Irschick D J, Jayne B C
Department of Biological Sciences, University of Cincinnati, Cincinnatti, OH 45221-0006, USA.
J Exp Biol. 1998 Jan;201(Pt 2):273-87. doi: 10.1242/jeb.201.2.273.
We examined the effects of incline on locomotor performance and kinematics in two closely related species of iguanian lizards that co-occur in sandy desert habitats. Callisaurus draconoides differs from Uma scoparia of equal snout-vent length by being less massive and having greater limb and tail lengths. We analyzed high-speed video tapes of lizards sprinting from a standstill on a sand-covered racetrack which was level or inclined 30 degrees uphill. C. draconoides sprinted significantly faster than U. scoparia on both level and uphill sand surfaces, although U. scoparia is considered to be more specialized for sandy habitats. Initial accelerations (over the first 50 ms) did not differ significantly either between species or between inclines within species. Overall, the effects of incline were more pronounced for C. draconoides than for U. scoparia. For example, the incline caused a significant decrease in the maximum stride length of C. draconoides but not in that of U. scoparia. For C. draconoides, uphill stride durations were significantly shorter than on the level surface, and this partially compensated for the effects of shorter uphill stride lengths on velocity. C. draconoides ran bipedally more often than did U. scoparia on both the level and uphill surfaces.
我们研究了坡度对两种同域分布于沙质荒漠栖息地的亲缘关系密切的鬣蜥科蜥蜴运动表现和运动学的影响。在吻肛长度相同的情况下，丽纹龙蜥（Callisaurus draconoides）与沙氏强棱蜥（Uma scoparia）相比，体型较小，四肢和尾巴更长。我们分析了蜥蜴在覆盖沙子的水平或30度上坡的跑道上从静止状态开始冲刺的高速录像带。尽管沙氏强棱蜥被认为更适应沙质栖息地，但丽纹龙蜥在水平和上坡沙质表面的冲刺速度都明显快于沙氏强棱蜥。在种间或种内不同坡度之间，初始加速度（前50毫秒内）均无显著差异。总体而言，坡度对丽纹龙蜥的影响比对沙氏强棱蜥更为显著。例如，坡度导致丽纹龙蜥的最大步幅显著减小，但对沙氏强棱蜥没有影响。对于丽纹龙蜥来说，上坡时的步幅持续时间明显短于水平表面，这部分弥补了上坡时较短步幅对速度的影响。在水平和上坡表面，丽纹龙蜥双足奔跑的频率都高于沙氏强棱蜥。
