Javier Ruiz, Federico Mansilla, J. Arsuaga, Elena Santos, A. Jiménez‐Díaz, I. Egea-González
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引用次数: 0
摘要
自1978年在Laetoli发现的古人类足迹化石以来,一直是人们对足迹制造者(名义上的南方古猿阿法种)的运动、速度、体型和行为进行广泛研究的焦点。在这项工作中,我们展示了对行走速度和位移的仔细检查,可以获得关于个体之间相互作用的有价值的信息,以及制造足迹的人类的群体行为。首先,我们使用合适的足迹长度/身高比计算了G和S遗址古人类的身高,得到了1.2至1.6 - 1.7 m的身高。这个范围比金的范围略高。阿法种的骨骼残骸(大约1.1到1.6米),因此表明在Laetoli脚印中可能代表了相对较大的个体。然后,我们根据人类的跨步长度-速度缩放来计算Site G轨迹制造者的速度。步幅和步长是从数字模型中测量的,使用G1和G3脚印的鞋跟区域的最深点作为参考,以及套印G2脚印的拇趾区域的最深点作为参考。负责Site G轨道的古人类都以非常相似的平均速度行走,大约0.8 m s - 1,这比之前一些研究提出的速度要快。G1和G3古人类详细的步间速度计算表明,在仅仅几米的距离内,行走速度变化很大(高达1.5倍),可能是由于地表条件或行为原因。G1和G3古人类的质心沿着被检查的轨道部分描画出非常相似的轨迹。因此,所有G遗址的足迹制造者似乎都是一起移动的:G1和G3古人类是平行走过莱托里灰烬的,G2古人类紧随其后。
The speed and displacement of the Laetoli Site G track-maker hominins
Abstract Since their discovery in 1978, the hominin fossil footprints from Laetoli have been the focus, of extensive research on the locomotion, speed, body size, and behavior of the responsible track-makers (nominally Australopithecus afarensis). In this work, we show that careful examination of walking speed and displacement yields valuable information regarding the interaction between individuals, as well as group behavior of the track-maker hominins. First, we calculate statures for the Site G and S hominins using appropriate footprint length/stature ratios, obtaining statures ranging from 1.2 to 1.6 − 1.7 m. This range is somewhat taller than that proposed for Au. afarensis from skeletal remains (roughly 1.1 to 1.6 m), thus suggesting that comparatively large individuals are possibly represented in the Laetoli footprints. We then calculate speeds for the Site G track-makers from a stride length-speed scaling for humans. Stride and step lengths are measured from a digital model using the deepest point on the heel area of the G1 and G3 footprints as reference, and the deepest point on the hallux area for the overprinted G2 footprints. The hominins responsible for the Site G trackways all walked at a very similar mean speed, around 0.8 m s−1, which is faster than the speeds proposed by some previous studies. Detailed step-to-step speed calculations for G1 and G3 hominins show that the walking speed varied substantially (up to a factor of 1.5) over distances of just a few meters, perhaps due to surface conditions or behavioral reasons. The centers of mass of the G1 and G3 hominins traced very similar trajectories along the trackway portion examined. Thus, all Site G track-makers appear to have been moving together: the G1 and G3 hominins walked over the Laetoli ashes together in parallel, following behind the G2 hominin.
期刊介绍:
The foremost aim of Ichnos is to promote excellence in ichnologic research. Primary emphases center upon the ethologic and ecologic significance of tracemaking organisms; organism-substrate interrelationships; and the role of biogenic processes in environmental reconstruction, sediment dynamics, sequence or event stratigraphy, biogeochemistry, and sedimentary diagenesis. Each contribution rests upon a firm taxonomic foundation, although papers dealing solely with systematics and nomenclature may have less priority than those dealing with conceptual and interpretive aspects of ichnology. Contributions from biologists and geologists are equally welcome.
The format for Ichnos is designed to accommodate several types of manuscripts, including Research Articles (comprehensive articles dealing with original, fundamental research in ichnology), and Short Communications (short, succinct papers treating certain aspects of the history of ichnology, book reviews, news and notes, or invited comments dealing with current or contentious issues). The large page size and two-column format lend flexibility to the design of tables and illustrations. Thorough but timely reviews and rapid publication of manuscripts are integral parts of the process.