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Out of the Past: A new species of Tantilla of the calamarina group (Squamata: Colubridae) from southeastern coastal Guerrero, Mexico, with comments on relationships among members of the group

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A new species of Tantilla in the calamarina group from southeastern coastal Guerrero, Mexico is described. This new species is part of a clade that contains T. calamarina, T. cascadae, T. ceboruca, T. coronadoi, T. deppei, T. sertula, and T. vermiformis. All of these species are endemic to Mexico, except for T. vermiformis, which is found along the Pacific coastal plain from El Salvador to northwestern Costa Rica. Members of this group of Tantilla show varying adaptations to fossoriality, which might reflect their phylogenetic relationships
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Amphibian & Reptile Conservation
16(2) [Taxonomic Section]: 120–132 (e320).
Out of the Past: A new species of Tantilla of the calamarina
group (Squamata: Colubridae) from southeastern coastal
Guerrero, Mexico, with comments on relationships among
members of the group
¹Ricardo Palacios-Aguilar, ²Lydia Allison Fucsko, 3Víctor H. Jiménez-Arcos, 4,*Larry David Wilson,
and 5Vicente Mata-Silva
1Museo de Zoología “Alfonso L. Herrera” de la Facultad de Ciencias, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/n,
Coyoacan, CP 04510, MEXICO; Totlok A.C., C. P. 04350, Delegación Coyoacán, Ciudad de México, MEXICO Department of Humanities and
Social Sciences, Swinburne University of Technology, Melbourne, Victoria, AUSTRALIA Laboratorio de Herpetología Vivario de la Facultad
de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Tlanepantla, CP 54090, MEXICO Centro
Zamorano de Biodiversidad, Escuela Agrícola Panamericana Zamorano, Departamento de Francisco Morazán, HONDURAS; 1350 Pelican Court,
Homestead, Florida 33035-1031, USA Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas 79968-0500, USA
Abstract.—A new species of Tantilla in the calamarina group from southeastern coastal Guerrero, Mexico is
described. This new species is part of a clade that contains T. calamarina, T. cascadae, T. ceboruca, T. coronadoi,
T. deppei, T. sertula, and T. vermiformis. All of these species are endemic to Mexico, except for T. vermiformis,
which is found along the Pacic coastal plain from El Salvador to northwestern Costa Rica. Members of this
group of Tantilla show varying adaptations to fossoriality, which might reect their phylogenetic relationships.
Keywords. calamarina group, centipede snake, fossoriality, phylogenetics, Reptilia, taxonomy
Resumen.— Describimos una nueva especie de Tantilla del grupo calamarina de la costa sureste de Guerrero,
México. Esta nueva especie forma parte de un clado que contiene a T. calamarina, T. cascadae, T. ceboruca, T.
coronadoi, T. deppei, T. sertula y T. vermiformis. Todas estas especies son endémicas de México, excepto T.
vermiformis, que se encuentra a lo largo de la planicie costera del Pacíco desde El Salvador hasta el noroeste
de Costa Rica. Los miembros de este grupo de Tantilla muestran diversas adaptaciones a la fosorialidad, lo
que podría reejar sus relaciones logenéticas.
Palabras claves. Culebra ciempiés, fosorialidad, grupo calamarina
Citation: Palacios-Aguilar R, Fucsko LA, Jiménez-Arcos VH, Wilson LD, Mata-Silva V. 2022. Out of the Past: A new species of Tantilla of the
calamarina group (Squamata: Colubridae) from southeastern coastal Guerrero, Mexico, with comments on relationships within members of the group.
Amphibian & Reptile Conservation 16(2) [Taxonomic Section]: 120–132 (e320).
Copyright: © 2022 Palacios-Aguilar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License
[Attribution 4.0 International (CC BY 4.0): https://creativecommons.org/licenses/by/4.0/], which permits unrestricted use, distribution, and reproduction
in any medium, provided the original author and source are credited. The o󰀩cial and authorized publication credit sources, which will be duly enforced,
are as follows: o󰀩cial journal title Amphibian & Reptile Conservation; o󰀩cial journal website: amphibian-reptile-conservation.org.
Accepted: 11 October 2022; Published: 12 November 2022
O󰀩cial journal website:
amphibian-reptile-conservation.org
Introduction
A recent paper by Palacios-Aguilar et al. (2021) noted a
specimen of Tantilla from Guerrero that was collected
over a century ago (BMNH 1906.6.1.241). This specimen,
a female clearly referable to the Tantilla calamarina
group (Wilson and Meyer 1981), was discussed by
Wilson and Mata-Silva (2014) and determined to be
either an atypical individual of Tantilla coronadoi or a
representative of an unnamed taxon. Palacios-Aguilar
et al. (2021) suspected the latter alternative because
the three hitherto known specimens of T. coronadoi are
consistent in key aspects of their scutellation, but they
also declined to name a new species based on specimen
BMNH 1906.6.1.241, which was collected in 1904 by
Hans Gadow and reported as Homalocranium miniatum
in his 1905 paper. According to Dixon et al. (2000), the
name H. miniatum is a synonym of T. rubra.
Correspondence. ricardopalaciosaguilar@gmail.com (RPA), lydiafucsko@gmail.com (LAF), victorhja@iztacala.unam.mx (VHJA),
* bufodoc@aol.com (LDW), vmata@utep.edu (VMS)
urn:lsid:zoobank.org:pub:7F752CB7-4667-46F5-A44E-E4D165D28CF4
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Palacios-Aguilar et al.
Results
After detailed comparisons of the BMNH specimen
with the pertinent published sources and specimens held
      
1906.6.1.241 does indeed represent a new species of the
genus Tantilla.
Tantilla carolina, new species
Figs. 1–2.
Suggested common name. Carolina’s Little Snake.
urn:lsid:zoobank.org:act:B8520FC0-94E1-4A6F-8312-F6D3EA3434EF
Holotype. BMNH 1906.6.1.241, an apparent subadult or
juvenile female from Tezonapan (= Tecoanapa), north of
Ayutla, Guerrero, Mexico, collected by Hans Gadow in
1904.
Diagnosis. Tantilla carolina is a member of the T.
calamarina      
Tantilla calamarina by the presence of more ventrals in
females (156 versus [hereinafter = vs.] 118–140), more
total segmental scales (194 vs. 146–179), a normally-
sized preocular scale in contact with the postnasal scale
(vs. a preocular with a tendency toward a decrease in size
to complete the loss of the scale), two postocular scales
(vs. one), seven supralabials (vs. usually six), a uniform
dorsal head color followed by two pale postparietal
spots (vs. a head pattern consisting of a spatulate dark

When the Palacios-Aguilar et al. (2021) paper
appeared, one author of this paper (LDW) contacted
the senior author and proposed reexamining the
BMNH specimen to determine whether its status could
       
understanding of the content and relationships within the
Tantilla calamarina group. Consequently, the authors
of this paper decided to collaborate in an attempt to
determine on the status of this curious specimen, which
has been lying in anonymity since it was collected 118
years ago.
   
the Past) are used in reference to the period of time this
specimen, which now becomes the holotype of a new
species of Tantilla, has resided in the BMNH collection.
These words also refer to the period of time that has
elapsed since the person after whom this snake is being
   
the tyranny in her homeland in her adopted land of
Out of the Past will

1947 work of French director Jacques Tourneur starring
Robert Mitchum, Jane Greer, and Kirk Douglas.
Materials and Methods
        
examining specimens of the genus Tantilla, resulting
in the publication of several taxonomic treatments and
species descriptions within this genus (e.g., Wilson and
Meyer 1981; Wilson 1999; Wilson and Campbell 2000;
Wilson and Mata-Silva 2014, 2015). While compiling
        T.
calamarina species group (Wilson and Meyer 1981),
measurements and scale counts were obtained for the
specimen that now is the focus of this paper (BMNH
1906.6.1.241). Soon after that work started, the Senior
Curator of Reptiles at the Natural History Museum,
London, was contacted to obtain morphological data
on the specimen, as well as high quality photographs.
The photographs aided in making comparisons with the
representatives of the T. calamarina species group.
In addition to the aforementioned works on the genus
Tantilla       
     
involving the calamarina species group (Canseco-
Márquez et al. 2007; Cisneros-Bernal et al. 2020;
       
      
2014; Rocha et al. 2016), as well from the examination of
comparative material housed at the Colección Nacional
        
      
(MZFC), both at the Universidad Nacional Autónoma
de México. Scale counts and digital photographs of
specimens deposited in the herpetological collection of
the University of Texas at Arlington (UTA-R) were also
obtained. The measurements are indicated in millimeters,
and the ventral scales were counted following the
method proposed by Dowling (1951), with the segmental
counts referring to the sum of the ventrals + subcaudals,
excluding the cloacal scute.
Fig. 1. Dorsal (A), lateral (B), and ventral (C) views of the
head of the holotype of Tantilla carolina sp. nov. (BMNH
1906.6.1.241).
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A new Tantilla species in the calamarina group from Guerrero, Mexico
  
with the pale postparietal spots), and a body pattern
involving a dark lateral stripe that does not extend to
the end of the body (vs. a dark brown lateral stripe on
rows 3 and 4 extending the length of the body). The new
Tantilla cascadae by the presence of
more ventrals in females (156 vs. 139–144), more total
segmental scales (194 vs. 176–192), seven supralabial
scales (vs. six), and the dorsum of the head without a
pattern but containing a pair of small pale postparietal
spots (vs. a spatulate dark anterior extension of the

      
narrowly separated from the pale postparietal spots). The
    Tantilla ceboruca by lacking
a pattern and a pair of small pale postparietal scales
on the dorsum of the head (vs. a spatulate extension of
       

anteriorly along the sides of the parietal scales and
across the supraoculars and prefrontals to join on the
internasals), and a lateral portion of the head without
a pattern (vs. one having each supralabial with a white
Tantilla coronadoi
by the presence of fewer ventral scales (156 vs. 165–
178), fewer subcaudal scales (38 vs. 40–41), fewer total
segmental scales (194 vs. 205–219), the anterior and
posterior temporals in contact with one another (vs. those
two scales separated from one another by contact of the
7th supralabial and the parietal scale), and the dorsal
and lateral portions of the head lacking a pattern (vs. a
dorsal head pattern consisting of a spatulate dark anterior
        
anterior extensions of the dorsolateral ground color, and
a lateral head pattern consisting of supralabials with dark
 
from Tantilla deppei by the presence of fewer subcaudal
scales (38 vs. 43–50), fewer total segmental scales (194
vs. 196–214), and the dorsal and lateral portions of the
head lack a pattern and a pair of small pale postparietal
spots (vs. a spatulate dark anterior extension of the

of a middorsally-divided pale nuchal band). The new
  Tantilla sertula by the presence of
fewer ventrals in females (156 vs.161), more subcaudals
in females (38 vs. 30), more total segmental scales (194
vs. 191), and the dorsal and lateral portions of the head
lack a pattern (vs. a dorsal head pattern consisting of a
spatulate dark anterior extension of the middorsal dark
      
      
    Tantilla vermiformis by the
presence of more ventral scales in females (156 vs.
120–129), more subcaudal scales (38 vs. 19–24), more
total segmental scales (194 vs. 140–150), as well as by
the presence of a small pair of pale postparietal spots

both parietal scales).
Description of the holotype (Figs. 1–2). An apparent
subadult or juvenile female with 15 smooth dorsal scales
throughout the trunk, 156 ventrals, a divided cloacal
scute (= anal plate), 38 subcaudals, a total length of 112
mm, a tail length of 14 mm, and a tail/total length ratio
of 0.125.
Nasal completely divided, posterior section in broad
contact with a single preocular on both sides of head; two
postoculars, approximately subequal in size; one anterior
and one posterior temporal, in contact with one another,
      
seven from parietal, posterior temporal shorter than
anterior temporal, approximately the shape of a dorsal
body scale, although somewhat larger; supralabials
7–7, the 1st in contact with rostral, prenasal, postnasal,
and 2nd supralabial, the 2nd with postnasal, preocular,
and 3rd supralabial, the 3rd with preocular, orbit, and
4th supralabial, the 4th with orbit, lower postocular, and
5th supralabial, the 5th with lower postocular, anterior
temporal, and 6th supralabial, the 6th with 5th supralabial,
anterior temporal, and 7th supralabial, the 7th with the 6th
Fig. 2. Dorsal view of the holotype of Tantilla carolina sp. nov. (BMNH 1906.6.1.241).
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Palacios-Aguilar et al.
Features T. carolina T. calamarina T. cascadae T. ceboruca T. coronadoi T. deppei T. sertula T. vermiformis
Total length (mm) 112 72–202 158–196 175–200 161–183 95–273 89–152 157
Tail length (mm) 14 13–36 30 33–35 25–31 16–62 12–21
Relative tail length 0.125 0.110–0.211 0.138–0.190 0.164–0.194 0.155–0.169 0.166–0.254 0.121–0.157 0.096–0.150
Ventrals in males 106–133 (119.7) 138–146 158 142–154 (145.9) 153? 115–123 (119.6)
Ventrals in females 156 118–140 (129.0) 139–144 (141.5) 153–178 165–178 (171.5) 148–168 (160.1) 160–161 120–129 (124.2)
Subcaudals in
males 30–43 (36.8) 42–47 35+ (?) 54–62 (57.2) 37? 23–28 (25.3)
Subcaudals in
females 38 22–43 (28.8) 37–48 (42.5) 36–41 40–41 (40.5) 43–58 (46.2) 30–33 19–24 (21.0)
Ventrals +
subcaudals in
males
145–166 (156.9) 180–193 196–213 (203.1) 190? 141–147 (144.5)
Ventrals +
subcaudals in
females
194 146–179 (158.0) 176–192 (184.0) 189–219 205–219 (212.0) 196–214 (206.3) 191–193 140–150 (144.7)
Preocular Present, in contact
with postnasal
Tendency toward
decrease in size to
complete loss
Present, in contact
with postnasal
Present, in contact
with postnasal or not
Present, in contact
with postnasal
Present, in contact with
postnasal
Present, in
contact with
postnasal
Present, in contact
with postnasal,
sometimes fused
with prefrontal
Number of
postoculars 2 1 2 2 2 2 2 2
Number of
supralabials
(number entering
orbit)
7 (3+4) Usually 6 (3+4) 6 (3+4) 7 (3+4) 7 (3–4) Usually 7 6–7 7
Table 1. Comparison of selected morphological features among the eight members of the Tantilla calamarina group. Data summarized from Wilson and Campbell (2000);
Savage (2002); Canseco-Márquez et al. (2007); Wilson and Mata-Silva (2014); Cruz-Sáenz et al. (2015); Rocha et al. (2016); and Palacios-Aguilar et al. (2021).
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A new Tantilla species in the calamarina group from Guerrero, Mexico
Features T. carolina T. calamarina T. cascadae T. ceboruca T. coronadoi T. deppei T. sertula T. vermiformis
Anterior and
posterior temporals
separated
No No No No Yes No No No
Fusion of anterior
temporals and
sixth supralabial
No No No No No No No 
Dorsal head
pattern
Dorsum of head
without pattern;
pale postparietal
spots limited
to single scale
located posterior to
juncture between
posterior temporal
scale and parietal
scale
Spatulate dark
anterior extension
of middorsal dark

by prominent
pale narrow
longitudinal
markings

postparietal spots
Spatulate dark
anterior extension
of middorsal dark

narrow longitudinal

with pale postparietal
spots or narrowly
separated from
postparietal spots
Spatulate extension
of middorsal dark

pale longitudinal

with pale postparietal
spots, and extending
anteriorly along sides
of parietals, and
across supraoculars
and prefrontals to join
on internasals
Spatulate dark
anterior extension
of middorsal dark

by pale anterior
extensions of
dorsolateral
ground color
Spatulate dark anterior
extension of middorsal

pale anterior extensions
of middorsally-divided
pale nuchal band
Spatulate dark
anterior extension
of middorsal dark

by prominent
pale narrow
longitudinal
markings

pale postparietal
spots
Dark brown
dorsally and
laterally with tan,
pale lavender, or
pale brown blotches
on posterior portion
of parietals
Lateral head
pattern Uniform in color
Each supralabial
scale with a white
border
Uniformly dark
brown in color
Body pattern
Dark lateral stripe
does not extend to
end of body
Tan to brown with
variously-sized
dark middorsal
stripe and a dark
brown lateral
stripe on rows 3
and 4
Pale brown with
dark middorsal stripe
occupying middle of
middorsal scale row;
dark lateral stripe on
rows 3 and 4 only in
neck region
Dark brown with
dark middorsal stripe
covering middle of
middorsal scale row
on most of body;
dark lateral stripe on
adjacent halves of
rows 3 and 4
Tan to brown with
dark middorsal
stripe occupying
middle of
middorsal scale
row and dark
lateral stripe on
rows 3 and 4
Tan to brown with

sized middorsal stripe
and dark lateral stripe
on row 3 or rows 2 and

row 5
Dorsum pale
brown on rows 5
to 7, dark brown
on rows 1 to 4;
dark middorsal
stripe on middle
of middorsal row,
narrowing to
series of disjunct
longitudinal
dashes continuing
to end of tail
Pale brown to
brown dorsum
with poorly-

dark middorsal

middorsal row
Ventral pattern Immaculate cream Immaculate cream
Cream to pale
greenish yellow, with
slight amount of dark
pigment at lateral
apices
Immaculate cream to
pale greenish yellow
Immaculate cream
to white Immaculate cream Immaculate
cream
Immaculate white,
cream, pale yellow,
or pale pink
Table 1 Continued. Comparison of selected morphological features among the eight members of the Tantilla calamarina group. Data summarized from Wilson and
Campbell (2000); Savage (2002); Canseco-Márquez et al. (2007); Wilson and Mata-Silva (2014); Cruz-Sáenz et al. (2015); Rocha et al. (2016); and Palacios-Aguilar et al.
(2021).
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Palacios-Aguilar et al.
supralabial, anterior and posterior temporals, and two
post-cephalic scales, with the 7th the largest; infralabials
6–6, with the 1st pair separated by contact of mental
        
anterior chin shields, with the 4th largest; and anterior
chinshields larger than posterior pair.
In preservative, the dorsal and lateral portions of
the head are uniform dark brown, without a pattern
(Fig. 1). A pair of pale postparietal spots, pale yellow
in color, are present on the single scales located at the
juncture of the parietal and posterior temporal scales,
one each on either side of the head (Fig. 1). The dorsal
ground color in preservative is brown with a dark
brown middorsal stripe confined to the middorsal scale
row, which extends to the end of the tail, breaking up
into isolated dark spots, one per scale on the posterior
region of the body and tail (Fig. 2). The remainder of
the dorsum lacks a pattern. The venter is a uniform
(perhaps cream) color in preservative.
Distribution. Known only from the type locality
(Fig. 3). Tecoanapa is the seat of the municipality of
Tecoanapa in the Pacific lowlands of southeastern
Guerrero (coordinates 16°53’N, 99°24’W). Tecoanapa
is a city located on Mexico Highway 95, east-northeast
of Acapulco and south-southeast of Chilpancingo.
The town lies at an elevation of 431 m (http://
PueblosAmerica.com; accessed 30 March 2022).
The vegetation in the region consists of a mixture
of tropical deciduous forest (selva baja caducifolia),
oak forest (bosque de encino), and agricultural lands,

Conservation assessment. The Environmental Vul-
nerability Score (EVS) for Tantilla carolina can be
calculated as 6 + 8 + 2 = 16, which places its score in
the middle of the high vulnerability category, as ex-
plained by Wilson et al. (2013).
Etymology. We are privileged to name this small
snake in honor of the Hungarian Freedom Fighter
Karolina Laszló (Fig. 4), in recognition of her
dedication to the maintenance of human rights for
all peoples in the face of totalitarianism, beginning
with the Hungarian Revolution in 1956. As a young
woman, Karolina was forced to join the exodus of her
country people, in the company of her new husband,
a soldier, Ede Károly Fucskó, who bravely defied the
Hungarian dictatorship, communism, and the invading
Soviet army. Ede Károly Udvarhelyi was adopted at
an early age, when his mother remarried and thus kept
the surname Fucskó. As the couple roamed through
several European countries, in search of a refuge from
the terror of oppressive political regimes, they escaped
to England before seeking asylum in Australia. Due
to unforeseen circumstances, however, the family of
Fig. 3. Geographic distribution of the Tantilla calamarina group species in western Mexico. The black star represents
the type locality of Tantilla carolina sp. nov. described herein.
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A new Tantilla species in the calamarina group from Guerrero, Mexico
Key to the members of the Tantilla calamarina group
1. Anterior and posterior temporals separated by contact of 7th supralabial and parietal. . . . . . . . . . . . . . . . . . . . T. coronadoi
Anterior and posterior temporals in contact, not separated by contact of 7th supralabial and parietal … . . . . . . . . . . . . . . 2
2. Postocular single .......................................................................... T. calamarina
Postoculars two.......................................................................................3
3.Ventrals fewer than 130; subcaudals fewer than 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. vermiformis
Ventrals 130 or more; subcaudals 30 or more ............................................................. 4
4.Ventrals 144 or fewer .........................................................................T. cascadae
Ventrals 153 or more .................................................................................. 5
5. Dark lateral stripe present ..............................................................................6
Dark lateral stripe absent ...............................................................................7
6. Dark lateral stripe on adjacent halves of rows 3 and 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. ceboruca
Dark lateral stripe on row 3 or on rows 2 and 3 ..................................................... T. deppei
7. Dorsal head pattern consists of a spatulate dark anterior extension of the middorsal dark stripe occupying dorsum of

three dorsal scales immediately posterior to the posterolateral portion of each parietal scale. . . . . . . . . . . . . . . . . . T. sertula

...................................................................................... T. carolina sp. nov.
Fig. 4. (Left) The Hungarian Freedom Fighters, Karolina and Ede Károly Fucskó, in Hyde Park, London, England,
1958. (Right) Enduring photographs of Karolina and Ede Károly Fucskó.
five later travelled back to Hungary, residing there
for several years before escaping again to Vienna,
Austria, then travelling to Italy, and from there they
journeyed to South Africa. There, they dared to oppose
the policy of apartheid but eventually, under duress,
had to flee as interracial tensions escalated into further
hostilities and reprisals. Finally, the family found
relative solace in the democratic land of Australia,
where life remained challenging in such a strangely
beautiful land. During this long trek to find a life of
freedom, Karolina and Ede were accompanied by their
three children, John Edward, Stephen Charles, and a co-
author of this paper, Lydia Allison Fucsko. Therefore,
in Karolina’s honor, we named this snake Tantilla
carolina sp. nov., with a reference to the meaning of

         
indomitable, and spirited lady whose humanitarian
efforts continue to inspire future generations.
Discussion
Wilson and Meyer (1981: 2 –3) established a case for
the recognition of the Tantilla calamarina group, which
they maintained consisted of four species, including T.
calamarina, T. coronadoi, T. deppei, and a species they
described as new, T. cascadae
recognition of the calamarina group primarily was based
        
(1981: 2) detailed that all four species they recognized
          
parietals covered with a spatulate anterior extension of
the middorsal dark stripe, which continues anteriorly to

central head mark is a postparietal pale spot that usually
grades posteriorly into the ground color of the dorsolateral
       
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Palacios-Aguilar et al.
anteriorly with a narrow extension that proceeds along
the side of the parietal, over the supraocular and onto the

this group also exhibit a dark middorsal stripe occupying
some portion of the middorsal scale row and, in some
cases, a portion of the adjacent dorsal scale rows.
In subsequent years, another species of Tantilla, T.
vermiformis, was allocated to the calamarina group
(Wilson 1999). This allocation, however, was questioned

him] to not include T. vermiformis in the T. calamarina
group as suggested by Wilson et al. (1999) and Wilson
and Campbell (2000). Similarities between these taxa
may be due to convergent adaptations for fossoriality and

     
material becomes available would include whether T.
vermiformis is more closely related to the members of
the T. melanocephala group (Wilson and Mena 1980) or
to some other member or members of the genus not yet

In 2000, Wilson and Campbell described Tantilla
sertula
Guerrero, Mexico, and allocated this species to the
calamarina group. A second specimen of this species
was documented from the coastal plain of Guerrero
by Canseco-Márquez et al. (2007). Thereafter, Rocha
et al. (2016) reported a third specimen of this species
from the lower foothills of the Sierra Madre del Sur
      
(2007) described Tantilla ceboruca from southern
Nayarit, Mexico. These authors also placed this species
in the calamarina group.
Thus, with the description of T. ceboruca in 2007,
the calamarina group was considered to consist of
seven species, including, in order of year of description:
T. vermiformis (Hallowell 1861), T. calamarina (Cope
1866), T. deppei (Bocourt 1883), T. coronadoi (Hartweg
1944), T. cascadae (Wilson and Meyer 1981), T.
sertula (Wilson and Campbell 2000), and T. ceboruca
(Canseco-Márquez et al. 2007). With the description
of T. carolina, the genus Tantilla currently is known to
contain 68 species (The Reptile Database, http://www.
reptile-database.org/; accessed 15 May 2022).
Most species in the calamarina group are distributed
in the western portion of Mexico, from northern Sinaloa
Tantilla vermiformis,

America from El Salvador to northwestern Costa Rica
(Wilson and Mata-Silva 2015; Antúnez-Fonseca et al.
2020a). The northernmost-occurring and most widely-
distributed species in the group is T. calamarina, which is
known from northern Sinaloa to south-central Guerrero,
       
   
is from near sea level to 1,677 m asl. In comparison,
the remaining species in the group are narrowly
distributed, as follows: T. cascadae (1,430–1,858 m
asl from south-central Jalisco to central Michoacán); T.
ceboruca (1,233–2,094 m asl from southeastern Nayarit
to north-central Jalisco); T. coronadoi (650–1,524 m asl
in northeastern and central Guerrero); T. deppei (1,524–
2,438 m asl in northern Morelos, northern Guerrero, and
  T. sertula (near sea level–487
m asl from northwestern Guerrero to south-central
  T. vermiformis (40–520 m asl from El
Salvador to northwestern Costa Rica).
        
presently allocated to the calamarina group is that
they show varying adaptations to a fossorial existence.
      
       
fossorial adaptation among the seven members of this
group, as then comprised, based on features of cephalic
scutellation and segmental counts. These features
were documented in Table 1 of that paper, converted
to character states that were placed in Table 2 of that
paper, which then were collated to produce an index of
fossoriality. The reader should refer to that paper for a
more thorough explanation of the index of fossoriality.
These authors concluded their analysis of fossoriality
in the calamarina group by stating (pp. 803–804) that
        
generalized calamarina group species, such as T. sertula
and T. deppei…, intermediate values are found in the
more adapted species, such as T. ceboruca, T. coronadoi,
T. cascadae, and T. vermiformis…, and high indices in
the most adapted species, i.e., T. calamarina and G.
redimitus
     
Bautista et al. (2014), we determined the index of
fossoriality for Tantilla carolina as follows:
Preocular present—1
Preocular in contact with postnasal—1
Preocular fused with prefrontal and supraocular—1
Number of postoculars—1
5th supralabial separated from parietal—1
6th supralabial fused with anterior temporal—1
7th supralabial and parietal in contact—1
Number of supralabials—1
Supralabials entering orbit—1
Number of ventrals—1
Number of subcaudals—2
The sum of these 11 character-values for T. carolina is 12,
the same value as calculated for T. sertula
Bautista et al. (2014). This index of fossoriality is the
lowest among the members of the calamarina group,
in which the indices range from 12 to 24 (including
that for Geagras redimitus, which was included in the
calamarina group by Holm [2008]). This determination
indicates that T. carolina and T. sertula are the two
members of the group that are the least adapted for a
fossorial existence. The indices of fossoriality for
the other species involved, in increasing value, are as
follows: T. deppei (13); T. ceboruca and T. coronadoi
(both 14); T. cascadae (15); T. vermiformis (16); T.
calamarina (21); and G. redimitus (24).
       
index of fossoriality is not intended to elucidate the
phylogenetic relationships within the calamarina group,
but it is tempting to hypothesize that this index perhaps

128
Amphib. Reptile Conserv. November 2022 | Volume 16 | Number 2 | e320
A new Tantilla species in the calamarina group from Guerrero, Mexico
proposal of Flores-Villela and Goyenechea (2001) that this
province serves both as a corridor for lowland species and
as a barrier for montane species of amphibians and reptiles.
Nonetheless, there are areas of the PCP where interesting
sets of microendemic species of reptiles are found (Palacios-
Aguilar et al. 2018), and overall, a high proportion of
endemic amphibians and reptiles occur in this province
(Johnson et al. 2017), which might suggest that it is not
as homogeneous as previously considered and that biotic
subprovinces may be present within it. Detailed, objective
biogeographic studies are necessary to test this hypothesis,
now that novel information on species previously known
from few localities or specimens is emerging.

we know about biodiversity. The biodiversity shortfalls such
as the Wallacean, the limited knowledge on the distribution
of species, and the Linnean, the proportion of undescribed
diversity, are two of the most important limiting factors
that beset our understanding and knowledge of the natural
          
the vertebrate fauna of southern Mexico has been reported
(Bojórquez-Tapia et al. 1994, 1995), and it is expected to
diminish progressively as collectors and researchers reach
previously inaccessible regions. In recent decades, it has
been reported that species extirpations and extinctions
have been augmented in an unprecedented way due to the
negative impact of human activities (Dirzo et al. 2014).
This highlights the importance of having accurate and

         
shortfalls and allow us to provide an accurate image of how
many, where, and which species exist in a particular region.
Also, one should note that not all taxa have the same rate of
species descriptions, and particularly in snakes, the shelf-life
that specimens have from their collection to their description
ranges from 0 to 146 years (mean 7.5 years, Guedes et al.
2020), inasmuch as the conduct of taxonomic treatments is
one of the factors that boosts species discovery. The new
  
118 years, which makes it a snake species with one of the
longest shelf lives, and thanks to the conduct of a taxonomic
treatment and the adequate housing of the individual in one

identify it as a novel taxon. We can only imagine how many
more species in Mexico (and the world) probably are now
on a shelf awaiting discovery.
Acknowledgments.—We are indebted especially to Patrick
Campbell, who made it possible for us to obtain basic
morphological data on the BMNH specimen we designated
as the holotype of the new species of Tantilla described
herein. We also wish to thank Louis W. Porras for assistance
in securing the necessary literature for use in this paper, and
for his masterful review of our work. We also are grateful to
David Lazcano for his review, which greatly improved our
manuscript. We also thank Marisol Gómez for her invaluable


      
access, associated data, photographs, and measurements
of the specimens under their care or those with which they
were working.
be substantiated by a molecular analysis, should such an
analysis ever become possible. The timeline for such an
        
the species involved are known from only a handful of
preserved specimens (or only one).
If and when a molecular analysis of the phylogenetic
relationships of this group of snakes becomes possible,
     
following: (1) Is Geagras redimitus closely related enough
to the members of the Tantilla calamarina group to be
subsumed into this group, as per the conclusion of Holm
(2008)? (2) Is Tantilla vermiformis closely related enough
to the unquestioned members of the calamarina group to be
included within it, or do its closest relationships lie elsewhere
in the genus Tantilla? (3) Is Tantilla carolina closely related
enough to the unquestioned members of the calamarina
group to be included within it? (4) What are the phylogenetic
relationships of the nine species involved to one another?
and (5) What are the relationships of these species to the
other members of the genus Tantilla?
In their treatment of the Tantilla clade, Wilson and Mata-
Silva (2015) noted that the genus Tantilla contained 61
species at that point. With the description of Tantilla carolina,
the genus now contains 68 species, and it remains the
second largest genus of snakes in the Western Hemisphere
after Atractus (currently containing 146 species, according
to The Reptile Database, http://www.reptile-database.org/;

more species than TantillaOligodon
(presently consisting of 88 species, according to The Reptile
Database, http://www.reptile-database.org/; accessed 9
April 2022). The seven species of Tantilla described since
the Wilson and Mata-Silva (2015) paper was published
are (listed alphabetically): T. berguidoi Batista et al. 2016;
T. excelsa McCranie and Smith 2017; T. gottei McCranie
and Smith 2017; T. lydia Antúnez-Fonseca et al. 2020b; T.
stenigrammi McCranie and Smith 2017; and T. tjiasmantoi
Koch and Venegas 2016. Six of these seven species are
allocated to the Tantilla taeniata group. The remaining
species (T. tjiasmantoi) was not placed in a species group by
the original authors, but its unusual pattern of dark banding
on a pale ground color might suggest that this species is
allied with another South American species that sometimes
is banded, T. semicincta (Wilson 1976).
In the last two decades, about 40 new species of snakes
have been described from Mexico, including four that are

the holotype of T. carolina was obtained (i.e., Tantilla
sertula Wilson and Campbell 2000; Thamnophis rossmani
Conant 2000; Coniophanes michoacanensis Flores-Villela
and Smith 2010; and Rhadinella dysmica Campillo et al.
2016). Surprisingly, this region has received less attention
when compared with the adjacent elevations of the Sierra
Madre del Sur, and few collections have been made in
this area (e.g., Holman 1964; Liner and Dundee 1969;
Saldaña de La Riva and Pérez Ramos 1987; Schätti and
Stutz 2016). Recent scattered reports have recorded several
species of snakes with hitherto restricted ranges that were
found hundreds of kilometers from their previously known
localities (Siria-Hernández et al. 2006; Rocha et al. 2016;
Blancas-Hernández et al. 2019; Arrazola-Bohórquez and
Palacios-Aguilar 2022), which apparently reinforces the
129
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Palacios-Aguilar et al.
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Palacios-Aguilar et al.
Ricardo Palacios-Aguilar is a Mexican biologist who earned his Bachelor’s degree at the Facultad
              
           
(UNAM). Ricardo’s main interests are biogeography, evolution, and systematics using amphibians
and reptiles as a model, especially those of the Neotropics. Currently, he is a Professor at Facultad
de Ciencias, UNAM, where he teaches courses in biogeography and evolution.
Lydia Allison Fucsko, who resides in Melbourne, Australia, is an environmental activist and
amphibian conservationist. As a photographer with international publications, she has taken
countless amphibian photographs, including photo galleries of frogs mostly from southeastern
Australia. Lydia has a Bachelor of Humanities from La Trobe University (Bundoora, Victoria,
Australia) and a Diploma in Education from the University of Melbourne (Parkville, Victoria,
Australia). She has postgraduate diplomas in computer education and in vocational education and
training from the University of Melbourne (Parkville). Additionally, Lydia has a Master’s Degree
in Counseling from Monash University (Clayton, Victoria, Australia). She received her Ph.D. on
Environmental Education, in which she promoted habitat conservation, species perpetuation, and
global sustainable management, from Swinburne University of Technology (Hawthorn, Victoria,
Australia), while being mentored by the late Australian herpetologist and scholar Dr. Michael James
  
interests that include: clinical psychology, focusing on psychopathology; neuroscience and empathy;
environmental education for sustainable development; sentient ecology; academic writing; and
            
adults. She also is the senior author (with Boria Sax) of a chapter in the 2019 Springer Encyclopedia
of Sustainability in Higher Education   
       
study of the introduced Mesoamerican herpetofauna, a treatment of conservation prospects of the
Mesoamerican salamander fauna, papers on the herpetofauna of Veracruz and Querétaro, Mexico,
a review of the book Advances in Coralsnake Biology, and a study on the biological and cultural
      Tantilla
lydia, with the suggested common name of Lydia’s Little Snake, was named in her honor.
Víctor H. Jiménez Arcos is an Associate Professor and the head of the Herpetology Lab, Facultad
de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México. Through studies on
ecology and evolutionary biology, his laboratory focuses on understanding the evolution of the
phenotypic diversity of amphibians and reptiles, as well as the changes and losses of geographical
range associated with anthropogenic factors. He also works intensively with human communities
  
the conservation of amphibian and reptile species in the short, medium, and long term.
Larry David Wilson is a herpetologist with lengthy experience in Mesoamerica. He was born
in Taylorville, Illinois, USA, and received his university education at the University of Illinois at
Champaign-Urbana (B.S. degree) and at Louisiana State University in Baton Rouge (M.S. and
Ph.D. degrees). He has authored or co-authored more than 465 peer-reviewed papers and books on
herpetology. Larry is the senior editor of Conservation of Mesoamerican Amphibians and Reptiles
and a co-author of seven of its chapters. His other books include The Snakes of Honduras, Middle
American Herpetology, The Amphibians of Honduras, Amphibians & Reptiles of the Bay Islands
and Cayos Cochinos, Honduras, The Amphibians and Reptiles of the Honduran Mosquitia, and
Guide to the Amphibians & Reptiles of Cusuco National Park, Honduras. To date, he has authored
or co-authored the descriptions of 75 currently recognized herpetofaunal species, and seven species
have been named in his honor, including the anuran Craugastor lauraster, the lizard Norops wilsoni,
and the snakes Oxybelis wilsoni, Myriopholis wilsoni, and Cerrophidion wilsoni, as well as the
oligochaete annelid Pheretima wilsoni and the coccidian parasite Caryospora wilsoni. In 2005,
he was designated a Distinguished Scholar in the Field of Herpetology at the Kendall Campus
of Miami-Dade College. Currently, Larry is a Co-chair of the Taxonomic Board for the website
Mesoamerican Herpetology.
132
Amphib. Reptile Conserv. November 2022 | Volume 16 | Number 2 | e320
A new Tantilla species in the calamarina group from Guerrero, Mexico
Vicente Mata-Silva   
include ecology, conservation, natural history, and biogeography of the herpetofaunas of Mexico,
Central America, and the southwestern United States. He received a B.S. degree from the Universidad
Nacional Autónoma de México (UNAM), and M.S. and Ph.D. degrees from the University of Texas
at El Paso (UTEP). Vicente is an Assistant Professor of Biological Sciences at UTEP, in the Ecology
and Evolutionary Biology Program, and Co-Director of UTEP’s Indio Mountains Research Station,
located in the Chihuahuan Desert of Trans-Pecos, Texas, USA. To date, Vicente has authored or
           
Section Editor for the journal Mesoamerican Herpetology, and is currently Associate Editor for the
journal Herpetological Review.
Appendix
Appendix I. In addition to published sources, the following comparative material was examined. All localities are in Mexico.
Tantilla calamarina             
815), Puerto Marquéz (CNAR 18729–735); Apaxtla de Castrejón, Tecolhuiztle (MZFC 2206); Arcelia, Campo Morado, Cañada El
Limón (MZFC19793, 19798–801), Campo Morado, Cañada El Naranjo (MZFC 19795, 19797), Agua Zarca (MZFC 19794, 19796);

28923–924).
Tantilla ceboruca
Tantilla coronadoi
Tantilla deppii
... Among these poorly studied South American colubrids, one of the least explored taxa is the genus Tantilla Baird & Girard, 1853, a group of small-bodied fossorial snakes mainly specialized in preying upon centipedes (Azevedo et al., 2021;Hofmann et al., 2021). Currently, 68 species are considered valid for the genus (Palacios-Aguilar et al., 2022) with the following 12 species occurring in South America: Tantilla alticola (Boulenger, 1903); Tantilla andinista Wilson & Mena, 1980; Tantilla boipiranga Sawaya & Sazima, 2003; Tantilla capistrata Cope, 1875; Tantilla insulamontana Wilson & Mena, 1980; Tantilla melanocephala (Linnaeus, 1758); Tantilla miyatai Wilson & Knight, 1987; Tantilla nigra (Boulenger, 1914); Tantilla petersi Wilson, 1979; Tantilla semicincta (Duméril et al., 1854); Tantilla supracincta (Peters, 1863); and Tantilla tjiasmantoi Koch & Venegas, 2016. Among these species, Tantilla melanocephala (Linnaeus, 1758) has the largest geographic distribution, one of the highest levels of morphological variation, and by far the most convoluted taxonomic history within the genus. ...
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