Symphylella patrickmuelleri sp. nov. (Myriapoda: Symphyla): The oldest known Symphyla and first fossil record of Scolopendrellidae from Cretaceous Burmese amber

Symphyla are one of the least known of the four classes of the Myriapoda. While Symphyla are dated to have split from the other myriapods at about 430-593 Ma, there are no fossil specimens known aside from seven specimens of the family Scutigerellidae preserved in Dominican and Baltic amber, with a maximum age of ca. 54 Ma. Here we describe the first fossil representative of the second Symphyla family, the Scolopendrellidae, Symphylella patrickmuelleri sp. nov., from Burmese amber (ca. 99 Ma). Utilizing micro-computed tomography (μCT) technology, as well as light microscopy and multi-layer photography, our specimen, despite being juvenile, can be assigned to the genus Symphylella Silvestri, 1902, a species-rich Recent genus that has an almost worldwide distribution. The specimen is preserved after ejecting long threads of silk from its large spinnerets. Our findings show that the recent genera and families of the Symphyla diverged already before the end of the Mesozoic.