The monotypic genus Cheliceroides Żabka, 1985 is revalidated based on both molecular sequence data (ultra-conserved elements and protein coding genes of mitochondrial genomes) and morphological evidence. Our molecular phylogenetic analyses show that Cheliceroides is not closely related to Colopsus Simon, 1902, not even in the same tribe, and a comparative morphological study also demonstrates significant differences in the genital structures (i.e. in the shape of embolus, and with or without pocket on epigynum) of the two genera. Therefore, we remove Cheliceroides from the synonymy of Colopsus, and its generic status is revalidated.

Colopsus, mitogenome, morphology, phylogeny, ultra-conserved element

The jumping spider genus Cheliceroides Żabka, 1985 originally contained only the type species, Cheliceroides longipalpis Żabka, 1985, which has been commonly collected from Vietnam and southern China (World Spider Catalog 2024). A second species, Cheliceroides brevipalpis Roy, Saha & Raychaudhuri, 2016, was later reported from India (Roy et al. 2016), but it has been transferred to the genus Bathippus Thorell, 1892 (tribe Euophryini Simon, 1901; see Logunov 2021). Based on the results of a molecular phylogenetic study using Sanger-sequenced data (Maddison et al. 2014), Maddison (2015) included Cheliceroides in the tribe Hasariini Simon, 1903 in the phylogenetic classification of jumping spiders. Later, Logunov (2021) synonymized Cheliceroides with Colopsus Simon, 1902 based on similarities of morphological characters, such as the modified and elongate male chelicerae and male palpal characteristics, and transferred its type species to Colopsus, as Colopsus longipalpis (Żabka, 1985). Colopsus has been placed in the tribe Plexippini Simon, 1901 based on other molecular phylogenetic results (Kanesharatnam and Benjamin 2021). However, in a recent comparative mitogenomic study of jumping spiders, Colopsus longipalpis was not clustered with the other members of the tribe Plexippini on the phylogeny (Zhang et al. 2023a), which challenged Logunov’s taxonomic treatment of Cheliceroides.

Here we thoroughly investigate the phylogenetic placement of Cheliceroides in relation to Colopsus and other putatively related genera using both ultra-conserved element (UCE) and mitochondrial genome datasets. Comparative morphological study on the type species of both Cheliceroides and Colopsus is carried out to further clarify the taxonomic status of Cheliceroides. The implication of phylogenomic results on the classification of salticids is also discussed.

All specimens are preserved in 85–100% ethanol and stored at −20 °C. The photographs of genitalia were taken under a Leica M205A stereomicroscope. Photographs of palp, epigyne, and spiders were stacked using Helicon Focus v. 7 and retouched in the Adobe Photoshop CC 2022. Specimens were measured by the measuring tool of Leica LAS v. 4.3. Female vulvae were cleared with Pancreatin (BBI Life Sciences) or macerated in clove oil. All specimens studied are deposited in the Museum of Hebei University, Baoding, China (MHBU). Abbreviations used in the study: CD, copulatory duct; CO, copulatory opening; E, embolus; FD, fertilization duct; P, pocket; S, spermatheca; SD, sperm duct; RTA, retrolateral tibial apophysis.

Molecular data were obtained for ultra-conserved elements (UCEs) and mitogenomes to compose the UCE and mitogenomic datasets, each with 46 species (see Table 1 for detailed information). Genomic DNA extraction was performed using the QIAGEN dNeasy Blood & Tissue Kit, and the RNA was removed with 4 μL of rNase A (Solarbio) followed by a 2-minute incubation at room temperature. The library preparation was conducted using the NEXTFLEX Rapid DNA-Seq Kit 2.0 and the NEXTFLEX Unique Dual Index Barcodes (Set C) (Bioo Scientific) following the protocols by Zhang et al. (2023b). UCE enrichment followed the myBaits protocol 5.01 (Daicel Arbor Biosciences) using a modified version of the RTA probes, the “RTA_v3” probe set (42,213 probes targeting 3818 UCE loci) that was proposed by Zhang et al. (2023b). The enriched UCE libraries were then sent to Novogene Co. Ltd for sequencing using the Illumina NovaSeq platform with 150-bp paired-end reads. The UCE loci were extracted from the empirically enriched and sequenced raw reads following the protocols applied in Zhang et al. (2023b) with the PHYLUCE (Faircloth 2016) workflow. For ten species with whole genome sequencing data, the genomes were first assembled using the Phylogenomics from Low-coverage Whole-genome Sequencing (PLWS) pipeline (Zhang et al. 2019), and then the UCEs were harvested using the “RTA_v3” probes and the PHYLUCE workflow (see Zhang et al. 2023b for details).

The UCEs extracted from genomes and target enrichment data were combined and organized by locus, and then aligned using Mafft v. 7.313 (Katoh and Standley 2013) with the L-INS-I strategy. Poorly aligned regions were initially trimmed by the heuristic method “-automated1” in Trimal v. 1.4.1 (Capella-Gutiérrez et al. 2009). We then applied Spruceup v. 2020.2.19 (Borowiec 2019) to convert the remaining obviously misaligned fragments to gaps in each alignment (cutoff as 0.75). The gappy regions in each alignment were later masked using Seqtools (PASTA; Mirarab et al. 2014) with “masksites = 23”. Loci with trimmed alignment length less than 200 bp or less than 50% of taxon occupancy were removed, which resulted in 2593 loci in the final dataset for phylogenetic inference. All remaining UCE loci were concatenated by FASconCAT v. 1.0 (Kück and Meusemann 2010). The maximum-likelihood (ML) analyses were conducted in IQ-TREE v. 2.0.6 (Minh et al. 2020) with the best-fitting model and optimized partition scheme inferred using the option “-m MF+MERGE”. Ten independent ML tree searches (five with random starting trees and five with parsimonious starting trees) were run with the optimized model and partition scheme, and 5,000 replicates of ultrafast bootstrap analysis was conducted to assess the node supports.

Mitochondrial genomes were assembled and annotated using MitoZ v. 3.4 (Meng et al. 2019) and MITOchondrial genome annotation Server (MITOS; Bernt et al. 2013) from the raw reads of UCEs, WGS (whole genome sequencing), or transcriptomes following the protocols described by Ding et al. (2023) and Zhang et al. (2023b). In addition, two mitochondrial genomes were downloaded from the GenBank. Thirteen mitochondrial protein-coding genes (PCGs) were extracted for phylogenetic analysis. Each of the 13 PCGs was aligned using Mafft v. 7.505 (Katoh and Standley 2013) with the L-INS-i strategy, and then the gaps and misaligned sites were trimmed in Trimal v. 1.2rev57 (Capella-Gutiérrez et al. 2009) with the “automated1” mode. The trimmed alignments were concatenated in PhyloSuite v. 1.2.3 (Zhang et al. 2020), and PartitionFinder2 was used to select the best partition and model. ML analyses were performed in IQ-TREE v. 2.2.0 (Minh et al. 2020) using the optimized model and partition scheme, and an ultrafast bootstrap analysis with 1,000 replicates was conducted to assess the node support.

Logunov (2021) synonymized Cheliceroides with Colopsus due to their similarities in body coloration, male chelicerae, and palp features (see Diagnosis above). The type species of Colopsus, C. cancellatus Simon, 1902, as well as two other Colopsus species (C. ferruginus Kanesharatnam & Benjamin, 2021 and C. magnus Kanesharatnam & Benjamin, 2021), were included in the molecular phylogenetic analyses using four gene regions (cytochrome c oxidase subunit I, 18S rRNA, 28S rRNA, and histone H3), and the results strongly supported the monophyly of Colopsus and its placement within the tribe Plexippini (Kanesharatnam and Benjamin 2021). The genitalia structures of Colopsus show clear similarities to those of Evarcha Simon, 1902 and Pancorius Simon, 1902, both typical plexippine genera, which also supports the placement of Colopsus within Plexippini (Kanesharatnam and Benjamin 2021). However, the molecular phylogenetic analyses on both UCE and mitogenomic datasets show that Cheliceroides is not a member of Plexippini, and is therefore not closely related to Colopsus (Figs 1, 2). Comparison of the genital features of Cheliceroides longipalpis (type species of Cheliceroides) and Colopsus cancellatus Simon, 1902 (type species of Colopsus) reveals significant differences in the trajectory of sperm duct and the shape of embolus of the palp in males, and the pockets and copulatory ducts of the epigynum in females (see Diagnosis above; Figs 16–21). Therefore, both molecular phylogeny and comparative morphology support removing Cheliceroides from the synonymy of Colopsus. The similarities of these genera represent an example of parallel evolution of morphological traits in separate lineages likely due to the adaptation to a similar microhabitat, which is commonly known in jumping spiders.

Figures 16–21. 

Comparison of genital structures of Cheliceroides longipalpis Żabka, 1985 (16–18) and the type species of Colopsus, Colopsus cancellatus Simon, 1902 (19–21, modified from Kanesharatnam and Benjamin 2021) 16, 19 left palp, ventral view 17, 20 epigynum, ventral view 18, 21 epigynum, dorsal view.

Cheliceroides was considered to be a member of Hasariini in the phylogenetic classification of jumping spiders (Maddison 2015), which was supported by the mitogenomic phylogeny but with poor support (bootstrap = 77%; Fig. 2). The UCE phylogeny recovered Cheliceroides as sister to the clade containing Hasariini (excluding Bristowia), Agoriini, and Chrysillini with strong support (bootstrap = 100%; Fig. 1). This indicates the placement of Cheliceroides within Hasariini is questionable. Another interesting finding from our study is the phylogenetic placement of Bristowia, which was also earlier included in the tribe Hasariini (Maddison 2015). We included the type species, Bristowia heterospinosa Reimoser, 1934 (JXZ743 and DRR297628), in our phylogenetic analyses, and the results show that it is not closely related to other Hasariini. The UCE phylogeny suggests it is sister to the clade containing Euophryini, Leptorchestini, Aelurillini, Salticini, and Plexippini (bootstrap = 100%; Fig. 1), and the mitogenomic phylogeny recovered it as sister to the clade composed of Agoriini and Chrysillini, but with low support (bootstrap = 44%; Fig. 2). Further phylogenetic study with an extended taxon sampling of major lineages of jumping spiders is needed to further clarify their phylogenetic placement.

We thank Weihang Wang for providing living spider photographs of Cheliceroides longipalpis, Dr Wayne P. Maddison for helpful discussion on this topic and sharing UCE raw reads for mitogenome assembly, the reviewers (Dr Cheng Wang, Dr Kiran Marathe, Dr Wayne P. Maddison, Dr Tamás Szűts, and one anonymous reviewer), and editor (Dr Ingi Agnarsson) for valuable comments to improve the manuscript, and the Hebei Basic Science Center for Biotic Interaction for support.