Trogulidae

Trogulidae can be distinguished from other harvestman families by their short legs relative to body size, flattened leathery body texture, and the presence of a small hood in adults that hides the short chelicerae and pedipalps. The habit of adhering soil to the body surface is a notable behavioral trait visible in the field. Within the family, species identification is challenging due to uniform morphology; the genus Trogulus exhibits particularly high cryptic diversity with molecular studies suggesting three times more species than currently recognized. The genus Anelasmocephalus is distinguished by its flattened body form and is the only Trogulidae genus present in Ireland.

Soil-dwelling; occupies terrestrial habitats in western and southern Europe and adjacent regions. Specific microhabitat preferences vary by genus and species. Anelasmocephalus cambridgei in Ireland has been recorded from bogs and open ground. Trogulus species occupy diverse terrestrial habitats across their range. The introduced North American population of Trogulus tricarinatus occupies similar soil habitats in the eastern United States.

Native range: western and southern Europe, extending to western North Africa, the Levant, the Caucasus, and northern Iran. Introduced range: eastern North America (Trogulus tricarinatus only). The family reaches its northern distributional limit in Scandinavia (records from Denmark, Norway, Sweden) and its eastern limit in northern Iran and Kyrgyzstan.

Specialist predators of terrestrial snails; not strictly obligate. Trogulus tricarinatus is documented as a predator of terrestrial snails. Anelasmocephalus cambridgei feeds on snails but diet breadth beyond this is not fully established.

Eggs are laid in empty snail shells (documented for Anelasmocephalus cambridgei). Newly hatched individuals are purple in color. Through successive moults, juveniles lose the purple coloration and acquire the soil-covered appearance characteristic of adults by adhering soil particles to their bodies.

Adheres soil or dirt particles to the body surface, creating a camouflaged, soil-covered appearance that serves as predator avoidance. This behavior begins after the early juvenile moults and continues through adulthood.

Predator of terrestrial snails; may contribute to regulation of snail populations in soil ecosystems. Potential vulnerability to molluscicides due to specialized snail-based diet and life history.

Trogulus tricarinatus has been introduced to eastern North America, presumably through human-mediated transport. Molluscicide use poses a potential threat to populations due to reliance on snails as prey and for oviposition sites (empty shells). Anelasmocephalus cambridgei is considered rare in parts of its range (e.g., Northern Ireland) and is a conservation interest species.

• Other Dyspnoi families (e.g., Nemastomatidae, Ischyropsalididae)Trogulidae differs in short leg proportions, flattened leathery body, hood structure concealing mouthparts, and soil-covering behavior; other Dyspnoi typically lack the soil-adherence habit and hood structure.
• Eupnoi harvestmen (e.g., Phalangiidae)Trogulidae has much shorter legs relative to body, different body texture, and soil-dwelling habit versus the typically long-legged, often vegetation-dwelling Eupnoi.

• soil-dwelling
• camouflage
• snail predator
• cryptic species
• introduced species

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Northern Ireland, invertebrate finds in review 2023 - Buglife Blog - Buglife
• Revision of the genus Trogulus Latreille: the Trogulus coriziformis species-group of the western Mediterranean (Opiliones : Trogulidae)