A Remarkable Discovery: Exploring a Rare Eresus and Spider Wasp Interaction

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  Photo Credit: © Antonino Rametta . All photographs are used with permission. No part of these images may be reproduced, distributed, or used in any form without the prior written permission of the photographer. A Remarkable Discovery: Exploring a Rare Eresus and Spider Wasp Interaction One of the most rewarding aspects of maintaining Arácnido Taxonomy is hearing from naturalists and photographers around the world who take the time to share their discoveries. Every so often, an email arrives that immediately captures your attention. Not because it claims to rewrite what we know about biodiversity, but because it documents something that very few people have the opportunity to witness. Recently, I was contacted by a naturalist in Sicily who shared a series of exceptionally high-quality photographs of a female ladybird spider ( Eresus ) during what appeared to be an interaction with a spider wasp. Along with the images came a simple question: "Could this be scientifically import...

Osmooka, a new spider genus from Madagascar: a surprising relative of the Australian fauna (Araneae: Paraplectanoididae)

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Osmooka, a new spider genus from Madagascar: a surprising relative of the Australian fauna (Araneae: Paraplectanoididae) 

Abstract

Madagascar is a biodiversity hotspot with high endemism and ancient phylogenetic diversity. We here report the discovery of Osmooka aphana gen. nov., sp. nov. from Marojejy National Park. Phylogenomic analyses place Osmooka as sister to the Australian Paraplectanoides Keyserling, 1886 and this doublet is sister to Nephilidae Simon, 1894. When proposed, Paraplectanoididae Kuntner, Coddington, Agnarsson & Bond, 2023 was exclusively Australian and monogeneric, but was predicted to contain additional, undescribed taxa. The discovery of Osmooka and its phylogenetic placement in Paraplectanoididae support this prediction. We present a taxonomic treatment of Osmooka and Paraplectanoides, and a reappraisal of Orbipurae morphological homologies. With this new discovery, we revalidate Paraplectanoididae, Nephilidae, and Phonognathidae Simon, 1894 ranks resurrected as exclusive, monophyletic, and well-diagnosed families, whereas Araneidae Clerck, 1757 requires further redefinition. Finally, we test the hypothesis of East Gondwanan vicariant origin of Osmooka and Paraplectanoides. This scenario would predict an ancient age of their ancestor, predating the 130 Ma breakup of Gondwana. Divergence dating refutes this hypothesis by estimating their common ancestor at 57 Ma. Rather than through vicariance, the disjunct distribution of Osmooka and Paraplectanoides is best explained through Cenozoic intercontinental dispersal and/or extinctions. Potential discovery of additional paraplectanoidid diversity might better elucidate the timing, modes, and trajectories of historic dispersal and extinction events.


Matjaž Kuntner, Kuang-Ping Yu, Matjaž Bedjanič, Matjaž Gregorič, Eva Turk, Klemen Čandek, Jonathan A Coddington, Ingi Agnarsson, James Starrett, Jason E Bond, Osmooka, a new spider genus from Madagascar: a surprising relative of the Australian fauna (Araneae: Paraplectanoididae), Insect Systematics and Diversity, Volume 9, Issue 6, November 2025, ixaf050, https://doi.org/10.1093/isd/ixaf050