Novo Rodríguez, MartaFernández Marchán, DanielGérard, SylvainMartínez Navarro, AlejandroMonteiro, RitaBöhne, AstridMarcussen, ThomasStruck, Torsten HOomen, Rebekah AAguilera, LauraGut, MartaFerreira, Francisco CâmaraGómez-Garrido, JèssicaCruz, FernandoAlioto, TylerLazar, AnnaHaggerty, LeanneMartin, FergalBrown, Tom2026-04-092026-04-092026-01-26Novo, M., Marchán, D. F., Gérard, S., Navarro, A. M., Monteiro, R., Böhne, A., Marcussen, T., Struck, T. H., Oomen, R. A., Aguilera, L., Gut, M., Ferreira, F. C., Gómez-Garrido, J., Cruz, F., Alioto, T., Lazar, A., Haggerty, L., Martin, F., & Brown, T. (2026). ERGA-BGE Genome of Ailoscolex lacteospumosus Bouché, 1969 – the enigmatic milky worm endemic to the Pyrenees. Open Research Europe, 6(26). https://doi.org/10.12688/openreseurope.22136.110.12688/openreseurope.22136.1https://hdl.handle.net/20.500.14352/134575Grant information: Biodiversity Genomics Europe (Grant no.101059492) is funded by Horizon Europe under the Biodiversity, Circular Economy and Environment call (REA.B.3); co-funded by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract numbers 22.00173 and 24.00054; and by the UK Research and Innovation (UKRI) under the Department for Business, Energy and Industrial Strategy’s Horizon Europe Guarantee Scheme. The sampling for the Ailoscolex lacteospumosus reference genome was funded by Grant PID2021-122243NB-I00 from MCIN/AEI/10.13039/501100011033/FEDER, UE.Ailoscolex lacteospumosus represents one of the basal taxa of the earthworm family Hormogastridae and was initially placed in a different family, Ailoscolecidae, including just this species. Its genome can help unravel the evolution of this earthworm family, which is endemic to the Mediterranean and adapted to soils exposed to adverse conditions such as prolonged droughts. This species presents a very restricted distribution, endemic to the Pyrenees, and the genome will help study its conservation status as well as provide insights into earthworm evolution. A total of 17 contiguous chromosomal pseudomolecules were assembled from the genome sequence. This chromosome-level assembly encompasses 493 Mb, composed of 46 contigs and 24 scaffolds, with contig and scaffold N50 values of 15.1 Mb and 29.9 Mb, respectively.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/journal article2732-5121https://doi.org/10.12688/openreseurope.22136.1open access592Ailoscolex lacteospumosusGenome assemblyEuropean reference genome atlasBiodiversity genomics EuropeEarth biogenome projectMilky wormZoología2401.17 Invertebrados2409 Genética