OPILIONES Sundevall, 1833

Palencia, Lorena, Peñalver, Enrique, Prieto, Carlos E. & Poyato-Ariza, Francisco José, 2019, First fossil harvestmen (Arachnida: Opiliones) from Spain and notes on the fossil record of Opiliones, Palaeontologia Electronica (5 A) 22 (1), pp. 1-18 : 3

Order OPILIONES Sundevall, 1833

Suborder indet.

Figure 1

Description (specimen LH-29969). Typical harvestman habitus, compact body and slender legs. The eight legs appear radiating closely together. Leg lengths are indicated on Figure 1 . Leg articulations only are clear in three locations ( Figure 1.2 ).

Taphonomy. The body of this specimen is poorly preserved, lacking any detail; chelicera and pedipalps are not observable. Anatomical orientation is uncertain due to the poor preservation of the body, which was collapsed in a small area during fossilization. Legs appear radiating very close, nearly together, probably due to this collapsing of the body.

Remarks. The habitus is typical of harvestmen, especially that of the suborders Laniatores and Eupnoi . However, no distinctive morphological details such as pedipalps and tarsal claws of legs are preserved. Although most long-legged harvestmen show a typical I–IV leg length pattern (short, longest, short, long), this feature is not discernible in the specimen. A few articulations in the legs can, nonetheless, be observed. The radiation and habitus of the legs are consistent with those of harvestmen. The habitus and the thin legs are similar to those of the family Pholcidae , Order Araneae . This family shows a body clearly divided into two tagmata, but the body of the fossil specimen, in spite of its poor preservation, seems to present fused tagmata (“compact body”). In spite of its unsatisfactory preservation, this specimen is worth reporting because of the Mesozoic fossil record of harvestmen is remarkably scarce.

Figures

FIGURE 1. Cretaceous harvestman of uncertain subor- der, LH-29969, from Las Hoyas. 1, Photograph of LH- 29969. 2, Camera lucida drawing of LH-29969. Arrows indicate the detected leg articulations.