Nemesiidae

Simon, 1889

Tubetrapdoor and Wishbone Spiders, wishbone spiders

Nemesiidae is a of mygalomorph first described by Eugène Simon in 1889 and elevated to family status in 1985, having previously been considered part of Dipluridae. The family comprises relatively large, darkly colored spiders with elongated bodies and legs, commonly known as wishbone spiders due to the distinctive shape of their burrows. Members are primarily , constructing -lined burrows often equipped with hinged trapdoors for ambush . The family includes ten and approximately 195 distributed across diverse including coastal sands, forests, and mountainous regions on multiple continents.

Calisoga longitarsis by (c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda. Used under a CC-BY license.

Calisoga longitarsis by (c) Ken-ichi Ueda, some rights reserved (CC BY). Used under a CC-BY license.

Calisoga longitarsus lew 2,5light by Stephen Lew. Used under a CC BY-SA 2.5 license.

Pronunciation

How to pronounce Nemesiidae: //nɛˈmɛzi.aɪ.diː//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Nemesiidae can be distinguished from other mygalomorph by the combination of: three-segmented with a short domed ; absence of a third ; divided on III–IV; and specific male genitalic features including with keels near the base resting in a deep tibial excavation. Females of some possess sclerotized supraspermathecal chambers. The family differs from Dipluridae (to which it was formerly assigned) in these spinneret and claw characteristics. Within Nemesiidae, genera are distinguished by details of embolus , spermathecal structure, and leg scopulation patterns.

Images

Habitat

Primarily , inhabiting self-constructed burrows in diverse substrates. Documented include: sandy soils of oceanic and river coastal areas with psammophyte vegetation (Chaco spp. in Uruguay); oak forests in mountainous regions (Raveniola niedermeyeri in Iran's Alborz Mountains); Atlantic Forest (Mata Atlântica) in Brazil (Psalistopoides); and various forest and grassland environments across Central Asia, Western Asia, and the Neotropics. Some show high habitat specificity, such as dependence on old hollow myrtle beech trees in humid forests.

Distribution

Widespread across multiple continents including: South America (Brazil, Uruguay, Argentina), Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, Turkmenistan, Afghanistan), Western Asia (Iran, Turkey, Armenia, Azerbaijan, Georgia, Russia), East Asia (China), Europe (Italy), and Australia. The exhibits significant diversity in the Neotropical region and across Eurasia, with many showing restricted, locally distributions.

Seasonality

activity observed in natural conditions for some (e.g., Chaco spp.). Specific seasonal patterns not well documented across the due to limited field observations and the difficulty of these secretive, burrow-dwelling .

Life Cycle

Developmental stages include , spiderling, and . Females of some guard eggs in burrows. Detailed information is sparse due to the difficulty of observing these in their sealed burrows.

Behavior

Strictly , spending the majority of their lives in -lined burrows. Burrows are typically constructed with a flap-like or hinged trapdoor that the pushes up with its legs to ambush passing . The door provides cover for the ambush and is quickly closed after prey capture. Spiders rarely leave their burrows except for mating, when both sexes emerge briefly before returning to their respective burrows. Some burrows have side tubes. Hunting involves lifting the burrow entrance, seizing prey, and rapid withdrawal. Activity is primarily .

Ecological Role

in soil and litter ; specific ecological impacts not well studied. Burrowing activity may contribute to soil aeration and in some .

Human Relevance

Vulnerable to destruction, particularly where psammophyte vegetation or old-growth forests are degraded. Some (e.g., Chaco spp. in Uruguay) are of concern due to declining coastal sand dune habitats. No documented medical or economic importance.

Similar Taxa

DipluridaeNemesiidae was formerly classified within Dipluridae; distinguished by three-segmented with short domed , absence of third , and specific genitalic
HexurellidaeAnother of small mygalomorph ; Nemesiidae differs in burrow construction with trapdoors and specific segmentation
IdiopidaeAlso contains trapdoor ; distinguished by different burrow architecture and male genitalic features

More Details

Taxonomic History

Elevated from status within Dipluridae to rank in 1985 based on morphological distinctiveness. The family has undergone significant revision, with such as Pycnothele, Raveniola, and Psalistopoides receiving detailed taxonomic treatment.

Conservation Concerns

Several are vulnerable due to specificity and lifestyle. In Uruguay, psammophyte vegetation is critically decreasing, threatening Chaco species. Old-growth forest dependence makes some sensitive to logging and forest fragmentation.

Research Challenges

Biology remains poorly known due to difficulty of collection and observation. ' reclusive burrow-dwelling habits make field studies challenging, and many are known from few specimens.