Predation by the Texas Patch-nosed Snake (Salvadora lineata) on the Texas Alligator Lizard (Gerrhonotus infernalis) in the Sierra Zapalinamé, Municipalities of Saltillo and Arteaga, Coahuila, Mexico

Abstract

In this document we report predation by the Texas patch-nosed snake (Salvadora lineata) on the Texas alligator lizard (Gerrhonotus infernalis) in the state of Coahuila, Mexico. In addition, we describe certain aspects related to the biology of each species and provide a brief description of the study site. Resumen En este documento reportamos la depredación de la Serpiente Nariz Parche Tejana (Salvadora lineata) sobre el Lagarto Cocodrilo Tejana (Gerrhonotus infernalis), en el estado de Coahuila, México. Además, describimos algunos aspectos relacionados con la biología de cada especie y proporcionamos una breve descripción del sitio de estudio.

Full text

The star indicates the site of the event. Map by Javier Banda-Leal.
1. Profauna AC, Emilio Castelar 956, Zona Centro, Saltillo, Coahuila, C.P. 25000, México. cruz@profauna.org.mx
2. Sistemas de Innovación y Desarrollo Ambiental S.C., Tepeyac 159, Col. Churubusco, Monterrey, Nuevo León, C.P. 64590, México.
javier_banda@hotmail.com
3. Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, Laboratorio de Herpetología, Apartado Postal 157, San Nicolás de los Garza,
Nuevo León, C.P. 66450 México. imantodes52@hotmail.com.
4. Department of Humanities and Social Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia. lydiafucsko@gmail.com
5. Centro Zamorano de Biodiversidad, Escuela Agrícola Panamericana Zamorano, Departamento de Francisco Morazán, Honduras; 1350 Pelican Court,
Homestead, FL 33035-1031, USA. bufodoc@aol.com.
Bulletin of the Chicago Herpetological Society 57(12):214-218, 2022
Notes on the Herpetofauna of Mexico 40:
Predation by the Texas Patch-nosed Snake (Salvadora lineata) on the
Texas Alligator Lizard (Gerrhonotus infernalis) in the Sierra Zapalinamé,
Municipalities of Saltillo and Arteaga, Coahuila, Mexico
Arturo Cruz-Anaya 1, Javier Banda-Leal 2, David Lazcano 3, Lydia Allison Fucsko 4 and Larry David Wilson 5
Abstract
In this document we report predation by the Texas patch-nosed snake (Salvadora lineata)
on the Texas alligator lizard (Gerrhonotus infernalis) in the state of Coahuila, Mexico. In
addition, we describe certain aspects related to the biology of each species and provide a
brief description of the study site.
Resumen
En este documento reportamos la depredación de la Serpiente Nariz Parche Tejana
(Salvadora lineata) sobre el Lagarto Cocodrilo Tejana (Gerrhonotus infernalis), en el estado
de Coahuila, México. Además, describimos algunos aspectos relacionados con la biología
de cada especie y proporcionamos una breve descripción del sitio de estudio.
While conducting a survey of the condition of the piñonero
pine forest vegetation community of Sierra de Zapalinamé on 23
April 2022, we found a Gerrhonotus infernalis that had been
run over and killed on a dirt road by a group of ATVs that had
passed us previously. This finding was at 18:46 P.M., 11. 4 km
from the city of Saltillo, Coahuila, 6 km from the ejido “El
Diamante” (25E22'2.82"N, 100E54' 45.34"W).
On the next day, when we continued our survey at 11:39 A.M.,
we encountered the same DOR Gerrhonotus infernalis, but this
time it was being consumed by a Salvadora lineata. We also
noted that the snake had expelled ovarian follicles. We don’t
know if this was because we got too close without realizing it,
or if it was because the snake did it to make more space for its
food. We were observing the event at a prudent distance so as
not to disturb the snake. The event lasted 15 minutes. Later, the
snake slipped through the vegetation and disappeared.
Background on the predator, Salvadora lineata
Salvadora lineata Schmidt, 1940, the Texas patch-nosed
snake, is a colubrid snake distributed from eastern Texas in the
United States southward through northwestern Mexico in the
states of Chihuahua, Coahuila, Nuevo León, Tamaulipas,
Durango, Zacatecas, San Luis Potosí, Guanajuato, Querétaro,
Michoacán, northern Hidalgo, Puebla and western Veracruz
(Lemos-Espinal and Dixon, 2013; Ramírez-Bautista et al., 2014;
Heimes, 2016; Nevárez-de los Reyes et al., 2016; Terán-Juárez
et al., 2016; Lazcano et al., 2019; Hernández-Jiménez et al.,
2021; Torres-Hernández et al., 2021; Cruz-Elizalde et al., 2022).
The elevational distribution of this snake is from near sea level
to about 2600 m (Degenhardt et al., 1996; Stebbins, 2003;
Lazcano-Villareal et al., 2010; Heimes, 2016).
Salvadora lineata is primarily a montane snake, inhabiting
canyons, plateaus, mountain slopes, and occasionally desert
floors (Lemos-Espinal and Dixon, 2013; Heimes, 2016; Owens
et al., 2020). This patch-nosed snake primarily inhabits open
woodlands, prairies, and scrublands (Heimes, 2016). It is largely
terrestrial, agile, and fast-moving, occasionally moving into
shrubs to bask and escape predation; it is known to feed on a
broad variety of vertebrates, such as small mammals, birds,
small snakes, and lizards and their eggs (Tennant, 1984; Werler
and Dixon, 2000; Lazcano-Villareal et al., 2010; Lemos-Espinal
214

Early stages in the process of a Salvadora lineata consuming a road-killed Gerrhonotus infernalis. Note the expelled ovarian follicles in the lefthand image.
Photographs by Arturo Cruz-Anaya.
Later stages in the feeding process. Photographs by Arturo Cruz-Anaya.
and Dixon, 2013; Heimes, 2016; Lemos-Espinal et al., 2018;
Owens et al., 2020).
Salvadora lineata have been documented to prey on the
following lizard species: Aspidoscelis exsanguis and A.
marmoratus (Buford et al., 2018); possibly on Cophosaurus
texanus (DeSantis et al., 2016); Sceloporus grammicus (Cruz
and Suárez, 2019); S. olivaceus (Blair, 1960); S. scalaris
(Ramírez-Bautista et al., 2000).
Salvadora lineata is an oviparous snake, which reproduces
in March in Texas, and lays clutches of 3 to 10 eggs, with neo-
nates seen in August (Lemos-Espinal and Dixon, 2013; Heimes,
2016). The annual activity period of this snake usually extends
from March to November (Heimes, 2016).
The IUCN conservation status of this patch-nosed snake is
Least Concern, but the last assessment was in 2007 (IUCN,
2022). Its EVS (sensu Wilson et al., 2013) is 10, placing it at the
lower limit of the medium vulnerability category. This species is
not listed by SEMARNAT (Nevárez-de los Reyes et al., 2016).
Background on the Prey, Gerrhonotus infernalis
Gerrhonotus infernalis Baird, 1859, the Texas alligator
lizard, is an anguid lizard found from central Texas southward
through Chihuahua, Coahuila, Nuevo León, and Tamaulipas and
on into Durango, Zacatecas, San Luis Potosí, Querétaro, and
Hidalgo (Lemos-Espinal and Dixon, 2013; Ramírez-Bautista et
al., 2014; Nevárez-de los Reyes et al., 2016; Terán-Juárez et al.,
2016; Lazcano et al., 2019; Cruz-Elizalde et al., 2022). The
elevational distribution of this lizard is from 1350 to 3400 m
(Lemos-Espinal and Dixon, 2013).
This lizard primarily inhabits rocky hills in juniper-oak
woodlands, often in the vicinity of cliffs which can provide
refuges (Lemos-Espinal and Dixon, 2013). It moves slowly and
deliberately, seeking prey by stealth (Lemos-Espinal and Dixon,
2013). Its diet consists primarily of arthropod invertebrates,
such as beetles, crickets, cockroaches, grasshoppers, spiders,
and scorpions. It is an opportunistic feeder, so it also preys on
lizards and snakes (Greene et al., 2009; Lemos-Espinal et al.,
2018).
Gerrhonotus infernalis is oviparous and, as reported by
Lemos-Espinal and Dixon (2013), it appears to mate in the fall,
with oviposition occurring in the spring and hatching taking
place some 43–49 days thereafter. The eggs, which are laid
215

The pinoñero pine forest community in the Sierra de Zapalinamé, where
the event described here took place. Photograph by Arturo Cruz-Anaya.
under different natural shelters, are attended by the females
(Lemos-Espinal and Dixon, 2013).
Recently, Fielder et al. (2022) documented finding two nests
of Gerrhonotus infernalis underneath a small boulder at Selah,
Bamberger Ranch Preserve, Blanco County, Texas, USA. The
two females were coiled around separate clutches of eggs. Dur-
ing the study to document the nesting behavior of the lizard they
observed on video the frequent entrance of a Salvadora lineata
into the nests. When they returned to look at the site, the eggs
were missing, presumably consumed.
In another incident at the same place at Selah, Bamberger
Ranch Preserve, Blanco County, Texas, USA, they also ob-
served and video-recorded an adult Masticophis taeniatus prey-
ing upon an adult Gerrhonotus infernalis (J. Holmes, personal
communication).
The IUCN Red List conservation status for Gerrhonotus
infernalis is Least Concern (IUCN, 2022), and its EVS (sensu
Wilson et al., 2013) is 13, placing it at the upper limit of the
medium vulnerability category. This species is not listed by
SEMARNAT (Nevárez-de los Reyes et al., 2016).
Background on the Study Site
Sierra de Zapalinamé is a Natural Protected Area decreed in
1996 by the government of the state of Coahuila (Gobierno de
Coahuila, 1996). This mountain range is located north of the
Sierra Madre Oriental and is in the transition zone between the
floristic provinces of the Sierra Madre Oriental and the Mexican
Plateau (UAAAN, 1998). This area lies between 100E47' 14.5"
and 101E5'ì3.8" West longitude and between 25E13' 8.77" and
25E24'13.46" North latitude, and covers a bit more than 50,000
hectares.
The following plant communities are found within the area:
oak forest --- elevations between 2000 and 2600 m (area 692 ha);
oyamel (fir) forest --- elevations between 2700 and 3000 m (area
414.1 ha); pine forest --- elevations greater than 2600 m (area
2610.8 ha); piñonero (pinyon pine) forest --- elevations of 2150
to 2650 m (area 11,100.6 ha); chaparral scrubland --- elevations
of 1800 to 2800 m (area 13,253.1 ha); streams in scrubland ---
elevations of 1600 to 2100 m (area 584.2 ha); microphyllous
desert scrub --- elevations of 1900 to 2000 m. (area 1265.0 ha;
rosettophyllous desert scrub --- elevations of 2000 to 2500 m
(area 3234.4 ha); Juniperus forest --- elevations of 1970 to 2100
m (area 463.2 ha); zacatal --- elevations between 1850 and 2350
m (2917.2 ha); and riparian vegetation --- elevations of 1800 to
2300 m (area 26.7 ha) (Encina-Domínguez et al., 2019).
The area is home to a floristic richness estimated at 921
species, allocated to 110 families and 475 genera (Encina-
Domínguez et al., 2008; Encina-Domínguez et al., 2009;
Encina-Domínguez et al., 2012; Encina-Domínguez et al.,
2019), which represents 28.7% of the 3207 plant taxa reported
for the state of Coahuila by Villarreal-Quintanilla (2001).
Vegetation at the study site
The piñonero pine forest vegetation community is found at
altitudes between 2150 and 2650 m, in intermontane valleys
with deep soils and low slopes. This community is fragmented
by the establishment of rural anthropocentric settlements. The
forest is dominated by Pinus cembroides (Mexican pinyon pine /
pino piñonero) with an average diameter of 25 cm and height of
8 m. At higher altitudes there are isolated trees of Pinus
arizonica (Arizona pine / pino blanco); in the branches of the
trees it is common to find abundant epiphytic plants. On the
middle slopes with northern and northwestern exposure, the
forest presents an open canopy and is associated with montane
chaparral; on the drier slopes which have a southern exposure
xeric species infiltrate the area, with common rosettophyllous
desert scrub. The shrub stratum includes isolated individuals of
Juniperus deppeana (alligator juniper / sabino); in addition,
Agave gentryi (green agave / maguey verde) occurs. In areas
near the Cuauhtémoc ejido, the shrub stratum is dominated by
Prunus cercocarpifolia (wild peach / duraznillo silvestre). The
herbaceous stratum is dominated by Piptochaetium fimbriatum
(pinyon ricegrass / arocillo). In areas with more disturbance we
find Asphodelus fistulosus (onionweed / gamocillo), which is an
exotic plant, and Gymnosperma glutinosum (gumhead). On
slopes of southern exposure, on Cerro de los Elotes (northeast of
the ejido Sierra Hermosa) and south of the sierra in the ejido El
Recreo, there is forest, usually with an open canopy, in which
Pinus pinceana (Pince’s pinyon pine / piñón rosa) predominates
(Encina-Domínguez et al., 2019).
Materials and Methods
Monitoring flora and fauna is one of the main activities
regularly carried out by the staff of Profauna A.C., a non-gov-
ernmental organization (NGO) responsible for the administra-
tion, management, and protection of the Sierra de Zapalinamé
Protected Natural Area, located south of the City of Saltillo,
Coahuila, Mexico, and covering the municipalities of Saltillo
and Arteaga. On this occasion, the inspection area corresponded
to the pine community. That portion of the protected area ac-
counts for about 2610.8 hectares.
Discussion and Conclusions
The food preferences of Salvadora lineata have not been
well documented, so we are able to add an additional lizard
species. In addition, since the prey was dead at the time the
216

snake consumed it, technically it feeds on carrion. The expulsion
of the snake’s egg follicles during the consumption of the lizard
is a curious event, which requires further study.
Acknowledgment
To Profauna, A.C., for supporting and promoting research in
the Sierra de Zapalinamé State Nature Reserve.
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