Ceratophysella bengtssoni is common and widespread in the UK but there is only one confirmed record for Ireland. This species is often found in large 'swarms' (Fig. 1). It is particularly common among accumulations of dead leaves in gardens. There are some records in the literature for 'Ceratophysella sigillata' from England but the few specimens labelled with this name in the NHML collection are Ceratophysella bengtssoni. Ceratophysella sigillata lacks an expanded dental sac, and lacks seta m2 on th2 (these features are PRESENT in all the specimens of Ceratophysella bengtssoni I have seen; Figs. 9, 10).

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Fig. 1 (left): 'Swarm' of Ceratophysella bengtssoni on the surface of a puddle.
Fig. 2 (above left): Ceratophysella bengtssoni of 1.2 mm in length.
Fig. 3 (above right): Ceratophysella bengtssoni attached to the substrate by the sticky expandable sac between ant3 and ant4 after a jump (see Fig. 9).

Fig. 5 (above): Post-antennal organ (PAO) and adjacent ocelli (A-C) of Ceratophysella bengtssoni collected from a cave in the Avon Gorge in September 1966 by the Cave Research Group.

Fig. 4 (above): Post-antennal organ (PAO) and eight ocelli (A-H) of Ceratophysella bengtssoni collected from Harpenden in December 1951 by Theresa Clay .

Fig. 8 (above): Furca of Ceratophysella bengtssoni collected from Ruislip in January 1951 by M.E. Bacchus. Note the spoon-shaped mucro visible in profile (left) and from the dorsal side (right). D, dorsal side of furca; V, ventral side of furca.

Fig. 6 (above left): Foot of leg3 of Ceratophysella bengtssoni collected from a cave in the Avon Gorge in September 1966 by the Cave Research Group. Note the empodium (emp) possesses a basal lamella.
Fig. 7 (above right): Anal spines on the sixth abdominal segment (abd6) of the same specimen as Fig. 6 at the same magnification. Note that the anal spines are less than half the length of a foot claw.

Fig. 10 (below) : Dorsal chaetotaxy (arrangement of setae) on the cuticle of the dorsal side of the second thoracic segment (th2) of Ceratophysella bengtssoni collected from Harpenden in December 1951 by Theresa Clay.  Note that seta m2 is PRESENT (seta m2 is absent from Ceratophysella sigillata). a1-a3 = setae in anterior 'a' row; m1-m2 = setae in middle 'm' row; p1-p3 = setae in posterior 'p' row.

Fig. 9 (above): Antenna of Ceratophysella bengtssoni collected from a cave in the Avon Gorge in September 1966 by the Cave Research Group. Note the expandable sac (sac) between antennal segments 3 and 4.