Elite Award: Selected

Discovery of a new ant genus: exploring Taiwan’s biodiversity.

Fu-Ya Chung
National Chung Hsing University
Co-author: Po-Wei Hsu, Feng-Chuan Hsu Chung-Chi Lin

Abstract

This study employs an integrative taxonomic approach, combining multiple lines of evidence from morphology and molecular phylogenetics, to formally describe a new genus within the subfamily Myrmicinae, Unicumyrmex gen. n., and its type species, U. fushanensis sp. n., from Taiwan. In addition to providing morphological descriptions and phylogenetic reconstructions, systematic comparisons between U. fushanensis and its morphologically similar and phylogenetically related species were conducted. The ultrastructure of workers, males, and male genitalia was documented using scanning electron microscopy (SEM). Furthermore, keys to Solenopsidini workers with 11-segmented antennae, as well as to known Solenopsidini males from 14 genera, were provided. These findings not only add a new endemic taxon to Taiwan’s fauna and refine the local biodiversity inventory but also underscore the conservation value of forest habitats.

Methodology and Implementation Steps

  1. Morphological study: Morphological examination and measurements of workers, males, and the microstructure of male genitalia were conducted using a stereomicroscope and scanning electron microscopy (SEM). Comparisons of morphological traits between the ant specimens from this study and its morphologically similar and phylogenetically related species were also carried out.
  2. Molecular phylogenetic analysis: Genome data of historical ant specimens was obtained using shotgun sequencing via Illumina NovaSeq 6000 NGS platform. The sequences of key nuclear genes and the mitochondrial cox1 gene were reconstructed using de novo assembly and bioinformatics analyses, and phylogenetic analysis were subsequently performed.

Innovation and Cross-Disciplinary Collaboration

Successful delimitation of the new genus and species, Unicumyrmex fushanensis, in Taiwan represents an important discovery for the exploration of biodiversity within the hyper-diverse Myrmicinae. This study emphasizes the taxonomic value and importance of male ant morphology in genus-level revision, and reinforces taxonomic accuracy by examining male genitalia using SEM.

Expected Results and Contributions

By demonstrating integrative taxonomy, this study highlights our advanced capability to address cryptic diversity and extract genetic information from historical specimens. Through modern genomic technology, molecular biological data can be obtained from previously unidentified historical museum specimens, re-establishing them as vital evidence for conservation and evolutionary research while revitalizing the natural history collections of Taiwan. This study also provided standard taxonomic tools (identification keys) for global myrmecological researchers, promoting species identification and biodiversity monitoring.

Fig. 1: Unicumyrmex fushanensis gen.n. et sp.n. holotype worker (ANTWEB1060402, NCUESIL002532). A, full-face view; B, dorsal view; C, profile view.
Fig. 2: Unicumyrmex fushanensis gen.n. et sp.n. paratype male (ANTWEB1060403, NCUESIL002538). A, full-face view; B, dorsal view; C, profile view.
Fig. 3: Phylogenetic analysis of the subfamily Myrmicinae and the placement of Unicumyrmex fushanensis gen.n. et sp.n. The maximum likelihood phylogeny was reconstructed using IQ-TREE v2.2.0 with a total of 9422 bp from 11 nuclear genes. The analysis consisted of 232 ants across Myrmicinae, 8 ants from other subfamilies, and one bradynobaenid wasp as an outgroup. The tribes within Myrmicinae are differentiated by color boxes, and the branches of Unicumyrmex fushanensis gen.n. et sp.n., as well as the two control samples, Wasmannia auropunctata (Roger, 1863), and Monomorium pharaonis (Linnaeus, 1758), were marked in red. Highly supported nodes (Shimodaira-Hasegawa-like approximate likelihood ratio test, SH-aLRT ≥ 80 and ultrafast bootstrap, UFBoot ≥ 95) are denoted in red, while nodes with moderate support (SH-aLRT ≥ 75 and UFBoot ≥ 90) are denoted in blue. Nodes proximal to Unicumyrmex fushanensis gen.n. et sp.n. were annotated with detailed SH-aLRT and UFBoot values.
Fig. 4: Scanning micrographs of male genitalia. The figures are oriented with the distal end at the top, and the basal end (toward the head) at the bottom. A, E, I, Unicumyrmex fushanensis gen.n. et sp.n.; B, F, J, Monomorium chinense Santschi, 1925; C, G, K, Solenopsis geminata (Fabricius, 1804); D, H, L, Solenopsis invicta Buren, 1972. A, B, C, D, genital capsule in ventral view; E, F, G, H, right volsella in mesal view; I, J, K, L, penisvalva in lateral view. Scale bar = 50 µm. Abbreviations: Bm basimere; Bv basivolsella; Cu cupula; Cs cuspis; Di digitus; Pv penisvalva; Te telomere; Vo volsellae.
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