Pacullidae
Pacullidae·Pacullidae·Adults of the Pacullidae family always exceed 5 mm in body length, making them larger than spiders in the Tetrablemmidae family.·https://upload.wikimedia.org/wikipedia/commons/thumb/a/a9/Pacullidae_species.jpg/320px-Pacullidae_species.jpg
Pacullidae is a family of araneomorph spiders distinguished by their three-clawed feet, six eyes, and the absence of a cribellum. These spiders are notably larger than their relatives in the Tetrablemmidae family, with adults consistently exceeding 5 mm in length and possessing a very wrinkled body surface. Originally described by Eugène Simon in 1894, the family was temporarily merged into Tetrablemmidae before being re-established in 2017 following significant phylogenetic research.
Key Facts
- ›Pacullidae spiders have three claws on each foot.
- ›They possess six eyes, unlike many other spider families.
- ›Adults of this family always measure over 5 MM in body length.
- ›Their cuticle is characterized by a very wrinkled (rugose) texture.
- ›The family includes four genera and 38 species, with one extinct genus found in Burmese amber.
Three-Clawed Spiders, Six Eyes, Lacking A Cribellum, Very Wrinkled Cuticle, Females Lack Large Membranous Receptacles
About Pacullidae
Pacullidae represents a distinct family of araneomorph spiders, identified by several unique morphological traits. First described by Eugène Simon in 1894, this family has undergone taxonomic shifts, being merged into Tetrablemmidae in 1958 before its re-establishment as a separate family in 2017 based on significant phylogenetic research.
Key Characteristics
Spiders in the Pacullidae family are characterized by their three-clawed feet and the presence of six eyes. They notably lack a cribellum, an organ used for silk production found in some other spider groups. A defining feature of Pacullidae is their highly wrinkled, or rugose, cuticle. Furthermore, they are generally larger than spiders in the related Tetrablemmidae family, with adults consistently exceeding 5 mm in body length, and females do not possess the large membranous receptacles found in Tetrablemmidae.
Taxonomy and Phylogeny
Within the broader classification of spiders, Pacullidae falls under the Synspermiata clade, a group of spiders that evolved from haplogyne ancestors and possess encapsulated sperm cells. Within this clade, Pacullidae is grouped with four other families, including Tetrablemmidae, though it is most closely related to the Diguetidae family. Together with Pholcidae, these families form the "lost trachea clade," indicating a shared evolutionary trait of having lost their posterior respiratory system.
Genera and Species
As of January 2026, the Pacullidae family encompasses four genera and a total of 38 known species. This includes one extinct genus, †Furcembolus, which comprises nine species discovered as fossils within Burmese amber from Myanmar, dating back to the Cenomanian geological period.
Source: Wikipedia ↗
Frequently Asked Questions
What are the defining physical characteristics of Pacullidae spiders?
Pacullidae spiders are characterized by having three claws on each of their feet and possessing six eyes. They also lack a cribellum, which is a silk-spinning organ found in some other spider families. A distinctive feature is their very wrinkled, or rugose, cuticle.
How large do Pacullidae spiders typically get?
Spiders belonging to the Pacullidae family are generally larger than those in the related Tetrablemmidae family. Adults of Pacullidae consistently exceed 5 mm in body length.
Where does the family Pacullidae fit in spider classification?
Pacullidae is classified within the Synspermiata clade, a group of former haplogyne spiders. It is closely related to the Tetrablemmidae family, but is distinct and considered most closely related to Diguetidae. They also belong to a "lost trachea clade" alongside Pholcidae, indicating a loss of their posterior respiratory system.
Are there any extinct species within the Pacullidae family?
Yes, there is an extinct genus named †Furcembolus, described by Wunderlich in 2008. This genus contains 9 species and fossils have been found in Burmese amber from Myanmar, dating back to the Cenomanian period.
When was the family Pacullidae first described, and has its classification changed?
The family Pacullidae was first described by Eugène Simon in 1894. It was later merged into the family Tetrablemmidae in 1958. However, following a large phylogenetic study in 2017, it was re-established as its own distinct family.