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Drymobius chloroticus (Cope, 1886) occurs in
disjunct populations on the Atlantic versant from south-
eastern San Luis Potosí, México to Honduras, and on
the Pacific versant from central Guerrero, México to
northern Nicaragua, with an elevational distribution
that ranges from around 500 to 2500 m (Köhler, 2008;
Heimes, 2016; Bernal et al., 2022). In Chiapas, the
range includes the physiographic regions Northern
Highlands (including records from the municipalities
of Jitotol, Pueblo Nuevo Solistahuacán, and Rayón)
and the Sierra Madre de Chiapas (including records
from the municipalities of Acacoyagua, Angel Albino
Corzo, Cintalapa, Escuintla, Huixtla, Mapastepec,
Ocozocoautla de Espinosa, Siltepec, Unión Juarez,
and Villaflores) (Johnson et al., 2015; GBIF, 2021).
Information on the biology of this uncommon snake
is scarce; it is known to be diurnal and terrestrial, and
inhabits tropical montane forest, cloud forest and pine
oak forest (Wilson, 1975; Heimes, 2016). It feeds
primarily on anurans (Craugastor bocourti) and small
lizards (anoles) (Stuart, 1948; Wilson, 1970; Álvarez del
Toro, 1982). Females captured in mid-May contained
well-formed eggs (Stuart, 1948). It is not a nationally
protected species in Mexico (NOM-059-SEMARNAT-
2010; SEMARNAT, 2010), but is listed by IUCN as
Least Concern (LC) (López-Luna et al., 2013), and
its Environmental Vulnerability Score (EVS) has been
calculated as eight (8), placing it in the low vulnerability
category (Johnson et al., 2015).
Drymobius chloroticus is a medium-sized snake
reaching a total length (TL) of up to 1200 mm. It has 7–
10 supralabials, 8–12 infralabials, 1 loreal, 1 (rarely 2)
preocular, 1–4 (usually 2) postoculars, 2+2 temporals,
151–171 ventrals, 107–125 divided subcaudals, and
dorsals keeled in 17 (rarely 15) rows at midbody
(Wilson, 1970, 1975). The dorsal colouration is green
in dorsum and yellow ventrally, and occasionally brown
or grey on dorsum with dark brown paravertebral stripes
(varies geographically) (Wilson, 1970, 1975; Heimes,
2016). There is a slight sexual dimorphism in mean
number of ventrals (males = 151–167 [160.8]; females
= 157–171 [165.7]) and subcaudals (males = 108–124
[118.7]; females = 107–125 [117.8]) (Wilson, 1970).
The Central Plateau of Chiapas is one of the seven
physiographic regions of Chiapas; it is a highland block
situated east and northeast of the Central Depression,
south of the Northern Highlands, and west of the Eastern
Highlands. The highest portion of the Central Plateau is
in the middle segment near to San Cristóbal de las Casas,
where the maximum elevation is about 2900 m (Johnson
et al., 2015). There are 108 species of amphibians and
reptiles in the Central Plateau of Chiapas, with the
highest resemblance of species with the Northern
Highlands and is in the third position within Chiapas of
the Relative Herpetofaunal Priority (RHP), based on the
number of state and country endemics (Johnson et al.,
2015). Here, we present a new record for D. chloroticus
in the Central Plateau of Chiapas, Mexico.
On 15 September 2020, during fieldwork, we found
a juvenile male individual of D. chloroticus at 1.76 km
northeast of Santiago Guelatao in the Municipality of
Las Margaritas, Chiapas, (16.479097° N, -91.77853
Herpetology Notes, volume 16: 565-568 (2023) (published online on 08 August 2023)
The Green Highland Racer, Drymobius chloroticus (Squamata:
Colubridae): a new record for the Central Plateau of Chiapas,
México
Rubén Alonso Carbajal-Márquez1,2, J. Jesús Sigala-Rodríguez1,*, Juan José Ayala-Rodríguez1, Jorge Arturo
Hidalgo-García3, and Víctor Armando Moreno-Avendaño4
1 Universidad Autónoma de Aguascalientes, Centro de Ciencias
Básicas, Departamento de Biología, Colección Zoológica,
Aguascalientes, Aguascalientes 20100, México.
2 Conservación de la Biodiversidad del Centro de México
A. C., Andador Torre de Marfil No. 100, Aguascalientes,
Aguascalientes 20229, México.
3 El Colegio de la Frontera Sur, Unidad Chetumal,
Departamento de Sistemática y Ecología Acuática, Chetumal,
Quintana Roo 77014, México.
4 Universidad de Ciencias y Artes de Chiapas, Instituto de
Ciencias Biológicas, Tuxtla Gutiérrez, Chiapas 29029,
México.
* Corresponding author. E-mail: jesus.sigala@edu.uaa.mx
© 2023 by Herpetology Notes. Open Access by CC BY-NC-ND 4.0.
Rubén Alonso Carbajal-Márquez et al.
566
W; 2078 m elevation), in the physiographic region
Central Plateau of Chiapas. It was moving on the
ground on a path surrounded by secondary vegetation
and cloud forest. The specimen (snout-vent length = 435
mm, tail length = 216 mm), was identified following
Wilson (1970, 1975), and presents 2 internasal scales, 2
prefrontals, 1 frontal, 1–1 supraoculars, 1–1 parietals, 1
1 loreals, 1–1 preoculars, 2–2 postoculars, 1–1 anterior
temporals, 1–1 posterior temporals, 9–9 supralabials
scales, 11–11 infralabials scales, 17 midbody dorsal
scale rows, 159 ventrals, 113 subcaudals, and a
divided anal plate (Table 1). The colour on the top of
the head and dorsum of body is olive green, keels of
paravertebral rows are dark brown, forming a pair of
paravertebral stripes extending the length of the body,
tail above dark brown, dorsal ground colour extending
onto lateral one-fourth of ventral scutes, with dark
spots on the lateral edges of the ventrals; pale yellow
supralabials and chin shields, medial portion of venter
pale yellow on the anterior third of the body, whitish
in the second third, turning reddish in the last third
(Fig. 1). The specimen was collected under the permit
SEMARNAT SGPA/DGVS/7494/19 and deposited in
the Zoological Collection of the Universidad Autónoma
de Aguascalientes with catalogue number UAA-REP-
809.
Although there is individual variation in D.
chloroticus, very little of it is due to geographic,
sexual, or ontogenetic variation (Wilson, 1970). Also,
there is a slight ontogenetic change in colour, and it
seems advisable to consider that D. chloroticus has at
least two, and possibly more, colour phases (Wilson,
1970). Wilson (1975) stated a need to determine the
range and status of the colour pattern variants. Heimes
(2016) mentioned that dorsal colouration varies
geographically, with individuals from west of the
Isthmus of Tehuantepec usually grey or brown with
dark paravertebral keels, whereas those from east of the
Isthmus are uniform green. Our specimen (UAA-REP-
809) is a juvenile male captured east of the Isthmus of
Tehuantepec; however, it has an olive-green dorsum and
dark paravertebral stripes, so it does not agree with the
pattern suggested by Heimes (2016), and points to the
need of further investigation of this variation in dorsal
colouration.
This specimen represents the first record of the species
for the physiographic region Central Plateau of Chiapas
and for the municipality of Las Margaritas, and extends
the known geographic range 140 km in a straight-
line southeast from the closest records in the vicinity
of Pueblo Nuevo Solistahuacán, Chiapas (MZFC-
4224, MZFC-22043; CAS-165186) in the Northern
Highlands (Table 1; Fig. 2; GBIF, 2021). Additionally,
we found a specimen labelled as D. chloroticus
collected previously in the locality Finca San Jerónimo
in the coordinates 16.758333 °N, -91.541667 °W;
1490 m elevation (catalogue number UMSNH-54851);
however the coordinates correspond to Cruz de Plata,
Ocosingo municipality, Chiapas, when in fact, the
locality Finca San Jerónimo is in the municipality of
Unión Juarez, Chiapas (15.041126 °N, -92.137408 °W;
760 m elevation) and not in Ocosingo. Furthermore, the
specimen was incorrectly identified as D. chloroticus
and, it is in fact a specimen of D. margaritiferus (Chris
Phillips, pers. comm.). The area where we found D.
chloroticus is being rapidly transformed into crop and
livestock production, and probably threatened by use
of pesticides (Morales, 2013), which can cause the
populations of this species to disappear from the Central
Figure 1. Juvenile male specimen of Drymobius chloroticus
from Santiago Guelatao, Las Margaritas, Chiapas, Mexico
(UAA-REP-809). Photograph by J. Jesús Sigala-Rodríguez.
Table 1. Morphological data (body measurements and numbers for se lected scale characters) for specimens of
Drymobius chloroticus from the Central Plateau (UAA-REP-809) and the Northern Highlands (MZFC-22043,
CAS-165186) of Chiapas, Mexico. (SVL = Snout-vent length; TL = Tail length; VEN = ventral scales; SBC =
subcaudal scales; AP = anal plate; MDR = middorsal scale rows; SLS = supralabials scales; ILS = infralabial
scales).
Specimen number
SVL
TL
Sex VEN
SBC
AP MDR
SLS
ILS
UAA-REP-809 435 216
Male 159 1 13 divided
17 9–9 11– 11
MZFC-22043 400 180
Female
164 105 divided
17 9–9 11– 11
CAS-165186 743 406
Male 154 1 19 divided
17 9–9 11– 11
Table 1. Morphological data (body measurements and numbers
for selected scale characters) for specimens of Drymobius
chloroticus from the Central Plateau (UAA-REP-809) and the
Northern Highlands (MZFC-22043, CAS-165186) of Chiapas,
Mexico. (SVL = Snout-vent length; TL = Tail length; VEN =
ventral scales; SBC = subcaudal scales; AP = anal plate; MDR
= middorsal scale rows; SLS = supralabials scales; ILS =
infralabial scales).
The Green Highland Racer: a new record for the Central Plateau of Chiapas, México 567
Plateau of Chiapas. Our finding of D. chloroticus in
the Central Plateau suggests that additional species
from neighbouring physiographic regions of Chiapas
and Guatemala likely remain to be documented in this
region.
Acknowledgments. We thank L.D. Wilson for the pre-peer
review. We thank Chris Phillips (Illinois Natural History Survey
Amphibian and Reptile Collection), Lauren Scheinberg and
Erica Ely (Herpetology Collection of the California Academy of
Sciences), and Oscar Flores Villela and Israel Solano Zavaleta
(Museo de Zoología “Alfonso L. Herrera”, Universidad Nacional
Autónoma de México) for providing information and photographs
of specimens in their respective collections.
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Accepted by Javier Ernesto Cortés Suárez
ResearchGate has not been able to resolve any citations for this publication.
Article
Variation in and relationships between Drymobius chloroticus and D. melanotropis are discussed. A pattern phase of D. chloroticus from Oaxaca, Mexico is discussed.
  • P Heimes
Heimes, P. (2016): Herpetofauna Mexicana Vol. I. Snakes of Mexico. Frankfurt am Main, Germany, Edition Chimaira.
composition, distribution, and conservation
  • J D Johnson
  • V Mata-Silva
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  • L D Wilson
Johnson, J.D., Mata-Silva, V., García-Padilla, E., Wilson, L.D. (2015): The herpetofauna of Chiapas, Mexico: composition, distribution, and conservation. Mesoamerican Herpetology 2(3): 272-329.
Plaguicidas: una amenaza para la salud, la biodiversidad y los servicios ambientales
  • H Morales
Morales, H. (2013): Plaguicidas: una amenaza para la salud, la biodiversidad y los servicios ambientales. In: La biodiversidad en Chiapas: Estudio de Estado, p. 307-319. D.F., Mexico, Comisión Nacional para el Conocimiento y Uso de la
The Amphibians and Reptiles of Alta Verapaz, Guatemala. Miscellaneous publications, Museum of Zoology
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Stuart, L.C. (1948): The Amphibians and Reptiles of Alta Verapaz, Guatemala. Miscellaneous publications, Museum of Zoology, University of Michigan 69: 1-109.
Drymobius chloroticus (Cope) Green Highland Racer. Catalogue of American Amphibians and Reptiles 171
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Wilson, L.D. (1975): Drymobius chloroticus (Cope) Green Highland Racer. Catalogue of American Amphibians and Reptiles 171.