Porrhomma Simon 1884
- Dataset
- A review of the spider genus Porrhomma (Araneae, Linyphiidae)
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Arachnida
- order
- Araneae
- family
- Linyphiidae
- genus
- Porrhomma
description
Description. Prosoma longer than wide, opisthosoma oval. Clypeus hairy, particularly in males. Chelicerae with three promarginal teeth and four retromarginal teeth. Eyes often reduced. Femora I and II mostly with one dorsal spine, Fe I with or without prolateral spine (s). All Ti always with two dorsal spines (not repeated in descriptions). The Ti I usually with one prolateral and one retrolateral spine, Ti II with one retrolateral spine. Metatarsal spines absent (except in P. errans). Mt I – III with trichobothrium, Mt IV without trichobothrium. Male palp with no tibial apophysis. Paracymbium hook-like. Distal suprategular apophysis is hooked and uniform in all species. Tegulum is provided with a protegulum (composed of two parts). Two linyphiid genra, viz. Bathyphantes and Porrhomma, are characterised by an embolic plate as a part of the embolic division (Millidge 1977). The embolic plate has a characteristic anterior process. The embolus is attached to the lateral side of this embolic plate. The embolus of the genus Porrhomma is characteristic by a transparent border of the concave side, called velum, and is accompanied by an embolic membrane. Epigynum is characterised by the location of the genital openings inside a well-defined, deep circular aperture. The form of the internal organs is usually seen through the integument. Vulva is composed of a pair of copulatory ducts ending by spermathecae.
diagnosis
Diagnosis. Males of the genus Porrhomma can be distinguished from other genera of the family Linyphiidae by the presence of a transparent concave border of the embolus, known as the velum.
materials_examined
Type species: Erigone convexa Westring, 1851.