Kaliwatan sa kaka ang Theridion pigrum^[1]. Una ning gihulagway ni Eugen von Keyserling ni adtong 1886.^[2] Ang Theridion pigrum sakop sa kahenera nga Theridion, ug kabanay nga Theridiidae.^[1][3]

Kini nga matang hayop na sabwag sa:

• Brasil

Walay nalista nga matang nga sama niini.^[1]

1. ↑ ^{1.0 1.1 1.2} Roskov Y., Kunze T., Orrell T., Abucay L., Paglinawan L., Culham A., Bailly N., Kirk P., Bourgoin T., Baillargeon G., Decock W., De Wever A., Didžiulis V. (ed) (2019). "Species 2000 & ITIS Catalogue of Life: 2019 Annual Checklist". Species 2000: Naturalis, Leiden, the Netherlands. ISSN 2405-884X. TaxonID: 54091075. Retrieved 2019-11-11. {{cite web}}: |author= has generic name (help)CS1 maint: multiple names: authors list (link)
2. ↑ Keyserling, E. (1886) Die Spinnen Amerikas. Theridiidae , Nürnberg 2: 1-295
3. ↑ Kropf C., Nentwig W., Blick T. & Gloor D. (organizing board). (2019). WSC: World Spider Catalog (version 19.5, Jan 2019). In: Species 2000 & ITIS Catalogue of Life, 2019 Annual Checklist (Roskov Y., Ower G., Orrell T., Nicolson D., Bailly N., Kirk P.M., Bourgoin T., DeWalt R.E., Decock W., Nieukerken E. van, Zarucchi J., Penev L., eds.). Digital resource at www.catalogueoflife.org/annual-checklist/2019. Species 2000: Naturalis, Leiden, the Netherlands. ISSN 2405-884X.