Ischyropsalidoidea Simon 1879

Introduction

Ischyropsalidoidea is defined as group of Dyspnoi with a penis operated by a single muscle (Martens 1976, Martens et al. 1981). They lack clavate hairs on the palps, the ovipositor is short, secondarily unsegmented, with an undivided furca (Martens 1976) and a common channel for cement glands (Martens et al. 1981). Some members possess metapeltidial sensory cones (Shear 1986) that have an unknown function. Further characters are hard to establish for the high morphological divergence of the included taxa. Many characters used in older approaches appear plesiomorphic or convergent (Gruber 2007).

Taxonomy and Discussion of Phylogenetic Relationships

Ischyropsalidoidea has been proposed as family since Simon (1879) and was redefined as superfamily by Martens (1976) and Martens et al. (1981). It is accepted as monophyletic, supported by molecular analyses (e.g. Giribet et al. 2010) and morphology (Shear 1986, Gruber 2007). The Ischyropsalidoidea include very heterogeneous taxa hard to place in a morphology based phylogenetic framework. The cladistic analysis by Shear (1986) organized them within three accepted families but the arrangement of genera was questioned by Giribet et al. (2010) based on molecular results, combining both approaches does not clarify the position of all genera.

Ecology and Life History

General trends within Ischyropsalididae show preference to permanently wet and cool to cold habitats. This preference has led to a respective number of cave inhabiting species and alpine endemics, while true troglobionts, lacking eyes, are rare. Most species show a distinct phenology of adults being present only during a short time of the year, mostly from summer to late autumn, but cave species can occur year round.

References

Giribet, G., Vogt, L. Pérez-González, A., Sharma, P. and A. B. Kury. 2010. A multilocus approach to harvestman (Arachnida: Opiliones) phylogeny with emphasis on biogeography and the systematics of Laniatores. Cladistics 26:408-437.

Gruber, J. 2007. Dyspnoi - Historical systematic synopsis. In: Pinto-da-Rocha, R., Machado, G., & Giribet, G. (eds.), Harvestmen: the biology of Opiliones. Harvard University Press, Cambridge:131-135.

Martens, J. 1976. Genitalmorphologie, System und Phylogenie der Weberknechte (Arachnida: Opiliones). Entomologica Germanica 3(1/2):51-68.

Martens, J., Hoheisel, U. and M. Götze 1981. Vergleichende Anatomie der Legeröhren der Opiliones als Beitrag zur Phylogenie der Ordnung (Arachnida). Zoologische Jahrbücher, Abteilung für Anatomie und Ontogenie der Tiere 105(1):13-76.

Shear, W. A. 1986. A cladistic analysis of the opilionid superfamily Ischyropsalidoidea, with descriptions of the new family Ceratolasmatidae, the new genus Acuclavella, and four new species. American Museum Novitates 2844:1-29.

Simon, E. 1879. Contenant les ordres des Chernetes, Scorpiones et Opiliones. Les Arachnides de France 7:1-332.