Context: In an influential 1988 paper, Timothy Rowe defined Mammalia phylogenetically as the crown group mammals, the clade consisting of the most recent common ancestor of living monotremes (echidnas and platypuses) and therian mammals (marsupials and placentals) and all descendants of that ancestor. Since this ancestor lived in the Jurassic period, Rowe's definition excludes all animals from the earlier Triassic, despite the fact that Triassic fossils in the Haramiyida have been referred to the Mammalia since the mid-19th century.

Question: Who defined mammalian as the crown group mammals?
Answer: Timothy Rowe

Question: By Rowe's definition, when did he start to exclude animals?
Answer: Triassic

Question: Which group do marsupials and placentals belong to?
Answer: therian mammals

Question: How did Timothy Rowe define Mammalia in the mid 19th century?
Answer: Unanswerable

Question: What are two examples of the most recent ancestor of the Jurassic period?
Answer: Unanswerable

Question: In what period did mammals live?
Answer: Unanswerable

Question: For how long have Juassic fossils been referred to the Mammalia?
Answer: Unanswerable

Question: What is one thing Triassic fossils are shown to consist of according to a 19th century paper?
Answer: Unanswerable