(278FOspi) Folsomia spinosa (Kseneman, 1936 )

*montigena Stach, 1946


Folsomia spinosa is moderately common and is probably widespread. It is white with scattered pigment, has 0+0 ocelli and reaches a maximum length of 1.1 mm. The body setae are numerous and long; the ratio of the length of the longest setae at the tip of the abdomen/length of mucro is between 4.0 and 4.5. The manubrium has 4+4 (rarely 4+3) apical ventral (anterior) setae with 3+3 in a transverse row and 1+1 above (Fig. 1). The dens has 12-14 ventral (anterior) setae and 4 dorsal (posterior) setae. The PAO is narrow and is about the same length as, or slightly longer than, the width of ant1 (Fig. 2). In well-cleared specimens of Folsomia penicula, the 2+2 ocelli may be difficult to resolve (especially the posterior pair) and care should be taken not to confuse this species with Folsomia spinosa.

 

 

Fig. 1: Folsomia spinosa collected from Wylye, Wilts by Harold Gough in September 1967. The manubrium (ma) has 4+4 (rarely 4+3) apical ventral (anterior) setae with 3+3 in a transverse row and 1+1 above (*). d, dens.

Fig. 2: Folsomia spinosa collected from 'Yorks.' (no locality information so not possible to map) in 1968 by B. Lasebakin. The post-antennal organ (PAO) is slightly longer than the width of ant1.

 
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