A review of the Madagascan pelican spiders of the genera Eriauchenius O. Pickard-Cambridge, 1881 and Madagascarchaea gen. n. (Araneae, Archaeidae)

Abstract

An endemic genus of Madagascan spiders (Araneae, Archaeidae, Eriauchenius) is revised. All 20 species of Eriauchenius are described and keyed, of which 14 are new species: Eriauchenius andriamanelo sp. n., Eriauchenius andrianampoinimerina sp. n., Eriauchenius goodmani sp. n., Eriauchenius harveyi sp. n., Eriauchenius lukemacaulayi sp. n., Eriauchenius milajaneae sp. n., Eriauchenius milloti sp. n., Eriauchenius rafohy sp. n., Eriauchenius ranavalona sp. n., Eriauchenius rangita sp. n., Eriauchenius rixi sp. n., Eriauchenius sama sp. n., Eriauchenius wunderlichi sp. n., Eriauchenius zirafy sp. n. Additionally, six species of the new genus Madagascarchaea gen. n. are described and keyed, of which four are new species: Madagascarchaea fohy sp. n., Madagascarchaea lotzi sp. n., Madagascarchaea moramora sp. n., Madagascarchaea rabesahala sp. n. Diagnostic characters for the Madagascan and African genera are described, and based on these characters and previous phylogenetic analyses the following species transfers are proposed: Eriauchenius cornutus (Lotz, 2003) to Afrarchaea; Afrarchaea fisheri (Lotz, 2003) and Afrarchaea mahariraensis (Lotz, 2003) to Eriauchenius. Finally, we propose that the distribution of Afrarchaea be restricted to South Africa. While several Madagascan specimens have previously been identified as Afrarchaea godfreyi (Hewitt, 1919), we argue that these are likely misidentifications that should instead be Eriauchenius.

Another Laurasian connection in the Early Eocene of India: Myrmecarchaea spiders (Araneae, Archaeidae)

“…While A. paradoxa and M. antecessor have different somatic features, the morphology of the male pedipalps is conserved. This scenario is similar to what has been observed in the extant Madagascan "workmani-group" and the "vadoni-group", where genitalic differences are subtle, but non-sexual, somatic features, such as carapace shape and abdomen color, are distinct (Wood and Scharff 2018). The diagnostic features of Myrmecarchaea argue for monophyly of the genus, but the conserved genitalia suggest shared common ancestry for Myrmecarchaea and Archaea.…”

“…Decades later, extant species were discovered in the forests of Madagascar (Pickard-Cambridge 1881), and then were also found and documented from South Africa and Australia (Forster and Platnick 1984). The number of extant species contin-ues to grow due to taxonomic revision, some recent (e.g., Lotz 2015;Wood and Scharff 2018). Yet thus far, the extant clades remain known only from these three areas.…”

The Hercules pseudoscorpions from Madagascar: A systematic study of Feaellidae (Pseudoscorpiones: Feaelloidea) highlights regional endemism and diversity in one of the “hottest” biodiversity hotspots

“…Many studies on invertebrates have emphasized the importance of mountain or rainforest refugia (Wesener et al 2011;Wood et al 2015) and pointed out that in-situ speciation in such refugia, together with time and adaptive niche radiation, has been fundamentally important in diversification. Many taxonomic revisions have also focused on taxa that are exclusively or predominantly found in the high-altitude forests of the east (Griswold 1997;Griswold et al 2012;Wood and Scharff 2018) and documented substantial microendemism. For more arid habitats, a study by Wesener (2009) found that endemism in pill millipedes from dry forests was not as pronounced as that of species occurring in mesic habitats.…”

“…In the past two decades, there has been major progress in documenting the Malagasy invertebrate fauna at the taxonomic level, including many arachnid lineages (e.g., Griswold et al 2012;Saucedo et al 2015;Wood and Scharff 2018). Several studies have addressed patterns and causes of invertebrate speciation (e.g., Miraldo et al 2011;Wesener et al 2011;Agnarsson et al 2015), but no data are presently available for pseudoscorpions, a mesodiverse arachnid lineage, following the more diverse spiders and mites, which are found in all ground habitats on Madagascar (WPC 2022).…”