Wednesday, March 21, 2018

[Herpetology • 2018] Tropidurus azurduyae • A New Collared Lizard (Tropidurus, Tropiduridae) endemic to the western Bolivian Andes and Its Implications for Seasonally Dry Tropical Forests


Tropidurus azurduyae
Carvalho, Rivas, Céspedes & Rodrigues, 2018


Abstract
In this study we describe Tropidurus azurduyae, a new species of lizard endemic to the Andes. This species is restricted to inter-Andean dry valleys of central and southern Bolivia, within the ecoregion known as Bolivian Montane Dry Forests. It is currently known from the departments of Chuquisaca, Cochabamba, Potosí, and Santa Cruz, where it ranges in elevation from about 1000 to 2800 m. In addition, our analyses of closely related populations of Tropidurus from Argentina, Bolivia, Brazil, and Paraguay revealed undescribed species in central and northeastern Brazil and eastern Bolivia that render T. etheridgei Cei, 1982, paraphyletic. These results underscore the need for a comprehensive revision of peripheral and disjunct populations currently assigned to widely distributed species of Tropidurus. The phylogenetic relationships and distribution patterns of these new taxa concur with recent findings supporting seasonally dry tropical forests and open formations of dry vegetation from South America as distinct biotic units. Furthermore, they offer no support for seasonally dry tropical forests as closely related areas. In line with these discoveries, we refute biogeographic scenarios based exclusively on vicariance to explain the biogeographic history of Tropidurus


Adult male of Tropidurus azurduyae, sighted (not collected) at the type locality in the Torotoro National Park, Potosí, Bolivia.

FIGURE 1. Habitats visited in the Torotoro National Park, Potosí, Bolivia.
A–D, Prepuna (~2798 m). E–G, Inter-Andean dry valleys at the type locality of Tropidurus azurduyae (~2264 m). H, Adult male of Tropidurus azurduyae, sighted (not collected) at the type locality of the species.


FIGURE 3. Live specimens of Tropidurus azurduyae.
E, G, Adult female (allotype MHNC-R 3009); F, H, Adult male (holotype MHNC-R 3011). 


Tropiduridae Bell, 1843
Tropidurus Wied, 1825
Tropidurus azurduyae, n. sp.

Morphological Diagnosis: Tropidurus azurduyae is here morphologically diagnosed as a Tropidurus based on the observation of a set of characters suggested by Frost et al. (2001) as exclusive to the genus: skull not highly elevated at the level of the orbits; “flash” marks on underside of thighs present; circumorbitals distinct from other small supraorbital scales; lateral fringe not developed on both sides of fourth toes; enlarged middorsal scale row absent; tail terete; and hemipenis attenuate without apical disks. The presence of a maxilla not broad, nutritive foramina of maxilla strikingly enlarged, lingual process of dentary extending over lingual dentary process of coronoid, angular strongly reduced, and absence of medial centrale could not be examined without dissecting or clearing and staining specimens. These characters should be revised whenever larger series of individuals become available. 
Tropidurus azurduyae is a member of the T. torquatus group per Frost et al. (2001). It differs from other species groups by lacking an enlarged middorsal scale row (well marked in species of the T. spinulosus group, especially in males), by exhibiting black “flash” marks on the underside of thighs and cloacal flap of adult males (yellow, cream, or orangey “flash” marks are present in males of the T. spinulosus group), and also by lacking a dorsoventrally flattened body (as observed in species of the T. semitaeniatus group and, more moderately, in T. bogerti). 
Tropidurus azurduyae is the only species in the genus with lower flanks pigmented orange, a condition consistently observed in both sexes (fig. 3E–H). Its ventral head is darkly pigmented and offers contrast to the light circular blotches present on chin and also laterally (fig. 3G, H). The ground color of its throat is charcoal gray impregnated with strong orange coloration (fig. 3G, H). A pair of mite pockets is present on the lateral neck, with the posterior one larger; the anterior pocket originates lower than the posterior, but both usually end ventrally at the same level (fig. 3F). No pockets are found in the armpit and inguinal region of the new species. An elliptical or subrhomboidal black mark is present on the mid venter of adult males of T. azurduyae in addition to black “flash” marks on the underside of thighs and precloacal flap (fig. 3H). Tropidurus azurduyae is saxicolous, but may climb tree trunks and fallen logs occasionally (fig. 1H). In combination, this set of characters provides a safe diagnosis, distinguishing T. azurduyae from all other congeners.


Etymology: The species name azurduyae is a noun in the feminine genitive case honoring Juana Azurduy de Padilla (Chuquisaca, Bolivia: July 12, 1780–May 25, 1862), one of the most distinguished Latin American leaders who bravely fought for the independence of the Spanish territory of Upper Peru, which comprised part of today’s Bolivia and Peru, and formed along with Argentina, Uruguay, and Paraguay the Viceroyalty of the Río de La Plata during colonial times. Her memory remained nearly forgotten for more than a century, until President Cristina Kirchner conferred on her the title of General of the Argentinian Army in 2009, and in that same year, the Bolivian Senate promoted Juana Azurduy posthumously to the rank of Marshal of the Republic, declaring her “Liberator of Bolivia.” Although the biography of Juana Azurduy assuredly places her as one of the most important women of Latin America, the history of her fight for freedom and equality has not received enough attention outside history classes and political events. Naming Tropidurus azurduyae we do not aim to merely reverence her as a historical personage and revolutionary soldier, but to genuinely honor her intelligence, courage, and heroic actions against a male-dominated colonialist world whose roots remain alive at the present time. This is an affirmative action to remind all Latin American women and men of our female heritage of strength and combativeness. 

 For a more comprehensive biography of Juana Azurduy, refer to the work of the Argentinian writer Mario “Pacho” O’Donnnel (1994), available online (portaldesalta.gov.ar). Those interested may follow the YouTube link (youtu.be/SERg8GKCNeA) to hear the song “Juana Azurduy” in the voice of the Argentinian singer Mercedes Sosa, honoring the valiant spirit of Juana Azurduy.

CONCLUDING REMARKS: 
The taxonomic description and reconstruction of the phylogenetic relationships of Tropidurus azurduyae reflect on our efforts to advance the systematics of widely distributed complexes of cryptic species of Tropidurus. Because tropidurine fossils have not been discovered to date, we were unable to perform a safe chronological analysis to determine minimum ages for clades and species. However, the identification of endemic species restricted to the inter-Andean dry valleys from central and southern Bolivia and other seasonally dry tropical forests and open dry areas from South America allow us to expand the body of evidence supporting these areas as distinct biotic units. Furthermore, our results provide evidence against the Pleistocene Arc hypothesis, and call our attention to revisiting the biogeographic history of the dry areas of South America based on improved data sets and comparative analyses of a larger number of clades. For the first time, our results show with clarity that scenarios based exclusively on vicariance are unlikely to explain the complex biogeographic history of Tropidurus. Nevertheless, even if the distribution data and phylogenetic patterns recovered thus far allow us to rule out certain hypotheses in favor of others, determining the timeframe of the events involved in the diversification and biogeographic history of Tropidurus is crucial. Certainly, the incorporation of the time component (Donoghue and Moore, 2003) remains as a major challenge for us to fully understand the evolutionary history of this lizard clade (Carvalho et al., 2013). 


 André L. G. Carvalho (André Luiz Gomes), Luis Rolando Rivas, Ricardo Céspedes and Miguel Trefaut Urbano Rodrigues. 2018. A New Collared Lizard (Tropidurus, Tropiduridae) endemic to the western Bolivian Andes and Its Implications for Seasonally Dry Tropical Forests. American Museum Novitates. 3896; 1-56. DOI:  10.1206/3896.1  digitallibrary.amnh.org/handle/2246/6852

   


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