Sclerobunus robustus idahoensis by Hedin cropped
Sclerobunus idahoensis Briggs, 1971 - USA - from flickr - cropped. Copyright © Marshal Hedin [1]









Sclerobunus Banks, 1893:152[1] is a genus of the family Paranonychidae, subfamily Sclerobuninae. They are limited to moist, dark microhabitats, typically found under logs and rocks in high elevation forests or in caves in the mountainous regions of western North America[2].

History of Sclerobunus and CyptobunusEdit


  • In 1877, Packard described a new species Scotolemon robustum[3]
  • In 1893, Banks described a new genus (Sclerobunus) and species (S. brunneus). He also moved Scotolemon robustum into Sclerobunus[1].
  • In 1905, Banks described another new genus (Cyptobunus) for his new species C. cavicolus[4].
  • In 1924, Crosby & Bishop synonymized Sclerobunus & Cyptobunus[5]
  • In 1931, Roewer described a new species - Sclerobunus parvus[6].
  • In 1971, Briggs[7] (who rejected the synonymy of Sclerobunus and Cyptobunus):
    • described a new species of Sclerobunus (Sclerobunus nondimorphicus) and three subspecies of Sclerobunus robustus (robustus, glorietus & idahoensis);
    • described a new species of Cyptobunus (ungulatus) with two subspecies (ungulatus & madhousensis);
    • described a new genus (Paranonychus) and species (P. concolor). He also moved Sclerobunus brunneus into this new genus.
  • In 2008, Shear & Derkarabetian synonymized Sclerobunus parvus with Paranonychus brunneus[8].

At this point, therefore, Sclerobunus contained two species: Sclerobunus nondimorphicus & Sclerobunus robustus (which had three subspecies: robusticus, glorietus, idahoensis), and Cyptobunus contained two species: C. cavicolus & C. ungulatus (which had two subspecies: ungulatus, madhousensis)


Type species Sclerobunus robustus (Packard, 1877) [original designation by Banks, 1893:152[1]]

Species GroupsEdit


Species groups. From Derkarabetian & Hedin, 2014.

Derkarabetian & Hedin isolated three "species groups" within the genus, based on (a) the presence or absence of tubercles on the anterior margin of the scute, and (b) whether the dorsal surface of the ventral plate of the penis is smooth or has "many folds".[2]

  • The cavicolens group is characterised by the absence of tubercles on the anterior margin of the scute. This group contains Sclerobunus cavicolens, Sclerobunus ungulatus and Sclerobunus madhousensis.
  • The nondimorphous group is characterised by having tubercles on the anterior margin of the scute and the dorsal surface of the ventral plate of the penis being smooth. This group contains Sclerobunus nondimorphicus and Sclerobunus idahoensis.
  • The robustus group is characterised by having tubercles and having many folds on the dorsal surface of the ventral plate of the penis. This group contains the remaining seven species.

Species ListEdit


Group robustus, from Derkarabetian & Hedin, 2014.


  1. 1.0 1.1 1.2 1.3 Banks, N. (1893). The Phalangida Mecostethi of the United States. T Am Entomol Soc 20:149-152
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Derkarabetian S, Hedin M (2014). Integrative Taxonomy and Species Delimitation in Harvestmen: A Revision of the Western North American Genus Sclerobunus (Opiliones: Laniatores: Travunioidea). PLoS ONE 9(8): e104982. doi:10.1371/journal.pone.0104982
  3. 3.0 3.1 Packard, A.R. (1877). On a new cave fauna in Utah. B US Geological Survey Territories 3:157-169
  4. 4.0 4.1 4.2 Banks, N. (1905). A new genus and species of Phalangida. Entomol News 1:251-253.
  5. Crosby C.R. & S.C. Bishop (1924). The genus Cyptobunus Banks (Phalangida). Entomol News 35: 104.
  6. Roewer, C.F. (1931). Über Triaenonychiden. Zeitschr Wiss Zool 138: 137–185.
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Briggs, T.S. (1971). The harvesmen of the family Triaenonychidae in North America. Occ P Cal Acad Sci 90:1-43
  8. Shear, W.A. & S. Derkarabetian (2008). Nomenclatorial changes in Triaenonychidae: Sclerobunus parvus Roewer is a junior synonym of Paranonychus brunneus (Banks), Mutsunonychus Suzuki is a junior synonym of Paranonychus Briggs, and Kaolinonychinae Suzuki is a junior synonym of Paranonychinae Briggs (Opiliones: Triaenonychidae). Zootaxa 67: 1809.