Cryptic, Sympatric Diversity in Tegu Lizards of the Tupinambis teguixin Group (Squamata, Sauria, Teiidae) and the Description of Three New Species

Cryptic species conservation: a review

Cryptic species are groups of two or more taxa that were previously classified as single nominal species. Being almost morphologically indistinguishable, cryptic species have historically been hard to detect. Only through modern morphometric, genetic, and molecular analyses has the hidden biodiversity of cryptic species complexes been revealed. Cryptic diversity is now widely acknowledged, but unlike more recognisable, charismatic species, scientists face additional challenges when studying cryptic taxa and protecting their wild populations. Demographical and ecological data are vital to facilitate and inform successful conservation actions, particularly at the individual species level, yet this information is lacking for many cryptic species due to their recent taxonomic description and lack of research attention. The first part of this article summarises cryptic speciation and diversity, and explores the numerous barriers and considerations that conservation biologists must navigate to detect, study and manage cryptic species populations effectively. The second part of the article seeks to address how we can overcome the challenges associated with efficiently and non-invasively detecting cryptic species in-situ, and filling vital knowledge gaps that are currently inhibiting applied conservation. The final section discusses future directions, and suggests that large-scale, holistic, and collaborative approaches that build upon successful existing applications will be vital for cryptic species conservation. This article also acknowledges that sufficient data to implement effective species-specific conservation will be difficult to attain for many cryptic animals, and protected area networks will be vital for their conservation in the short term.

Redescription of the two most recorded Physaloptera (Nematoda: Physalopteridae) parasitizing lizards in the Americas: first step towards a robust species identification framework

Despite being the two most recorded species of Physaloptera from lizards in the Americas, P. retusa and P. lutzi are either incompletely described or have accumulated inaccurate morphological data through the years. Here, we redescribe both species from Tropidurus torquatus in the State of Minas Gerais, Brazil, including evaluation of specimens from the Coleção Helmintológica do Instituto Oswaldo Cruz. In P. retusa, the presence and location of amphids, presence and pattern of porous areas on pseudolabia, detailed pattern of cuticular ornamentations on ventral surface of the caudal bursa, structure of cloacal labia, presence of dome-shaped elevation between the last pair of postcloacal papillae and location of phasmids in males, were revealed for the first time. Additional morphometric data are also provided. In P. lutzi, the detailed morphological analysis revealed for the first time, porous areas on pseudolabia, as well as presence of amphids, phasmids, and the detailed ornamentation and papillae arrangement on the male bursa. Also, the presence of an internal tripartite and an external triangular labial tooth in the specimens were observed to be constant, diverging from the assertions by other authors. Finally, in P. lutzi was possible to observe that deirids are consistently located close to muscular oesophagus base with excretory pore slightly posterior to it, and the vulva is always close to anal aperture. The present observations confirmed the validity of P. lutzi and strengthened its taxonomic diagnosis. An up-to-date list of records of both species is provided, including a brief discussion on their host spectrum and geographic range.

Two new species of Hypostomus suckermouth-armoured catfishes (Teleostei: Loricariidae) from central Brazil

This study describes two new endemic Hypostomus species from central Brazil, which were previously identified as genetically distinct lineages in a recent genomic study that recommended their testing and potential description based on morphological data. A machine learning classification procedure (random forest) was used to investigate morphological variation and identify putatively diagnostic characters for these candidate species and revealed that each is morphologically distinct. The new species Hypostomus cafuringa is characterized by small size, dark spots under a light background, deeper caudal peduncle and shorter first ray of the pectoral fin and base of the dorsal fin when compared to congeneric species from the region. H. cafuringa is known from the headwaters of the Maranhão River, upper Tocantins River basin, Distrito Federal, Brazil. The second new species, Hypostomus crulsi, is characterized by dark spots under a light background, absence of plates along the abdomen region, shorter first ray of the pelvic fin, shorter first ray of the pectoral fin and smaller body size. H. crulsi is known from the headwaters of the São Bartolomeu River, upper Paraná River basin, Distrito Federal, Brazil. The rapid conversion of natural habitats for agricultural development and the isolation of protected areas represent a serious threat to the continued existence of these two newly described endemic species, which warrant conservation assessment.

Molecular phylogeny of Neotropical Parrot Snakes (Serpentes: Colubrinae: Leptophis) supports underestimated species richness

Tetrapod taxa with broad geographic distributions across the Neotropics are often composed of multiple evolutionary lineages. In this paper, we present the most complete phylogeny of Leptophis to date and assess morphology-based species limits within the broadly distributed green parrot snake Leptophis ahaetulla sensu lato, which occurs from Mexico to Argentina. Although L. ahaetulla sensu stricto, L. nigromarginatus and L. occidentalis were recovered as paraphyletic, tree topology tests failed to reject their monophyly. Monophyly of L. bocourti, L. coeruleodorsus, L. cupreus, L. depressirostris, L. marginatus, L. riveti and L. sp. nov. was strongly supported. Our phylogenetic trees support recognition of multiple species within Leptophis ahaetulla sensu lato and suggest that color evolution and the uplift of the Andes played an important role in the diversification of parrot snakes.

Patterns of morphological diversification in giant Berberomeloe blister beetles (Coleoptera: Meloidae) reveal an unexpected taxonomic diversity concordant with mtDNA phylogenetic structure

Delimiting species boundaries is a complex challenge usually hindered by overlooked morphological diversification or misinterpretation of geographically structured phenotypic variability. Independent molecular data are extremely useful to characterize and understand such morphological diversity. Morphological and molecular variability of the non-phoretic and apterous, widely distributed, giant blister beetles of the genus Berberomeloe, were investigated within and between lineages across most of the distributional range of the genus. We used two mtDNA gene fragments to characterize genetic variability and to produce a time-calibrated phylogeny of the genus. Our results reveal several mitochondrial lineages, allopatrically, parapatrically and sympatrically distributed. Most clades are not distinguishable between each other based on morphometrics. However, no morphometric overlap is observed between two closely related clades, one of them occurring in sympatry with a distantly congeneric species (B. insignis), suggesting that sympatry could trigger morphological diversification. Although most species share a morphometric space, they can be morphologically identified by a combination of easily observed characteristic qualitative features. Based on the concordance between mtDNA clades and morphological units, we describe six new species of Berberomeloe (B. castuo sp. nov., B. comunero sp. nov., B. indalo sp. nov, B. yebli sp. nov., B. payoyo sp. nov. and B. tenebrosus sp. nov.), revalidate two taxa (B. maculifrons comb. nov. and B. laevigatus comb. nov.) and redefine B. majalis.

Eight in one: morphological and molecular analyses reveal cryptic diversity in Amazonian alopoglossid lizards (Squamata: Gymnophthalmoidea)

Among the currently recognized species of Alopoglossus, the Amazonian Alopoglossus angulatus has the widest distribution. We here analyse variation in scutellation and morphometrics of A. angulatus by examining 785 specimens of Alopoglossus. We also analyse intra- and interspecific genetic structure and differentiation using two mitochondrial (Cytb and ND4) and two nuclear (SNCAIP and PRLR) genes from 97 samples. Both morphological and molecular analyses are based on specimens and samples from Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru and Suriname. Our results reveal A. angulatus as a monophyletic group composed of eight independently evolved lineages: A. angulatus s.s. plus three revalidated species plus two newly described species plus two putative species. We provide descriptions of all taxa, except for the putative species, including the first description of the neotype of A. angulatus and redescriptions of resurrected junior synonyms. Illustrations, diagnoses and geographical distribution maps are provided. Gene and species trees are also provided. The two new taxa recognized in this paper, along with the revalidation of three taxa, increase the total number of known species of Alopoglossus from nine to 14.

Evidence of cryptic lineages within a small South American crocodilian: the Schneider's dwarf caiman Paleosuchus trigonatus (Alligatoridae: Caimaninae)

Schneider’s dwarf caiman Paleosuchus trigonatus is one of the smallest living crocodilians. Due to its broad distribution, cryptic behavior, and small home range, the species is well suited for the study of phylogeographic patterns on a continental scale. Additionally, this species is under threat due to habitat loss, trade and harvest, but is considered at low conservation risk by the IUCN. In the present study we test the hypothesis that P. trigonatus is comprised of geographically structured lineages. Phylogenetic reconstructions of the mitochondrial cytochrome b gene and single locus species discovery methods revealed the existence of two well-supported lineages within P. trigonatus—an Amazonian and Guianan lineage. Fossil calibrated divergence of these lineages was estimated to have occurred in the Late Miocene (7.5 Ma). The hypothesis that the Atlantic coast drainages might have been colonized from the southeast or central Amazon is supported by demographic metrics and relatively low genetic diversity of the Coastal and upper Branco populations when compared to the Amazon basin populations. The Amazon basin lineage is structured along an east-west gradient, with a sharp transition in haplotype frequencies to the east and west of the Negro and Madeira rivers. These lineages are already under anthropogenic threat and, therefore, are conservation dependent. Recognition of these lineages will foster discussion of conservation future of P. trigonatus and these lineages.

Modeling the distributions of tegu lizards in native and potential invasive ranges

Invasive reptilian predators can have substantial impacts on native species and ecosystems. Tegu lizards are widely distributed in South America east of the Andes, and are popular in the international live animal trade. Two species are established in Florida (U.S.A.) - Salvator merianae (Argentine black and white tegu) and Tupinambis teguixin sensu lato (gold tegu) – and a third has been recorded there— S. rufescens (red tegu). We built species distribution models (SDMs) using 5 approaches (logistic regression, multivariate adaptive regression splines, boosted regression trees, random forest, and maximum entropy) based on data from the native ranges. We then projected these models to North America to develop hypotheses for potential tegu distributions. Our results suggest that much of the southern United States and northern México probably contains suitable habitat for one or more of these tegu species. Salvator rufescens had higher habitat suitability in semi-arid areas, whereas S. merianae and T. teguixin had higher habitat suitability in more mesic areas. We propose that Florida is not the only state where these taxa could become established, and that early detection and rapid response programs targeting tegu lizards in potentially suitable habitat elsewhere in North America could help prevent establishment and abate negative impacts on native ecosystems.