A new cave-dwelling scorpion from Brazil

 

More or less obligatory, cave-dwelling scorpions are found in several areas. Some with distinct troglomorphic traits like reduced pigmentation and the lack of eyes. Jonas Eduardo Gallão and Deyvison Bonfim Ribeiro have recently described a new obligatory, subterranean species in the genus Troglorhopalurus Lourenço, Baptista & Giupponi, 2004 (Buthidae) from three caves in Ituaçu, State of Bahia in Brazil.

Troglorhopalurus araras Gallão & Ribeiro, 2026

The new species lack typical troglomorphic traits except for having thinner cuticle than normal. This may represent a troglomorphic trait.

An identification guide for the genus is presented. Please note that this guide (and article) is missing Troglorhopalurus iuiu Carvalho, Silva, Emanuela de Souza & Feirreira, 2025. According to the authors, the reason for this was that they weren't aware of the description of this species when the paper was submitted. [Info about the missing species updated 02.03.26]

Abstract:
We describe Troglorhopalurus araras sp. n. based only on females, as a new obligatory and exclusively subterranean scorpion occurring in three caves from Ituaçu, State of Bahia, Brazil. The caves of Ituaçu belong to an isolated portion of the Una geomorphological group. Troglorhopalurus araras is the third known species of Troglorhopalurus and differs from its congeners by size, carination mainly in chela hand and metasoma, teeth of pecten, shape of telson spine, and colour. This new species enhances the diversity of cave-dwelling species in Brazilian caves, as well as the knowledge of cave scorpions. Troglorhopalurus araras must be considered threatened due to its restricted endemism at caves in the Chapada Diamantina.

Reference:
Gallão JE, Ribeiro DB. Troglorhopalurus araras (Scorpiones: Buthidae) a new subterranean scorpion from Chapada Diamantina, Bahia, Brazil. Journal of Natural History. 2026;60(9-12):557–72. [Subscription required for full text]

Family Buthidae 

A study of circadian rhythms in two species of cave-dwelling Troglorhopalurus species in Brazil

 

Circadian rhythms are important for all animals including humans in governing the organisms daily activities when it comes to both physiology and activity. These rhythms are controlled by a biological clock that usually are adjusted by external stimuli like light and dark.

Cave-dwelling scorpions like members of the genus Troglorhopalurus Lourenço, Baptista & Giupponi, 2004 (Buthidae) are more or less living in the dark permanently. Priscila Emanuela de Souza and Rodrigo Lopes Ferreira have recently published an article studying locomotor behavior in two species of Troglorhopalurus when exposed to different light-dark regimes. 

Interestingly, their study show that both species were able to retain their normal circadian rhythmicity in all regimes (they were able to "keep the time"), even though this varied between the two species. This can be explained by the different degree of adaptation to cave habitats seen in the two species.

Abstract:
Circadian rhythms, typically synchronized with light–dark cycles, regulate key biological processes in surface organisms. In caves, however, the absence of light may disrupt these rhythms or promote alternative temporal patterns. We examined locomotor activity in two cave-dwelling scorpions with contrasting degrees of subterranean adaptation: Troglorhopalurus translucidus (troglobitic) and Troglorhopalurus lacrau (troglophilic). Activity was monitored under constant darkness (DD), light–dark (LD), and constant light (LL). Both species retained circadian rhythmicity, but with distinct responses: T. translucidus and T. lacrau exhibited diurnal activity under LD and changes in period under DD and LL. These findings demonstrate that circadian regulation persists in cave adapted scorpions, but its expression is shaped by evolutionary pressures, highlighting the plasticity of biological clocks in light-deprived environments.

Reference:
de Souza PE, Ferreira RL. Oscillating in darkness: Circadian rhythms of cave-dwelling scorpions. Chronobiol Int. 2025:1–8. [Subscription required for full text]

A new species in the enigmatic genus Troglorhopalurus from Northeastern Brazil

 

 Leonardo Sousa Carvalho and co-workers have recently published an article describing a new species of the rare and partly troglobitic genus Troglorhopalurus Lourenço, Baptista & Giupponi, 2004 (Buthidae) form five caves in the municipalities of Iuiú and Malhada, in the western region Bahia state, Northeastern Brazil.

Troglorhopalurus iuiu Carvalho, Silva, Emanuela de Souza & Feirreira, 2025

The new species was found quite deep into the caves and is probably a troglobite, but shows only minor troglomorphic traits. Due to the limited distribution and potential negative human impact on the habitat, the authors suggest that the new species should be classified and endangered.

Abstract:
The genus Troglorhopalurus (Scorpiones: Buthidae) is endemic to northeastern Brazil and comprises cave-dwelling species with limited distributions. Based on newly collected specimens, this study provides a description of a new cave-dwelling Troglorhopalurus species and the first detailed description of the male hemispermatophore of the genus. Troglorhopalurus iuiu n. sp. is diagnosed based on morphometric characters, distinct carapace granulation, and differences in the pedipalps and metasomal carinae and peg sensillae shape. The hemispermatophore of Troglorhopalurus is like other Centruroidinae species, with internal, external, and basal lobes. Additionally, we discuss the distribution and conservation status of Troglorhopalurus species. Troglorhopalurus lacrau distribution range is extended based on additional epigean and hypogean records. This species may be reassessed from data deficient to least concern. Based on the limited localities and declining habitat quality, we propose that T. iuiu n. sp. be considered endangered. This research underscores the importance of further sampling to explore species-specific variations and promote conservation efforts for these ecologically specialized scorpions.

Reference:
Carvalho LS, Silva MIL, Souza PEd, Ferreira RL. Taxonomy and Distribution of the Cave-Dwelling Scorpions Troglorhopalurus (Scorpiones, Buthidae), with the Description of a New Cave-Restricted Species. Arthropoda. 2025;3(2):6. [Open Access]

Thanks to Gerard for sending me this article!

Family Buthidae

A systematic revision of the neotropical club-tailed scorpions, Physoctonus, Rhopalurus, and Troglorhopalurus has been published

Lauren Esposito and several co-workers have recently published a major systematic revision of the neotropical club-tailed scorpions, Physoctonus Mello-Leitao, 1934, Rhopalurus Thorell, 1876 and Troglorhopalurus Lourenço, Baptista & Giupponi, 2004 (Buthidae). This is a major study with many taxonomical changes. I have tried to sum up the main results here:

New genera:

Ischnotelson Esposito, Yamaguti, Souza, Pinto da Roacha & Prendini, 2017 (Brazil).

Jaguajir Esposito, Yamaguti, Souza, Pinto da Roacha & Prendini, 2017 (North and northeastern South America).

Heteroctenus Pocock, 1893 (revalidated from synonymization).

New species:

Ischnotelson peruassu Esposito, Yamaguti, Souza, Pinto da Roacha & Prendini, 2017 (Brazil).

Physoctonus striatus Esposito, Yamaguti, Souza, Pinto da Roacha & Prendini, 2017 (Brazil).

Rhopalurus ochoai Esposito, Yamaguti, Souza, Pinto da Roacha & Prendini, 2017 (Venezuela).

New combinations:

All of these species previously belonged to the genus Rhopalurus Thorell, 1876.

Heteroctenus abudi (Armas and Marcano Fondeur, 1987)

Heteroctenus bonettii (Armas, 1999)

Heteroctenus garridoi (Armas, 1974)

Heteroctenus gibarae (Teruel, 2006)

Heteroctenus princeps (Karsch, 1879)

Ischnotelson guanambiensis (Lenarducci et al., 2005)

Jaguajir agamemnon (C.L. Koch, 1839)

Jaguajir pintoi (Mello-Leitão, 1932)

Jaguajir rochae (Borelli, 1910)

Troglorhopalurus lacrau (Lourenço and Pinto-da-Rocha 1997)

Synonymizations:

"=" means "synonymized with".

Rhopalurus crassicauda Caporiacco, 1947 = Rhopalurus laticauda Thorell, 1876.

Rhopalurus amazonicus Lourenço, 1986 = Rhopalurus laticauda Thorell, 1876.

Rhopalurus crassicauda paruensis Lourenço, 2008 = Rhopalurus laticauda Thorell, 1876.

Rhopalurus brejo Lourenço, 2014 = Troglorhopalurus lacrau (Lourenço and Pinto-da-Rocha, 1997).

Rhopalurus acromelas Lutz and Mello, 1922 = Jaguajir agamemnon (C.L. Koch, 1839).

Rhopalurus melleipalpus Lutz and Mello, 1922 = Jaguajir agamemnon (C.L. Koch, 1839).

Rhopalurus iglesiasi Werner, 1927 = Jaguajir agamemnon (C.L. Koch, 1839).

Rhopalurus lambdophorus Mello-Leitão, 1932 = Jaguajir agamemnon (C.L. Koch, 1839).

Rhopalurus dorsomaculatus Prado, 1938 = Jaguajir agamemnon (C.L. Koch, 1839).

Rhopalurus goiasensis Prado, 1940 = Jaguajir agamemnon (C.L. Koch, 1839).

Rhopalurus aridicola Teruel and Armas, 2012 = Heteroctenus junceus (Herbst, 1800).

Rhopalurus melloleitaoi Teruel and Armas, 2006 = Heteroctenus junceus (Herbst, 1800).

Rhopalurus granulimanus Teruel, 2006 = Heteroctenus gibarae (Teruel, 2006).

Rhopalurus virkkii Santiago-Blay, 2009 = Heteroctenus abudi (Armas and Marcano Fondeur, 1987).

The article has an updated identification key for the involved taxa.

Abstract:

Reference:
Esposito LA, Yamaguti HY, Souza CA, Pinto da Rocha R, Prendini L. Systematic revision of the neotropical club-tailed scorpions, Physoctonus, Rhopalurus, and Troglorhopalurus, revalidation of Heteroctenus, and descriptions of two new genera and three new species (Buthidae: Rhopalurusinae). Bulletin of the American Museum of Natural History. 2017(415):1-134. [Open Access]

Thanks to Ricardo Pinto-da-Rocha and Carlos Turiel for sending me this article!

Family Buthidae

On the enigmatic troglobitic scorpion Troglorhopalurus translucidus and comments on troglobitic buthids

Gallão and Bichuette have recently published an article with a description of the adult female of the troglobitic scorpion Troglorhopalurus translucidus Lourenço Baptista & Giupponi, 2004 from Brazil. The article also present new data on distribution and life history. The situation for Rhopalurus lacrau Lourenço & Pinto-da-Rocha, 1997 and other buthid troglobites is also discussed.

Abstract:
We describe for the first time the adult female of the troglobitic scorpion Troglorhopalurus translucidus Lourenço Baptista & Giupponi, 2004, and broaden its known distribution to other sandstone caves at Chapada Diamantina’s region. The life history of T. translucidus is reconstructed through morphometric measurements, with a multivariate analysis applied on a set of 16 specimens in all stages (including the holotype) and biological notes. The ontogeny of T. translucidus has seven stages and the litter size is 43 (n = 1). We discuss the isolation of T. translucidus and Rhopalurus lacrau Lourenço & Pinto-da-Rocha, 1997 in caves of Chapada Diamantina, and discuss their troglomorphisms (autapomorphies) among other species related with Rhopalurus. Both species must be considered fragile due their restricted endemism at Chapada Diamantina.

Reference:
Gallao JE, Bichuette ME. On the enigmatic troglobitic scorpion Troglorhopalurus translucidus: distribution, description of adult females, life history and comments on Rhopalurus lacrau (Scorpiones: Buthidae). Zoologia. 2016;33(6):e20150193. [Open Access]

Thanks to Dr. Andre Felipe de Araujo Lira for sending me this article!

Scorpions of Bahia State, Brazil

Tiago Porto and co-workers have written a review on the scorpion fauna in the state of Bahia in northeastern Brazil.

Abstract:
We report herein an updated and commented list of scorpions occurring in state of Bahia, northeastern Brazil. Data comprising a period of 100 years (1908-2008) were obtained from seven major Brazilian collections. Twenty eight species were identified and grouped in seven genera (Bothriurus Peters, 1861, Ananteris Thorell, 1891, Isometrus Ehrenberg, 1828, Physoctonus Mello-Leitão, 1934, Rhopalurus Thorell, 1876, Tityus C.L.Koch, 1836 and Troglorhopalurus Lourenço, Baptista and Giupponi, 2004) and two families (Bothriuridae Simon, 1880 and Buthidae C.L. Koch, 1837). This new list increases in 50 % the known scorpiofauna of Bahia, which now represents approximately 22 % of the Brazilian species, recorded in all biomes and phytophysiognomies from the coastal zone to high altitude areas (3-1,268 m). Seven species are endemic to Bahia and three of them could be included in the Brazilian National Red List, which would promote action plans towards their conservation.

Reference:
Porto TJ, Brazil TK, Lira-da-Silva M. Scorpions, state of Bahia, northeastern Brazil. Check List. 2010;6(2):292-7. [Free fulltext]

Thanks to Tiago Porto for sending me this paper!