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The family Gymnophthalmidae contains nearly 235 species with a distribution range from southern Mexico to central Argentina as well as in the Antilles. Among gymnophthalmids, the genus Colobosaura is a member of the tribe Iphisini, and currently is considered monotypic (C. modesta). The diversity of the tribe was studied recently, with the erection of several new genera. In this work genetic and morphological data of specimens of Colobosaura recently collected in Paraguay were analyzed. Genetic (16S barcode) data indicate that these samples are not conspecific with C. modesta and they are allocated to the nominal species C. kraepelini. Because the original primary type of the latter taxon is considered to be lost, a neotype (SMF 101370) is designated for this species and a redescription provided based on our material. Colobosaura kraepelini is distributed in the Humid Chaco, being the only member of the whole tribe in this ecoregion.
The gecko genus Phyllopezus is distributed mainly along South America’s "Dry Diagonal" (Caatinga, Cerrado, and Chaco). The genus has been the subject of recent taxonomic analyses and includes four described species and seven candidate species referred to here as Phyllopezus pollicaris sensu lato. In Paraguay, Phyllopezus is known from the Chaco and Cerrado where it is abundant, and also from a small isolated population from a rocky hill formation named "Cordillera de Los Altos" (Los Altos mountain range). Here we analyzed genetic samples from across its range, including new samples from Paraguay, using DNA barcoding analysis of the mitochondrial 16S gene and phylogenetic analyses using both Bayesian and Maximum Likelihood methods. We found genetic and morphological differences among geckos from the Los Altos mountain range and the remaining Phyllopezus populations. Using both molecular and morphological evidence we describe a new Phyllopezus species, sister to P. przewalskii. Genetic differentiation among described and putative Phyllopezus species is greater than their morphological differences, which likely accounts for these cryptic taxa remaining undescribed for so long.
Lizards of Paraguay: an integrative approach to solve taxonomic problems in central South America
(2018)
Paraguay is located in the center of South America with drier and warmer climatic conditions in the western part of the country, and more temperate and humid in the eastern region. Biogeographically, Paraguay is a key spot in South America, where several ecoregions converge. In my study, I sampled most of the ecoregions of Paraguay. The main objective of my work is to solve taxonomic problems, identified through genetic barcoding analyses, in the central region of South America. To achieve this objective, I used selected taxa of the Paraguayan Squamata as models taking into consideration the crucial geographic position of the country, plus the scarce available genetic data of Paraguayan reptiles.
The collecting activities were performed in the framework of a barcoding inventory project of the Paraguayan herpetofauna and carried out mostly in rural areas searching for animals in different types of habitats using active search as the sampling technique.
For genetics, the extraction of DNA was performed with DNeasy® Blood & Tissue Kit of Qiagen® for sets of few samples, and the fiber glass plate protocol for sets of 96 samples. I assessed the quality of sequences after amplification in agarose gel electrophoresis. The first marker sequenced was 16S mtDNA, used for barcoding analysis. A DNA barcode is a genetic identifier for a species. Once a taxonomic problem was detected, I generate more gene sequences to target the issue.
All the analyses to test phylogenetic hypotheses (based on single genes or concatenated datasets) were performed under Maximum Likelihood and Bayesian approaches. To root the phylogenetic trees, I chose the available taxon (or taxa) most closely related to the respective studied group as outgroups. For the general tree of Paraguayan Squamata, based on barcodes of 16S, I chose Sphenodon punctatus.
I generated a total of 142 sequences of 64 species of Squamata from Paraguay (Appendix I). The final alignment of 615 bp comprised 249 samples. The best substitution model for the Barcoding dataset based on the gene 16S was GTR+G, according to the BIC.
To complement molecular evidence generated with the ML grouping of 16S barcodes, I took a morphological approach based on voucher specimens collected during fieldwork (usually the same specimens that I used for genetic analysis), supplemented by the revision of museum collections.
Summarizing my results, samples of Colobosaura exhibit large genetic distances, and accordingly I revalidated Colobosaura kraepelini (Appendix II). Tropidurus of the spinulosus group show two clades and among them there is little genetic and morphological variation, I synonymized T. tarara and T. teyumirim with T. lagunablanca, and T. guarani with T. spinulosus (Appendix III). I detected the presence of candidate species of Homonota, and I restricted the name H. horrida for Argentina, and described two new species of Homonota (Appendices IV and V), and a new species of Phyllopezus also in the Family Phyllodactylidae (Appendix VI).
In this work I present the most comprehensive analysis of genetic samples of Squamata from Paraguay. The results obtained here will be useful to help to clarify further taxonomic issues regarding the squamate fauna from the central region of South America. Moreover, the data generated for this study will have a positive impact in a larger geographic context, beyond Paraguayan borders.
Regarding the conservation of the Paraguayan reptiles, and considering the taxonomic changes accomplished here, it is important to note that many species lack legal protection. In Paraguay, the major problem for conservation is habitat loss due to extensive crop farming. Thus, currently, the protected areas are the best strategy for conservation of biodiversity in the country. However, many such areas face legal problems (e.g., lack of official measurements, management plans, forest guards, infrastructure, etc.) so that the maintenance of their biodiversity over time is not guaranteed.
In conclusion, in this study I present contributions on the taxonomy of mostly lizards from Paraguay. Due to lack of samples, I was not able to deal with a deep taxonomic revision of the country's snakes. Based on my results, I can argue that analyses of Xenodontini and Pseudoboini are currently a pressing research issue. This barcoding project may continue since some colleagues in Paraguay are interested in collaboration. Given that the sequenced specimens are yet a small portion of the actual diversity of Paraguay, it will be of utmost importance to continue and expand these studies that will further improve our taxonomic knowledge. Furthermore, it is desirable to have Paraguayan scientists not only involved, but to see them taking the lead of high quality taxonomic research.