A NEW POLYZONIID MILLIPED (DIPLOPODA) FOSSIL FROM MYANMAR: DESCRIPTION, TAPHONOMY AND EVOUTIONARY SIGNIFICANCE

A new polyzoniid milliped species is identified from the Lower Cretaceous (Albian) amber from Myanmar (Burmite). The specimen is from the collection of George Poinar Jr. It is one of a number of undescribed Burmite millipeds. The specimen has a beaklike projection from the head that is dissimilar to known polyzoniids, in fact resembling that of siphonophorids. The configuration of setae is unique among colobognathans, which generally either lack setae completely or are densely setose. Body segments 2-14 have two long, posterolateral setae on each side of the tergite; body segments 8-11 also have two shorter setae on the posteromedial edge of the tergite. All other observed features correlate with known, modern polyzoniid characteristics. Questions about the development of a beaklike structure in colobognathans and the patterns of the appearance of setae are raised by this specimen.

The exoskeleton is fairly well preserved, although covered with hairline cracks; the specimen lacks soft tissue. During the preservation process, the legs shriveled and the pleurites disassociated, shifting position. In addition, the beak cracked open ventrally.

This, and other Cretaceous millipeds, including the polyxenid Phryssonotus burmiticus already described from Burmite, are very similar to their modern counterparts in general form, contrasting with earlier Late Paleozoic and early Mesozoic forms.