Testing the Limits of Morphology: A Comprehensive Morphometric Study of the Sister Lineages Lasiocyano Galleti-Lima, Hamilton, Borges and Guadanucci, 2023 and Lasiodora C. L. Koch, 1850 (Theraphosidae, Mygalomorphae)

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  Testing the Limits of Morphology: A Comprehensive Morphometric Study of the Sister Lineages Lasiocyano Galleti-Lima, Hamilton, Borges and Guadanucci, 2023 and Lasiodora C. L. Koch, 1850 (Theraphosidae, Mygalomorphae) ABSTRACT Morphological conservatism and homoplasy pose significant challenges for the systematics of mygalomorph spiders, limiting the number of reliable morphological characters available for species identification, particularly in Theraphosidae. Closely related taxa frequently display high phenotypic similarity, which limits the resolution of morphology-based approaches. In this study, we conducted the most extensive morphometric analysis to date within Theraphosidae, with the objective of explicitly testing how much morphological information is retained within the  Lasiocyano sazimai  and  Lasiodora  lineage. We applied a morphometric framework combining linear morphometry and geometric morphometry, including multivariate statistics, discrimina...

Uncovering the worldwide footprint of an ancient relictual lineage of harvestmen: new genus and species of Buemarinoidae from Australia (Opiliones: Laniatores: Triaenonychoidea)

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Uncovering the worldwide footprint of an ancient relictual lineage of harvestmen: new genus and species of Buemarinoidae from Australia (Opiliones: Laniatores: Triaenonychoidea)

Abstract

Phocyx gen. nov. and Phocyx australis sp. nov. have been newly described from New South Wales, Australia. This represents the first record of the family Buemarinoidae in Australia, thereby remarkably extending the known distribution of this ancient and relictual group of Opiliones. Our descriptions include images of genital morphology, a critical element in group diagnosis. Additionally, we present a discourse on the conserved external morphology within Triaenonychoidea and underscore the significance of genital morphology in the taxonomy of this superfamily. Very low species diversity and relict taxa surviving in scattered isolated refugia (tropical environments of the Southern Hemisphere and hypogean habitats of the Northern Hemisphere) are a clear signature that extinction probably played a major role in shaping the current distribution ranges of Buemarinoidae. That is also reflected in buemarinoid systematics by the prevalence of monotypic genera, a product of the large-scale extinction process affecting this old harvestman lineage.

Willians Porto, Lionel Monod, Abel Pérez-González, Uncovering the worldwide footprint of an ancient relictual lineage of harvestmen: new genus and species of Buemarinoidae from Australia (Opiliones: Laniatores: Triaenonychoidea), Zoological Journal of the Linnean Society, 2024;, zlae067, https://doi.org/10.1093/zoolinnean/zlae067