There are not many mammals with crenulated/serrated teeth.
Pseudictops lophiodon (Matthews, Granger and Simpson 1929, Sulimski 1968, Late Paleocene, 57 mya; Fig. 1; AMNH 21727) is one such mammal. From the start Pseudictops was compared to anagalids like Leptictis (Fig. 2), a basal elephant shrew and ancestor to tenrecs, pakicetids and odontocete whales.
The dentary incisors
are deeply rooted in a deep dentary. Not sure why the two dentaries (Fig. 1) have distinct shapes. Perhaps they are not actually related to one another or perhaps some parts are missing from the smaller one and plasterered over.
Now that you’ve met Pseudictops, a quick look at Ictops
reveals a cranium with a double parasagittal crest, as in sister taxon, Leptictis.
Matthew WD, Granger W and Simpson GG 1929. Additiions to the fauna of the Gashato Formatin of Mongolia. American Museum Novitates 376:1–12.
Sulimski A 1968. Paleocene genus Pseudictops Matthew, Granger and Simpson 1929 (Mammalia) and its revision. www.palaeontologia.pan.pl/Archive/1968-19–1011-129–10-14.pdf