Historically, these animals were grouped with others such as treeshrews, elephant shrews, and colugos, under the broader category Insectivora, comprising all small insect-eating placental mammals. Wilhelm Peters identified two sub-groups of Insectivora, distinguished by the presence or absence of a cecum in the large intestine.[2] In his 1866 Generelle morphologie der organismen, Ernest Haeckel named these groups Menotyphla and Lipotyphla,[2] respectively from μένω ("remain")/λείπω ("lack" or "leave behind") + τυφλὸν literally "blind", as in τυφλὸν ἔντερον ("blind intestine", from which the Latin intestinum caecum derives as a calque).[3][4]
The upper and lower basal subclades within the tree are the suborders Solenodonota and Erinaceota, respectively.[13] These two branches are estimated to have split ~72–74 million years (Ma) ago.[13][8][9] The Nesophontidae and Solenodontidae are thought to have separated roughly 57 Ma ago.[13] Split times for talpids vs. soricids plus erinaceids, and for soricids vs. erinaceids, have been estimated at 69 Ma and 64 Ma ago, respectively.[14]
^ abcDouady, C. J.; Chatelier, P. I.; Madsen, O.; de Jong, W. W.; Catzeflis, F.; Springer, M. S.; Stanhope, M. J. (October 2002). "Molecular phylogenetic evidence confirming the Eulipotyphla concept and in support of hedgehogs as the sister group to shrews". Molecular Phylogenetics and Evolution. 25 (1): 200–209. doi:10.1016/S1055-7903(02)00232-4. PMID12383761.
^Ohl, Michael (2018). The art of naming. Translated by Lauffer, Elisabeth. Cambridge, Massachusetts London: The MIT Press. pp. 7–9. ISBN978-0-262-03776-1.
^Bininda-Emonds, O. R. P.; Cardillo, M.; Jones, K. E.; MacPhee, R. D. E.; Beck, R. M. D.; Grenyer, R.; Price, S. A.; Vos, R. A.; Gittleman, J. L.; Purvis, A. (2007-03-29). "The delayed rise of present-day mammals". Nature. 446 (7135): 507–512. Bibcode:2007Natur.446..507B. doi:10.1038/nature05634. PMID17392779. S2CID4314965.
^Springer, M. S.; Murphy, W. J.; Roca, A. L. (2018). "Appropriate fossil calibrations and tree constraints uphold the Mesozoic divergence of solenodons from other extant mammals". Molecular Phylogenetics and Evolution. 121: 158–165. doi:10.1016/j.ympev.2018.01.007. PMID29331683.