An unusual harvestman from Eocene Baltic amber presenting a previously unknown morphology of the pedipalps

Harvestmen are common elements of the modern-day fauna, however, the fossil record of harvestmen is sparse, with only about 50 fossil species in comparison to almost 7000 extant species. A new fossil harvestman (Arachnida, Opiliones) is described here, from Eocene Baltic amber. While having common harvestmen features such as elongated legs with highly subdivided tarsi, the specimen exhibits a unique feature on the pedipalps in the form of an additional element, possibly representing a subdivided tarsus. Such a pedipalp morphology is so far unknown in both modern and fossil representatives of Opiliones. It highlights a rare morphological singularity in Opiliones and complements the sparse fossil record of harvestmen preserved in amber. The massive pedipalps resemble those of armoured harvestmen (Laniatores), yet the specimen is more likely a representative of Phalangiidae. The additional joint in the pedipalps of the newly described specimen possibly allowed it to catch small-sized prey.