In this article, Phillips has anargument that transference errors are dependent on a mammal’s body size andlifespans, causing a rise in previous estimates of interordinal divergencetimes. Later on, he makes a suggestion that the majority of interordinaldivergences are positioned after the KPg boundary. Although Phillips doesbelieve in using the explosive model to post the majority of interordinal diversificationafter the KPg mass extinction, he also presented the idea that a soft explosivemodel would allow the Xenarthra, Afrotheria, Euarchontoglires, andLaurasiatheria lineages to emerge during the Cretaceous period. Assumptionswere formed from using the explosive mode, believing that extinctions werecaused by both interordinal and intraordinal diversification after the KPg mass,making morphological cladistic studies of Cretaceous eutherians and crownPlacentalia to become segregated from one another. In the methods section of this article, thefollowing things were calculated : number of lineages, number of new lineages,and number of new lineages per million years for each stage, percentageincrease or decrease across stage boundary, which were are all based onPhillips’ preferred timetree (dR27b) using Meredith’s DNA supermatrix whichcontained 169 species and 27 calibrations.
The 2010 version of the geologicaltime scale was used to find the rates for dR27b and Mer82c, while the 2014version calculated the Emer15 rates. These authors decided to use differentversions of the geologic time scale. Emer15 recorded two speciation events thatoccurred near the end of the Lutetian that were unrelated to Meredith’s taxonsampling, which included deep splits in Soricidae and Emballonuridae which werenot included in the analysesIn conclusion, Ghost lineages werepresumed to exist without having any fossil records, while zombie lineages werefound to have fossil records that are not compatible with the timetree dates.Ghost lineages are expected to be products of incomplete fossil records, whilezombie lineages are only possible with inaccurate minimum ages of fossils orwhen fossils have not been assigned to their proper taxonomic group .Eventhough there is a great number of zombie lineages that contradict the fossilrecord, Phillips’ timetree does contain various ghost lineages that are olderthan the fossil record, having fewer incompatibilities compared to most otherstudies.
Fossils are unable to provide any conclusive evidence related to theancestry of extant mammals , due to not being able to find any relationshipsbetween Cretaceous and Paleocene fossils and modern placental lineages.