Variation in ovipositor morphology among laniatorean harvestmen (Arachnida: Opiliones)

Abstract

There are relatively few published illustrations of ovipositors for harvestmen belonging to the suborder Laniatores. As a result, the ovipositor of these harvestmen has largely been ignored as a source of informative characters. We used scanning electron microscopy to examine the ovipositor of eight species representing several major lineages (Gonyleptoidea, Phalangodoidea, Samooidea, and Zalmoxoidea). We observed interspecific variation with respect to the number of external lobes on the distal tip, the surface texture of the distal tip, and the morphology of the peripheral setae. The ovipositors of Bishopella (Phalangodoidea) and Stygnomma (Samooidea) were similar in appearance and differed with respect to the number and position of peripheral setae. We observed significant interspecific variation among the gonyleptoidean species, especially with respect to the peripheral setae. The ovipositors of Zalmoxoidea harvestmen had smooth, spatulate peripheral setae but differed with respect to the surface texture of the distal tip. The unusual morphology of these setae has not been observed previously and may represent a new synapomorphy for the family. Characters based upon ovipositor morphology have the potential to illuminate phylogenetic relationships within and between families and genera in these harvestmen.