Sminthurides parvulus is generally blue in colour and is common and widespread. Males reach 0.3 mm in length whereas females grow to 0.5 mm. In Sminthurides species, the male antenna is modified to grasp the female during mating and the long spine on the second antennal segment (ant2) is curved (Fig. 1). Females do not possess sub-anal appendages (SAA). In Sminthurides parvulus, the fourth antennal segment in the female is divided into five subsegments (Fig. 2). The mucro does not bear lamellae and is 'gutter'-shaped (Figs. 3, 4). A tibiotarsal organ (tt organ) is present on the third leg (Fig. 5) and the empodium of the foot has a long filament that reaches well beyond the tip of the claw (Figs. 6). Most records for Sminthurides parvulus are from wet moss.
Fig. 1 (above): Antenna of a male Sminthurides parvulus collected from St. Austell, Cornwall in January 1960 by T. Clay.
Fig. 2 (above): Antenna of a female Sminthurides parvulus collected from Tryfaen, North Wales in September 1933 by W.M. Davies. The fourth antennal segment (ant4) is divided into five subsegments (1 to 5).
Figs. 3 (above) and 4 (below): Distal furca at two levels of focus of Sminthurides parvulus collected from Moorhouse National Nature Reserve in 1954 by D.H. Murphy.
Figs. 5 (above) and 6 (below): Foot of the third leg at two levels of focus of the same specimen of Sminthurides parvulus shown in Fig. 2.
