|Fig. 1 Large theropod track from the Early Jurassic.|
It should come as no surprise that dinosaur tracks are known from thousands of sites across the globe. After all, an individual dinosaur left hundred of thousands of footprints throughout its life but had only one skeleton to contribute to the fossil record. Many dinosaur sites, when discovered, have bone exposed just as fragments or as a ghostly cross section visible in a rock outcrop. Such subtle clues are not easy to see or make sense of. However, footprints are often more easily recognized. True, footprints can be distorted and poorly preserved, especially when the animal was walking on a wet, muddy substrate. But often fossil tracks are easy to see, even if you are not a paleontologist. Indeed, the late paleoichnologist W.A.S. Sarjeant surmised that fossil footprints were probably recognized as being made by animals well before fossil bones were recognized as the remains of animals (1)
Lida Xing and his colleagues, and his colleagues Adrienne Mayor, Yu Chen, Jerry Harris, and Mike Burns, have recently published a very interesting and enlightening review of Chinese folklore as it relates to dinosaur tracks and how such myths might help in paleontological prospecting (see link at ref 2 for free pdf of this paper). The paper focuses on eight localities scattered across the country. The Chinese written record of ‘dragon bones”, (i.e. fossil bone, most often of mammals) used for medicinal purposes go back as far as the 3rd century BC. However, fossil bone is more transient because it is fragile and easily destroyed by erosion. Fossil footprints are often less susceptible to such damage and are often visible in large numbers on extensive surface exposures. The authors suggest that because of this difference fossil tracksites can remain exposed for long periods of time and be seen by many generations of people. Hence it is not surprising that myths would arise in prescientific cultures to explain these striking features.
|Fig 2 Examples of theropod tracks associated with the various bird legends in China (not to scale).|
These three toed footprints are usually made by bipedal theropod (carnivorous) dinosaurs. They are strikingly bird-like in appearance (not unexpected since birds are direct descendents of small maniraptoran theropods) so it is not surprising that the myths surrounding them attribute them to birds. In China they go under a variety of names -- “Divine Birds”, “Feng Huang tracks (a giant Phoenix mythological bird), “Golden Chicken” and “Heavenly Chicken”. At one locality, the deeply impressed tracks were thought to have been impressed directly into the rock, suggesting something supernatural. Today funeral processions progress along the trackway in the belief that this guides the dead to heaven. (2)
|Fig 3 Lianhua Baozhai footprint site and rock building on an eroded surface cut into the cliff face.|
The large herbivorous hadrosaur dinosaurs left three toed tracks but with a different look than the elegant tracks of theropods. Hadrosaur tracks have thick blunt toes and a broad rounded heels. At the Lianhua Baozhai site the hadrosaur tracks were thought to be lotus petals, while fossil mudcracks with the tracks were interpreted as the veins of lotus leaves. Ripple marks on the rock surface reinforced a watery environment for these impressions and help lead to the interpretation of the footprints as lotus plant remains. The fossil site is located in the middle of a cliff face next to a rock shelter built in 1256 with an associated Chinese inscription. The lotus symbolizes purity in many Asian cultures and the translation of “Lianhua Baozhai” is “The mountain stronghold protected by lotus.” (2, 3)
Fig 4 Lianhua Baozhai.
|Fig 5 Lotus petal shaped hadrosaur tracks on the overhang at Lianhua Baozhai.|
The gigantic sauropod dinosaurs have a foot structure quite different from that of theropods and, not surprisingly, leave strikingly different tracks. These dinosaurs are quadrupedal and the hand and foot impressions are often close together. Given the great weight of sauropods their tracks can be deep and somewhat nondescript impressions. In Fushun County a trail of eighteen sauropod tracks are attributed to an ancient tale of a rhinoceros that ascended the mountain to get mushrooms. Counting these tracks is thought to lead to good fortune.(2)
|Fig 6 Sauropod tracks posing as a lucky rhinoceros trackway.|
However, fossil footprint folklore is not restricted to China --- there is a rich tradition from around the world (4). One of the most interesting comes from the coast of Portugal and involves, again, sauropod footprints.
|Fig 7 The Church of Nossa Senhora da Mua at the cliff's edge.|
At Cabo Espichel steeply dipping rocks of Late Jurassic and Early Cretaceous age rise from the sea to form tall cliffs hundreds of feet high along the small bay of Lagosterios. On the top of the cliffs is the Sanctuary of Our Lady of Cape Espichel which dates back to the 15th century. Of most interest to our present story is the Memory Heritage or Church of Nossa Senhora da Mua (Our Lady of the Mule), a small building located away from the rest the Sanctuary at the very edge of the cliff.
|Fig 8. The steeply dipping dinosaur track layers at Cabo Espichel. Arrow point to location of the small white Church of Nossa Senhora da Mua perched precariously at the edge of the cliff.|
The legend underpinning this small building involves two elderly men who lived in separate cities (Caparica and Alcabideche). Both men, on the same night, dreamt that the Virgin Mary appeared on the cliff top astride a giant she-mule. Later, both men went to the site of their shared dream vision and found a miraculous image of Our Lady. Beneath this spot, on the great cliff wall rising out of the ocean, can be seen lines of large depressions and those closest to the church were interpreted as the footprints of the Virgin’s giant mule that she rode out of the ocean and to the top of the cliff. (5)
Inside the Church of Nossa Senhora da Mua is a panel of 18th century painted, tin-glazed, ceramic tiles commemorating the appearance of Our Lady on the mule. The tracks can be clearly seen coming out of the ocean and up the cliff face. However, we now know that these “mule tracks” are not miraculous, but are nevertheless interesting, as they are the footprints of Late Jurassic sauropod dinosaurs. Remarkably, this panel turns out to be the oldest known illustration of dinosaur tracks! (6)
On the cliffs of Lagosterios forty sauropod trackways occur at eight different levels. The sauropod tracks, known in the area as far back as the 13th century, are large and quite visible even from a great distance.
|Fig 10 Stratigraphic column for Cabo Espeichel, showing the positions of the eight sauropod track bearing horizons.|
Although the setting is magnificent, the height of the exposures and the tilt of the beds making accessing and studying the tracks difficult and dangerous. Martin Lockely and his colleagues used ropes, climbing equipment, and bolts to study and map these sites in detail in the mid-1990s (7, 8).
One of the track horizons at Cabo Espichel (level 3) provides evidence of social behavior in sauropods. Here one can see the footprints of seven subadult dinosaurs, all about the same size, traveling close together in the same direction, and evenly spaced. The details of track morphology clearly show that they were made by sauropods and not a small herd of celestial mules.
|Figure 11 Map of track level 3 at Cabo Espichel showing the trackways made by a group of seven juvenile sauropods traveling together. Tracks 8 and 9 are from adults crossing the area earlier.|
|Fig 12. Reconstruction of the juvenile sauropod crossing recorded in level 3 at Cabo Espichel. Note larger adult sauropod trackway already present as the herd crosses the area. That is trackway 8 in fig 11.|
|Fig 13 Edward Hitchcock, the father of the scientific study of dinosaur tracks.|
Although fossil tracks have long been recognized as tracks of some sort, the serious scientific study of dinosaur tracks did not begin until the early 19th century when Congregationalist Minister and geologist Edwin H. Hitchcock (1793-1864) began collecting and describing fossil tracks from the Late Triassic and Early Jurassic rocks of the Connecticut River Valley. Hitchcock amassed an immense and diverse collection of fossil footprints that became part of the museum collections at Amherst University and some of it is still on exhibit today.
|Fig 14 Part of Hitchcock's immense dinosaur track collection as exhibited in the Amherst museum in the 19th century.|
His studies spanned several decades and resulted in three book-length monographs and numerous scientific papers (9, 10, 11). Ironically, when Hitchcock began his studies dinosaurs were not even known to exist. Faced with peculiar tracks, many of which were three toed, he made careful study of foot structure in many different terrestrial vertebrates. After making these comparison Hitchcock reached the conclusion that the tracks were made by (you guessed it) giant birds! (12) Sadly, he never recognized the dinosaurian nature of his discoveries.
For a really great series of photos of the Hitchcock tracks in the collections at Amherst take a moment to visit John McCauley's May 31 2011 post at http://njtntm.blogspot.com/2011/03/amherst-college-beneski-museum-of.html
PhotosFigs 2 (modified), 3, 6: Xing et al (ref 2)
Fig 1: NPS
Figs 4, 5: http://english.cntv.cn/program/cultureexpress/20111027/103571.shtml
Fig 7: http://pt.wikipedia.org/wiki/Ermida_da_Mem%C3%B3ria_%28Sesimbra%29
Fig 8: http://portugalfotografiaaerea.blogspot.com/2011/02/baia-dos-lagosteiros.htmlFig 9: Antuns and Mateus (ref 6)
Fig 10, 11, 12: Lockley et al (ref 7)
Fig 13: http://en.wikipedia.org/wiki/Edward_Hitchcock
Fig 14: http://oficina.cienciaviva.pt/~pw011/jazidas/icnotaxa_teropodes_triassicofinal_jurassicoinicial.html
References(1) Sarjeant, W.A.S. 1997. The Earliest Discoveries. in: Farlow, J.O. and Brett-Surman, M.K. (eds.) The Complete Dinosaur. Indiana Univeristy Press: 3-5.
(2) Xing, L., Mayor, A., Chen, Y. and Harris, J.D. 2011. The folklore of dinosaur trackways in China: impact on paleontology. Ichnos 18:213-220. (copy freely available for download at: http://www.xinglida.net/paper_list.htm)
(3) Xing,L., Mayor, A., and Chen, Y. 2011. Lianhua Baozhai (Lotus Mountain Fortress, Qijiang County of Chongqing City): Direct evidence of co-existing ancient Chinese and dinosaur tracks. Geological Bulletin of China. 30(10): 1530-1537 (copy freely available for download at: http://www.xinglida.net/paper_list.htm)
(4) Mayor, A. and Sarjeant, W.A.S. 2001. The folklore of footprints in stone: from Classical Antiquity to the Present. Ichnos 82: 143-163.
(5) Antunes, M.T. 1976. Dinosauros eocretacicos de Lagosteieros. Lisboa: Universidad de Lisboa.
(6) Antunes M.T. and Mateus, O. 2003. Dinosaurs of Portugal. Comptes Rendus PaleoVol 2: 77-95 (copy freely available for download at http://www.miketaylor.org.uk/tmp/luso.pdf)
(7) Lockley, M.G., Meyer, C.A., and Santos, V.F.d. 1994. Trackway evidence for a herd of juvenile sauropods from the Late Jurassic of Portugal. Gaia 10: 27-25.
(8) Lockley, M. and Meyer, C. 2000. Dinosaur Tracks and Other Fossil Footprints of Europe. Columbia University Press, N.Y.: 323 pages.
(9) Hitchcock, E. 1848. An attempt to discriminate and describe the animals that made the fossil footmarks of the United States, and especially of New England. American Academy of Arts & Sciences Memoir (n.s.) 3:129-256.
(10) Hitchcock, E. 1858. Ichnology of New England: A Report on the Sandstone of the Connecticut Valley, especially its Fossil Footmarks. Commonwealth of Massachusetts: 220 pp.
(11) Hitchcock, E. 1865. Supplement to the Ichnology of New England. Commonwealth of Massachusetts: 96 pp. (copy freely available for download at http://www.ldeo.columbia.edu/~polsen/nbcp/EH1865download.html)
(12) Pick, N. and Ward, F. 2006. Curious Footprints: Professor Hitchcock's Dinosaur Tracks and Other Natural History Treasures at Amherst College. Amherst College Press:121 pages