Detection of nidoviruses in samples collected from captive snakes in Europe between 2016 and 2021.

BACKGROUND: Nidoviruses are increasingly detected in various snake species worldwide, but much remains to be learned about their distribution and the factors influencing their epidemiology. METHODS: This retrospective study evaluated the results of routine nidovirus testing, by PCR, of 5210 swab samples from pet snakes from various European countries that were submitted to a commercial veterinary laboratory in Germany between 2016 and 2021. RESULTS: The overall detection rate was 19.96%. However, the detection rate varied significantly depending on the snake species (p < 0.0001), with the highest rate in Indian pythons (Python molurus) (42.24%). Rates also varied depending on the season of sample collection (p < 0.0001), with the highest rate in winter (24.46%), and the country of sample origin (p < 0.0001), with the highest rate in Austria (36.69%). The detection rate also decreased significantly (p = 0.0003) over the 6-year observation period, from 26.43% to 17.64%. LIMITATION: No information on clinical signs was available for most of the sampled snakes. CONCLUSION: The present study supplies new information on the distribution of python nidoviruses (subgenus Roypretovirus) in pet snakes in Europe and indicates a dynamic situation with possible changes in prevalence over time.

Pythons in the Eocene of Europe reveal a much older divergence of the group in sympatry with boas.

Extant large constrictors, pythons and boas, have a wholly allopatric distribution that has been interpreted largely in terms of vicariance in Gondwana. Here, we describe a stem pythonid based on complete skeletons from the early-middle Eocene of Messel, Germany. The new species is close in age to the divergence of Pythonidae from North American Loxocemus and corroborates a Laurasian origin and dispersal of pythons. Remarkably, it existed in sympatry with the stem boid Eoconstrictor. These occurrences demonstrate that neither dispersal limitation nor strong competitive interactions were decisive in structuring biogeographic patterns early in the history of large, hyper-macrostomatan constrictors and exemplify the synergy between phylogenomic and palaeontological approaches in reconstructing past distributions.

Haematological reference of snakes: Amazon tree boa (Corallus hortulanus, Linnaeus, 1758) and Burmenese Python (Python bivittatus, Kuhl, 1820) in captive

Hematology has become important for making clinical diagnoses in snakes because maintenance techniques in captivity have been improving and increasing their life expectancy. The emergence of diseases in captivity requires the creation of parameters to understand the species in their healthy state. The possible association between the onset of neoplasia, immunosuppression, and viral infection are also important factors to consider. Thus, hematology is a fundamental tool for observing the responses of animals to diseases and treatments. The present study aims to study hematology between two species of snakes and compare the profiles observed with published results. Blood samples were collected from 16 male and female snakes: seven Corallus hortulanus from the family Boidae and nine Python bivittatus from the family Pythonidae belonging to the Biological Museum of the Butantan Institute, Sao Paulo, Brazil. Complete blood count results including blood smear, total erythrocyte count, leukocytes, and differential leukocyte count were evaluated. The data obtained in this study could help with the diagnosis, the treatment of snakes in captive conditions and in of nature conservation programs.

Haematological reference of snakes: Amazon tree boa (Corallus hortulanus, Linnaeus, 1758) and Burmenese Python (Python bivittatus, Kuhl, 1820) in captive / Parâmetros hematológicos das serpentes: suaçuboia (Corallus hortulanus, Linnaeus, 1758) e píton birmanesa (Python bivittatus, Kuhl, 1820) em cativeiro

Hematology has become important for making clinical diagnoses in snakes because maintenance techniques in captivity have been improving and increasing their life expectancy. The emergence of diseases in captivity requires the creation of parameters to understand the species in their healthy state. The possible association between the onset of neoplasia, immunosuppression, and viral infection are also important factors to consider. Thus, hematology is a fundamental tool for observing the responses of animals to diseases and treatments. The present study aims to study hematology between two species of snakes and compare the profiles observed with published results. Blood samples were collected from 16 male and female snakes: seven Corallus hortulanus from the family Boidae and nine Python bivittatus from the family Pythonidae belonging to the Biological Museum of the Butantan Institute, São Paulo, Brazil. Complete blood count results including blood smear, total erythrocyte count, leukocytes, and differential leukocyte count were evaluated. The data obtained in this study could help with the diagnosis, the treatment of snakes in captive conditions and in of nature conservation programs.(AU)

A hematologia das serpentes tem se tornado algo de grande importância para o diagnóstico clínico, visto que as técnicas de manutenção em cativeiro vêm aumentando a expectativa de vida. O surgimento de doenças em cativeiro leva à necessidade de criar parâmetros para conhecer as espécies em seu estado hígido. A possível associação entre o surgimento de neoplasias, imunossupressão e infecção viral também é um importante fator a ser considerado. Assim, a hematologia é uma ferramenta fundamental para se observarem as respostas dos animais diante das doenças e dos tratamentos. Nesse contexto, o presente estudo tem como objetivo o estudo hematológico entre duas espécies de serpentes e a comparação dos perfis encontrados com a literatura atual. Foi coletado sangue de 16 serpentes de ambos os sexos da família Boidae: sete Corallus hortulanus, e da família Pythonidae: nove Python bivittatus, pertencentes ao Museu Biológico do Instituto Butantan, São Paulo, Brasil. Foram avaliados o hemograma completo com esfregaço sanguíneo, a contagem total de eritrócitos, os leucócitos e a contagem diferencial de leucócitos. Os dados obtidos neste estudo poderão auxiliar no diagnóstico e no tratamento de serpentes em cativeiro e em programas de conservação da natureza.(AU)

Evolution of extreme ontogenetic allometric diversity and heterochrony in pythons, a clade of giant and dwarf snakes.

Ontogenetic allometry, how species change with size through their lives, and heterochony, a decoupling between shape, size, and age, are major contributors to biological diversity. However, macroevolutionary allometric and heterochronic trends remain poorly understood because previous studies have focused on small groups of closely related species. Here, we focus on testing hypotheses about the evolution of allometry and how allometry and heterochrony drive morphological diversification at the level of an entire species-rich and diverse clade. Pythons are a useful system due to their remarkably diverse and well-adapted phenotypes and extreme size disparity. We collected detailed phenotype data on 40 of the 44 species of python from 1191 specimens. We used a suite of analyses to test for shifts in allometric trajectories that modify morphological diversity. Heterochrony is the main driver of initial divergence within python clades, and shifts in the slopes of allometric trajectories make exploration of novel phenotypes possible later in divergence history. We found that allometric coefficients are highly evolvable and there is an association between ontogenetic allometry and ecology, suggesting that allometry is both labile and adaptive rather than a constraint on possible phenotypes.

Toward a Tree-of-Life for the boas and pythons: multilocus species-level phylogeny with unprecedented taxon sampling.

Snakes in the families Boidae and Pythonidae constitute some of the most spectacular reptiles and comprise an enormous diversity of morphology, behavior, and ecology. While many species of boas and pythons are familiar, taxonomy and evolutionary relationships within these families remain contentious and fluid. A major effort in evolutionary and conservation biology is to assemble a comprehensive Tree-of-Life, or a macro-scale phylogenetic hypothesis, for all known life on Earth. No previously published study has produced a species-level molecular phylogeny for more than 61% of boa species or 65% of python species. Using both novel and previously published sequence data, we have produced a species-level phylogeny for 84.5% of boid species and 82.5% of pythonid species, contextualized within a larger phylogeny of henophidian snakes. We obtained new sequence data for three boid, one pythonid, and two tropidophiid taxa which have never previously been included in a molecular study, in addition to generating novel sequences for seven genes across an additional 12 taxa. We compiled an 11-gene dataset for 127 taxa, consisting of the mitochondrial genes CYTB, 12S, and 16S, and the nuclear genes bdnf, bmp2, c-mos, gpr35, rag1, ntf3, odc, and slc30a1, totaling up to 7561 base pairs per taxon. We analyzed this dataset using both maximum likelihood and Bayesian inference and recovered a well-supported phylogeny for these species. We found significant evidence of discordance between taxonomy and evolutionary relationships in the genera Tropidophis, Morelia, Liasis, and Leiopython, and we found support for elevating two previously suggested boid species. We suggest a revised taxonomy for the boas (13 genera, 58 species) and pythons (8 genera, 40 species), review relationships between our study and the many other molecular phylogenetic studies of henophidian snakes, and present a taxonomic database and alignment which may be easily used and built upon by other researchers.

Variation in mating systems and sexual size dimorphism between populations of the Australian python Morelia spilota (Serpentes: Pythonidae).

Although adaptationist hypotheses predict a functional relationship between mating systems and sexual size dimorphism, such predictions are difficult to test because of the high degree of phylogenetic conservatism in both of these traits. Taxa that show intraspecific variation in mating systems hence offer valuable opportunities for more direct tests of evolutionary-ecological hypotheses. Based on a collation of published and unpublished records, we document intraspecific geographic variation in mating systems (presence versus absence of male-male combat) within the widely-distributed Australian python Morelia spilota. Radiotelemetric monitoring of 19 free-ranging pythons in a population in north-eastern New South Wales showed that these animals display a mating system of female defence polygyny. Previous studies on a southern population of the same species found that males engaged in long mate-searching movements, showed no overt agonistic behavior, and formed long-term (>2 months) aggregations around reproductive females. In strong contrast, our adult male carpet pythons (i) moved about relatively little (mean displacement <11 m/day) during the mating season, (ii) remained with females only briefly (<5 days), and (iii) engaged in male-male combat in the vicinity of females. This male-male combat included vigorous biting as well as ritualised "wrestling" matches, resulting in a high incidence of bite scars in adult males. In keeping with predictions from sexual selection theory, males attain larger body sizes than females in this population, whereas females grow larger than males in the previously-studied southern population where males do not engage in physical combat for mating opportunities.