but we agree with what
these authors state, namely, that it is a mass laying on flooded areas like
the "mallines", since larvae in the earlier stages of development were col¬
lected at the confluence of a //mallin,/ with a stream. In this case, many
eggs were also observed; they formed small groups of 10-20 each and
were surrounded by gelatinous filaments which adhered to the vegeta¬
tion around the water. It is not possible to describe the egg-mass ad¬
equately, as the place was much altered by the trampling of bovine cattle;
however, it may be stated that no evidence was found of a foam-nest, as

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supposed by Duellman & Veloso (1977).

Family Bufonidae Gray 1825
Bufo achalensis Cei 1972.

Reference material: ZV-UNRC 3508 to 3513, 1696 to 1699.

This is the most abundant species after H. pulchella cordobae. In Spring-
Summer, it shows an intense nocturnal activity and during the day it is
found in large numbers under stones of small and medium size, also in
cracks under the great rock outcrops and of abandoned humanmade con¬
structions. Its activity increases after the strong Summer precipitation, and
extends even to cool periods with ambient temperatures of 10°-15° C.

Melanophryniscus cfstelzneri stelzneri (Weyembergh 1875)

Reference material: ZV-UNRC 3194, 3523 to 3538.

This species was collected only in two opportunities, although its
song was recorded in several occasions during the day. A single adult
specimen was found together with one of B. achalensis under a small stone
at a considerable distance from any permanent source of water. On an¬
other occasion, after a night of heavy rain, many individuals were ob¬
served during the day in reproductive activity. Many couples (between
10 and 20 per pool) were found in amplexus in several temporary pools
not more than 10 cm deep; most of the latter had formed on small rocky
ledges like miniature mesas within the "lawn" of Alchemilla pinnata. Sev¬
eral individuals were collected, together with spawn, which produced
larvae inside the same container after 24 hs. In this case, more than 80
individuals were observed and the song of a large number was recorded
along a transect more than 1 km long. The species appears to be abun¬
dant, but its activity is rarely observed.

This is the second species of amphibian found in sympatry with
amphibian species endemic to Pampa de Achala: B. achalensis , P. kriegi
and 0. achalensis. Gallardo (1966) recorded this species for Puesto Perez,
Pampa de Achala, a record repeated by Di Tada et al (1976) but not men¬
tioned in subsequent papers (Di Tada et al 1980, 1996). There is additional
material from "Pampa de Achala" in the herpetological collection of the
former CENAI, now deposited in the Museo Argentine de Ciencias Natu-
rales (CENAI 3310, 3311, 10914, 10917); this material was collected after

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the record by Gallardo (1966).

The assignation of these specimens to subspecies M. stelzneri stelzneri
is provisional, since all the collected specimens have chromatic peculiari¬
ties which place them apart from the individuals of this subspecies known
up to date. A preliminary exomorphologic analysis does not show enough
differences to consider the existence of diagnostic characters at this level.
M. stelzneri stelzneri is found very frequently at lower altitudes on the
Sierra (in the "romerillar" and the mountain woods) and also in the high
grasslands at the southern end of Comechingones. Its dorsal coloring is
dark or even black, with yellow dots placed towards the sides and rarely
coalescent; there are small yellow points on the extremities and the ven¬
tral coloring is black with red dots on the belly and the femora, and with
red feet and hands. In the case of M. cf stelzneri stelzneri , the black dorsal
coloring is reduced to the middle of the body, yellow coloring predomi¬
nating towards the sides and extending to the middle part of the head
and to the sides of this. The extremities are also yellow with black spots.
In ventral view, the black coloring is reduced to the gular area, and the
red extends over the whole underside, body and extremities.

At a lower altitude, close to the village of Alpa Corral, three speci¬
mens with chromatic characters very similar to those of the high grass¬
land steppe were found, (ZV-UNRC 3832 to 3834). An important point we
must stress is that individuals presenting as well coloring patterns simi¬
lar to those of specimens from high grasslands were collected on the way
to Intihuasi ("c amino a Intihuasi"), Carolina, Coronel Pringles Depart¬
ment, in the middle of the Sierra de San Luis. These specimens are depos¬
ited at the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"
(MACN 35404 to 35420).

More to the south, in an area at a lower altitude situated about 10
Km west of Villa El Chacay, on the peak of the mountain range and on
the high grassland immediately adjacent to it, the collected material is
similar in coloring to the description of M. stelzneri stelzneri (ZV-UNRC
3595 to 3602). At a short distance from this locality, a diurnal mass migra¬
tion of adults was once observed, a fact not recorded in the literature on
this species.

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Family Hylidae Gray 1825 (1815)

Hyla pulchella cordobae Barrio 1965.

Reference Material: ZV-UNRC 2978 to 2980, 2450 to 2452, 2374 and 2375,
2376, 2037 to 2039, 3319-3320.

This is the species more widespread in the whole area; it was re¬
corded in all the trips and it shows a relatively intense diurnal and noc¬
turnal activity. Its tadpoles, of considerable size, are very frequent in the
deep pools of the streams during the whole year. Adult activity was regis¬
tered, also along the whole year, except in July (mid-winter). In one case,
in May (Fall), three adults were observed moving among periaquatic veg¬
etation, with temperature under 0°C, from which it may be inferred that
low temperatures do not affect wholly the activity of this species. Its pres¬
ence was not recorded for the season of the great winter snowfalls, a time
where it seeks refuge among the cracks of the stones around the streams
or among aquatic vegetation and the streambed stones.

Class Reptilia
Order Squamata
Suborder Lacertilia
Family Polichrotydae

Pristidadylus achalensis (Gallardo, 1964).

Reference material: ZV-UNRC 2414 to 2416, 2976, 2977.

The species was observed in several opportunities, but reference
specimens were not always taken, since nothing indicates a high popula¬
tion density. It is a saxicolous lizard, and on the high grassland steppe the
availability of rocky stretches with cracks and large rocky blocks for shel¬
ter is not homogeneous.

Until a little time ago, this species was considered endemic to Pampa
de Achala, but some records outside the area were given by Cabrera and
Bee de Speroni (1984) based on material from the Museo Argentino de
Ciencias Naturales "Bernardino Rivadavia": one specimen collected at
Mina Clavero, San Alberto Department, and two paratypes (MACN 7877
and 7878) from La Paz, San Javier Department. These specimens corre¬
spond, almost certainly, to captures made at the level of the villages men¬
tioned, but on the Sierra Grande, and not near the said villages. Tiranti

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(com. pers.) found this species at the level of Merlo, Junin Department
San Luis Province, on the western skirts of the Sierra de Comechingones.
The most southern record for this species is the one by Avila (1994). Search¬
ing 30 km to the South of this place, at the level of Villa El Chacay, did not
yield any specimen of this species, and given the physiography of the
area it appears quite dubious that it may be found there; however, there
are some mentions of green lizards ("lagartos verdes"), some 10 km to the
South of the Cerro de Oro (1), at the level of San Bartolome.

In the analyzed area, individuals of this species have always been
found performing heliothermic heating on large rock outcrops, where they
have hiding cracks at their disposal. Only on two opportunities have ju¬
veniles been observed in grassland environments, in which burrows ex¬
cavated into the soil are used as shelter. Although no quantitative records
have been made of population density, their abundance appears to be
much lower than that observed at Pampa de Achala.

Family Scincidae
Mabuya dorsivittata Cope, 1862.

A single individual, which could not be captured, was observed.

Suborder Serpentes

Family Colubridae

Liophis vanzolini Dixon 1985.

Reference material: FML 02738.

A single specimen was taken 2 km north of the "puesto Gonzalez"
(2). According to the local settlers, and to observations of some colleagues
(Cantero com. pers.), this species is common in "mallm" areas and among
the vegetation along the water courses, but in all the campaigns a single
specimen was observed and taken among the periaquatic vegetation.

Family Crotalidae

Bothrops ammodytoides Leybold 1873.

Reference material: ZV-UNRC 1498.

A single specimen was taken on a rocky stretch surrounded by high
grassland. Di Tada et al (1980) consider that this species is "marginal" for

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the formation called "pampa de altura", since, as they point out, the spe¬
cies is found in gorges and peripherical grassland around Pampa de
Achala; however, the reference specimen was found in a well-character¬
ized high grassland steppe ("pampa de altura") area.

Comments on the sympatry among "achalena" and plain species.

Sympatry between altitude species and others which are not typical
of the analyzed area, such as M. dorsivittata and Liophis vanzolini, and most
specially the population of Melanophryniscus which differs considerably
in colouring pattern from the typical specimens of the species M. stelzneri
stelzneri, present an interesting point. More detailed studies may possibly
confirm the presence of Leptodactylus ocellatus , a species which was taken,
but not collected, at the same place where the presence of Odontophrynus
achalensis was recorded. This place is the Quebrada del Tala, a gorge
separating two mesa-like formations at the level of Alpa Corral (in the
west of Cordoba Province), and it shows alteration from pine plantations,
because of which it cannot be said to be a characteristic high grassland
site. Both L. ocellatus and Bufo arenarum were found at the Quebrada del
Rio Seco, one of the access paths to the sampling sites coming by the west¬
ern skirts, up to some 1,000 m of altitude. Another Leptodactylid species
observed on several opportunities in areas near to the high grassland
steppe environments, Leptodactylus gracilis , was not observed in sympa¬
try with the species from Pampa de Achala, but the possibility of its oc¬
currence cannot be discarded, since it was found in environments quite
similar to high grasslands in gorges up to 1,500 m of altitude.

Considerations on the conservation problems of the herpetofauna
in the Sierra de Comechingones.

The populations of Amphibia are in a frank decline in many parts of
the world, and in some of these they have reached the extinction point; in
many cases, this decline is related to obvious modification or destruction
of habitats, but in other cases, the causes are still little known (Wake 1991).
Sierra de Comechingones has seen human activity since many years ago,
with agriculture, cattle-rearing and mining. Some 40 years ago, human
presence was greater than nowadays, with many "puestos" where sub¬
sistence agriculture was undertaken and low-scale cattle production cen¬
tered mainly on sheep and goats. A quantification of the effects that this

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presence may have had on the native animal populations is difficult to
make, since no ancient recordings are available, but we can submit a few
considerations about the present and future situations. Cattle exploita¬
tion shows a much larger number of bovines than in the past, and in some
areas great inversions are being made to fence fields with a view to in¬
crease the number of heads of cattle. This increase is due to the fact that
the present economic situation has caused many of the small producers
to disappear and the large properties must try to maximize their produc¬
tion to obtain an adequate gain. The effect of bovine cattle on hillside
areas with delicate soil is studied in several regions of the world and it is
known to cause important alterations, among which erosion may be one
of the more evidents and dangerous ones.

In the studied area, it was observed that the continued trampling of
bovine and equine cattle produces tracks on the slopes and sloping flats,
and with the passing of time these, with the action of rain, thaw and winds,
turn into large ravines. The material carried away by rain increases tur¬
bidity of the water courses where many amphibians are reared, a situa¬
tion which may extend over several days, and the effects of which on the
development of larvae is not quite clear. However, it is known that tur¬
bidity in water produces the disappearance of many species of fishes; there¬
fore, it is possible that the same may happen with tadpoles. On the other
hand, cattle usually comes to drink at places which are also easily acces¬
sible for some species of Amphibians at their reproduction time. This
causes death of both adults and tadpoles by trampling, destruction of
spawn and also of the vegetation and even of the microambients used as
reproduction sites. On several occasions, specimens of Bufo achalensis and
Odontophrynus achalensis were observed trampled to death in pools and
stream-margins.

In the past few years, the two provinces which share the Sierra de
Comechingones, supported by several Government entities, have been
making efforts to enlarge the goat rearing, which is an additional menace
for the conservation of this fauna. Indeed, this is quite alarming, as the
negative effects of goat pasturing on natural ecosystems are well known
and proven the whole world round, and in particular on relatively fragile
systems, such as islands and also semidesertic and mountain areas.

The reproduction sites of Amphibia in the streams also are threat-

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ened by mining, which usually employs stream water at some point of
the process of extraction and returns it directly to the course after use,
heavily charged with contaminating sediments, thus causing death of
aquatic and periaquatic plants of the invertebrate fauna and of the tad¬
poles. Also, access to heights is easier along water-courses; therefore, the
margins of the latter are chosen to build roads and to deposit residue
from the exploitation. This, on addition, produces an important destruc¬
tion by hydric erosion, particularly in the gorges of the western areas,
which run along more abrupt slopes. Fortunately, in the few last years no
increase of mining activities has been observed on the highest areas of the
high grasslands where the herpetozoa populations are more numerous;
for this reason, mining is not considered an immediate danger for these
populations. Most of the high altitude mines, in fact, have been aban¬
doned, and these are the ones which used to cause appreciable damage to
many altitude streams.

In several regions, a forestation project with exotic conifers has been
implemented, together with important plans for promotion and expan¬
sion. As it is well known, conifers produce great unbalancing of the soil
pH, which turns acid, and afterwards by rainwater washing the alter¬
ation is carried to the streams, which usually lose their natural fauna. The
sole amphibian species found in streams around these artificial woods is
Hyla pulchella cordobae, but in the streams within the woods no species of
amphibian is found.

Another additional danger is the introduction of the trout
(Oncorynchus sp.), an exotic species which usually eliminates from streams
all the autochthonous amphibians and fishes. In several streams in the
basins of the rivers Calamuchita, Chocancharagua and the closed basins
between the last and the river Fopopis, trout were released a few years
ago and many native species eliminated. It is possible that the upper ba¬
sins of the local streams, taken up by high grassland, may be safe from
their presence because of the small quantity of water which they carry
during most of the year and of the abruptness of the streambed slope, but
this cannot be predicted at the present moment. However, in mountain
areas of San Juan Province (El Fachon), it was observed that specimens of
trout manage to enter streams with a very low water-level and with abrupt
sloping of the streambed.

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Discussion

The studied area shelters an herpetofauna of little variety, but very
interesting by the presence of species considered endemic to Pampa de
Achala until a little ago. The finding in this area of these species of Am¬
phibia and Reptilia, together with several species of birds, mammals
(Priotto et al, 1996) and invertebrates, also known previously from Pampa
de Achala alone, allows the reconsideration of the character of "faunistic
island" frequently assigned to the last, and sustained only by the lack of
sampling or observing in adjacent areas.

It is important to try to obtain measures for the protection of the
species of Amphibia and Reptilia in high grassland areas. The still incom¬
plete knowledge of their biological characters, their importance from the
biogeographic and evolutive point of view, their distribution, restricted
to central mountain areas of Argentina and the fragility of the environ¬
ments in which they are found, all these make the said species deserve to
be taken into account in future conservation politics. In a recent paper,
Avila and Acosta (1996) consider that at least one of the saurian species,
Pristidactylus achalensis, and four of the Amphibian species, Bufo achalensis,
Odontophrynus achalensis , Pleurodema kriegi and Melanophryniscus stelzneri
stelzneri, must be considered of maximal priority for conservation, and
that Hyla pulchella cordobae should be considered with special attention. It
is probable that Liophis vanzolini may be inside the same category that the
first species, in view of its limited distribution, but up to now no study
has been made about this species of serpent. The chromatic particularity
of the population of Melanophryniscus may perhaps reflect a different
evolutive history from the rest of the mountain populations, such as may
justify its nomination as a new species, which would enhance the impor¬
tance of the area for conservationist measures.

Avery important protection measure would be to exclude from this
area the projects of mining and farm exploiting which are encouraged
and/ or which may be initiated in future, and that protected areas, such
as those already established more to the North, at Quebrada del Condorito
and Pampa de Achala, are created. Due to the biogeographic and eco¬
logical importance of the area, and to the fact that this is the capturing
and regulating basin of the waters of a vast area in the south of Cordoba
province, these measures and other conservationist policies should be

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implemented in a brief space of time to aim at a sustentable use of our
biotical wealth.

Literature cited

Avila, L.J.,

1994. Geographic Distribution: Pristidactylus achalensis.
Herpetol. Rev. 25(4): 165166.

Avila, L.J.,

1997. Geographic distribution: Pseudotomodon trigonatus.
Herpetol. Rev. 28(2): 98.

Avila, L.J., J.M. Cei, R. A. Martori y J.C. Acosta,

1992. A new species of Liolaemus of the bibroni group from gra¬
nitic ravines of Achiras, Sierra de Comechingones,
Cordoba, Argentina (Reptilia: Tropiduridae). Boll. Mus.
Reg. Cs. Nat. Turin 1 0(1): 101-111.

Avila, L.J. y J.W. Priotto,

1995. Geographic Distribution: Odontophrynus achalensis.
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Avila, L.J. y J.W. Priotto,

1995. Geographic Distribution: Bufo achalensis. Herpetol. Rev.
26(2):104. 1995.

Avila, L.J. y J.W. Priotto,

1995. Geographic Distribution: Pleurodema kriegi. Herpetol.
Rev.: 26(2): 106. 1995.

Avila, L.J. y J.C. Acosta

1996. Evaluacion del estado de conservacion de la fauna de
saurios, anfisbenidos y anfibios de la provincia de
Cordoba (Argentina). FACENA 12: 77-92.

Avila, L.J. y M. Morando

1998. Natural History Notes: Bothrops ammodytoides (Yararanata
Patagonian lancehead). Prey. Herpetol. Rev. 29(3): 169.

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December 1999

Barrio, A.

1977. Aportes para la elucidation del "status" taxonomico de
Pleurodema bibroni tschudi y Pleurodema kriegi (Miiller)
(Amphibia, Anura, Leptodactylidae). Physis, Sec. C.
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1987. Formaciones vegetales del suroeste de la provincia de
Cordoba (Republica Argentina). Rev. U.N.R.C. 7(1)5-66.

Cabrera, M.R. y N.T. Bee de Speroni,

1984. Composition y distribution de la lacertofauna de la
Provincia de Cordoba, Argentina. 11. Amphisbaenidae,
Amguidae e Iguanidae. Hist. Nat, 6(1): 112.

Cabrera, AX. y A. Willink,

1973. Biogeografia de America Latina. Washington D.C. 177 pp.
Cei, J.M., 1972. Segregation coriologica y procesos de
especiacion por aislamiento en anfibios de la Pampa de
Achala, Cordoba. Acta. Zool. LilL 29:233-244.

Cei, J.M.

1980. Amphibians of Argentina. Mon. Zool. ItaL Mon. 2.
Florencia. 609 pdgs.

Cei, J.M. y R.A. Martori

1991. A new species of Cnemidophorus of the lacertoides species
group from the eastern sierras de Cordoba, Central Ar¬
gentina (Lacertilia, Teiidae). BoL Mus. Reg. Sci. Nat.
Torino 9(1): 233-244.

Di Tada, LE., M.M. Salusso y R.A. Martori

1976. Lista de los batracios de Cordoba (con notas sobre su
historia natural). BoL Acad. Nac. Cs. Cba. 51(3-4): 325-
362.

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Di Tada, I.E., R. Martori, A.C. de Ocana y M.J.Barla

1980. Herpetofauna endemica de la Pampa de Achala
(Cordoba, Argentina). Ac. I Reu. Iberoam. Zool. Vert. La
Rabida: 493-512. Di Tada, L, M.J. Barla, R.A. Martori y
J.M. Cei

1984. Odontophrynus achalensis. Una nueva especie de anfibio
de la Pampa de Achala (Cordoba, Argentina). Hist. Nat.
4(17): 149-155. Giambelluca, L.A. 1991. Nueva cita de Bufo
achalensis Cei, 1972. Bol. Asoc. Herp. Arg. 7(1): 21-22.

Polop, J.J.

1989. Distribution and ecological observation of wild rodents
in Pampa de Achala, Cordoba, Argentina. Studies on
Neotropical Fauna and Environment 24(2): 53-59. Polop,

J.J.

1991. Distribucion de cricetidos en las Sierras de Achala
(Provincia de Cordoba, Rep. Arg.). Rev. U.N.R.C. 11(2):
115-121.

Priotto, J., M. Morando y L.J. Avila

1996. Nuevas citas de roedores de los pastizales de altura de la
Sierra de Comechingones. FACENA 12:135-138.

Ringuelet, R.A.

1961. Rasgos fundamentales de la zoogeografia de la Argen¬
tina. Physis 26(65): 151-170.

Wake, D.B. (chairman)

1991 . Declining amphibian populations - a global phenomenon?
Findings and recommendations. Alytes 9(2): 33-42.

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(LJA and MM): Centro Regional de Investigaciones Cientificas y Transferencia
Tecnologica La Rioja - Consejo Nacional de Investigaciones Cientificas y
Tocnicas (CRILAR CONICET). Mendoza y Entre Rios s/n. 5301 Anillaco, La
Rioja , Argentina. E-mail: lavila/mmorando@crilar.com.ar. (fWP): CONICET -
Departamento de Ciencias Naturales. Universidad Nacional de Rio Cuarto.
Agenda Postal 3 (5800). Rio Cuarto , Cordoba, Argentina.

E. mail: jpriotto@exa.unrc.edu. or.

Received 19 May 1999

Accepted 16 July 1999

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Removal of an Evolutionarily-Reduced Color
Signal, and Restoration of the Signal to
the Ancestral State, Influence Male-Male
Interactions in the Striped Plateu Lizard,
Sceloporus virgatus

Allison J. Abell

Department of Life Sciences , Indiana State University , Terre Haute , IN 47809
Address present: Department of Biological Sciences, University of Texas at
Brownsville and Texas Southmost College , Brownsville , TX 78520
aabell@aya.yale.edu

Abstract

Male Sceloporus lizards vary tremendously in the intensity and cov¬
erage of blue belly and throat coloration. In the striped plateau lizard, S.
virgatus , the amount and intensity of blue coloration have been greatly
reduced during evolutionary history to only two small, pale throat patches
and, in some individuals, a few pale blue belly scales. I examined the
influence of male coloration on male-male interactions and female choice
in S. virgatus . Using paint to manipulate male color, I enhanced the amount
and brightness of blue throat and belly coloration to restore the evolu-
tionarily-reduced coloration to the ancestral state. In another experiment,
I covered the naturally-occurring blue throat coloration. The presence or
absence of blue coloration had no discernible effect on female choice, but
I found an influence of coloration on male-male interactions. Resident
males tended to win contests against intruders with restored levels of blue
belly and throat coloration only when residents were larger than the in¬
truders, suggesting a possible advantage of the restored color for larger
intruders but not for smaller intruders. In the presence of a female, males
with natural levels of blue coloration tended to exhibit social dominance
over males lacking coloration and to lose less weight than males lacking
normal levels of throat coloration. In S. virgatus the vestigial expression of
the suspected sexual signal coexists with no apparent female response
but a weak male response to the coloration.

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Introduction

Darwin (1871) proposed two primary mechanisms by which sexual
selection can cause the elaboration of display traits in males: male-male
contests for access to females and female choice of mates. Although the
mechanism of female choice was not widely accepted at first, current theo¬
retical and empirical research in sexual selection strongly emphasizes the
intersexual mode over the intrasexual mode. Many models for the evolu¬
tion of sexually dimorphic traits are based on female response to male
traits (reviews in Kirkpatrick and Ryan, 1991; Andersson, 1994; Muller,
1994; Holland and Rice, 1998). Recently, particular attention has focused
on the sensory response of females to male signals (Endler and Basolo,
1998; Ryan, 1998). Sexual selection models based on male response to the
traits of other males are far less common (review in Muller, 1994), but
male traits under sexual selection can evolve simultaneously as signals
for attracting mates and repelling rival males by signalling status (Morris
and Ryan, 1996). Studies of within-genus or within-species variation in
the coevolution of a male display signal, the female response to the sig¬
nal, and the male response to the signal are important for evaluating mod¬
els of secondary sexual character evolution. A few authors have exam¬
ined the influence of male display signals on both male and female re¬
ceivers of the signal, using closely related species (or different popula¬
tions of the same species) exhibiting variation in the male trait (McKinnon,
1995; McKinnon and McPhail, 1996; Morris and Ryan, 1996). More stud¬
ies of male and female response to male signals are needed, particularly
in taxa for which the phylogenetic history is known.

Male lizards of many species have bright coloration, often most vivid
during tire breeding season (Regamey, 1935; Harris, 1964; Werner, 1978;
Schall, 1986; Losos and Chu, 1988; Cooper and Vitt, 1993; Mouton and
van Wyk, 1993; Hearing and Schall, 1994; Mori and Hikida, 1994; Galan,
1995). The coloration may aid in species recognition (Losos, 1985) or sex
identification (Vinegar, 1972; Cooper and Bums, 1987). In many species
variation in male coloration is associated with variation in male repro¬
ductive, territorial, or aggressive behavior (Hover, 1985; Madsen and
Loman, 1987; Rand, 1991; Thompson and Moore, 1992; Diaz, 1993;
Ellingson, 1994; Olsson, 1994a; Carpenter, 1995; Sinervo and Lively, 1996;
Baird et al, 1997; Molina-Borja et al, 1998), suggesting a high potential
for intrasexual selection on coloration.

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Female choice based on male color or other morphological traits has
rarely been documented in lizards (reviews in Tokarz, 1995; Olsson and
Madsen, 1998). Experiments found no evidence for female mate prefer¬
ence based on male coloration in Lacerta agilis (Olsson and Madsen, 1995)
or Eumeces laticeps (Cooper and Vitt, 1993). When establishing home ranges,
female lizards may be more influenced by the distribution of food or other
resources than by the distribution of males (Hews, 1993). Only three stud¬
ies suggest female mate choice based on male color in lizards (Sigmund,
1983; Ellingson, 1994; Baird et al., 1997).

The degree of sexual dichromatism may be associated with the in¬
tensity of aggression in some lizards. In Texas populations with strong
sexual dichromatism, Uta stansburiana lizards of both sexes were highly
territorial and aggressive; in Colorado populations with little sexual dichro¬
matism, within-sex home range overlap was extensive and aggressive
behavior was rare or non-existent (Tinkle and Woodward, 1967). Com¬
parative studies involving a larger number of taxa would allow evalua¬
tion of the co-evolution of aggressive behavior with sexually dimorphic
morphological traits.

The lizard genus Sceloporus is especially suitable for comparative
work on the evolution of sexually dimorphic behavioral and morphologi¬
cal traits and on the response of males and females to those traits. The
phylogeny has been well-studied (Wiens and Reeder, 1997), and males of
various species differ greatly in the amount and intensity of blue colora¬
tion on the belly and throat. Within one subgroup of the genus, for ex¬
ample, the amount of blue ventral coloration ranges from none (S. exsul,
Dixon et aL, 1972) or almost none (a few pale blue belly scales in some
individuals, and two small, pale throat patches; S. virgatus, Cole, 1963; A.
J. Abell, pers. obs.) to bright blue on almost the entire ventral surface (S.
occidentalis taylori, Camp, 1916). Much of the variation in blue coloration
is due to repeated losses of the trait in various lineages, including the
lineage of S. exsul and S. virgatus (Wiens, 1999). The ventral coloration is
exposed during aggressive and courtship displays to other individuals
(Carpenter, 1978). It is widely believed that the blue coloration functions
primarily in aggressive displays (Cooper and Bums, 1987). For S. undulatus,
Noble (1934) wrote that " the bright colors of the male fence lizard are
employed to bluff possible rivals into withdrawing from a fight. The adorn¬
ment of the male is not wedding finery but a gladiator's vestment." Male

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courtship and male-male display behavior is qualitatively similar across
species with varying levels of blue ventral coloration (Carpenter, 1978;
Fitzgerald, 1982), but variation in color may correlate with variation in
the intensity of behavior. Comparing S. virgatus , S. undulatus consobrinus ,
and 8. undulatus tristichus , Vinegar (1975) found the highest levels of male
aggressive behavior in the most sexually dichromatic form (S. u.
consobrinus). The extent of male-male home range overlap reported for 8.
virgatus (74%; Abell, 1999) is considerably higher than for any other
Sceloporus species (49%, Tanner and Hopkin, 1972; 52%, Ferner, 1974; 33%,
Ruby, 1978; 27%, Jones and Droge, 1980; 53%, Ruby and Baird, 1994), pos¬
sibly indicating reduced levels of male territorial defense in this species
with greatly reduced ventral coloration.

Despite the prominence of the blue ventral coloration in many
Sceloporus species and the belief that it has an important role in male con¬
test, there have been only three studies of sexual selection on male colora¬
tion, all considering natural variation in coloration relative to behavior of
males in die field. Rand (1991) found that males of 8. undulatus erythrocheilus
with a certain color pattern are socially dominant over other males and
spend relatively more time in proximity to females. However, Rand fo¬
cused on a chin color polymorphism (orange or yellow) rather than the
blue ventral coloration. In 8. jarrovi , Dixon (1993) found no direct sexual
selection on blue color traits of males, apart from the correlation of these
traits with aspects of male body size under selection. In 8. virgatus , Abell
(1998) found no sexual selection on male throat coloration.

To experimentally examine the correlation between male ventral
coloration and the behavioral response of males and females to the col¬
oration, I used protocols and sample sizes similar to those in other recent
experimental studies of male secondary sexual traits (Thompson and
Moore, 1991; Cooper and Vitt, 1993; Ellingson, 1994; Olsson, 1994a; Mor¬
ris and Ryan, 1996). Males of 8. virgatus have retained stereotyped behav¬
ioral displays similar to those of more colorful con.gene.tics, though these
postural displays expose areas of the body that have little or no coloration
compared to the extensive bright blue patches of most other species. I
predicted that males would likewise retain a behavioral response to the
experimentally manipulated coloration of other males, both to restora¬
tion of the faint coloration to the large and bright patches typical of close
relatives, as well as to the removal of the faint patches normally present.

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In addition to behavioral responses, I measured seasonal weight
change of males as a possible indicator of longer-term dominance relation¬
ships. Males of many squamate species, including S. virgatus, lose weight
during the breeding season (Nagy, 1983; Merker and Nagy, 1984; Baron et
al., 1996; Saint Girons, 1996; Olsson et al., 1997). The amount of weight loss
can vary with the level of aggressive behavior (Marler and Moore, 1988). If
the color of his opponent causes a male of S. virgatus to vary his level of
aggressive behavior or his response to the behavior of other lizards, then
the degree of weight loss could vary according to male color.

Previous experimental work on male response to the badges or or¬
naments of other males has generally enhanced or reduced a trait already
present in the population, either within or outside the range typical of the
population (Rohwer, 1985; Marchetti, 1993; Omland, 1996; Qvarnstrom.
1997). Restoration of a lost or reduced signal to the level typical of the
ancestral state, as I did with one of the experiments reported here, is much
less common. In a population of Anolis carolinensis lizards that has lost the
usual red dewlaps, Christman (1980) reported that grey-throated male
anoles responded in the same way to grey-throated and red-throated
males, but no quantitative details were provided.

Methods

General Experimental Protocols

During the spring breeding season, body size has a bimodal distri¬
bution in both sexes of S. virgatus , with the smaller lizards experiencing
their first potential breeding season after hatching and the larger lizards
in at least their second potential breeding season (Abell, 1998). All lizards
in this study were from the large side of the bimodal size distribution. I
captured all experimental males in April and housed them in individual
terraria until I set up the experiments. I conducted all experiments during
the breeding season, around the time of peak courtship and mating activ¬
ity (Rose, 1981; pers. obs.).

I extended the range of variation in coloration by painting lizards
(Noble, 1934; Cooper and Burns, 1987; Thompson and Moore, 1991). In
one experiment (1992) I supplemented the natural level of blue to restore
S. virgatus to the ancestral levels of bright throat and belly coloration. In
another experiments (1994) I covered the little blue that males normally

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have. I tested the effect of the restored blue coloration on male-male inter¬
actions and the effect of removal of natural blue on male-male interac¬
tions and female choice. In the restored color experiment, I presented teth¬
ered intruder males (restored or normal color) to resident males in the
field (Noble, 1934; Vinegar, 1972; Cooper and Burns, 1987; Thompson and
Moore, 1992). In the color removal experiments, I established pairs of males
in large outdoor enclosures (Carpenter, 1995; Zucker and Murray, 1996)
with an adult female present. I observed interactions between normally-
colored and uncolored males and the response of the females to the males.
Social relationships that can persist over relatively long periods of time
are an important determinant of mating success in males of S. virgatus
(Abell, 1997), suggesting that response to male color over a period of sev¬
eral days to weeks may be important in this species. For the enclosure
experiments, I measured the long-term behavioral response and weight
change of receiver individuals to the experimentally-manipulated color
signal over at least several days, as well as the initial short-term response.

To manipulate the throat color of males, I used flexible fabric paint
(Deka brand) blended to match either the pale blue coloration of an aver¬
age male S. virgatus , the brighter blue coloration of the closely related S.
undulatus consobrinus, or the off-white background coloration. All paint
treatments lasted for the duration of the experiments. In the tethered in¬
truder experiments, I painted some males with bright blue paint (brighter
than the normal throat color of S. virgatus) on the belly as well as the
throat. These males, which I will refer to as Super Blue, resembled males
of S. undulatus consobrinus in the intensity and coverage of ventral colora¬
tion. Populations of S. undulatus consobrinus are located within a few kilo¬
meters of the study population of S. virgatus , but the study population is
not part of a contact zone. The Super Blue males did not resemble any
species of phrynosomatid lizard found sympatrically with the study popu¬
lation (S. jarrovi, S. clarki, or Urosaurus omatus). The control treatment (Blue)
for the Super Blue males resembled normal S. virgatus males, with light-
blue paint on the throat and off-white paint on the belly. Clear paint (in¬
stead of blue and off-white) was not used for the controls because all avail¬
able clear paints had strong chemical odors unlike the faint smell of the
non-toxic fabric paint. In the enclosure experiments, I painted one male in
each pair with white paint to cover the natural blue throat patches. As a
control, I painted the other male with pale blue on the natural blue throat

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patches. The control males looked the same as they did before I applied
the paint. I will refer to these paint treatments as White and Blue, respec¬
tively.

Because lizards are sensitive to different parts of the light spectrum
than humans (Fleishman et aL, 1993), one might ask whether these paint
treatments truly mimic blue versus white coloration, from the perspec¬
tive of a lizard. Other studies using similar paints have shown that S.
virgatus and the closely related species S. undulatus made mistakes in sex
recognition when stimulus animals were painted to resemble the oppo¬
site sex (Vinegar, 1972; Cooper and Burns, 1987), suggesting that my paint
treatments are a reasonable means of manipulating lizard coloration. Also,
the patterns reported here mirror those I found in unstaged encounters
with S. virgatus males varying in natural levels of blue throat coloration
(Abell, submitted ms), suggesting that my experimental results are not an
artifact of the paint treatment.

Male Contest, Normal Blue and Super Blue Tethered Intruders

On 10 May 1992 1 applied the Blue and Super Blue paint treatments
to six stimulus males, which I used as intruders in tethered encounters.
For comparison of body size among individuals, I used individual growth
rates obtained from repeated measurements (Abell 1998) to estimate the
snout-vent length (SVL) of all residents and intruders on a standard day
(31 May). The resident population is the same one described in Abell (1998).
I chose 12 resident males in this population and presented them with the
tethered intruders. I staged tethered encounters during the mating sea¬
son, from 11 May through 30 May, between about 0930 hr to 1600 hr (ex¬
cluding the hot midday period around 1200 hr to 1330 hr).

Male traits other than coloration that can influence the outcome of
dominance interactions include body size, familiarity with the opponent,
and prior experience as a winner or loser (Olsson, 1992, 1994b; Carpenter,
1995; Zucker and Murray, 1996). I controlled for the possible effect of body
size by presenting residents with the same intruder twice, once with the
intruder painted Blue and once with the same intruder painted Super
Blue. The time from one encounter to the next encounter for a given pair
ranged from two to 15 days (mean 6.1 ± 4.7 days). I determined which
intruder treatment (Blue or Super Blue) a resident received first by flip-

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ping a coin. In seven of the 12 paired encounters, the resident met the
Blue male first and in the remaining five paired encounters he met the
Super Blue male first. In these experiments, the order of presentation did
not influence the outcome of the interaction.

During the tethered introductions, I tied the intruder male to the
end of a long, thin bamboo pole with heavy thread. The intruder was
allowed about 50-70 cm of slack at the end of the tether. Preliminary ob¬
servations suggested that a strong intrusion (introduction at a close dis¬
tance) was necessary to reliably elicit a response from the resident, so
during the experimental trials I placed the tethered male about 10-30 cm
from the resident male, with the long axis of the intruder facing towards
the resident. I watched the interaction until one individual retreated from
the other (indicated by movement away from the other, usually accompa¬
nied by an attempt to seek cover) or for 15 minutes. I noted which indi¬
vidual retreated.

To evaluate the possible influence of both blue color and the size
difference between opponents on the aggressive response of the resident,
I examined the overall outcome of the trial, as indicated by one of the
individuals retreating from the other. Most natural (unstaged) encoun¬
ters between males of S. virgatus involved males differing in body size
(Abell, submitted ms), so it is reasonable to examine whether the size dif¬
ference varied according to the outcome of the trial. For cases where the
resident performed better against one color treatment than against the
other, I used the t-test to compare the size difference between resident
and intruder.

Male Contest and Female Choice, White and Normal Blue Males in

Enclosures

For these studies, I chose to examine male-male interactions in the
presence of a female. Similar experiments using only a basking site as a
resource resulted in extremely low rates of male-male interactions (Abell,
unpubl. data), suggesting that the presence of a female was necessary to
stimulate male-male behavior in enclosure experiments.

Each outdoor enclosure measured 1.3-1. 5 m2 and was paired with
an adjoining space of the same size. Enclosures were considerably smaller
than breeding season home range sizes (average 363 m2; Abell, 1999) but

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were exposed to natural temperature and light conditions and were large
enough to allow the expression of courtship behavior and mating (pers.
obs.) Each enclosure was furnished with a single cinder block for a perch,
and lizards were provided ad libidum vitamin-dusted mealworms and
waxworms to supplement naturally-occurring insects.

In late April 1994 1 established 20 males in the outdoor enclosures.
Each enclosure was connected to another of the same size by two doors
(one 7.6 cm long and the other 30.5 cm long), kept closed until females
were introduced. I matched males in connecting enclosures for tail break¬
age status and tail length (within a few mm), for SVL (within 1 mm), and
for body weight (within 1.1 g; weight difference > 0.4 g for only one pair,
established about a week after the others to replace a previously estab¬
lished pair). Males were allowed more than a week to acclimate to the
outdoor enclosures. I applied the Blue and White paint treatments on 7
May, using a coin toss to determine which male in a pair would get the
control treatment (Blue) and which would receive the experimental treat¬
ment (White).

I captured females in early April (13-17 April), prior to the usual
onset of courtship in this population, and housed them temporarily in
outdoor enclosures with other females. Because female throat color (blue,
orange, or mixed) may signal reproductive state (Vinegar, 1972; Weiss et
al, 1997), I recorded throat color of females at the time of introduction. I
introduced females to males from 8-15 May, with one or two introduc¬
tions per afternoon. On the day of introduction, I lifted the doors between
adjacent males and placed a female in the smaller doorway. I watched
enclosures carefully for one hour after the introduction of the female for
any instances of courtship or aggressive behavior. I recorded the follow¬
ing male behaviors: approaching the other male (walking or running),
head bobbing, and moving away from the other male (walking or run¬
ning). I also rated the maximal level of aggression of each male according
to the ranking system of Moore (1987): 0 = no response, 1 = head bobs or
push ups not accompanied by approach, 2 = fullshow with no approach,
3 - shudder with no approach, 4 = approach, 5 = faceoff, 6 = charge or
bite. On every subsequent day through 3 June, I scanned enclosures once
or twice a day for five minutes each (at approximately 0930 h and 1330 h)
to detect the possible presence of aggressive interactions, basking part-

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nerships (Abell, 1997) or courtship behavior. I tested for an effect of male
color treatment on female response to males and on the initial and long¬
term interactions between males. I weighed males again at the conclusion
of the experiment and compared the rate of weight change of Blue and
White males.

Results

Normal Blue and Super Blue Tethered Intruders

In five of the 12 pairs of trials, the resident either won against both
color treatments (n = 3 cases) or lost against both colors (n = 2 cases). In
both cases where the resident always performed worse than the intruder,
the resident was smaller than the intruder (Figure 1). In the three cases
where the resident always performed better than the intruder, there was a
wide range of size differences (Figure 1).

Although color did not always influence the outcome of the interac¬
tions, there were seven pairs of trials (out of 12) for which the resident
performed better (won instead of lost or tied) against one of the color
treatments. Overall, residents did not perform significantly better against
Blue than against Super Blue (better against Blue in 4 of 7 pairs of trials,
exact binomial, P=0.500), but the size difference between opponents me¬
diated the influence of color on the outcome of the contest (Figure 1). Con¬
sidering the seven trials in which a resident won against one color treat¬
ment but not the other, the resident size advantage (measured as resident
SVL - intruder SVL) was significantly larger when the resident won against
Super Blue intruders than when the resident won against Blue intruders
( 1 1 1 = 2.707, df = 5, P = 0.042). That is, residents won against Super Blue
intruders when residents were larger than the intruders but not when
residents were smaller than the intruders. This result suggests a possible
advantage of Super Blue coloration for larger intruders but not for smaller
intruders.

Male Contest in Outdoor Enclosures, White and Normal Blue Males

The presence or absence of male throat color did not influence the
outcome of male-male contests during the first hour of contact. In one
case the Blue male dominated the White, as shown by the control Blue
male chasing the White male, biting him, or supplanting him from a po-

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Figure 1. Resident size advantage (resident SVL - intruder SVL; in mm; mean
±SE) relative to the outcome of contests between residents and intruders. In 5
of the 12 pairs of trials, residents either lost against both colors (R<B & SB; n
= 2) or won against both colors (R> SB & B; n = 3). In the remaining 7 of 12
pairs of trials, indicated with arrows, residents performed better against one
color treatment than against the other. R>B refers to cases where the resident
won over Blue but not over Super Blue (n = 4); R> SB refers to cases where
the resident won over Super Blue but not over Blue (n = 3). The size difference
between the males was significantly larger when the resident won against
Super Blue intruders than when the resident won against Blue intruders (\t\
~ 2.707, df~5,P = 0.042); residents won against Super Blue intruders when
residents were larger than the intruders but not when residents were smaller
than the intruders.

sition. In another trial, the White male dominated the Blue male, and in
two other trials males interacted but neither male demonstrated clear
dominance. In another initial trial, the Blue male courted the White male.
This Blue male had previously courted the female without success. In

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December 1999

the remaining six of 10 trials, neither male performed any of the behav¬
iors required to assign dominant status (chasing, biting, supplanting).

In the first hour of contact. Blue and White males did not differ in
their rate of approaching the other male (Wilcoxon's signed ranks test, z =
-0.412, P = 0.680), number of head bob bouts (z = -0.813, P = 0.416), rate of
moving away from the other male (z = 0.422, P = 0.673), or maximal ag¬
gression score on Moore's (1987) ranked scale (z = -0.368, P = 0.713).

During the days following the initial introduction of the female, the
males exhibited aggressive behavior towards each other in seven of the
ten arenas. One male demonstrated dominance over the other in six of
these seven cases. There was a nonsignificant trend for males with Blue
throat color to dominate males with White throat color (5 of 6 cases, exact
binomial, P-0.109). The initial dominance relationship did not always
predict the long-term dominance relationship. The Blue male eventually
achieved dominance in one relationship that was initially unsettled and
in another relationship where the White male was initially dominant.

Most males lost weight during the experiment (Figure 2). The mag¬
nitude of weight loss was not dependent on initial (April) SVL for either
the Blue (r=0.181, n=10, P=0.617) or the White males (r-0. 0.092, n=10,
P=0.801). White males tended to lose weight at a faster rate during the
experiment, but this trend just barely missed statistical significance (paired
t-test: I tl =2.196, df=9, F=0.056; binomial test: White males lost more
weight than Blue in 8 of 10 cases, P = 0.055).

Female Choice in Enclosures, White and Normal Blue Males

During the initial encounters, females exhibited little or no associa¬
tion preference. Females always moved from the door to one side of the
arena within a few seconds, well before the females could assess the males.
In half of the trials, the female moved to the side of the control Blue male
first and in the other half she moved first to the side of the White male.

Male response to females did not vary according to female throat
color. In half of the ten trials, a male attempted copulation almost immedi¬
ately upon detecting the female. For these five females, no courtship pre¬
ceded the copulation or copulation attempt. Instead, the male would ap¬
proach the female, bite her neck, and attempt to insert a hemipenis, usu-

page 126

Bulletin of the Maryland Herpetological Society

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December 1999

Figure 2. Weight loss (g/day) of Blue (solid circles) and White (open triangles)
males in the enclosures with two males and a female. The two males in each
pair are shown one above the other. The order (from left to right) is the pair
with the White male dominant in the long term (W > B), the five pairs with the
Blue male dominant (B > W), and the four pairs with no clear agonistic
hierarchy (Neither dominant).

io

5

3

<D

O)

c

<0

o

CD

I

0.01

•

0.0

•

A

-0.01

A

• •

-0.02

A

. A

A “

• •

-0.03

•

•

A

•

-0.04

A

A

A a

-0.05

-

-0.06

-0.07

W> B

B > W

Neither
dominant _

ally while the two twirled rapidly in a donut formation. One of these five
females had all orange throat coloration, two had all blue, and two had
primarily orange with some blue. Two other females were courted but not
subjected to a copulation attempt. In all cases where a female was courted
in the first hour, she moved away immediately after the male initiated
courtship. One of the courted females had predominantly blue throat color
with some orange, and the other had mainly orange with some blue. Males
neither courted nor attempted to copulate with the remaining three fe¬
males. One of these females had all blue throat color, one all orange, and
the other (the smallest female) lacked throat coloration.

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 4

December 1999

Male throat color treatment was not associated with the sexual be¬
haviors males directed towards females (Table 1). Male throat color also
did not influence either female responses to male behaviors or the behav¬
iors that females directed towards males. Of the three females approached
by both the Blue and White male, in every case the female either moved
away from both males (n = 2 females) or didn't move away from either
male (n = 1 female). Of the five females approached by only one of the
two males, in three cases the female both moved away and didn't move
away, on different occasions, and in two cases the female always moved
away (one of these females from a Blue male and the other female from a
White male). Behaviors that females were observed to direct toward males
were approaching and head bobbing. Three females approached a Blue
male and three females approached a White male. Two females head
bobbed at Blue males and one at a White male.

During the days following the initial introductions, only two of the
ten females exhibited any affiliative preference for one of the males. In
both cases, the possible preference was for a Blue, socially dominant male.
I saw one female within 45 cm of the Blue male twice but never within
that distance of the White male. I saw the other female six times within 35
cm of the Blue male (with the White male at least 80 cm away on each of
these occasions) but only once within 35 cm of the White male (with the

Table 1

Number of males performing at least one instance of a behavior directed
towards females. The maximum possible value for each entry is 10 (number of
pairs of Blue and White males).

Male color treatment

Male Behavior

Blue

White

Attempt copulation

3

3

Bite female's neck
(outside of copulation attempt)

4

3

Court female
(no copulation attempt)

2

1

page 128 Bulletin of the Maryland Herpetological Society

Volume 35 Number 4

December 1999

Blue male 100 cm away on that occasion). The other eight females were
found near the Blue and White males at similar distances and with equal
frequency.

Discussion

In the introductions of tethered males to field residents, there was
an interaction between the throat color of intruder males (normal Blue or
Super Blue) and the size difference (between intruder and resident) on
the outcome of the interaction. Considering only cases where the resident
performed better against one or the other of the color treatments, resi¬
dents won against intruders with restored levels of blue coloration when
residents were larger than the intruders but not when residents were
smaller than the intruders. The extra coloration in the Super Blue treat¬
ment thus conferred no advantage to smaller intruders in contests with
larger residents.

Several experimental studies of birds suggest that an enhanced sta¬
tus signal or badge only improves dominance rank if the individual with
the enlarged badge can "back up" the signal with real quality (Rohwer,
1975, 1985; Qvarnstrom, 1997). Similarly, smaller S. virgatus intruders with
Super Blue coloration may not be able to back up the apparent dominant
status signalled by the supplemental coloration. In the present study, the
"enhancement" of the coloration is actually a restoration to the ancestral
condition rather than enlargement to the level typical of large or domi¬
nant males. Natural male-male encounters in S. virgatus are most often
between individuals of different sizes (Abell, submitted ms). Despite the
advantage of large male size, smaller lizards sometimes do dominate in
male-male encounters. These experimental studies suggest that restored
blue throat and belly patches can confer an advantage in male-male en¬
counters in S. virgatus and that the advantage of blue color depends on
the size difference between opponents.

In the first hour of interaction in the enclosure experiments, there
was no evidence that the presence or absence of throat color influenced
male-male interactions. The trends were so weak (P > 0.4 in every case,
even unadjusted for multiple comparisons) that I believe the lack of sta¬
tistical significance represents a lack of biological effect and not a lack
of power.

Bulletin of the Maryland Herpetological Society

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December 1999

Perhaps because of the relatively low levels of aggression in S. virgatus,
males in only six of the ten pairs in outdoor enclosures exhibited social
dominance hierarchies on the days following the initial introduction. Blue
males tended to be socially dominant over the White males and to lose
less weight than White males. Neither trend was statistically significant,
but the patterns were strong enough to suggest a phenomenon of real bio¬
logical significance. With one or two additional animals, statistical signifi¬
cance would have been reached with trends of similar magnitude.

Color and dominance status were associated with male seasonal
weight loss; White males tended to be subordinate and to lose more weight.
When lizards are housed in enclosures, socially dominant individuals
sometimes control access to prime feeding sites and reproduce more suc¬
cessfully (Saint Girons, 1977). Subordinate male Turks Island iguanas
(Cyclura carinata) often failed to eat in captivity, even when abundant food
was available (Iverson, 1979). However, I do not believe that differences
in food intake can entirely explain the different levels of weight loss of
the dominant Blue and subordinate White males of S. virgatus. Levels of
weight loss in the enclosures were comparable to those in free-ranging S.
virgatus during the breeding season (Merker and Nagy, 1984; Abell, in
press), even though food was available ad libidum in the enclosures. In
feeding experiments with free-ranging S. virgatus during the breeding
season. Rose (1981) and Phelan and Niessen (1989) noted that males often
decline offers of supplemental food, even though the males are thin at
that time. With the lizard Anolis carolinensis in captivity, Bels (1982) like¬
wise observed greater weight loss in socially subordinate males than in
dominant males. Greenberg et al. (1984) found higher levels of plasma
corticosterone in subordinate captive males of A. carolinensis than in domi¬
nant males. Laboratory-housed females of A. carolinensis had an extra daily
peak of corticosterone as well as higher levels of weight loss when housed
in dry conditions, even though these females were force-fed the same diet
as control females housed under more humid conditions (Summers and
Norman, 1988). Glucocorticosteroids have a variety of complex physi¬
ological and behavioral effects, including glucose and protein mobiliza¬
tion and changes in foraging behavior (Wingfield, 1994), suggesting a
possible physiological mechanism for the greater weight loss of the so¬
cially subordinate White males.

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December 1999

There was no evidence that blue coloration of males influenced fe¬
male mate choice. During the initial introductions, neither female response
to male behavior nor female behavior directed towards males varied ac¬
cording to the throat color of the males. On the days after the initial en¬
counters, only two of the ten females tended to associate preferentially
with one male or the other. Additional female choice studies are needed to
assess possible female preferences in the absence of male-male interactions.

Correlational studies indicated no sexual selection on male ventral
coloration in S. virgatus (Abell, 1998). However, males with a greater ex¬
perimental expression of color (Super Blue versus Blue, or Blue versus
White) had a weak advantage in staged encounters with smaller or size-
matched males. My results are consistent with those of another experi¬
mental study of S. virgatus (V. S. Quinn and D. K. Hews, pers. comm.), in
which large males with painted blue belly patches were more aggressive
than size-matched control males. Similarly, males with naturally large blue
throat patches exhibited more aggressive behaviors than males with natu¬
rally small throat patches, in unstaged encounters with larger opponents
(Abell, submitted ms). Additional experimental and correlational work
should examine male and female response to coloration and other male
traits in a variety of lizards in the genus Sceloporus , with an emphasis on
subgroups of the genus with particularly large amounts of variation in
coloration. The results of the present study also suggest a need for addi¬
tional studies of relatively long-term effects of variation in male display
signals. The influence of the presence or absence of blue color patches
was only apparent in the long-term weight loss and social status mea¬
surements, not in the short-term behavioral responses. Relatively long¬
term studies may be especially important in species such as S. virgatus ,
where the overall level of sexual selection on male coloration is so weak
as to be undetectable in correlational studies (Abell, 1998).

Acknowledgements

I am grateful to the many people who assisted with the field and
laboratory work in 1992 (J. Ascher, M. Fore, S. Ho, A. Ringia, T. Szabo)
and 1994 (S. Cho, B. Jaffe). The staff of Southwestern Research Station
of the American Museum of Natural History provided logistical support.

I thank G. Carpenter, B. Leuck, M. Olsson, and R. Tokarz for advice on

Bulletin of the Maryland Herpetological Society

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December 1999

experimental design, and D. Hews and V. Quinn for comments on an
earlier version of the manuscript. Funding for experimental work was
provided by the Theodore Roosevelt Memorial Fund, the Hinds Fund
(University of Chicago), Sigma Xi, the Gaige Fund, and the Illinois
Academy of Sciences; support during manuscript preparation was
provided by Indiana State University.

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Received 2 June 1999

Accepted 16 July 1999

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December 1999

The Challenge of the Plateau and Prairie Lizards
(Sceloporus undulatus) of New Mexico

Hobart M. Smith, David Chiszar and Frank van Breukelen

Abstract

Eight subspecies of Sceloporus undulatus occur in New Mexico -
twice as many as in any other state. That exceptional diversity reflects a
vastly varied topography and ecology. However, the range limits of most
subspecies are even yet known as approximations, and although all are
allopatric the full extent of their interdigitation is unknown. The species
appears to be absent only at high elevations (over about 2750 m) and per¬
haps in open terrain with inadequate refuges where predation is most
intense. More accurate delineation of subspecific ranges opens the door
to more critical appraisal of differences in scalation that have been masked
in the past by failure to distinguish distinct taxa.

One of the most challenging problems of intraspecific variation in
reptiles of North America is found in the ubiquitous Sceloporus undulatus
of New Mexico, where three subspecies (S. u. elongatus, S. u. erythrocheilus,
S. u. tristdichus) of the Plateau Lizard (tristichus) exerge (subspecies group)
occur, along with five of the Prairie Lizard (consobrinus) exerge (S. u.
consobrinus, S. u. cowlesi, S. u. garmani, S. u. tedbrowni), as listed by Smith et
al. (1992 submitted a, b).

In their exhaustive monograph of New Mexican herpetology,
Degenhardt et al (1996) did not attempt to differentiate or delineate the
ranges of these subspecies, which were simply noted as having been re¬
corded from the state. The most recent attempt to map their ranges in
New Mexico (Lemos-Espinal et al, 1998) was on too small a scale to de¬
pict them with much accuracy.

Our present purpose is to attempt a more detailed approximation to
the ranges of the New Mexican subspecies, based on published informa¬
tion and a recent examination of some especially critical material in the
Museum of Southwestern Biology (MSB), through the courtesy of Mark
A. Jordan, Alexandra Snyder and Dr. William G. Degenhardt.

On those bases we here present (Fig. 1) our best estimates of range

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Fig. 1. Distribution of the subspecies of Sceloporus undulatus, modified from
the spot map in Degenhardt et al. (1996: 182). 1, S. u. elongatus; 2, S. u.
tristichus; 3, S. u. erythrocheilus; 4, S. u. garmani; 5, S. u. consobrinus; 6, S. u.
tedbrozvni; 7, S. u. cowlesi ; 8, S. u. speari.

109° 108° 107° 106° 105° 104° 103°

109° 108° 107° 106° 105° 104° 103°

37°

36°

35°

34°

33°

32°

limits, superimposed on an enlarged version of the detailed spot map for
the species in Degenhardt et al. (1996). The county names, to which the
following discussion frequently refer, are given in Fig. 2, also modified
from Degenhardt et al. (1996).

Sceloporus undulatus tedbrowni

The greatest surprise of our recent visit to MSB was the discovery of
the extensive range of this subspecies throughout the southern half of the

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eastern border of the state in the extensive sand dunes and Shinnery oak
habitat of that area. The subspecies is also now known along the adjacent
western border of Texas, in Andrews, Cochran, Hockley, Lamb, Terry and
Yoakum counties (Smith and Chiszar, submitted). It appears (Fig. 1) that
the subspecies may even be dichopatric relative to other subspecies of S.
undulatus, at least in New Mexico.

S.u. tedbrowni is also one of the most distinctive races of the species, in
size and pattern. It is the smallest, with a maximum known SVL of 59 mm in
females, 54 mm in males; the nearest in size is S. u. garmani, with a recorded
maximum SVL of 68 mm in females, 59 in males (Fitch, 1978). It is most
similar to S. u. garmani , but their ranges are separated by that of S. u.
consobrinus (Fig. 1), and the northern subspecies has a very distinct dorsal
pattern sharply different from the degenerate dorsal pattern of S. u. tedbrowni.

Fig. 2. Names of counties in New Mexico, modified from Degenhardt et
al. (1996: xii, fig. 1).

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In the 35 specimens examined from Lea Co. (Fig. 2), the dorsal pat¬
tern was mostly without dark marks; at most 4 females in 20 showed
them, 6 males in 15; where present, the spots were small and confined to
the median border of the dorsolateral light stripes. The latter were absent
in a few nearly unicolor females, dim and never sharply defined in the
others; in males they were usually dim, but sharply defined in 7. In all of
both sexes the lateral light stripe was essentially absent, very faint and/
or interrupted where present. There was no evidence whatever of either
gular or abdominal semeions in females. The gular semeions were essen¬
tially absent in males, represented in some by a few black flecks on the
extreme posterolateral gular scales; their abdominal semeions were sepa¬
rated minimally by 6-8 scales in a row.

The 23 specimens examined from eastern Chaves and southern
Roosevelt counties (Smith et al., submitted b) were essentially the same as
those described from Lea Co.

Sceloporus undulatus cowlesi

This subspecies, limited to the White Sands, is readily distinguish¬
able from the other arenicolous subspecies, S. u. tedbrowni, by its larger
size (maximum SVL 69 nun in females, 60 mm in males) and by the pres¬
ence of both gular and abdominal semeions in both sexes. The presence of
abdominal semeions in females suggests derivation from S. u. tristichus,
which occurs nearby and in which females usually possess abdominal
semeions, sometimes indistinguishable from those of males. On the other
hand, this subspecies appears to be a member of the consobrinus exerge,
whereas S. u. tristichus belongs to a different exerge bearing its own name
(Smith et al., 1992). The exerges differ in evolutionary trends in pattern
(striped vs barred), semeion development (weaker vs stronger), size
(smaller vs larger) and behavior (cursorial vs scansorial). Biochemical
analyses may be useful eventually in confirming the origin of S.u. cowlesi.

At present, the White Sands subspecies has been recorded only from
Otero Co., but since the Sands extend into Dona Ana and perhaps even
into Sierra Co., S. u. cowlesi may well occur there also.

Sceloporus undulatus garmani

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Although occurrence of this subspecies in New Mexico has long been
inferred from its distribution in Colorado and Oklahoma, Applegarth
(1969) was the first to document it, on the basis of four adult females (MSB
18538-9, 18794-5) he collected 10 mi N, 6.25 mi W Logan, Harding Co. We
independently confirmed that identification. Its adjacent subspecies, S.
U consobdrinus , is readily distinguished by the presence of well devel¬
oped, often large gular semeions in both sexes. It appears to have no con¬
tact with any other subspecies anywhere in its range, although the sepa¬
ration is in some cases only a matter of a mile or so, except for possibly
S.u. tristichus , narrowly (Fig. 1), in Harding Co. (Applegarth, 1969).

Sceloporus undulatus speari

Smith et al (submitted a) have already recorded this subspecies in
the southern Jornada del Muerto Basin (= the Cabeza de Vaca Basin) in
southwestern New Mexico, occupying much of Dona Ana Co., southwest¬
ern Sierra and Otero counties, and southeastern Luna Co. It had formerly
been thought to be limited to the extensive sand dune area of adjacent Chi¬
huahua. It differs from the adjacent S. u. consobrinus in its loss or reduction
of dark dorsal spots, its uninterrupted dorsolateral light lines, and its re¬
duced gular semeions (absent or small in females, usually separate in males).

Sceloporus undulatus consobrinus

This, the remaining subspecies of the consobrinus exerge, is the sec¬
ond most widely distributed subspecies of S. undulatus in New Mexico
(Fig. 1). Only S , u. tristichus is more widely distributed. Between the two
of them they take up most of the state. It is also apparently the most gen¬
eralized member of the exerge, and likely has been ancestral to all its
members. It is characterized by having dark spots present and well de¬
veloped, usually distinct dorsolateral light lines that may be interrupted,
usually well-developed gular semeions in females, and gular semeions in
males usually broadly fused.

In spite of the fact that S. u. consobrinus and S. u. tristichus are thought
to belong to separate exerges, they appear to intergrade throughout their
extensive and intricately interdigitating contacts, thus leading to diverse
identification of populations in intergrading zones. Intergradation with
other members of its exerge also is expected or documented, except for
the seemingly isolated S. u. tedbrowni.

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Sceloporus undulatus tristichus

This is a scansorial and predominantly arboreal subspecies living
on trees and rocks at relatively high elevation where oaks are dominant
or at least prominent (Applegarth, 1969). It is relatively large, has poorly
defined dorsolateral light lines interrupted by lateral extensions of the
paravertebral dark spots, is of general dark tone dorsally, and has large
semeions in both sexes, although usually less well developed in females
than in males. Presence of distinct abdominal semeions in females is a
notable hallmark of the subspecies; they occur in only a small percentage
(11%) of female S. u. consobrinus.

As a subspecies of relatively high elevation. and cool climate, this
subspecies occurs, with the other members of its exerge (S. u. elongates, S.
u. erythrocheilus) farther to the north in the state than the subspecies of the
consobrinus exerge. Not surprisingly, it is isolated on some higher eleva¬
tions surrounded by S. u. consobrinus , as for example in the Gavilan Mts.
of northern Lincoln Co., and the Capitan Mts. in the southern part of the
same county (Fig. 1). Still other high altitude populations of the species in
Otero Co,, might also be more properly referable to S. u. tristichus than to
S. u. consobrinus.

It is of considerable interest that intergradation of S. u. garmani with
S. u. tristichus (Applegarth, 1969) or with S. u. consobrinus (pers. obs.), or
perhaps with both, is suggested in the contact zones of these three sub¬
species near the common borders of San Miguel and Quay counties, and
extending into adjacent Harding Co. (Fig. 1).

Sceloporus undulatus erythrocheilus

Applegarth (1969) devoted much effort to determine the ranges of
S. u. erythrocheilus and S. u. tristichus in northeastern New Mexico, and
the limits indicated on our map (Fig. 1) in that area are based on his find¬
ings and on those of Hammerson (1986). Like S. u. tristichus , S. u.
erythrocheilus is scansorial, but predominantly petricolous instead of ar¬
boreal. Applegarth's data (1969) indicate that the femoral pore total count
is usually 34 or more, and the dorsal scale count usually 47 or more, in S.
u. erythrocheilus , and 33 and 46 or fewer, respectively, in S. u. tristichus.
The primary chromatric difference he found was the absence of erythris-
tic (yellow, orange and red) colors on the lips and throat of adult S. u.

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tristichus (white instead), and their presence, varying seasonally in inten¬
sity, in S. u, erythrocheilus.

Sceloporus undulatus elongatus

The range of this subspecies in Colorado (Hammerson, 1986) indi¬
cates that it occurs in extreme northwestern New Mexico, as indicated in
Fig. 1. In S. u. elongatus , 95% have 46 or more dorsals, 80% 18 or more
femoral pores on a side, and 92% 7 or more minimal scales in a row be¬
tween the femoral pore series; in 5. u. tristichus those figures are 9%, 18%
and 18%, respectively (Smith and Chiszar, 1989).

Discussion

Although approximate ranges of the eight subspecies of S. undulatus
occurring New Mexico are now reasonably well roughed out as never
before, understanding of geographic variation of the species in the state
remains rudimentary because of (1) the highly complex topography and
climate in the state, with which there is considerable apparent correla¬
tion, and (2) the unexplored morphological correlations that may exist in
addition to the differences in color, pattern, behavior, size and habitat pref¬
erences that largely define the geographic races as now understood. Some
attempts in the past to detect morphological correlations with taxonomy
have yielded poor or no results through ignorance of what the races are
and where they are found. Yet more recent analyses of more discrete popu¬
lations, as for example of the tristichus exerge subspecies (Applegarth,
1969; Smith and Chiszar, 1989) suggest that additional morphological cor¬
relations do exist and should be sought.

It is also not unlikely that still other subspecies at present not recog¬
nized exist in limited areas of the state, as for example on the vast ex¬
panses here and there of black lava, where the populations of S. undulatus
are especially dark.

These are all derivatives of the consobrinus exerge, which in general
tend toward the other extreme, of light coloration, hence are of special
interest.

There is also the enigmatic Arizona population currently referred to
5. u, consobrinus , extending Into southwestern New Mexico, that has

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strange unicolor hatchlings (Smith and Bock, 1990), and at times reaches
a rather large size at which a unicolor dorsum appears. At intermediate
sizes the dorsal pattern appears more or less normal for the subspecies.
That population is but tenuously continuous with more eastern popula¬
tions of the subspecies, or may actually be isolated from them by contact
of the ranges of S. u. tristichus and S. u. speari (Fig. 1).

Acknowledgments

We are much indebted to the authorities of the Museum of South¬
western Biology for their repeated courtesies in supplying information,
loaning specimens and making our studies there as comfortable as pos¬
sible; and to the authorities of the University of Colorado Museum and
Department of Environmental, Population and Organismic Biology, for
provision of space and facilities for study.

Literature Cited

Applegarth, J. S.

1969. The variation, distribution, and taxonomy of the Eastern
fence lizard, Sceloporus undulatus Bose in Latreille, in
northeastern New Mexico. M.S. Diss., Univ. New Mexico.
124 pp.

Degenhardt, W. G., C. W. Painter, and A. H. Price.

1996. Amphibians and reptiles of New Mexico. Albuquerque,
Univ. New Mexico, xix, 431 pp.

Fitch, H.

1978. Sexual size differences in the genus Sceloporus. Univ., Kan¬
sas Sci. Bull., 51: 441-461.

Hammerson, G. A.

1986. Amphibians and reptiles in Colorado. Denver, Colorado
Div. Wildlife, vii, 129 pp.

Lemos-Espinal, J. A., H. M. Smith, R. E. Ballinger, G. R. Smith, and D.
Chiszar.

1998. A contribution to the superspecies concept of the lizard
Sceloporus undulatus: S. u. belli a species. SW Naturalist,
43: 20-24.

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December 1999

Smith, H. M., E. L. Bell, J. S. Applegarth, and D. Chiszar.

1992. Adaptive convergence in the lizard superspecies Sceloporus
undulatus. Bull. Maryland Herp. Soc, 28: 123-149.

— and C. E. Bock.

1990. Unicolor hatchling coloration in a population of the liz¬
ard Sceloporus undulatus consobrinus in southeastern Ari¬
zona. Bull. Maryland Herp Soc., 28: 1416.

— and D. Chiszar.

1989. The subspecific identity of the population of Sceloporus
undulatus sympatric with S. occidentalis. Bull. Maryland
Herp. Soc., 25: 143-150.

Submitted. Geographic distribution: Sceloporus undulatus tedbrowni.
Herp. Rev.

- - - R. Axtell, and R. G. Webb.

Submitted a. Geographic distribution: Sceloporus undulatus speari.
Herp. Rev.

- M. A. Jordan and A. D. Belcher.

Submitted b. Geographic distribution: Sceloporus undulatus tedbrowni.
Herp. Rev.

— — - and J. A. Lemos-Espinal.

1995. A new subspecies of the polytypic lizard species
Sceloporus undulatus (Sauria, Iguanidae) from northern
Mexico. Texas J. Sci., 47: 117-143.

— — - - - - and E. L. Bell.

1995. The Cabeza de Vaca subspecies of the lizard Sceloporus
undulatus. Trans. Kansas Acad. Sci., 98: 44-60.

EFO Biology , Psychology and Museum, University of Colorado, Boulder,

Colorado 80309, U.S.A.

Received 30 April 1999

Accepted 15 May 1999

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The Known Distribution in 1998 of the Members of
the undulatus Group of the Lizard Genus
Sceloporus in Chihuahua, Mexico

Julio A. Lemos-Espinal, David Chiszar, Hobart M. Smith and Clint Henke

Abstract.

Collections of members of the Sceloporus undulatus group in Chi¬
huahua, Mexico, in 1997 and 1998, extend the known ranges of these taxa
and permit a more precise estimate of their limits than has been possible
up to the present time. Variation is summarized for the newly acquired
specimens, and for a series of S. virgatus in the University of Colorado
museum, and criteria for identification are reviewed.

Three species of the undulatus group of Sceloporus are known for
the state of Chihuahua, Mexico: S. belli Smith et al (1995a), elevated from
subspecific (in S. undulatus) to species rank by Lemos-Espinal et al. (1998);
S. virgatus Smith (1938), elevated from subspecific (in S. undulatus) to spe¬
cific rank by Cole, 1963; and S. undulatus (Bose and Daudin, 1801). The
latter is represented by two subspecies: S. u. consobrinus Baird and Girard
(1853) and S. u. speari Smith et al. (1995b).

No other state of either Mexico or the United States has more than
two species of the S. undulatus group, although New Mexico has by far
the greatest number of species-group taxa (9, two species) of that group.
No other state exceeds six such taxa (California, one species), and only
one other (Colorado) has as many as four (one species). Some member of
the group appears likely to occur at any given locality in Chihuahua (Fig.
1), but extensive areas have not been sampled and therefore unknown
distributional gaps may exist.

The range of S. virgatus was depicted in detail by Cole (1968), and of
the others, in less detail, by Smith et al. (1995a,b) and in Lemos-Espinal et
al (1998). We here review current distributional knowledge, and add to
variational knowledge, on the basis of 86 additional specimens of S. belli
and S. undulatus obtained June 2-7, 1997, by all of the authors and Adam
Chiszar, and July 8-9 and 14-19, 1998, by JAL-E. All of their catalog num¬
bers are field numbers; those with four digits are in the JAL-E collection.

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and those with five digits are at UCM. In addition we record data on 16
previously unreported specimens of 8. virgatus in the UCM,

Sceloporus belli

Thirty-three specimens are in the collections.

Northwestern localities represented are 1 km N Ascension (36299) ;
Rancho La Viuda (31°23'32.3" N, 107°48'20. 3" W) , 1457 m (2902-4, 2907-
10, 36300, 36302-3, 36305-12); Rancho El Miiagro (36314, 36316-8) ; Rancho
Bosque Bonito (31°10'50.0" N, 107°54'54.6" W), 1271 m (36315); km 19 on
road to Bismark mine (31°14'2.4" N, 107°41"26.4" W) , 1222 m (2914). Two
are from northcentral Chihuahua, at Cerros Colorados (31° 915.5" N,
106°22'42.5" W), 1420 m (2828-9), and five from the southeastern part of
the state: Rancho Tacubaya (28°19'20.4" N, 104°33'44" W) , 1560 m, km 100
on the Cd. Camargo-Ojinaga Hy (2587-91); and 400 m N military toll,
Desviacion Santa Elena (28°18'30.8" N, 104°34'24.4" W), 1580 m, fence post
next to Cd. Camargo-Ojinaga Hy (2592). The two from Cerros Colorados
were on large boulders, the others on large tree trunks or fence posts.

This series demonstrates for the first time an attribute of this species
that is rare in S. undulatus: a maximum 8VL in males (88 mm) exceeding
that of females (77 mm); the only exception recorded (Fitch, 1978) is in 8.
u. consobrinus with 74 mm the maximum in 45 males, 71 mm in 46 fe¬
males. Five males in the present series exceed the recorded maximum for
females (Smith et al, 1995a); all, however, are from La Viuda, The maxi¬
mum SVL in S. belli exceeds that of any other member of the S. undulatus
group, although it is only slightly greater than that of 8. occidentalis (87
mm.; Fitch, 1978) and of 8. u. undulatus (86 mm., Conant and Collins, 1998).
Furthermore, in most members of the S. undulatus group females have
greater mean SVL than males (range of M/F mean ratios extending from
a low of 87.7 in S. u. elongatus to 103.6 in southern S. occidentalis, only
the latter exceeding 100; Fitch, 1978).

The pattern of these specimens agrees in general with that origi¬
nally described. The gular semeions in 24 males are separated by the width
of one scale in one, two in one, but fused over a length of 1-18 scales
(M=6.1) in the others. Gular semeions are absent in the two smallest of 7
females (46, 49.5 mm SVL) and one at 63 mm SVL. They are small and
weak in two (63, 69 mm SVL), moderately developed in two (58.5, 70 mm

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SVL). There is no evidence of abdominal semeions in any of the females.

Pertinent scalation data are as follows. Dorsals 36-42 (M=39.5); femo¬
ral pores 13-17, totals 26-33 (M=30.5); minimum scales in a row between
pore series 3-7 (M=5.3); prefrontals separated by contact of median
frontonasal and frontal in 5, by an azygous scale in 10, and in contact in
15; frontal separated from interparietal in 8, in contact in 23; fewest
internasals in a row between median frontonasal and rostral on each side
of the median line 3-3 except for two with 2-3, six with 3-4, and one with
4-4; preocular undivided in all except on one side in 5; iorilabials in two
complete rows below subocular on 30 sides, reduced to one row at least at
one scale in 32.

As indicated in Fig. 1, S. belli occurs over most of the state east of
the continental divide. Records are lacking or sparse in the southeast
and southwest. Peripheral sympatry with S. u. speari is known (Lemos-
Espinal et al., 1998) at least in the Cerros Colorados area, and may occur
elsewhere. The species may possibly occur in extreme southeastern
Hidalgo Co., New Mexico, east of the continental divide, which it ap¬
pears not to cross.

Sceloporus undulatus consobrinus

As indicated in Fig. 1, we are aware of only one confirmed locality
where this species and subspecies has been taken in Chihuahua. Although
there are many records under this name for the state, all actually pertain
to S. belli or S. u. speari. Even our own record (Lemos- Espinal et al., 1998)
for 24 airline km NNE Ascension (UTEP 3568), in the northwestern cor¬
ner of the state, was in error and pertains to S. u. speari.

The locality here reported is at km 140 on the Cd. Chihuahua-Ojinaga
highway (Mexico 16), near Coyame (29°27'48.2" N, 105°5'1.2" W), 1270 m
(2594, 2596-7), in the central eastern part of the state (Fig. 1). Presumably
the subspecies borders the Rio Bravo throughout its length in the state;
further documentation is much to be desired.

The specimens from Coyame are all adult males 55-56 mm SVL, but
their dorsal pattern is obscured by formalin discoloration. A continuous,
broad dorsolateral light line is evident in the lightest example. The ab¬
dominal semeions are relatively weak in one, well developed or strong in

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Fig. 1. Suggested range limits of members of the Sceloporus undulatus group
in Chihuahua, Mexico. Circles, S. belli; triangle, S. u. consobrinus; solid
squares, S. u. speari; hollow square, locus of sympatry of S. belli and S. u.
speari; stars, S. virgatus.

the others. The gular semeions are well developed, in contact over 3-5
scale lengths, each covering 30-43 scales. The dorsals are 39(l)-40; femoral
pores 16(2), 17(2) or 18(2); minimum scales in a row between femoralpore
rows 6 in all; frontoparietals all 1-1, in contact in one, separated by fron¬
tal-interparietal contact in two; prefrontals in contact in two, separated by

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median frontonasal-frontal contact in one; minimum internasals in a row
on each side of median line between median frontonasal and rostral all 3-
3; preoculars single in all; lorilabials in two complete rows below subocular
on two sides, reduced to one row at least at one scale on four sides.

Sceloporus undulatus speari

This subspecies was originally described on the basis of 69 speci¬
mens from the extensive active sand dunes south and southwest of Cd.
Juarez, to which it was thought to be confined. Subsequent field work
and the present study have revealed that its range extends well beyond
the dunes (Fig. 1) northwestward to the U.S. border, eastward at least to
Puerto Ventana (31°9,15.3" N, 106°13'25.2" W) , 1532 m, and southward
to the range of S. belli , where the two species are marginally sympatric
and syntopic (Lemos-Espinal et al., 1998).

The 52 previously unreported specimens are from km 306, Hy 45,
sand dunes near Samalayuca (31°13'34.9" N, 106°30,29.7" W) 1282 m (2778-
80) ; Ojo de Enmedio sand dunes (31022'45.5" N, 106°35'2.8" W), 1290 m
(2838); Rancho El Espejo sand dunes (31°36'46.2" N, 106o53'41.3,, W), 1250
m (2852, 2855, 2857, 2863, 2866-7, 2899); El Tule (36331-2); El Ligato (36333-
4); 5 km N Hy 2, road to El Espejo (=Los Chontales) (36341); rest stop 11.2
km S Samalayuca, km 307. 65, Hy 45 (31°161.1" N, 106O3O'16.3" W) , 1320
m (36349, 36351-5, 36358); Cerros Colorados (36362-3, 36366); Puerto Ancho
(36372-97).

One female (2866) at 70 mm SVL slightly exceeds the previously
recorded maximum (69 mm). Color and pattern are much as previously
described. In the 18 females, 47.5-70 mm SVL, gular semeions are present
in all, but are always separated, usually small and dim; abdominal
semeions are completely absent in all but three, in which they are faint;
dorsolateral light lines always evident and uninterrupted, but dim in light-
colored individuals; lateral light lines always evident, seldom interrupted
but often weak; no clearly outlined dark spots bordering the dorsolateral
light lines medially, but vestiges usually visible.

In the 25 males, 43-60 mm SVL, for which data are available, the
gular semeions are separated in 17, in contact for a length of one scale in
1, two in 3, four in 1, five in 2, nine in 1; they are black-bordered in 2. The

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abdominal semeions are well developed in all, and separated by a mini¬
mum of 2-6 scales, usually 4; the dorsolateral light lines are broad and
uninterrupted in all; the lateral light lines are not evident at all in a few
(4), and where present are narrowly and often dimly margined by dark
color below.

Dorsals 34-43 (M-37.6), only one exceeding 40; femoral pores 13-19
(M=16.3), totals 28-37 (M-32.8); minimum scales in a row between pore
series 3-6 (M=4.4); prefrontals separated by contact of median frontonasal
and frontal in 9, by an azygous scale in 14, in contact in 20; frontoparietals
1-1 (30), 1-2 (7), 2-2 (5) or 1-3 (1), separated medially by contact of frontal
and interparietal in 31, by an azygous scale in 7, in contact in 5; fewest
internasals in a row between median frontonasal and rostral on each side
of the median line usually 3-3(29), but 2-2 in 6, 2-3 in 1, 3-4 in 5, 4-4 in 2;
preocular usually single (52 of 85 sides), but frequently divided into two
(30) or three (3) parts; lorilabials in two complete rows below subocular
on 40 sides, reduced to one row at least at one scale in 45.

The range of S. u. speari as now understood occupies the southern
part of the Cabeza de Vaca Basin (Axtell, 1978), extending a short distance
into New Mexico. A specimen (UTEP 3568) from 24 airline mi NNE
Ascenci6n, Chihuahua, is typical of the subspecies, and was erroneously
referred to S. u . consobrinus in Lemos-Espinal et al. (1998), before it was
realized that S. u. speari ranged so widely.

Sceloporus virgatus

Sixteen previously unreported but cataloged UMC specimens are
from 11 mi NW El Largo, 7900’ (20974-6); 1 mi N Garcia (20971); 9 mi W
Mesa de Huracan, 7000' (20977-9); 10 mi SE Mesa de Huracan, 3 mi NW
Chico, 7000' (20973); 14 mi SW Mesa de Huracan (20972); 7 mi SW Natachic
(20965-70); 71 mi SW Natachic, 5 mi NE Pinos Altos, 7800' (20964).

All specimens, both males (7) and females (9), exhibit small gular
semeions, widely separated by a distance of 5-9 scales (M=7.6). There is
no evidence of abdominal semeions in either sex. The dorsolateral and
lateral light stripes are prominent on a dark background; especially note¬
worthy is the broad dark brown line bordering the lateral light line below.
Dorsals 35-40 (M=37.5); femoral pores 12-16 (M=13.9), totals 25-30 (M=2S);
fewest scales in a row between pore series 3-6 (M=4.3); prefrontals sepa-

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rated by contact of median frontonasal and frontal in one, by an azygous
scale in 15, in contact in none; frontoparietals 1-1 in 9, 1-2 in 3, 2-2 in 3,
separated by contact of frontal and interparietal in 11, by an azygous scale
in 1, in contact in 2; fewest interna sals in a row between median frontonasal
and rostral on each side of the median line usually 3-3(8), but 2-2 in 3, 2-3
in 1, 3-4 in 3, and 4-4 in 1; preoculars 1-1 except 2 with 2-2 and 1 with 3-3;
lorilabiais in two complete rows below the subocular on 17 sides, reduced
to one row at least at one scale on 15; median frontonasal separated from
lateral frontonasal on 24 sides, in contact on 7 sides.

The entire range of this species is restricted to the Pacific side of the
continental divide, where it occurs in oak, pine and mixed oak-pine habi¬
tats at elevations of 5000-9600’ (Cole, 1968). Its southern distributional
limit in Chihuahua remains as uncertain today as it was thirty years ago
(Cole, 1968).

Comparisons

All of the S. undulatus group taxa of Chihuahua are allopatric, al¬
though marginal sympatry is known to occur at least at one locality (Cerros
Colorados) between S. belli and S. u. speari, and possibly occurs elsewhere
between those two taxa and between S. belli and S. u. consobrinus. Allopa-
try can aid greatly in identification by locality, but in the extensive areas
not yet sampled it can also be fallible because range limits there are at
present guesses based on topography.

The most distinctive species of the S. undulatus group in Chihua¬
hua is S. virgatus. It is the only one occurring west of the continental di¬
vide. It is unique, among the taxa of this group in Chihuahua, in com¬
pletely lacking abdominal semeions in males as well as females; in its
combination of bright, continuous lateral as well as dorsolateral light lines,
the former bordered ventrally by a broad, continuous, solid brown stripe;
by femoral pore scales usually notched both dorsally and ventrally (rather
than just ventrally as in most taxa); and by the presence of rugosity and
keels on some of the dorsal head scales. (Keels are especially evident on
the oculociliaries.) A distinct, median prefrontal concavity is present; the
adjacent scales are bulged somewhat, and lateral ridges are present on
the anterior moiety of the frontal. Those scales are characteristically flat
and smooth in the other species of the group. A weak prefrontal concavity

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December 1999

is present in S. belli of all sizes, but is not or scarcely evident in S. undulatus.

In addition, as pointed out by Cole (1963), the dorsals and femoral
pores average fewer in S. virgatus than in the other taxa of the group in
the state, and the scales around body average more numerous. In the data
on our series, the total femoral pore count is the most distinctive, only
17% of S. virgatus having as high as 30, whereas all of S. u. consobrinus (3)
do, 90% of S. u. speari (41), and 65% of S. belli (31). An azygous scale sepa¬
rates the prefrontals in 94% of S. virgatus (15 of 16), but only 33% of S. belli
(10 of 30), and of S. u. speari (14 of 43), none of the 3 S. u. consobrinus.
Similarly, the median frontonasal is separated from the lateral frontonasal
in 77% of S. virgatus (24 of 31 sides), but in only 8% of S. u. speari (3 in 40
sides), 10% of 5. belli (3 in 31 sides), and in none of the 3 S. u. consobrinus.

Sceloporus belli occupies most of the state east of the continental di¬
vide, except near the boundaries of the United States, where S. u. speari
and S. u. consobrinus occur. Mature S. belli are readily identified by pattern
and size, often exceeding 70 -mm SVL - a size rarely reached by S. u. speari ,
and seldom in S.u. consobrinus. Mature females lack distinct, continuous
dorsolateral light stripes, which area is invaded by relatively large, dark
transverse bars; they have no vestiges of abdominal semeions, and have
no or weak gular semeions. Mature males have very weak or no dorsolat¬
eral light lines, its area bordered laterally by a broad, continuous, uninter¬
rupted dark stripe, bordered in turn by a light area continuous ventrad
with the abdominal semeions; no or small, weak dark spots are present in
the area between the dorsolateral dark lines. Their gular semeions are
commonly (but not always) fused throughout their length, appearing as
one, and lack the black edging common in S. u. consobrinus.

Immature S. belli are less easily distinguished from either adjacent
subspecies of S. undulatus. No categorical distinctions exist in scalation.
The prefrontal concavity is subjectively more pronounced in S. belli than
in S. undulatus. The dorsals in the present specimens are usually (77%) 39
or more in S. belli (23 in 30), 32% (13 in 41) in S. u. speari. The minimum
number of scales in a row between femoral pore series is 5 or more in 77%
of S. belli (24 of 31), in 39% of S. u. speari (16 of 41). We find no other useful
distinctions from either subspecies of S. undulatus.

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December 1999

The two subspecies of S. undulatus in Chihuahua are distinguish¬
able to an acceptable degree in both pattern and scalation, as indicated in
Smith et al. (1995b), utilizing exotic material of S. u. consobrinus. That same
material, plus the three specimens of that subspecies here recorded, is
compared as follows with the data on S. u. speari here reported. Gular
semeions narrowly fused in 28% (8 of 29) of male S. u. speari , vs 71% of
male S. u. consobrinus (89% of those over 49 mm SVL), although rarely is
the fusion so extensive as to appear as a single semeion as is common in
male S. belli; where they are fused, a median black streak commonly sepa¬
rates two blue patches in S. u. consobrinus , not in either S. belli or S. u.
speari.

In male S. u. speari the abdominal semeions are mostly short; sel¬
dom do they reach the groin, whereas they mostly do so in S. u. consobrinus.

In female S. u. speari, gular semeions are usually absent, and when
present are small and faint, whereas they are regularly present and of
moderate size in female S. u. consobrinus. The latter occasionally have faint
evidence of abdominal semeions, never in S.u. speari.

The dorsal pattern is brightly striped in both sexes of S. u. speari ,
with no interruptions of the light lines; the lines are evident in S. u.
consobrinus , but often interrupted and not so distinct.

The most useful distinction in scalation is the more numerous dor¬
sals in S. u. consobrinus (84% 40 or more) than in S. u. speari (17% 40 or
more). In the latter, 61% have a minimum of 3 or 4 scales in a row between
the femoral pore series, as opposed to 18% in S. u. consobrinus.

Key to the Members of the Sceloporus undulatus

Group in Chihuahua

1 A. Found west of the continental divide; no abdominal semeions in
either sex; a uniformly dark, distinct sublateral line; lateral light
line well defined, uninterrupted; free edge of most femoral pore
scales notched; head scales microscopically rugose . virgatus

B. Found east of the continental divide; abdominal semeions promi¬
nent in all males except except the youngest; lateral light line less
well defined or interrupted, not bordered ventrad by such a

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sharply defined lateral dark line; free edge of femoral pores scales
not fully notched (notch if present limited to ventral surface); head
scales microscopically smooth . 2

2A. In females, paravertebral dark spots bar-like, interrupting dim
dorsolateral light lines, and gular semeions absent or weak or
small; in mature males, dorsum between broad, continuous, very
dark lateral dark lines mostly uniform brown, lacking distinct
dark spots and dorsolateral light lines; gular semeions with little
or no black, BLUE components at least partially fused, in males,
except the youngest . belli

B. In females, paravertebral dark spots, where evident, more nearly
rounded, less bar-like, and gular semeions well developed; males
with dorsal markings like females, and BLUE component of gu¬
lar semeions never fused (if the semeions are fused, it is by black
borders on the blue); dorsolateral light lines well developed in
both sexes . 3

3A, Females with no or small, faint gular semeions; abdominal
semeions usually short, not reaching groin, in males; dorsals 39
or fewer (§3%) . . . . . . . . . S. undulatus speari

B. Females regularly with well-developed gular semeions, except
In the youngest; abdominal semeions usually reaching groin, in
males; dorsals 40 or more (84%) . S. u. consobrinus

Ackno wled gments

We are grateful for the support of CONABIO project L103 for field
work by JAL-E; for the provision by Drs. Jane Bock, Michael Breed, Frank
van Breukelen, Alan de Queiroz, and Todd Gleeson of facilities and sup¬
port for studies at the University of Colorado; and for execution of the
map by Deborah Aguiar.

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 4

December 1999

Literature Cited

Axtell, R. W.

1978. Ancient playas and their influence on the recent
herpetofauna of the northern Chihuahua desert. Pp. 493-
512, figs. 1-10 in R. H. Wauer and D. H. Riskind, USDI
Natl. Park Serv., Trans, and Pdroc., 3: i-xxii, 1-658 (1977).

Cole, C. J.

1963. Variation, distribution, and taxonomic status of the liz¬
ard, Sceloporus undulatus virgatus Smith. Copeia, 1963: 413-
425.

1968. Sceloporus virgatus H. M. Smith. Cat. Am. Amph. Rept.,
(72): 1-2.

Conant, R. and J. T. Collins.

1998. Reptiles and amphibians: eastern central North America.
New York, Houghton Mifflin, xviii, 616 pp.

Fitch, H.

1978. Sexual size differences in the genus Sceloporus. Univ. Kan¬
sas Sci Bull., 51: 441-461.

Lemos-Espinal, J. A., H. M. Smith, R. E. Ballinger, G. R. Smith, and D.
Chiszar.

1998. A contribution to the superspecies concept of the lizard
Sceloporus undulatus: S. u. belli a species. Southwestern
Naturalist, 43: 20-24.

Smith, H. M., E. L. Bell, J. S. Applegarth, and D. Chiszar.

1992. Adaptive convergence in the lizard superspecies Sceloporus
undulatus. Bull. Maryland Herp. Soc, 28: 123-149.

_ _ D. Chiszar, and J. A. Lemos-Espinal.

1995a. A new subspecies of the polytypic lizard species
Sceloporus undulatus (Sauria: Iguanidae) from northern
Mexico. Texas J. Sci., 47: 117-143.

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Bulletin of the Maryland Herpetological Society

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December 1999

D. Chiszar, J. A. Lemos-Espinal, and E. L. Bell.

1995b. The Cabeza de Vaca Basin subspecies of the lizard
Sceloporus undulatus. Trans. Kansas Acad. ScL, 98: 44-60.

(JAL-E) Laboratorio de Ecologia , UBIPRO , Escuela Nacional de Estudios
Profesionales Iztacala, UN AM, Apartado Postal 314 , Avenida de Los Barrios s/
n, Los Reyes Iztacala Tlalnepantla , Estado de Mexico , 54090 Mexico; (DC)
Department of Psychology, and Museum , University of Colorado, Boulder ;
Colorado , 80309-0345 USA.; (HMS) Department of Environmental, Popula¬
tion and Organismic Biology, and Museum , University of Colorado, Boulder ,
Colorado , 80309-0334 USA.; and (CH) 11823 Eaton Way , Westminster,

Colorado , 80020 USA .

Received 3 May 1999

Accepted 18 June 1999

Bulletin of the Maryland Herpetological Society

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Volume 35 Number 4

December 1999

News and Notes

Reptile and
Amphibian Rescue
410-580-0250

We will try to take as many unwanted pet reptiles
and amphibians as we can.

Leave a message with your name and number to
give up an animal for adoption;
or to volunteer to help with our efforts.

WE NEED:

• Cages, Lights, Other Equipment & Food
• Drivers to Transport Animals
• Foster Homes • Adoptive Homes

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December 1999

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