Dwarfs under dinosaur legs: a new millipede of the order Callipodida (Diplopoda) from Cretaceous amber of Burma

Abstract

Abstract

The entire Mesozoic Era is rather poor in millipede (class Diplopoda ) fossils, with less than a dozen species being taxonomically described. Here, we describe the first fossil millipede of the order Callipodida , Burmanopetalum inexpectatum gen. nov. et sp. nov., found in early Cenomanian amber of Burma, 98.79±0.62 Mya. The species possesses a number of morphological traits that exclude it from all extant suborders, and Burmanopetalidea suborder nov. and Burmanopetalidae fam. nov. are here erected to accommodate it. The new suborder can be recognized by the following unique characters: pleurotergal setae absent; telson with a specific spatulate shape twice the size of the penultimate body ring; hypoproct devoid of setae; and eyes composed of five well-separated ommatidia. While the callipodidan habitus seems to have remained generally unchanged for at least 99 million years, pleurotergal and hypoproctal setation, as well as the complexity of eyes in ground-dwelling forms may have evolved recently in the order. As B. inexpectatum gen. nov. et sp. nov. is the first true callipodidan in the fossil record, the minimum age of Callipodida is thus at least 99 Mya.