Harvestmen Systematics

I am involved in a collaborative project on the evolution of mating systems in Leiobunum, a species-rich group of harvestmen that is particularly diverse in eastern North America, Mexico and Japan. Work thus far indicates that "mating" in Leiobunum is actually a multi-phase process involving copulation preceded by close-contact courtship, including the transfer of a fluid, penis-associated nuptial gift. Jeff Shultz (University of Maryland) is the leader of the project team, that also includes Rogelio Macías Ordóñez (Instituto de Ecologia, Mexico), Nobuo Tsurusaki (Tottori University, Japan), and Eileen Hebets (Univ. of Nebraska). We are using molecular-sequence data to determine phylogenetic relationships within and among Leiobunum and related taxa, documenting their sexual morphology and behavior, and testing the hypothesis that mating-system diversity is the result of a long-term sexual arms race. This project is supported by the National Science Foundation.
In concert with on-going studies of cryophilic arachnids of the southern Appalachians, we have begun to study several harvestman taxa, including Theromaster, Fumontana, Sabacon, and eastern phalangodids (i.e., Bishopella and relatives). This research is in collaboration with my students Steven Thomas and Maureen McCormack, and has been supported by the US Fish & Wildlife Service. All of these taxa are generally under-studied, and field studies have greatly increased our knowledge of the distribution and natural history of these harvestmen (example from Fumontana). In addition, studies of morphology and molecular phylogeography/phylogenetics have uncovered a general pattern of deep phylogenetic divergence without associated morphological divergence ("cryptic" divergence). Current taxonomy is a generally poor reflection of the species diversity and biogeographic history in these systems (example from Bishopella).
Master's students Shahan Derkarabetian and Casey Richart have begun evolutionary studies focusing on members of the rich harvestmen fauna of the western United States. Focal taxa include sclerobunine laniatoreans (Sclerobunus, Cyptobunus, Zuma), cladonychiid laniatoreans (Cryptomaster and Speleomaster), and the ischryopsalidoid genus Acuclavella.

A photogallery of some North American harvestman taxa



	Harvestmen Systematics in the Hedin Lab I am involved in a collaborative project on the evolution of mating systems in Leiobunum, a species-rich group of harvestmen that is particularly diverse in eastern North America, Mexico and Japan. Work thus far indicates that "mating" in Leiobunum is actually a multi-phase process involving copulation preceded by close-contact courtship, including the transfer of a fluid, penis-associated nuptial gift. Jeff Shultz (University of Maryland) is the leader of the project team, that also includes Rogelio Macías Ordóñez (Instituto de Ecologia, Mexico), Nobuo Tsurusaki (Tottori University, Japan), and Eileen Hebets (Univ. of Nebraska). We are using molecular-sequence data to determine phylogenetic relationships within and among Leiobunum and related taxa, documenting their sexual morphology and behavior, and testing the hypothesis that mating-system diversity is the result of a long-term sexual arms race. This project is supported by the National Science Foundation. In concert with on-going studies of cryophilic arachnids of the southern Appalachians, we have begun to study several harvestman taxa, including Theromaster, Fumontana, Sabacon, and eastern phalangodids (i.e., Bishopella and relatives). This research is in collaboration with my students Steven Thomas and Maureen McCormack, and has been supported by the US Fish & Wildlife Service. All of these taxa are generally under-studied, and field studies have greatly increased our knowledge of the distribution and natural history of these harvestmen (example from Fumontana). In addition, studies of morphology and molecular phylogeography/phylogenetics have uncovered a general pattern of deep phylogenetic divergence without associated morphological divergence ("cryptic" divergence). Current taxonomy is a generally poor reflection of the species diversity and biogeographic history in these systems (example from Bishopella). Master's students Shahan Derkarabetian and Casey Richart have begun evolutionary studies focusing on members of the rich harvestmen fauna of the western United States. Focal taxa include sclerobunine laniatoreans (Sclerobunus, Cyptobunus, Zuma), cladonychiid laniatoreans (Cryptomaster and Speleomaster), and the ischryopsalidoid genus Acuclavella. A photogallery of some North American harvestman taxa