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NOTES ON GEOGRAPHIC DISTRIBUTION Check List 16 (3): 753–757 
https://doi.org/10.15560/16.3.753
Range expansion of the Gulf Coast Toad, Incilius valliceps 
(Wiegmann, 1833) (Anura, Bufonidae), from Costa Rica
Jeremy Klank1, Gerardo Chaves1, Erick Arias1, 2
1 Museo de Zoología de la Escuela de Biología de la Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro de Montes 
de Oca, San José, 11501, Costa Rica. 2 Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad 
Universitaria, AP 70-153, CP 04510, Ciudad de México, México.
Corresponding author: Jeremy Klank, jklank97@gmail.com
Abstract
We report the range expansion of the Gulf Coast Toad, Incilius valliceps (Wiegmann, 1833), from tropical moist 
forests to tropical wet forests and towards southeastern Costa Rica. We evaluated erroneous reports of this species in 
databases on the web. Also, we discussed that movements to areas with wet conditions for a species known from humid 
and xeric habitats can be explained by the trends in deforestation and increments of the dry conditions during recent 
decades in the country.
Keywords
Central America, DNA barcoding, herpetofauna, Neotropics, species distribution.
Academic editor: Marcelo Kokobum | Received 15 February 2020 | Accepted 2 June 2020 | Published 23 June 2020
Citation: Klank J, Chaves G, Arias E (2020) Range expansion of the Gulf Coast Toad, Incilius valliceps (Wiegmann, 1833) (Anura, Bufonidae), 
from Costa Rica. Check List 16 (3): 753–757. https://doi.org/10.15560/16.3.753
Introduction seems to adapt very well to open and human-altered 
The genus Incilius (Cope, 1863), often referred to areas (Leenders 2016).
as the Mesoamerican Toads, currently contains 35 spe- In Costa Rica, I. valliceps was previously known 
cies which range from the southern edge of the United only from the most north-central part of the country, 
States down to the northern edge of Colombia (Frost et close to the San Juan River and the frontier with Nica-
al. 2009). Incilius valliceps (Wiegmann, 1833) belongs ragua (Leenders 2016). Related species that inhabit 
to the Incilius valliceps group, which is characterized by Costa Rica are I. melanochlorus (Cope, 1877), I. leutke-
having cranial crests, medium to small parotoid glands, nii (Boulenger, 1891), and I. aucoinae (O’Neill & Men-
presence of an omosternum, and a fully developed audi- delson, 2004). Among these species, the ones that can 
tory apparatus (Savage 2002; Mendelson et al. 2011). occur sympatrically with I. valliceps are I. melanochlo-
This species presents one of the largest distributional rus, in the Atlantic versant, and I. luetkenii, across north-
ranges among toads of this genus, extending from cen- ern Costa Rica (Savage 2002; Leenders 2016). Herein, 
tral Veracruz in Mexico to the northern part of Costa we present new records of I. valliceps from Costa Rica, 
Rica (Mendelson et al. 2011). Even though I. valliceps expanding the current southern limit of distribution of 
mainly inhabits humid lowland forests, this species also this species.
© The authors. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, 
distribution, and reproduction in any medium, provided the original author and source are credited.
754 Check List 16 (3)
Methods numbers MT180485 (UCR 23196) and MT180486 (UCR 
23197). Sequence alignments used the MAFFT soft-
We carried out the fieldwork in La Tirimbina Bio- ware (Katoh et al. 2017) under the “auto” strategy and 
logical Reserve and nearby sites located in Sarapiquí, default parameters and were trimmed to the point where 
Heredia, Costa Rica. We collected the specimens dur- a majority of the taxa had sequence data. We used the 
ing standard visual encounter surveys (Crump and maximum likelihood analysis to infer the phylogenetic 
Scott 1994). We euthanized the toads with lidocaine relationships using RAxML–HPC v8 (Stamatakis 2014) 
and further collected and preserved the liver tissue in with the GTR + G model of nucleotide substitution 
96% ethanol. The specimens were fixed with 10% buff- and the -f a option, which searches for the best-scoring 
ered formaldehyde and stored in 70% ethanol in the tree and performs a rapid bootstraps analysis (i.e. 1000 
Museo de Zoología de la Universidad de Costa Rica bootstraps) to estimate node support by resampling the 
(MZUCR). The collection was conducted under the per-
mit R-SINAC-PNI-ACAHN-27-2019.
Table 1. Records of Incilius valliceps from the Museo de Zoología de 
We produced a distribution map (Fig. 1) for Incilius la Universidad de Costa Rica.
valliceps based in the herpetological records of the 
MZUCR (Table 1). We followed Holdridge (1967) and Voucher Latitude Longitude Altitude (m a.s.l.) Distribution status
considered three life zones: tropical dry forests (5–6 UCR9774 10.9583 −084.7500 100 Historical distribution
dry months per year), tropical moist forests (1–4 dry UCR9775 10.9583 −084.7500 100 Historical distribution
UCR9924 10.8944 −085.0250 54 Historical distribution
months per year) and tropical wet forests (0 dry months UCR9925 10.8944 −085.0250 54 Historical distribution
per year). This classification holds true for Costa UCR9926 10.8944 −085.0250 54 Historical distribution
Rican lowlands (i.e. 0–500 m a.s.l.) (Savage 2002). We UCR9927 10.8944 −085.0250 54 Historical distribution
obtained climatic and Holdridge life zones shapefiles UCR9933 10.9533 −085.1383 46 Historical distribution
from the Atlas Digital de Costa Rica project (Ortíz- UCR9934 10.9533 −085.1383 46 Historical distribution
Malavassi 2015). UCR9935 10.9533 −085.1383 46 Historical distribution
UCR9936 10.9533 −085.1383 46 Historical distribution
Molecular analysis. We determined partial sequences UCR9937 10.9533 −085.1383 46 Historical distribution
of the large subunit ribosomal RNA (16S) mitochondrial UCR9938 10.9533 −085.1383 46 Historical distribution
gene for one specimen of I. melanochlorus and one spec- UCR10257 10.8306 −084.9653 120 Historical distribution
imen of I. valliceps, both from La Tirimbina Biological UCR10258 10.8306 −084.9653 120 Historical distribution
Reserve and nearby sites located in Sarapiquí, Here- UCR10445 10.9533 −085.1383 46 Historical distribution
dia, Costa Rica (Fig. 1). We compared the sequences UCR10446 10.9533 −085.1383 46 Historical distribution
obtained herein with those available in GenBank for I. UCR10447 10.9533 −085.1383 46 Historical distribution
valliceps, I. aucoinae and I. melanochlorus. The proto- UCR10539 10.9035 −085.2649 450 Historical distribution
UCR10540 10.9035 −085.2649 450 Historical distribution
cols for DNA extraction, amplification, sequencing, and UCR10541 10.9035 −085.2649 450 Historical distribution
editing follow those of Arias et al. (2018). We deposited UCR10542 10.9035 −085.2649 450 Historical distribution
the obtained sequences in GenBank under the accession UCR10685 10.9722 −085.1028 30 Historical distribution
UCR12776 10.8694 −084.3194 192 Historical distribution
UCR12777 10.8861 −084.3333 70 Historical distribution
UCR12778 10.8861 −084.3333 70 Historical distribution
UCR12779 10.8639 −084.3278 182 Historical distribution
UCR12780 10.8639 −084.3278 182 Historical distribution
UCR12781 10.8639 −084.3278 182 Historical distribution
UCR15611 10.9139 −085.3017 344 Historical distribution
UCR15624 10.9139 −085.3017 344 Historical distribution
UCR15660 10.8961 −085.3353 491 Historical distribution
UCR15661 10.9039 −085.3031 344 Historical distribution
UCR15722 10.9139 −085.3017 491 Historical distribution
UCR17729 10.9078 −085.2922 343 Historical distribution
UCR17733 10.9078 −085.2922 343 Historical distribution
UCR17740 10.9078 −085.2922 343 Historical distribution
UCR17753 10.8946 −085.3842 500 Historical distribution
UCR17754 10.9078 −085.2922 343 Historical distribution
UCR19620 10.8964 −085.3356 400 Historical distribution
UCR19805 10.8711 −084.3501 90 Historical distribution
UCR20588 10.9572 −084.6518 51 Historical distribution
UCR20756 10.8770 −084.3288 100 Historical distribution
UCR20789 10.8078 −085.1865 400 Historical distribution
Figure 1. Distribution map of the locality records of Incilius val- UCR22634 10.8528 −085.1059 179 Historical distribution
liceps in Costa Rica. Dry months layer from the life zones shapefile UCR23197 10.4155 −084.1226 142 New locality
shows that the new locality (red dot) is in a wetter area than the UCR23198 10.4155 −084.1226 146 New locality
previous records (black dots). UCR23259 10.4113 −084.1219 150 New locality
Klank et al. | New records of Incilius valliceps from Costa Rica 755
data. All phylogenetic analyses were performed on the 
CIPRES portal (Miller et al. 2010).
Results
Incilius valliceps (Wiegmann, 1833)
Figures 2, 3A, C
New records. COSTA RICA • 1 ♂; Heredia Prov-
ince, Cantón de Sarapiquí, La Virgen, private property 
next to La Tirimbina Biological Reserve; 10.4155°N, 
084.1225°W; 145 m a.s.l.; 01 Feb. 2019; Jeremy Klank, 
Gerardo Chaves leg.; GenBank: MT180486; UCR 23197 
• 1 ♂; Heredia Province, Cantón de Sarapiquí, La Vir- Figure 2. Incilius valliceps (UCR23198). Adult male calling at the 
gen, private property next to La Tirimbina Biological breeding site.
Reserve; 10.4155°N, 084.1225°W; 145 m a.s.l.; 02 Feb. 
2019; Jeremy Klank, Gerardo Chaves leg.; UCR 23198 Remarks. Both specimens collected in February 2019 
• 1 juvenile; Heredia Province, Cantón de Sarapiquí, La (UCR 23197, UCR 23198) were part of an aggregation 
Virgen, La Tirimbina Biological Reserve; 10.4113°N, consisting of four more males of I. valliceps that were 
084.1219°W; 150 m a.s.l.; 05 Oct. 2019; Jeremy Klank, calling at night on low moist grass surrounding a small 
Gerardo Chaves leg.; UCR 23259. pond destined for growing Tilapia Fish (Tilapia sp.) and 
Figure 3. A, C. Incilius valliceps (UCR 23198). A. Dorsal view C. Ventral view. B, D. Incilius melanochlorus (UCR 23196). B. Dorsal view D. 
Ventral view.
756 Check List 16 (3)
a house located in the border of La Tirimbina river. The known record of the MZUCR. In the Global Biodiver-
other specimen collected in October 2019 (UCR 23259) sity Information Facility (GBIF 2020), we found 14 spec-
was found in a human-kept, open, grassy area, which is imens of I. valliceps reported from Colombia and two 
bordered by secondary forest. from Panama, collected between the decades of 1940 and 
Identification. We followed Savage (2002) for morpho- 1960. The specimens from Colombia are deposited in 
logical identification. The presence of well-defined cra- the Museum of Comparative Zoology of Harvard (MCZ) 
nial crests, a dark lateral stripe with pointy light warts, and the ones from Panama are in the Royal Belgian 
and oblong to semi-triangular shaped parotoid glands Institute of Natural Sciences and in the Natural History 
that are similar in area to its upper eyelid differentiate I. Museum of Los Angeles County. In the revision of the 
valliceps (Fig. 3A) from the rest of toad species in Costa Costa Rican herpetofauna, Savage (2002) did not include 
Rica. It is most easily distinguished from I. melanochlo- those specimens in the distribution of I. valliceps, which 
rus by its creamish gular area (Fig. 3C), which is usually possibly implies that those specimens have an identifica-
black or dark brown in the latter (Fig. 3D). The parotoid tion error. Specimens from Colombia likely correspond 
glands of I. melanochlorus (Fig. 3B) tend to be smaller to I. coniferus (Cope, 1862), given that is the only species 
than their upper eyelid area and more oval-shaped than of this genus reported from there (Acosta-Galvis 2019). 
those of I. valliceps. Also, I. valliceps presents a subacu- Nevertheless, inspection of the specimens housed in the 
MCZ is still needed to confirm their identification.
minate snout (Fig. 3A, C) while I. melanochlorus pres- VertNet database (VertNet 2020) reported a speci-
ents a truncated snout (Fig. 3B, C). men of I. valliceps deposited in the Cleveland Museum 
The phylogenetic analysis data matrix includes of Natural History (CMNH 115293) that was collected 
38 sequences, with a total sequence length of 568 bp, in 1986 in the road between Guápiles and Limón in the 
including gaps. The phylogeny obtained (Fig. 4) resulted Caribbean versant of Costa Rica. This specimen was col-
in three well-supported clades, corresponding to I. lected at least 100 km to the south from our observations. 
aucoinae, I. melanochlorus, and I. valliceps. The mor- We compared photos of the specimen (CMNH 115293) 
phological identification of the two specimens of Incilius with other Costa Rican Incilius species and concluded 
from La Tirimbina Biological Reserve was supported by that it belongs to I. coniferus because it presents a simi-
the molecular analysis, corroborating the presence of I. lar length between the first and second fingers, and has 
melanochlorus and I. valliceps in the site. an extensive membrane between the toes, morphological 
Discussion features relative to its arboricole habits (Savage 2002).
The new locality reported in this study for I. val-
The new records of Incilius valliceps expand the distri- liceps, a tropical wet forest without a dry season, is a 
bution of the species to 54 km to the south from the last new life zone for this species, which usually occurred in 
Figure 4. Maximum likelihood phylogram showing the the phylogenetic placement of the two specimens from La Tirimbina Biological 
Reserve within the three Incilius species analyzed: I. aucoinae, I. melanochlorus, and I. valliceps. Values above branch represent bootstraps 
proportions. The scale bar refers to the estimated substitution per site. Asterisks represent support >95.
Klank et al. | New records of Incilius valliceps from Costa Rica 757
comparative driest life zones in the rest of Mesoamerica tion. Leptodactylus poecilochilus. Herpetological Review 34 (3): 
(Khatun et al. 2013). Such cases have been reported for 258–259. 
two other Costa Rican species previously found in arid Crump ML, Scott NJ (1994) Visual encounter surveys. In: Heyer WR, 
Donnelly MA, McDiarmid RW, Hayek LC, Foster MS (Eds) mea-
zones of the Pacific versant, that were recently recorded suring and monitoring biological diversity: standard methods for 
in the wet forests of the Caribbean versant: Leptodac- amphibians. Smithsonian Institution Press, Washington/London, 
tylus poecilochilus (Cope, 1862) (Crawford et al. 2003) 84–92.
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altitude zones (Pounds et al. 1997; Pounds et al.1999; ocurrence download. https://doi.org/10.15468/dl.zztv34. Ac-
Acosta-Chaves et al. 2015; Acosta-Chaves et al. 2019). cessed on: 2020-03-15.
We believe that the deforestation and global drier con- Holdridge LR (1967) Life zone ecology. Tropical Science Center, San 
ditions during the last decades (Sanchez-Azofeifa et al. José, 206 pp.
2001; Pounds et al. 2006) forced the movement of xeric Katoh K, Rozewicki J, Yamada KD (2017) MAFFT online service: 
multiple sequence alignment, interactive sequence choice and vi-
species to current altered wet forests. sualization. Briefings in Bioinformatics 20 (4): 1160–1166. https://
doi.org/10.1093/bib/bbx108
Acknowledgements Khatun K, Imbach P, Zamora JC (2013) An assessment of climate 
change impacts on the tropical forests of Central America using 
We thank La Tirimbina Biological Reserve for giving us the Holdridge Life Zone (HLZ) land classification system. iForest 
the research grant that allowed this investigation, espe- —Biogeosciences and Forestry 6 (4): 183–189. https://doi.org/10. 
cially to the staff, Mariela García, Branko Hilje, and 3832/ifor0743-006
Leenders T (2016) Amphibians of Costa Rica. A field guide. Comstock 
Emmanuel Rojas for their support. We also like to thank Publishing Associates, Cornell University Press, Ithaca, 531 pp.
the private owners who allowed us access to their prop- Mendelson III JR, Mulcahy DG, Williams TS, Sites Jr JW (2011) A 
erties. Special thanks to Stevie Kennedy-Gold, collec- phylogeny and evolutionary natural history of Mesoamerican 
tion manager of the section of Amphibians and Reptiles toads (Anura: Bufonidae: Incilius) based on morphology, life his-
of the Carnegie Museum of Natural History, for sending tory, and molecular data. Zootaxa 3138 (1): 1–34. https://doi.org/ 
10.11646/zootaxa.3138.1.1
photos of the specimen CMNH 115293 that permitted Miller MA, Pfeiffer W, Schwartz T (2010) Creating the CIPRES Sci-
us to clarify its taxonomic status. We also thank Wag- ence Gateway for inference of large phylogenetic trees. Gateway 
ner Chaves-Acuña and Andrés Acosta-Galvis for their Computing Environments Workshop (GCE) 2010: 1–8. https://
review and comments on the manuscript. doi.org/10.1109/gce.2010.5676129
Ortiz-Malavassi E (2015) Atlas digital de Costa Rica 2014. Investiga.
TEC 23: 1.
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work. JK took the photographs, GC made the maps. EA BE (2006) Widespread amphibian extinctions from epidemic dis-
did the molecular analysis. All three authors wrote the ease driven by global warming. Nature 439: 161–167. https://doi.
manuscript. This work is a contribution from Museo de org/10.1038/nature04246
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to climate change on a tropical mountain. Nature 398: 611–615. 
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