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The systematics of humble-in-appearance brown spiders (“marronoids”), within a larger group of spiders with a modified retrolateral tibial apophysis (the RTA Clade), has long vexed arachnologists. Although not yet fully settled, recent phylogenomics has allowed the delimitation and phylogenetic relationships of families within marronoids to come into focus. Understanding relationships within these families still awaits more comprehensive generic-level sampling, as the majority of described marronoid genera remain unsampled for phylogenomic data. Here we conduct such an analysis in the family Cybaeidae Banks, 1892. We greatly increase generic-level sampling, assembling ultraconserved element (UCE) data for 18 of 22 described cybaeid genera, including all North American genera, and rigorously test family monophyly using a comprehensive outgroup taxon sample. We also conduct analyses of traditional Sanger loci, allowing curation of some previously published data. Our UCE phylogenomic results support the monophyly of recognized cybaeids, with strongly supported internal relationships, and evidence for five primary molecular subclades. We hypothesize potential morphological synapomorphies for most of these subclades, bringing a robust phylogenomic underpinning to cybaeid classification. A new cybaeid genusSiskiyugen. nov.and speciesSiskiyu armillasp. nov.is discovered and described from far northern California and adjacent southern Oregon and a new species in the elusive genusCybaeozyga,C. furtivasp. nov., is described from far northern California.
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This content will become publicly available on November 19, 2025
Plastid Phylogenomic Analysis of Podostemaceae with an Emphasis on Neotropical Podostemoideae
Abstract—Podostemaceae are a clade of aquatic flowering plants that form important components of tropical river ecosystems. Species in the family exhibit highly derived growth forms and high vegetative phenotypic plasticity, both of which contribute to taxonomic confusion. The backbone phylogeny of the family remains poorly resolved, many species remain to be included in a molecular phylogenetic analysis, and the monophyly of many taxa remains to be tested. To address these issues, we assembled sequence data for 73 protein-coding plastid genes from 132 samples representing 68 species (∼23% of described species) that span the breadth of most major taxonomic, morphological, and biogeographic groups of Podostemaceae. With these data, we conducted the first plastid phylogenomic analysis of the family with broad taxon sampling. These analyses resolved most nodes with high support, including relationships not recovered in previous analyses. No evidence of widespread, well-supported conflict among individual plastid genes and the concatenated phylogeny was observed. We present new evidence that four genera (Apinagia,Marathrum,Oserya, andPodostemum), as well as four species, are not monophyletic. In particular, we show thatPodostemum flagelliformeshould not be included inPodostemumand is better recognized asDevillea flagelliformis,and thatMarathrum capillaceumis embedded withinLophogynes.l. and should be recognized asLophogyne capillacea. We also place a previously unsampled and undescribed species that likely represents a new genus. In contrast to previous studies, the neotropical generaDiamantina,Ceratolacis,Cipoia,andPodostemumare resolved as successive sister groups to a clade of all paleotropical Podostemoideae taxa sampled, suggesting a single dispersal event from the neotropics to the paleotropics in the history of the subfamily. These results provide a strong basis for improving the classification of Podostemaceae and a framework for future phylogenomic studies of the clade employing data from the nuclear genome.
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- Award ID(s):
- 2109716
- PAR ID:
- 10631256
- Publisher / Repository:
- American Society of Plant Taxonomists
- Date Published:
- Journal Name:
- Systematic Botany
- Volume:
- 49
- Issue:
- 3
- ISSN:
- 0363-6445
- Page Range / eLocation ID:
- 580 to 616
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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