Abstract
The Liolaemidae radiation has resulted in three genera whose patterns of evolutionary diversification exhibit dramatic differences. Two of these lineages, Ctenoblepharys and Liolaemus, lay at the extremes, being a monotypic genus and one of the most extraordinary adaptive radiations among vertebrates, respectively. In Phymaturus, in contrast, 22 species are known, all characterized by similar ecological niches and life-history patterns. The Phymaturus genus consists of two major clades, flagellifer and patagonicus, restricted to Andean-Patagonian environments in Argentina and Chile. While the former lineage occurs primarily at the northern areas of the genus distribution, the latter mostly occupies central and southern Patagonia. In this study, we report evidence to support the existence of two new species of the genus belonging to the austral clade patagonicus. These new taxa, Phymaturus castillensis and Phymaturus videlai, occur close to the southernmost distributional limit known for the entire genus. At these austral latitudes, only two other species of the genus, P. indistinctus and P. patagonicus, have been found. Therefore, the two new species reported herein reveal a higher species richness at these cold and harsh South American environments, where the predominant lineage is Liolaemus. As in the rest of the species of the Phymaturus genus, P. castillensis and P. videlai are saxicolous, herbivorous, and viviparous, as revealed by our field and lab observations. A number of signals support the idea that these two Phymaturus populations are the result of speciation events. Essentially, both are strongly isolated by hundreds of kilometers from most species of the patagonicus clade, which precludes dynamic gene exchange among them, while substantial divergence in their patterns of coloration differentiate them from the two geographically closest species, P. indistinctus and P. patagonicus, and from each other. The differences in coloration are not, however, strongly accentuated between the sexes, being monochromatic in P. castillensis and moderately dichromatic in P. videlai. Interestingly, juveniles P. videlai exhibit also these signals of adult sexual dichromatism. Finally, the results reported in this study increase Phymaturus species richness up to 24 species.References
Andersson, M. (1994) Sexual selection. Princeton: Princeton University Press. 599 pp.
Bolnick, D. I. & Doebeli, M. (2003) Sexual dimorphism and adaptive speciation: two sides of the same ecological coin. Evolution, 57, 2433–2449.
Boretto, J. M. & Ibargüengoytía, N. R. (2009) Phymaturus of Patagonia, Argentina: reproductive biology of Phymaturus zapalensis (Liolaemidae) and a comparison of sexual dimorphism within the genus. Journal of Herpetology, 43, 96–104.
Cei, J. M. (1986) Reptiles del centro, centro-oeste y sur de la Argentina. Herpetofauna de las zonas áridas y semiáridas. Museo Regionale di Scienze Naturali di Torino, Monografie, 4, 528 pp.
Cei, J. M. & Castro, L. P. (1973) Taxonomic and serological researches on the Phymaturus patagonicus complex. Journal of Herpetology, 7, 237–247.
Collette, B. B. (1961) Correlations between ecology and morphology in anoline lizards from Havana, Cuba and southern Florida. Bulletin of the Museum of Comparative Zoology, 125, 137–162.
Corbalan, V., Scolaro, J. A. & Debandi, G. (2009) A new species of the genus Phymaturus of the flagellifer group from Central-Western Mendoza, Argentina (Reptilia: Iguania: Liolaemidae). Zootaxa, 2021, 42–56.
Coyne, J. A. & Orr, H. A. (2004) Speciation. Massachusetts: Sinauer Associates. 545 pp.
Díaz-Gómez, J. M. (2009) Historical biogeography of Phymaturus (Iguania: Liolaemidae) from Andean and Patagonian South America. Zoologica Scripta, 38, 1–7.
Donoso-Barros, R. (1966) Reptiles de Chile. Santiago: Ediciones Universidad de Chile, 458 pp.
Espinoza, R. E., Wiens, J. J. & Tracy, C. R. (2004) Recurrent evolution of herbivory in small, cold-climate lizards: breaking the ecophysiological rules of reptilian herbivory. Proceedings of the National Academy of Sciences, USA, 101, 16819–16824.
Etheridge, R. (1993) Lizards of the Liolaemus darwinii complex (Squamata: Iguania: Tropiduridae) in Northern Argentina. Bollettino del Museo Regionale di Scienze Naturali di Torino, 11, 137–199.
Etheridge, R. (1995) Redescription of Ctenoblepharys adspersa Tschudi, 1845, and the taxonomy of Liolaeminae (Reptilia: Squamata: Tropiduridae). American Museum Novitates, 3142, 1–34.
Etheridge, R. (2000) A review of lizards of the Liolaemus wiegmannii group (Squamata, Iguania, Tropiduridae), and a history of morphological change in the sand-dwelling species. Herpetological Monographs, 14, 293–352.
Fairbairn, D. J. & Roff, D. A. (2006) The quantitative genetics of sexual dimorphism: assessing the importance of sex-linkage. Heredity, 97, 319–328.
Field, A. (2006) Discovering statistics using SPSS. Second Edition. London: Sage. 779 pp.
Gavrilets, S. (2004) Fitness landscapes and the origin of species. Princeton: Princeton University Press. 476 pp.
Givnish, T. J. & Sytsma, K. J. (1997) Molecular evolution and adaptive radiation. Cambridge: Cambridge University Press. 621 pp.
Ibargüengoytía, N. R., Acosta, J. C., Boretto, J. M., Villavicencio, H. J., Marinero, J. A. & Krenz, J. D. (2008) Field thermal biology in Phymaturus lizards: comparisons from the Andes to the Patagonian steppe in Argentina. Journal of Arid Environments, 72, 1620–1630.
Isaac, N. J. B., Mallet, J. & G.M., M. (2004) Taxonomic inflation: Its influence on macroecology and conservation. Trends in Ecology and Evolution, 19, 464–469.
Lande, R. (1979) Quantitative genetic analysis of multivariate evolution, applied to brain:body size allometry. Evolution, 33, 402–416.
Lande, R. & Arnold, J. J. (1983) The measurement of selection on correlated characters. Evolution, 37, 1210–1226.
León, R. J. C., Bran, D., Collantes, M., Paruelo, J. M. & Soriano, A. (1998) Grandes unidades de vegetación de la Patagonia extra andina. Ecología Austral, 8, 125–144.
Lobo, F. & Espinoza, R. E. (1999) Two new cryptic species of Liolaemus (Iguania: Tropiduridae) from nothwestern Argentina: resolution of the purported reproductive biomodality of Liolaemus alticolor. Copeia, 1999, 122–140.
Lobo, F. & Quinteros, S. (2005a) A morphology-based phylogeny of Phymaturus (Iguania: Liolaemidae) with the description of four new species from Argentina. Papeis Avulsos de Zoologia, 45, 143–177.
Lobo, F. & Quinteros, S. (2005b) Taxonomic studies of the genus Phymaturus (Iguania: Liolaemidae): redescription of Phymaturus patagonicus Koslowsky 1898, and revalidation and redescription of Phymaturus spurcus Barbour 1921. Journal of Herpetology, 39, 533–540.
Losos, J. B. (2009) Lizards in an evolutionary tree. Ecology and adaptive radiation of anoles. California: University of California Press. 507 pp.
Mayr, E. (1963) Animal species and evolution. Massachusetts: Harvard University Press. 797 pp.
Piantoni, C., Ibargüengoytía, N. R. & Cussac, V. E. (2006) Age and growth of the Patagonian lizard Phymaturus patagonicus. Amphibia-Reptilia, 27, 385–392.
Pincheira-Donoso, D., Hodgson, D. J., Stipala, J. & Tregenza, T. (2009) A phylogenetic analysis of sex-specific evolution of ecological morphology in Liolaemus lizards. Ecological Research, 24, 1223–1231.
Pincheira-Donoso, D., Hodgson, D. J. & Tregenza, T. (2008a) Comparative evidence for strong phylogenetic inertia in precloacal signalling glands in a species-rich lizard clade. Evolutionary Ecology Research, 10, 11–28.
Pincheira-Donoso, D., Hodgson, D. J. & Tregenza, T. (2008b) The evolution of body size under environmental gradients in ectotherms: why should Bergmann’s rule apply to lizards? BMC Evolutionary Biology, 8, 68.
Pincheira-Donoso, D., Scolaro, J. A. & Schulte II, J. A. (2007) The limits of polymorphism in Liolaemus rothi: molecular and phenotypic evidence for a new species of the Liolaemus boulengeri clade (Iguanidae, Liolaemini) from boreal Patagonia of Chile. Zootaxa, 1452, 25–42.
Pincheira-Donoso, D., Scolaro, J. A. & Sura, P. (2008) A monographic catalogue on the systematics and phylogeny of the South American iguanian lizard family Liolaemidae (Squamata, Iguania). Zootaxa, 1800, 1–85.
Ritchie, M. G. (2007) Sexual selection and speciation. Annual Reviews of Ecology, Evolution and Systematics, 38, 79–102.
Schluter, D. (2000) The ecology of adaptive radiation. Oxford: Oxford University Press. 288 pp.
Schulte, J. A., Macey, J. R., Espinoza, R. E. & Larson, A. (2000) Phylogenetic relationships in the iguanid lizard genus Liolaemus: multiple origins of viviparous reproduction and evidence for recurring Andean vicariance and dispersal. Biological Journal of the Linnean Society, 69, 75–102.
Scolaro, J. A. (2005) Reptiles patagónicos: Sur. Una guía de campo. Trelew: Editorial Universidad Nacional de la Patagonia, 80 pp.
Scolaro, J. A. (2006) Reptiles patagónicos: Norte. Una guía de campo. Comodoro Rivadavia: Editorial Universidad Nacional de la Patagonia, 112 pp.
Scolaro, J. A. & Ibargüengoytia, N. R. (2008) A new fragment for the understanding of the puzzling evolutive process of the Phymaturus genus: a new species of the patagonicus group from Patagonia, Argentina (Reptilia: Iguania: Liolaemidae). Zootaxa, 1939, 38–50.
Scolaro, J. A., Ibargüengoytía, N. R. & Pincheira-Donoso, D. (2008) When starvation challenges the tradition of niche conservatism: on a new species of the saxicolous genus Phymaturus from Patagonia Argentina with pseudoarboreal foraging behaviour (Iguania, Liolaeminae). Zootaxa, 1786, 48–60.
Shine, R. (1989) Ecological causes for the evolution of sexual dimorphism: a review of the evidence. Quarterly Review of Biology, 64, 419–464.
Wiens, J. J. (2004) Speciation and ecology revisited: phylogenetic niche conservatism and the origin of species. Evolution, 58, 193–197.
Zar, J. H. (2009). Biostatistical analysis. Fifth edition. New Jersey: Pearson International. 944 pp.