of
Lotheridium|alt=Digital illustration of a mammal with reddish brown fur, a black head, orange belly and cream-coloured chin and tail tip
Lotheridium belongs to the family
Deltatheridiidae within an extinct
order of mammals known as the
Deltatheroida. The deltatheroidans are part of the larger clade
Metatheria, whose only extant members are the
marsupials, meaning that marsupials are the closest living relatives of
Lotheridium. In the 2015 study first describing this genus, a
phylogenetic analysis was carried out, recovering
Lotheridium in a
sister group position to a
clade including
Atokatheridium,
Nanocuris,
Deltatheridium and
Deltatheroides. |label1=
Deltatheroida}} The pattern of deltatheroidan dispersal has been debated among experts. Historically, the group was believed to have first evolved in Asia and later spread into North America. This was because the former continent has yielded most of their known specimens, including some of the oldest known at the time (
Coniacian-aged fossils of
Sulestes from
Uzbekistan). However, North American fossils of
Atokatheridium and
Oklatheridium which predate any known Asian deltatheroidans were later reported in the 2000s, leading some authors to believe that the group originated here. Even so, others continued to believe in an Asian origin for deltatheroidans, citing how Asian genera tend to be recovered in more
basal (earlier-diverging) positions in phylogenetic analyses. Being one of the geologically youngest deltatheroidans,
Lotheridium does not provide new information on the origins of the group, but its discovery in central China (where deltatheroidans had not been found previously) does show that the group was more widespread in Asia than formerly known. ==Paleobiology==