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The single published record of centipedes from the Chagos Archipelago, British Indian Ocean Territory, is for the scolopendrid Rhysida longipes Newport, 1845, from Eagle Island. Recent collections from Diego Garcia atoll include new records of R. longipes as well as four other centipede species, including the first records of the orders Lithobiomorpha and Geophilomorpha. A new species of the lithobiid Australobius Chamberlin, 1920, A. chagosensissp. n., is closely allied to species described from southern India, Sri Lanka and the Maldives. The henicopid Lamyctes is represented by two geographically widespread species, L. mauriesi Demange, 1981 and L. tristani (Pocock, 1893), from which sequence data for the COI barcode marker are presented and analysed phylogenetically. The types of Lamyctes albipes (Pocock, 1894), and L. tristani, from Java and Tristan da Cunha, respectively, are illustrated for the first time to facilitate taxonomic comparisons with Chagos material. Specimens of Mecistocephalus are identified as Mecistocephalus lohmanderi Verhoeff, 1939, closely resembling specimens from the Seychelles. Collections from the archipelago in 1971–1972 also included Mecistocephalus angusticeps (Ribaut, 1914), and Nycternyssa dekania dekania (Verhoeff, 1938). The Chagos centipede fauna reveals affinities to those of the southern Indian Subcontinent, East Africa, Madagascar, the Maldives, the Seychelles, and Java. [ABSTRACT FROM AUTHOR]

The Carboniferous myriapod Arthropleura is the largest arthropod of all time, but its fossils are usually incomplete, limiting the understanding of its anatomy, ecology, and relationships. Micro-computed tomography applied to exceptionally preserved specimens from the Carboniferous Montceau-les-Mines Lagerstätte (France) reveals unprecedented details of its functional anatomy, such as the head and mouthparts. Arthropleura shares features with both millipedes and centipedes. Total-evidence phylogeny combining morphological and transcriptomic data resolves Arthropleura alone as a stem group millipede, but the inclusion of the highly incomplete Siluro-Devonian Eoarthropleura draws it deeper into the myriapod stem. Arthropleura suggests transitional morphology between clades united primarily by molecular information and underscores the value of total-evidence phylogenetics to understanding evolutionary history. [ABSTRACT FROM AUTHOR]

Trigonotarbida, an extinct order of spider‐like arachnids, were significant predators between the late Silurian and early Permian. Characterized by their segmented opisthosoma, clasp‐knife chelicera, and paired book lungs, they played a pivotal role in the formation of Early Devonian terrestrial ecosystems. However, the compression‐fossil or mould preservation of most trigonotarbids has been a limiting factor in understanding their fine morphology. Here, we re‐examine the mouthparts of Palaeocharinus, a trigonotarbid genus from the c. 408 Ma Rhynie chert of Scotland. Rhynie preserves the palaeocharinid trigonotarbids in three dimensions with extraordinary fidelity, offering detailed insights into their anatomy, feeding and hunting behaviours, and phylogenetic position. Here we present the first confocal laser scanning microscopy (CLSM) data for Palaeocharinus using three‐dimensional modelling to reconstruct the morphology of a tiered filtration apparatus, comprising a coarse outer mesh of interlacing plumose setae and a fine inner filter of pinnate setae. Together with the clasp‐knife action of the chelicera and mastication by the cheliceral teeth, Palaeocharinus emerges as a sophisticated terrestrial predator with a feeding mechanism resembling that of extant representatives of Pedipalpi (Amblypygi + Uropygi + Schizomida). Phylogenetic analyses with new and modified mouthpart characters affirm the placement of Trigonotarbida within Pantetrapulmonata (Aranaeae + Pedipalpi). This study provides insights into the evolutionary innovations that facilitated the diversification and proliferation of trigonotarbids in early terrestrial landscapes. [ABSTRACT FROM AUTHOR]

Recent advances in higher‐level invertebrate phylogeny have leveraged shared features of genomic architecture to resolve contentious nodes across the tree of life. Yet, the interordinal relationships within Chelicerata have remained recalcitrant given competing topologies in recent molecular analyses. As such, relationships between topologically unstable orders remain supported primarily by morphological cladistic analyses. Solifugae, one such unstable chelicerate order, has long been thought to be the sister group of Pseudoscorpiones, forming the clade Haplocnemata, on the basis of eight putative morphological synapomorphies. The discovery, however, of a shared whole genome duplication placing Pseudoscorpiones in Arachnopulmonata provides the opportunity for a simple litmus test evaluating the validity of Haplocnemata. Here, we present the first developmental transcriptome of a solifuge (Titanopuga salinarum) and survey copy numbers of the homeobox genes for evidence of systemic duplication. We find that over 70% of the identified homeobox genes in T. salinarum are retained in a single copy, while representatives of the arachnopulmonates retain orthologs of those genes as two or more copies. Our results refute the placement of Solifugae in Haplocnemata. Subsequent reevaluation of putative interordinal morphological synapomorphies among chelicerates reveals a high incidence of homoplasy, reversals, and inaccurate coding within Haplocnemata and other small clades, as well as Arachnida more broadly, suggesting existing morphological character matrices are insufficient to resolve chelicerate phylogeny. [ABSTRACT FROM AUTHOR]