‘Housekeeping’ at the root
of the placental tree is moving several taxa into the Marsupialia in the large reptile tree (LRT, 2121 taxa). Among the moving taxa are Caenolestes and Rhyncholestes (Fig 1) which now nest with Early Cretaceous Acristotherium. Earlier these two shrew opossums were nested with convergently similar placental shrews like Scutisorex and Uropeltis (Fig 1). A new understanding of premolars and molars is at the core of these several changes.
Another tiny, furry taxon, Late Jurassic Henkeltotherium
(Fig 2) moved next to mouse-sized Early Cretaceous Eomaia (Fig 3) after rescoring in the LRT. The position of the eyeball was moved back, closer to the squamosal. This alone changed several proportional scores. A loose tooth was re-identified as a canine, rather than an incisor.
These are the sort of changes
that are essential elements of the current round of LRT ‘housekeeping’.
All for now.
Work continues. Corrections keep improving the LRT.