In a Miocene sand quarrel of Bavaria I found some compound leaves, where the distal leaflet of an alternating arranged compound leaf seems not to arise from the petiole but from the midrib within or at the base of the bigger terminal leaflet. Its blade is asymmetrically reduced on this side. Leaf margin has spiny little teeth.

If it would be just one indiviudal, I would think: just overlapping of different leaves, but there are several and allways they seem to be connected.

Does anybody know, in which extant plant group such construction might be present?