Hydrobiosidae

Introduction

Hydrobiosidae is a moderately sized family, originally established by Ulmer (1905) as a subfamily of Rhyacophilidae. The entire family was the subject of an extensive global revision by Schmid (1989). In many respects, Hydrobiosidae represents the Southern Hemisphere or Gondwanan equivalent of Rhyacophilidae. In contrast to the lack of generic diversity in Rhyacophilidae, some 50 genera are recognized for Hydrobiosidae. Most of the generic diversity is found in either the Chilean subregion of the Neotropics or in the Australasian region. However, in each region there is a diverse genus with species that extend well beyond the ancestral Gondwanan range of the family. In the Neotropics, the genus Atopsyche Banks (ca. 120 species) is widespread and extends northward to Central America, Mexico, and the southwestern United States. Within the Australasian fauna, the genus Apsilochorema (50+ species) extends into the Oriental and western Palaearctic regions.

A review of the species groups of Apsilochorema and their relationships was provided by Mey (1999) and Ward et al. (2004) presented a phylogeny of the genera in the family. Blahnik and Gottschalk (1997) discussed the phylogenetic position of some Costa Rican species of Atopsyche. The remaining genera include: Amphicorema Schmid, Androchorema Flint, Apatanodes Navás, Australobiosis Schmid, Cailloma Ross and King, Clavichorema Schmid, Heterochorema Schmid, Iguazu Ross and King, Isochorema Schmid, Metachorema Schmid, Microchorema Schmid, Neoatopsyche Schmid, Neochorema Schmid, Neopsilochorema Schmid, Nolganema Navás, Parachorema Schmid, Pomphochorema Flint, Pseudoradema Schmid, Rheochorema Schmid, Schajavskoya Flint, and Stenochorema Schmid from the Chilean subregion of the Neotropics, with a few extending northward along the Andes; and Allobiosis Mosely, Allochorema Mosely, Atrachorema McFarlane, Austrochorema Mosely, Costachorema McFarlane, Edpercivalia McFarlane, Erichorema Ward, Ethochorema Neboiss, Hydrobiosis McLachlan, Hydrochorema Tillyard, Ipsebiosis Neboiss, Koetonga Neboiss, Megogata Neboiss, Moruya Neboiss, Neurochorema Tillyard, Poecilochorema Schmid, Psyllobetina Banks, Psilochorema McLachlan, Ptychobiosis Neboiss, Synchorema Tillyard, Tanjilana Neboiss, Tanorus Neboiss, Taschorema Mosely, Tiphobiosis Tillyard, Traillochorema McFarlane, Ulmerochorema Kimmins, and Xanthochorema Kimmins from the Australasian region (Australia, New Zealand, New Guinea, and New Caledonia). Most of these genera have only a few species, but some contain 10-20 or so.

Characteristics

Larvae are free-living and actively predaceous; no structure is constructed by the larva until pupation, when a dome-shaped pupal chamber is built of rocks and cemented to the substrate. In larvae of many genera of Hydrobiosidae, the shortened foretibia and tarsus close against a concave extension of the femur, producing a chelate foreleg useful for grasping and holding prey. Adult males are remarkable for the complexity and variability of their genitalia.

References

Blahnik, R.J. & Gottschalk, R.M. (1997) New species of Atopsyche from Costa Rica (Trichoptera: Hydrobiosidae). Entomological News, 108, 161–174.

Mey, W. (1999) Notes on the taxonomy and phylogeny of Apsilochorema Ulmer, 1907 (Trichoptera, Hydrobiosidae). Deutsche Entomologische Zeitschrift, 46, 169–183.

Schmid, F. (1989) Les hydrobiosides (Trichoptera, Annulipalpia). Bulletin de l'Institute Royal des Sciences Naturelles de Belgique, Entomologie, 59, Supplement, 1–154.

Ward, J.B., Leschen, R.A.B., Smith, B.J. & Dean, J.C. (2004) Phylogeny of the caddisfly (Trichoptera) family Hydrobiosidae using larval and adult morphology, with the description of a new genus and species from Fiordland, New Zealand. Records of the Canterbury Museum, 18, 23–43.