At just 1.5 mm long, this species can easily be mistaken for one of the money spiders. Examination of the eye arrangment provides the easiest method of distinguishing it from one of the Lyniphiidae however. The species is widespread and common throughout the U.K. and is usually found at ground level among moss and grass. An interesting feature of this species is the presence of a sclerotised plate, known as a scutum (pl. scuta), on each side of the underside of the abdomen of the male. These can be easily seen in the micrograph in the middle of the top row.
Head, chelicerae and pedipalps of a female Pholcomma gibbum. The eye arrangement distinguishes it as a Theridiid rather than a Linythiid.
Ventral view of the abodmen of a male Pholcomma gibbum, with the scuta arrowed
Left Pedipalp (male sexual organ) of Pholcomma gibbum
Epigyne (female sexual organ) of Pholcomma gibbum. The micrograph does not bear a great resemblance to the drawings in the references, as much of the detail is beneath a transparent membrane. Note how the small opening is dwarfed by the epigastric fold