LOCOMOTOR ANALYSIS OF SURFACE PROPULSION BY 3 SPECIES OF REDUCED-LIMBED FOSSORIAL LIZARDS (LERISTA, SCINCIDAE) FROM WESTERN-AUSTRALIA

The relatively large, but superficially similar, Lerista macropisthopu s, L. connivens, and L. lineopunctulata differ in bodily elongation an d limb reduction, inhabit sandy areas, and move under sand. Visual ana lysis and computer-generated excursion and curvature graphs show that each species moves differently on smooth and rough surfaces, on surfac es with and without nails, and in channels. The reduced-limbed quadrup ed, Lerista macropisthopus walks frequently, using its four clawed lim bs, whenever traction is available. Its undulating body curves uniform ly but never generates slide-pushing curves. The biped L. connivens wa lks with its hindlimbs, although less frequently, and/or oscillates it s tail in propelling its relatively stiff, short body. The biped L. li neopunctulata rarely uses its hindlimbs but always undulates body and tail. It can use single nails in cam-follower progression. L. macropis thopus and L. connivens walk well in channels with rough bottoms, but only L. lineopunctulata uses tunnel concertina to travel in channels w ith smooth bottoms. Friction of body surfaces dragged and of those tra nsmitting propulsive forces is critical to these lizards and explains the division of movement into slow and rapid progression rates. Animal s that have clawed limbs, no matter how reduced, use them. Body and ta il generally are used differently. The tail may be flipped anteriorly to facilitate concertina. In nail arrays, travel is by simple, never b y lateral, undulation. Apparently distinct motor coordination patterns are associated with differences in morphology, habit, and habitat. (C ) 1994 Wiley-Liss, Inc.