Connecting elements for panels and panel covering assemblies

1) Connecting element for panels (11, 12) comprising a flange (19) having a presser (19′) at a first end, a first longitudinal seat (20a) for receiving and engaging an enlarged-head extension (13) of a first panel (11) in an intermediate portion, and an enlarged base (28) at a second end, said first longitudinal seat (20a) being open in an area adjacent to said flange and delimited, besides by said flange (19) also by a first lateral wall (22) opposite to said flange (19) and by a first base wall (25) for connecting said first lateral wall (22) with said flange (19), said enlarged base (28) defining with a first projection (29), which extends from a first end thereof towards said first base wall (25), a first longitudinal channel (20b) delimited by said flange (19), said first base wall (25), said enlarged base (28) and said first projection (29), said first base wall (25) extending in the direction orthogonal to said flange (19) at least over a section equivalent to the distance between said flange (19) and said first projection (29), said first base wall (25) being substantially orthogonal to said flange (19), said first lateral wall (22) being substantially orthogonal to said first base wall (25) and parallel to said flange (19), said enlarged base (28) being substantially orthogonal to said flange (19), said first projection (29) being substantially orthogonal to said enlarged base (28) and parallel to said flange (19), said first projection (29) being substantially flushed (F1) with said first lateral wall (22), provided for being means (24) for snap-holding said enlarged-head extension (13) inserted into said first longitudinal seat (20a), said snap-holding means (24) operating at contact—only at the upper part—with said enlarged-head extension (13) and being provided on the upper end of said first lateral wall (22).