Ovipositor morphology of cosmetid harvestmen (Arachnida, Opiliones, Laniatores): A new source of informative characters

Abstract

The external morphology of the penis is an important source of systematic characters in phylogenetic studies of harvestmen. Modern taxonomic studies generally include micrographs generated by scanning electron microscopy (SEM) to illustrate penis morphology. In contrast, the external morphology of the ovipositor has largely been ignored for harvestmen belonging to the suborder Laniatores. Comparative studies of ovipositor microanatomy using SEM are especially lacking for species belonging to the superfamily Gonyleptoidea. In an effort to determine if the ovipositor could be a useful source of informative characters for these harvestmen, we investigated interspecific variation in the external morphology of the ovipositor for 14 species from the family Cosmetidae. Our SEM-based study revealed that the external surface of the distal tips of the ovipositors of most species was generally divided into four symmetrical lobes, although we observed a bilobed condition in Erginulus clavotibialis and Erginulus subserialis. The distal surfaces were also generally smooth, with the exception of the ovipositor of Erginulus weyerensis, which featured small surface setae. In addition, we observed considerable interspecific variation in the morphology of the peripheral setae on the distal tip, especially with respect to relative size, morphology of the shaft, and number, symmetry, and shapes of the distal tips. The functional significance, if any, of variation in the structure of the peripheral setae is unclear. Additional behavioral studies of copulation and oviposition are needed to determine the functional relationships between reproductive morphology and behavior. The morphological variation that we observed suggests that future taxonomic studies of cosmetid harvestmen, and potentially other gonyleptoidean taxa, would benefit from the inclusion of descriptions of ovipositor morphology.

Taxonomic revision of the Andean genus Eulibitia Roewer, 1912 (Arachnida, Opiliones, Cosmetidae), with the description of five new species

“…The morphology of the reproductive organs in Gonyleptoidea has been shown to be very valuable in phylogenetic analyses (i.e., Kury & Villarreal 2015;Cruz-López & Francke 2015), and has been well explored in detail for some species (i.e., Bennett & Townsend 2013;Walker & Townsend 2014;Townsend et al 2015). In Cosmetidae, however, the genital morphology is somewhat uniform, if compared with Gonyleptidae for example.…”

Ontogenetic variation in the sensory structures on the pedipalps of cosmetid harvestmen (Arachnida, Opiliones, Laniatores)

“…We compared the morphology of different podomores (trochanter, femur, patella, tibia, and tarsus) from the pedipalps of nymphs and adults of three relatively common species of Neotropical cosmetid harvestmen using specimens that had been collected in previous studies (Townsend, Proud, & Moore, 2008;Townsend, Schaus, Zvonareva, Illinik, & Evans, 2017;Townsend et al, 2009;Walker & Townsend, 2014). Individuals of Cynortula granulata Roewer 1912 ( Figure 1 (10827 0 20 00 N, 8480 0 20 00 W, datum: WGS84) that were collected from 11 to 24 August 2015.…”

Interspecific variation in ovipositor morphology among Manaosbiid and Nomoclastid Harvestmen (Arachnida, Opiliones, Laniatores)

“…). The surface of these lobes may be relatively smooth, contain folds or be adorned with small denticles (Bennett and Townsend ; Walker and Townsend ; Townsend et al . ).…”

“…As a result, little is known about interspecific variation in ovipositor morphology among laniatorean harvestmen. Recent investigations have revealed considerable interspecific variation in the morphology of the peripheral setae as well as with respect to the surface texture of the external lobes (Bennett and Townsend ; Walker and Townsend ; Townsend et al . ).…”

“…). However, limited surveys (3–12 species) of interspecific variation in ovipositor morphology within families of laniatorean harvestmen have been restricted to the families Cosmetidae (12 species: Walker and Townsend ) and Zalmoxidae (three species: Townsend et al . ).…”