[6] The term Middle Pleistocene was in use as a provisional or "quasi-formal" designation by the International Union of Geological Sciences (IUGS).

[7] The International Union of Geological Sciences (IUGS) had previously proposed replacement of the Middle Pleistocene by an Ionian Age based on strata found in Italy.

[13] Eastern Africa's hydroclimate was governed primarily by orbital precession, although modulated significantly by the 100 kyr eccentricity cycle.

[15] The Early-Middle Pleistocene boundary saw the migration of true horses out of North America and into Eurasia.

[19] There was a major extinction of carnivorous mammals in Europe around the Early-Middle Pleistocene transition, including the giant hyena Pachycrocuta.

[23] Around 500,000 years ago, the last members of the largely European aquatic frog genus Palaeobatrachus and by extension the family Palaeobatrachidae became extinct.