A pseudoscorpion clinging to a cave salamander: phoresy or failed predation?

Posted by
  A pseudoscorpion clinging to a cave salamander: phoresy or failed predation? Abstract Pseudoscorpions are well known for phoretic associations with arthropods, but interactions with amphibians are rarely documented. Here we report a pseudoscorpion attached to the left palpebral region of an adult male Italian cave salamander, Speleomantes italicus , observed during a visual survey in a karst cave in Tuscany, Italy. The pseudoscorpion, assigned on the basis of visible morphology and locality to Chthonius cf. elongatus , was grasping a minute cutaneous fold on the lower margin of the left upper eyelid with one chela while the salamander moved slowly over the rock surface. No handling was performed and the initial contact between the two animals was not observed. The event therefore cannot be interpreted unambiguously, but may represent opportunistic phoresy or defensive attachment following a failed predation attempt. To our knowledge, this is the first published observation of a ...

Testing cohesive selective paths and evaluating loss of evolutionary information while delimiting species of Brazilian wandering spiders

Posted by

 


Testing cohesive selective paths and evaluating loss of evolutionary information while delimiting species of Brazilian wandering spiders

Abstract

Biodiversity is structured in nested Retrospective Reproductive Communities (RRCs) reflecting different levels of information about evolutionary processes. Ranking species involves deciding which level to emphasize, based on a trade-off in information gain and loss. Modeling the selective processes that maintain RRCs along distinct evolutionary paths can inform these trade-offs in species delimitation. We illustrate this approach using the Brazilian wandering spiders (Phoneutria). Integrating genetic markers, geometric morphometrics, color patterns, and environmental data, we applied both established and novel approaches to test divergence through historical natural and sexual selection. We found evidence that selection on ecological niche and ventral abdominal coloration contributed to the formation of four distinct RRCs. Two of these RRCs also showed evidence of a Lock-and-Key mechanism influencing genital morphology evolution. Despite the distinct cohesive forces, gene flow modeling revealed incomplete reproductive isolation, with potential hybrid individuals. We evaluate the implications of lumping versus splitting these lineages and argue that recognizing all four RRCs as distinct species would better preserve evolutionary information and minimize downstream impacts on other research fields such as pharmacology, public health and conservation. Our approach provides a quantitative basis to ponder the implications of choosing between different species hypotheses.

Azevedo, G. H., De Oliveira, U., Santos, F. R., Brescovit, A. D., & Santos, A. J. Testing cohesive selective paths and evaluating loss of evolutionary information while delimiting species of Brazilian wandering spiders. Evolution. https://doi.org/10.1093/evolut/qpag049