Boletín de la Sociedad Zoológica del Uruguay, 2026

Vol. 35(1): e35.1.1

ISSN 2393-6940

https://journal.szu.org.uy

DOI: https://doi.org/10.26462/35.1.1

ABSTRACT

We report the third confirmed record of Urostrophus

undulatus in Brazil, observed in Piratini, Rio Grande do

Sul, in November 2024. This finding extends its known

range and suggests potential overlooked populations.

Continued surveys and conservation efforts are crucial for

understanding and protecting the species.

Keywords: Urostrophus, Brazil, conservation, rare,

population.

RESUMEN

Redescubriendo el lagarto Urostrophus undulatus

(Squamata, Iguanidae) (Wiegmann, 1834) en el sur

de Brasil. Reportamos el tercer registro confirmado de

Urostrophus undulatus en Brasil, observado en

Piratini, Río Grande do Sul, en noviembre de 2024.

Este hallazgo extiende su distribución conocida y

sugiere la existencia de poblaciones posiblemente

pasadas por alto. Se requieren más estudios y

esfuerzos de conservación.

Palabras clave: Urostrophus, Brasil, conservación,

rara, población.

Urostrophus undulatus is a small diurnal lizard,

reaching approximately 30 cm in total length, with the

tail comprising about 70% of this measurement

(Etheridge & Williams, 1991). It inhabits the Pampa

biome and is considered semi-arboreal, moving among

trees and shrubs taller than 2 meters, although it also

uses the ground for locomotion (Gallardo, 1980;

Etheridge & Williams, 1991; Langone et al., 2000;

Machado et al., 2005). The species has cryptic

coloration and secretive behavior, which make it

difficult to detect in the field (Achaval & Olmos, 2003;

Machado et al., 2005; Ávila et al., 2013). Its biology

remains poorly understood (Machado et al., 2005;

Abdala et al., 2012), but it is known to be oviparous,

with females laying clutches but it is known to be

oviparous, with females laying clutches of

approximately 4–7 eggs (Langone et al., 2000; Winck

et al., 2012). The diet consists primarily of arthropods

(Machado et al., 2005).

Despite its historical range across Argentina,

Uruguay, and Brazil, U. undulatus remains poorly

documented, and conservation assessments reflect

this scarcity of information. Globally, it is listed as Data

Deficient (DD) on the IUCN Red List (Cacciali et al.,

2021). In Uruguay, where the species has been

recorded in several departments —including

Paysandú, Tacuarembó, Cerro Largo, Rocha,

Bol. Soc. Zool. Uruguay (2ª época). 2026. ISSN 2393-6940Vol. 35(1): e35.1.1

NOTA

REDISCOVERING THE LIZARD Urostrophus undulatus (SQUAMATA, IGUANIDAE) (WIEGMANN, 1834)

IN SOUTHERN BRAZIL

1 2* 1

Arthur Schramm de Oliveira , Wellington Vasconcelos de Souza , Martin Schossler

3 4

Guilherme Bard Adams , Rafael Lucchesi Balestrin

1 Orbis Consultoria Ambiental LTDA, Estrada Pedrolina Firme, Caixa Postal 2681, CEP: 95520-000, Osório, Rio

Grande do Sul, Brasil.

2 Engebio Projetos Ambientais LTDA. Rua Domingos de Almeida, 708. CEP: 96211-580, Cidade Nova Rio

Grande, Rio Grande do Sul, Brasil.

3 Prosul Projetos Supervisão e Planejamento Ltda, Rua Saldanha Marinho, Caixa Postal 116, CEP: 88010-450,

Florianópolis, Santa Catarina, Brasil.

4 Fieldwork Consultoria Ambiental, Mal. Humberto de Alencar Castelo Branco, Caixa Postal 1032, ap. 2707,

CEP: 82530-195, Curitiba, Paraná, Brasil.

*Corresponding author: wellingtonsouza1617@gmail.com

Fecha de recepción: 22 de mayo de 2025

Fecha de aceptación: 01 de octubre de 2025

SCHRAMM DE OLIVEIRA et al.

Canelones, San José, and Rivera— It is classified as

Data Deficient but considered a conservation priority

because of its limited range and signs of local

population declines (Etheridge & Williams, 1991;

Langone et al., 2000; Carreira et al., 2006; Canavero et

al., 2010; Abdala et al., 2012; Carreira & Estrades,

2013; Carreira & Maneyro, 2015). A previously cited

record from Montevideo was reassigned to Canelones

after verification of collection data (Carreira et al.,

2006). In Argentina, U. undulatus is known only from a

single locality in Punta Lara (Etheridge & Williams,

1991) and was excluded from national assessments

due to the absence of confirmed records for over a

century (Ávila et al., 2013). In Brazil, the species is

included within the National Action Plan for the

Conservation of Threatened Amphibians and Reptiles

of the Southern Region (Portaria nº 25, February

2012), underscoring the importance of updated

distributional data. After its original description in 1834

from São Lourenço do Sul (the type locality), U.

undulatus remained unrecorded in Brazil for over 179

years until it was rediscovered in 2013 in Cassino, both

in the state of Rio Grande do Sul (Oliveira et al., 2022)

(Fig. 1). Although a subsequent record was mentioned

by Cei (1993), the specimen in question appears to

correspond to U. grilli, based on both morphological

features and its locality of origin. Additionally,

specimens attributed to U. undulatus deposited at

MZUSP lack collection date information, preventing

confirmation of any records between the original

description and the 2013 rediscovery.

Here, we report the third confirmed record of U.

undulatus in Brazil, further expanding its known

distribution. The field observation was made on 30

November 2024 at a site known as Cerro do Ubaldo

(−31.510295, −53.111799; Datum WGS84), in the

municipality of Piratini, state of Rio Grande do Sul,

approximately 10 km from the urban perimeter (Fig. 1).

The area lies at an elevation of 360 meters and is

characterized by granite outcrops and open grassland

with scattered shrubs, a vegetation formation typical of

the southern Brazilian highlands. This locality is

situated about 120 km northeast of the most recent

record from Cassino and roughly 100 km west of the

historical type locality in São Lourenço do Sul (Oliveira

et al., 2022). The individual was photographed and

released (Fig. 2). Our finding suggests the possible

existence of additional populations in the region,

although the species may remain undetected due to its

elusive behavior and habitat use. The observed color

pattern corresponds to the “iheringi” morphotype,

which is the expected pattern for Brazilian populations

(Cei, 1993; Carreira & Maneyro, 2013), supporting the

identification.

Additional field surveys are essential to clarify the

current distribution of U. undulatus in Brazil, especially

in areas with similar ecological conditions that may host

undetected populations. New occurrence records,

such as the one reported here, are fundamental for

advancing knowledge of this elusive and poorly

documented species, whose actual range is likely

underestimated due to its rarity and the scarcity of

records. Expanding available information is therefore a

priority, as limited data hinder accurate assessments

and effective conservation planning. For rare and little-

known species like U. undulatus, key components of

IUCN (International Union for Conservation of Nature

Red List) assessments include geographic distribution

and potential threats. Documenting additional localities

not only refines the understanding of the species' range

but also helps identify priority areas for focused

ecological and conservation studies. We emphasize

the urgent need to implement targeted survey and

conservation programs aimed at locating and

monitoring existing populations. Such initiatives are

essential to bridge critical knowledge gaps and to

support informed strategies for the effective

management and protection of this species.

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3Rediscovering Urostrophus undulatus in southern Brazil

Bol. Soc. Zool. Uruguay (2ª época). 2026. ISSN 2393-6940Vol. 35(1): e35.1.1

Fig. 1. Geography distribution of Urostrophus undulatus in South America with the respective states or departments of each country. White circles = previous

records in state of Rio Grande do Sul, Brazil; Uruguay and Punta Lara, Argentina. Orange circle = new record in the city of Piratini, Rio Grande do Sul, Brazil.

SCHRAMM DE OLIVEIRA et al.

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Editor de Sección: Raúl Maneyro

Bol. Soc. Zool. Uruguay (2ª época). 2026. ISSN 2393-6940Vol. 35(1): e35.1.1

Fig. 2. Urostrophus undulatus observed in the municipality of Piratini, Rio Grande do Sul, Brazil, on 30 November 2024. (A) Lateral

view of the whole individual on a rocky outcrop. (B) Close-up of the head region, highlighting the cryptic coloration and head

morphology. Photos: Wellington Vasconcelos de Souza.