COLLEMBOLA > SYMPHYPLEONA > Sminthuridae

The two remaining families in the SYMPHYPLEONA order are Sminthuridae and the very similarly named Sminthurididae. They jointly include about a dozen extant species, but probably only six, possibly seven, are likely to be found. At present, I can only represent these families with a single species, but I would like to think that one or two more could be added in time.

The two most frequently observed species in the Sminthuridae family are Allacma fusca as featured here and Sminthurus viridis which, as its name suggests, is a small greenish or yellowish-brown species. In the Sminthurididae family, one of the most abudant species is Sphaeridia pumilis, but it's tiny, only around 0.25mm, and is mainly found in soil. Members of the Sminthurides genus are a tad larger, but still very small. Sminthurides parvulus is mainly found in wet moss and is light blue in colour, but only about 0.3mm long. Sminthurides schoetti is a similar size, and is described as being yellow with a band of blue pigment either side. The other two species in the genus, Sminthurides aquaticus and Sminthurides malmgreni are larger, up to 1mm, and possibly a bit easier to find as they live in wet habitats and can frequently be found on the surface of water. The former is yellow with blue pigment on the dorsal side of the body, and the latter is yellow with blue pigment in longitudinal bands.

In comparison, Allacma fusca is positively huge with larger specimens reaching 3.5mm. It is a common and widespread, rather attractive globular springtail that can be found in a variety of moist or wet habitats, mostly occurring on or near the ground under fallen branches or stones, or on low-growing vegetation. Most individuals are dark brown and shiny, but there are a number of variant forms with the ground colour ranging from pale brown to brownish-black. Some of these forms have names, such as var.albiceps (usually very dark), var.pustulata (a variable female form which is pale to mid brown with spot-like markings) and, probably the most common, being the only form that I've found, usignata (variable mid to dark brown with a distinctive pattern).

They have four antennal segments with the fourth (ant.4) divided into 16 subsegments and with the third (ant.3) having longer setae at the beginning of the segment, gradually shortening towards the end. The eye-patch has eight ocelli in bilateral symmetry. And, although unlikely to be seen in photos, the female's tiny sub-anal appendage is complete and unbranched.

The two different individuals that I found at Moors Valley were on the underside of a decaying wet branch, which was laying alongside a stream. The little one that I photographed at Blashford Lakes was on low vegetation and disappeared very quickly, which they're more prone to do when feeling exposed, whereas if you find them on the ground or on fallen branches they often stay still or just carry on going about their business.

New species added, Jan.25 (v.1)