Five new Caenorhabditis species from Indonesia provide exceptions to Haldane's rule and partial fertility of interspecific hybrids. - Devi, Mia Prastika; Haryoso, Elkana; Rais, Emha Ilhami; Karuniawan, Anggik; Yahya, Minhajul Qowim; Richaud, Aurélien; Wang, John; Rockman, Matthew V; Tarno, Hagus; Félix, Marie-Anne (G3: Genes | Genomes | Genetics, 2025)