An Eocene fossil plutoniumid centipede: a new species of Theatops from Baltic Amber (Chilopoda: Scolopendromorpha)

Abstract

Four specimens of the same species of scolopendromorph centipede from Eocene Baltic amber provide the first fossil occurrence of the family Plutoniumidae, a clade represented by seven extant species. The fossil material, documented by light microscopy and computed microtomography, is assigned to the genus Theatops Newport, 1844, which currently has a disjunct distribution in temperate North America, the Mediterranean region, and central China. The Eocene species is diagnostically distinct from extant congeners and is formally described as Theatops groehni sp. nov. Phylogenetic analysis of combined morphological and molecular data for three loci finds T. groehni to be nested within crown-group Plutoniumidae. The discovery of T. groehni constrains the minimal divergence date for crown-group Plutoniumidae and is consistent with hypotheses regarding the extent and nature of tropical to warm temperate European forests during the Eocene. The fossil reinforces the hypothesis that the distribution of Plutoniumidae, once more geographically widespread, has been pruned by extinction.

http://zoobank.org/urn:lsid:zoobank.org:pub:ECBF2C04-CA1B-4FBC-A19E-26A0094196EC

Keywords:

• Scolopendromorpha
• Plutoniumidae
• Theatops
• Baltic Amber
• Eocene

Acknowledgements

This work was enabled by the kind loan of specimens from Carsten Gröhn, who also provided the images in Figure 3A, B. We thank former members of the Microscopy and Digitisation Lab at the NHMUK, Vladimir Blagoderov and Rebecca Summerfield, for their assistance with imaging equipment, and the journal’s referees for advice.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental material

Supplemental material for this article can be accessed here: https://doi.org/10.1080/14772019.2023.2228796.

Associate Editor: Paul Barrett