Peter Praschag

Bio: Peter Praschag is an academic researcher from Smithsonian Conservation Biology Institute. The author has contributed to research in topics: Geoemydidae & Subspecies. The author has an hindex of 13, co-authored 18 publications receiving 317 citations.

Phylogeny and taxonomy of endangered South and South‐east Asian freshwater turtles elucidated by mtDNA sequence variation (Testudines: Geoemydidae: Batagur, Callagur, Hardella, Kachuga, Pangshura)

Abstract: Using DNA sequences of the mitochondrial cytochrome b gene, we investigated phylogeny and taxonomy of South and South-east Asian turtles of all species and subspecies of the genera Batagur, Callagur, Hardella, Kachuga and Pangshura. We found three major clades: (i) a moderately to well-supported clade containing all large riverine species assigned so far to Batagur, Callagur and Kachuga; (ii) a well-supported monophylum comprising the four Pangshura species; and (iii) Hardella that could constitute either the sister-taxon of Pangshura or of a clade comprising Batagur, Callagur, Kachuga and Pangshura. The genus Kachuga is clearly polyphyletic. Therefore, we recommend placing all Batagur, Callagur and Kachuga species in one genus. According to the International Code of Zoological Nomenclature Batagur Gray, 1856, being originally erected at higher rank, takes precedence over the simultaneously published name Kachuga Gray, 1856, and the younger name Callagur Gray, 1870, resulting in an expanded genus Batagur. Indonesian and Malaysian Batagur baska proved to be highly distinct from our sequences of this species from the Sundarbans (Bangladesh, adjacent India), suggesting that a previously unidentified species is involved. This finding is of high conservation relevance in the critically endangered B. baska. The currently recognized subspecies within Hardella thurjii, Pangshura smithii and P. tentoria do not correspond well with mtDNA clades. Considering that the two subspecies of H. thurjii are likely to be based only on individual ontogenetic differences, we propose abandoning the usage of subspecies within H. thurjii. In the Ghaghra River, Uttar Pradesh (India) we detected shared haplotypes in P. smithii and P. tentoria, implying that the unusual morphological characters of the Ghaghra River population of P. tentoria could be the result of interspecific hybridization.

Stable Cretaceous sex chromosomes enable molecular sexing in softshell turtles (Testudines: Trionychidae).

Abstract: Turtles demonstrate variability in sex determination ranging from environmental sex determination (ESD) to highly differentiated sex chromosomes. However, the evolutionary dynamics of sex determining systems in this group is not well known. Differentiated ZZ/ZW sex chromosomes were identified in two species of the softshell turtles (Trionychidae) from the subfamily Trionychinae and Z-specific genes were identified in a single species. We tested Z-specificity of a subset of these genes by quantitative PCR comparing copy gene numbers in male and female genomes in 10 species covering the phylogenetic diversity of trionychids. We demonstrated that differentiated ZZ/ZW sex chromosomes are conserved across the whole family and that they were already present in the common ancestor of the extant trionychids. As the sister lineage, Carettochelys insculpta, possess ESD, we can date the origin of the sex chromosomes in trionychids between 200 Mya (split of Trionychidae and Carettochelyidae) and 120 Mya (basal splitting of the recent trionychids). The results support the evolutionary stability of differentiated sex chromosomes in some lineages of ectothermic vertebrates. Moreover, our approach determining sex-linkage of protein coding genes can be used as a reliable technique of molecular sexing across trionychids useful for effective breeding strategy in conservation projects of endangered species.

Northern genetic richness and southern purity, but just one species in the Chelonoidis chilensis complex

Abstract: Fritz, U., Alcalde, L., Vargas-Ramirez, M., Goode, E.V., Fabius-Turoblin, D.U. & Praschag, P. (2012). Northern genetic richness and southern purity, but just one species in the Chelonoidis chilensis complex. —Zoologica Scripta, 41, 220–232. The Chelonoidis chilensis complex, the sister group of the famous Galapagos tortoises, is a widely distributed group of South American land tortoises, ranging from the dry Chaco of Bolivia, Paraguay and northern Argentina to northern Patagonia. Within this complex, up to three distinct species have been recognized. Using sequence data of the mitochondrial cytochrome b gene and length polymorphisms of 10 microsatellite loci, we investigate genetic differentiation among all three nominal species. We find only negligible differentiation, with decreasing genetic diversity from north to south. We conclude that only one species, Chelonoidis chilensis (Gray, 1870), is valid, with C. donosobarrosi (Freiberg, 1973) and C. petersi (Freiberg, 1973) as its junior synonyms. Morphological variation within C. chilensis sensu lato is in accord with the observation that size variation in chelonians follows Bergmann’s rule, with body size increasing with latitude. The observed phylogeographic differentiation inverses the well-known pattern of southern genetic richness and northern purity from the northern hemisphere, resulting from dispersal from glacial refugia. This implies that in higher latitudes of both hemispheres genetic diversity may decrease with increasing distance from the refugium. For C. chilensis sensu lato, it seems likely that long-distance dispersal via rafting on the Desaguadero River led to the foundation of the southernmost populations in northern Patagonia during the Holocene.

Genetic evidence for wild‐living Aspideretes nigricans and a molecular phylogeny of South Asian softshell turtles (Reptilia: Trionychidae: Aspideretes, Nilssonia)

Abstract: Aspideretes nigricans was long thought to be one of the rarest turtle species of the world, being restricted to a single site in Bangladesh; its specific distinctness was repeatedly doubted. Using mtDNA sequence data of all four Aspideretes species, we provide evidence that A. nigricans is a distinct species that is sister to A. hurum. Furthermore, A. nigricans is not endemic to Bangladesh, but also occurs in Assam, India. While all applied phylogenetic analyses (Bayesian Analysis, Maximum Likelihood, Maximum Parsimony, Neighbor Joining) strongly suggest a well-supported clade containing the four Aspideretes species and Nilssonia formosa, the monophyly of Aspideretes is at best weakly supported. We propose to synonymise the genera Aspideretes Hay, 1904 and Nilssonia Gray, 1872, resulting in an expanded genus Nilssonia with the species N. formosa (Gray, 1869), N. gangetica (Cuvier, 1825), N. hurum (Gray, 1831), N. leithii (Gray, 1872) and N. nigricans (Anderson, 1875). Genetic structure within N. nigricans is weak, while we detected two distinct genetic lineages within N. gangetica, one occurring in the Brahmaputra River system and the other in the Ganges and Indus River basins.

Turtles of the genera Geoemyda and Pangshura (Testudines: Geoemydidae) lack differentiated sex chromosomes: the end of a 40-year error cascade for Pangshura.

Abstract: For a long time, turtles of the family Geoemydidae have been considered exceptional because representatives of this family were thought to possess a wide variety of sex determination systems. In the present study, we cytogenetically studied Geoemyda spengleri and G. japonica and re-examined the putative presence of sex chromosomes in Pangshura smithii. Karyotypes were examined by assessing the occurrence of constitutive heterochromatin, by comparative genome hybridization and in situ hybridization with repetitive motifs, which are often accumulated on differentiated sex chromosomes in reptiles. We found similar karyotypes, similar distributions of constitutive heterochromatin and a similar topology of tested repetitive motifs for all three species. We did not detect differentiated sex chromosomes in any of the species. For P. smithii, a ZZ/ZW sex determination system, with differentiated sex chromosomes, was described more than 40 years ago, but this finding has never been re-examined and was cited in all reviews of sex determination in reptiles. Here, we show that the identification of sex chromosomes in the original report was based on the erroneous pairing of chromosomes in the karyogram, causing over decades an error cascade regarding the inferences derived from the putative existence of female heterogamety in geoemydid turtles.

International Code of Zoological Nomenclature

Abstract: DURING this year I have so often been asked how this Code could be obtained that I hasten, with your permission, to announce that the Washington Biological Society has just published a reprint at the price of one dollar. Prof. C. W. Stiles, secretary to the Commission, says: “I would suggest that, if your colleagues wish copies, it would expedite matters to order a number at once”. The address of the Society is at the Bureau of Entomology, Washington, D.C., U.S.A.

Compromising genetic diversity in thewild: unmonitored large-scale releaseof plants and animals

Abstract: Large-scale exploitation of wild animals and plants through fishing, hunting and logging often depends on augmentation through releases of translocated or captively raised individuals. Such releases are performed worldwide in vast numbers. Augmentation can be demographically and economically beneficial but can also cause four types of adverse genetic change to wild populations: (1) loss of genetic variation, (2) loss of adaptations, (3) change of population composition, and (4) change of population structure. While adverse genetic impacts are recognized and documented in fisheries, little effort is devoted to actually monitoring them. In forestry and wildlife management, genetic risks associated with releases are largely neglected. We outline key features of programs to effectively monitor consequences of such releases on natural populations.

Sparse Supermatrices for Phylogenetic Inference: Taxonomy, Alignment, Rogue Taxa, and the Phylogeny of Living Turtles

Abstract: As phylogenetic data sets grow in size and number, objective methods to summarize this information are becoming increasingly important. Supermatrices can combine existing data directly and in principle provide effective syntheses of phylogenetic information that may reveal new relationships. However, several serious difficulties exist in the construction of large supermatrices that must be overcome before these approaches will enjoy broad utility. We present analyses that examine the performance of sparse supermatrices constructed from large sequence databases for the reconstruction of species-level phylogenies. We develop a largely automated informatics pipeline that allows for the construction of sparse supermatrices from GenBank data. In doing so, we develop strategies for alleviating some of the outstanding impediments to accurate phylogenetic inference using these approaches. These include taxonomic standardization, automated alignment, and the identification of rogue taxa. We use turtles as an exemplar clade and present a well-supported species-level phylogeny for two-thirds of all turtle species based on a approximately 50 kb supermatrix consisting of 93% missing data. Finally, we discuss some of the remaining pitfalls and concerns associated with supermatrix analyses, provide comparisons to supertree approaches, and suggest areas for future research.

Categorización del estado de conservación de los anfibios de la República Argentina

Abstract: Fil: Vaira, Marcos. Universidad Nacional de Jujuy. Facultad de Ingenieria. Centro de Investigaciones Basicas y Aplicadas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina