Species of Mesaphorura are very small (typically 0.7 mm in length) soil-dwelling Collembola. Until relatively recently, most Mesaphorura were recorded under the name Mesaphorura krausbaueri but following work by Rusek and others, it is clear that there are several species 'hiding' under this name. Mesaphorura atlantica is known only from the type locality, a coal shale tip near Charnock Richard, Lancashire where 218 specimens were collected by F.R. Moore in the 1970s. It was described as a species new to science by Rusek (1979). Unfortunately, the two paratypes which Rusek placed in the NHML collection are missing and I have not been able to examine any specimens.
     Mesaphorura atlantica is similar to Mesaphorura sylvatica. However, Mesaphorura atlantica does not possess dorsal pseudocelli (PSO) on the second thoracic segment (th2), or on the first abdominal segment (abd1) 'quite unique in the genus Mesaphorura' according to Rusek (1979) in his original description.
     The dorsal PSO formula of Mesaphorura atlantica is 11/001/00001 (Confusingly, in Fig. 2 of Rusek's (1979) paper, PSO are not shown on abd5). Other diagnostic characters include five setae in tibiotarsal 'B' ring, seta a2 absent on th3, distance between p1 setae on abd4 shorter than the distance between the p2 setae, seta m0 on abd4 absent, only 2+2 short setae on abd5 between the long a4 setae, and anal setae l2' present.
     The status of Mesaphorura atlantica needs to be clarified.

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