The prickly blade mapped: establishing homologies and a chaetotaxy for macrosetae of penis ventral plate in Gonyleptoidea (Arachnida, Opiliones, Laniatores)


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April 2015


For the first time a hypothesis of homology is proposed for the macrosetae which compose the armature of the distal truncus penis of the Gonyleptoidea. Previous attempts to name them in the literature have not been continued because they started by referring to macrosetae based on their position, which may change widely, and all of them were very narrow in scope. The present project instead names groups of macrosetae that do not mandatorily refer to their position, thus compensating for their hypothesized secondary position shifts. Using criteria of topology, shape and exclusion, six groups of setae are recognized, A–E, and their topological and phylogenetic distribution is studied and described in all families of Gonyleptoidea and two other related families of Grassatores. A cladistic analysis is performed, providing the following results: (1) the Microsetata are recovered including Metasarcidae/Cosmetidae sister to an expanded Gonyleptidae; (2) the genera Quindina (Cranaidae) and Zygopachylus (Manaosbiidae) are transferred to Nomoclastidae rank nov., hitherto regarded as a subfamily of Stygnidae, now a sister group of the Microsetata; (3) Zamorinae, currently placed in Cranaidae, is the sister group to Nomoclastidae, and it is therefore transferred to this family; (4) an expanded Gonyleptidae is recovered, including Manaosbiidae and Cranaidae, but the independence of these families is also recovered because the Gonyleptidae stricto sensu form a clade; (5) the Ampycinae, in spite of many particularities, are recovered inside Gonyleptidae; (6) the zamorine-less Cranaidae are recovered as a monophyletic sister group to Gonyleptidae, but not nested inside it. Jabbastygnus gen. nov. is described in Stygnidae along with its type species J. huttorum, from Colombia.


Genital Morphology, Grassatores, Harvestmen, Neotropics

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Zoological Journal of the Linnean Society, Vol. 174, no. 1 (2015-04-21).