Evidence forEurogondwana: the roles of dispersal, extinction and vicariance in the evolution and biogeography ofIndo‐PacificHormuridae (Scorpiones:Scorpionoidea)

Abstract

Scorpions previously assigned to the genus Liocheles Sundevall, 1883, of the family Hormuridae Laurie, 1896, are widely distributed in the tropical forests of the Indo‐Pacific region. Revisionary systematics of these poorly known scorpions has revealed a tremendous diversity of species. As part of an ongoing investigation, the first analysis of Indo‐Pacific hormurid scorpion phylogeny based on morphological data scored for all currently recognized species of Hormiops Fage, , Hormurus Thorell, 1876, and Liocheles, is presented. The taxonomy of these scorpions is reassessed and their biogeography reinterpreted in the light of the phylogeny. Phylogenetic, morphological, and distributional data support the revalidation of Hormiops and Hormurus, previously synonymized with Liocheles. The phylogeny indicates that the Australasian hormurids are more closely related to the Afrotropical and Neotropical hormurids than to the Indian hormurids, as previously proposed, refuting the “out‐of‐India” origin of Asian hormurids. A recent paleogeographical hypothesis, the “Eurogondwana model”, is supported instead. According to this hypothesis, hormurid scorpions colonized Laurasia from Africa via the Apulia microplate (Europa terrane) in the Cretaceous, subsequently colonized the Australo‐Papuan archipelago in the early‐mid Cenozoic, and then went extinct in the Northern Hemisphere during the second half of the Cenozoic. These results suggest that, contrary to the traditional paradigm, dispersal and extinction may affect spatial and temporal biotic distributions as much as vicariance, even in animals with limited vagility, such as scorpions.

Phylogenomic resolution of scorpions reveals multilevel discordance with morphological phylogenetic signal

“…(b) A single origin of katoikogenic development Convergent evolution induced by adaptations to substrate type is prevalent in many lineages of scorpions, possibly driving homoplasy in many characters drawn from external morphology [67,68]. Internal morphology may be less prone to homoplasy that stems from adaptation to substrate, and thus may be more informative at the higher taxonomic levels, as exemplified by mode of embryonic development (electronic supplementary material, figure S25 and table S3).…”

Earliest Onychophoran in Amber Reveals Gondwanan Migration Patterns

“…Apart from Antarctica, which lacks living onychophorans, the other two areas are colonized exclusively by Peripatopsidae [2,15,[36][37][38]; therefore, it is reasonable to assume that, if any Gondwanan-derived population of Onychophora ever persisted in India, it would also be composed of peripatopsids. Second, insular India had a hostile paleoclimate during the Cretaceous [39] and underwent drastic geological events [34,40], suggesting that a viable population of Onychophora would be unlikely to survive in India during this period. Finally, onychophorans have never been reported from Madagascar, even though this landmass shares a similar paleogeographical history with India [1] ( Figure 4B).…”

Parsimony analysis of unaligned sequence data: maximization of homology and minimization of homoplasy, not minimization of operationally defined total cost or minimization of equally weighted transformations

“…Such morphological character suites with inapplicables are not uncommon. Recently published examples in this journal include the characters of the embolic membrane where applicable in the spider subfamily Mynogleninae and relatives (Araneae: Linyphiidae; Frick and Scharff, ; their characters 64–74); of the ventromedian carina on segment V where applicable in Hormuridae and relatives (Scorpiones: Scorpionoidea, Monod and Prendini, ; their characters 109–111); of the manidibular exopod and of the maxillular exopod where applicable in Cambrian pancrustacean larval fossils (Wolfe and Hegna, ; their characters 36–40 and 48–52); and of the lateral organs where applicable in Protodrilidae and relatives (Annelida; Martínez et al., ; their characters 25–29). In the current absence of a program that maximizes homology for such morphological data, it remains an open question if or to what degree this approach may affect phylogenetic inference.…”