Hexurella

Gertsch & Platnick, 1979

dwarf funnel web spiders

Hexurella is a of dwarf funnel web (Mygalomorphae, Hexurellidae) comprising some of the smallest mygalomorph spiders in the world. measure 2.5–5 mm in body size. The genus represents a phylogenetically ancient, relictual lineage that diverged from other atypoids approximately 300 million years ago. As of 2026, the genus contains eight , with four described in a 2023 taxonomic revision. Several species have highly restricted geographic ranges and may warrant attention.

Pronunciation

How to pronounce Hexurella: /hɛksjuːˈrɛlə/

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Identification

Distinguished from other mygalomorph by extremely small size (2.5–5 mm) combined with funnel web architecture. Differs from related atypoid by phylogenetic placement in Hexurellidae, an ancient lineage. -level identification requires examination of genitalic and geographic provenance.

Appearance

are minute mygalomorph , measuring 2.5–5 mm in body length—among the smallest of all mygalomorphs. The exhibits typical mygalomorph features including downward-directed (orthognath ) and two pairs of .

Habitat

Sclerophyllous , montane , and sky islands of southeastern Arizona. Occupies Mojave Desert regions and northern Baja California. Microhabitats include leaf litter and spaces beneath rocks. Shows strict microhabitat preferences across its range.

Distribution

United States–Mexico borderlands: central and southeastern montane Arizona, southern California, northern Baja California Norte. Range extends into the Mojave Desert of California, mountains of northwest Arizona, and montane sky islands of southeastern Arizona. Predicted occurrence in mountains of central and northwestern Arizona, northern mainland Mexico, and additional Mojave Desert localities.

Behavior

Vagrant lifestyle with web-building . Cryptic, occurring in leaf litter or under rocks. Exhibits strict microhabitat preferences and potentially poor capabilities, contributing to geographic isolation of .

Similar Taxa

  • CalisogaAnother mygalomorph studied in the same research program; differs in larger body size and different geographic distribution pattern around California's Central Valley
  • AtypusFunnel web mygalomorph in Atypidae; differs in much larger body size and different phylogenetic placement

More Details

Conservation status

Several are highly geographically localized with restricted ranges, characteristics that suggest vulnerability to loss and climate change. The 2023 taxonomic revision highlighted attention as warranted for these micro- species.

Phylogenetic significance

Hexurella represents a phylogenetically ancient lineage that diverged from other atypoid approximately 300 million years ago, making it an important relictual group for understanding mygalomorph evolution.

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Sources and further reading