On a new genus of dwarf tarantulas (Araneae: Mygalomorphae: Theraphosidae) endemic from Peru: evidence from morphology and molecular phylogeny, with description of three new species

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  On a new genus of dwarf tarantulas ( Araneae : Mygalomorphae : Theraphosidae ) endemic from Peru: evidence from morphology and molecular phylogeny, with description of three new species Abstract Recent field campaigns conducted in Peru along with the examination of museum specimens allowed us to identify small tarantulas that do not fit with any known Theraphosidae genera. Morphology and additional molecular evidence from the mitochondrial gene COI led us to propose Kiskalla gen. nov . from southern Peru, at Puno region. Three new species of Kiskalla gen. nov . ( K. ignacioi sp. nov ., K. yeisoni sp. nov . and K. zukuapasanka sp. nov .) are herein described, diagnosed and illustrated. Kiskalla gen. nov . differs from the known Theraphosinae genera in the presence of lateral stripes on the abdomen and a small dorsal arrowhead-shaped patch of type III urticating setae, presence of a large number of spines on all legs, short and stout setae on the dorsal metatarsi encirc...

Sperm Transfer Under Behavioral and Morphological Constraints in the Orb-Web Spider Genus Argiope

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Sperm Transfer Under Behavioral and Morphological Constraints in the Orb-Web Spider Genus Argiope


ABSTRACT

Sperm transfer constraints are common phenomena in spider mating systems, influenced by both behavioral and morphological factors. Non-motile, encapsulated sperm cells must navigate through narrow male and female ducts during short (only seconds) copulations, all while under the pressure of female aggression, which can include sexual cannibalism and genital damage. However, little attention has been paid to the impact of male and female internal genital morphology on sperm transfer. In this study, we quantify the number of sperm transferred by males in five species of the genus Argiope as a direct measure of reproductive success. We explore sperm transfer in relation to copulation duration, sperm availability, sexual dimorphism, and female aggression. Additionally, we compare intra- and interspecific variation in sperm transfer by examining internal male and female genital morphological traits. Finally, we discuss the allometry of internal genital morphology in terms of sperm transfer in spiders. Our findings indicate that the occurrence of sexual cannibalism is the significant factor impacting sperm transfer in the genus Argiope. We observed a positive, albeit non-significant, correlation between sperm duct width and sperm transfer. Nonetheless, interspecific variability in allometry and methodological challenges underscore the need for continued research to fully understand the complexities of internal genital evolution in spiders.

Dharmarathne, C., McLean, D. J., Michalik, P., & Herberstein, M. E. Sperm Transfer Under Behavioral and Morphological Constraints in the Orb-Web Spider Genus Argiope. Integrative Zoology. https://doi.org/10.1111/1749-4877.12956