A scolopocryptopid centipede (Chilopoda: Scolopendromorpha) from Mexican amber: Synchrotron microtomography and phylogenetic placement using a combined morphological and molecular data set

The first scolopocryptopid centipede known from the fossil record is a specimen of the subfamily Scolopocryptopinae in Miocene amber from Chiapas, southern Mexico. It is described here as Scolopocryptops simojovelensis sp. nov., displaying a distinct combination of morphological characters compared to extant congeners. Anatomical details of the fossil specimen were acquired by non-invasive 3D synchrotron microtomography using X-ray phase contrast. The phylogenetic position of the new species is inferred based on a combination of morphological data with sequences for six genes (nuclear 18S and 28S rRNA, nuclear protein-coding histone H3, and mitochondrial 12S rRNA, 16S rRNA, and protein-coding cytochrome c oxidase subunit I) for extant Scolopendromorpha. The data set includes eight extant species of Scolopocryptops and Dinocryptops from North America, east Asia, and the Pacific, rooted with novel sequence data for other blind scolopendromorphs. The molecular and combined data sets, analysed in a parsimony/direct optimization framework, identified a stable pattern of two main clades within Scolopocryptopinae. North American and Asian species of Scolopocryptops are united as a clade supported by both morphological and molecular characters. Its sister group is a Neotropical clade in which the type species of Dinocryptops is nested within a paraphyletic assemblage of Scolopocryptops species; Dinocryptops is placed in synonymy with Scolopocryptops. The strength of support for the relationships of extant taxa from the molecular data allow the Chiapas fossil to be assigned with precision, despite ambiguity in the morphological data; the fossil is resolved as sister species to the extant Laurasian clade.