OH 5

OH 5
OH 5 can also refer to Ohio's 5th congressional district or to Ohio State Route 5.
Zinj or Nutcracker Man
Zinj or Nutcracker Man
Catalog number OH 5
Common name Zinj or Nutcracker Man
Species Paranthropus boisei
Age 1.75 mya
Place discovered Olduvai Gorge, Tanzania
Date discovered July 17, 1959
Discovered by Mary Leakey


OH 5 (Olduvai Hominid number 5, also known as Zinjanthropus or "Nutcracker Man"; colloquially as "Dear Boy"[1]) is a fossilized cranium and the holotype of the species Paranthropus boisei. It was discovered in Olduvai Gorge, Tanzania, by archaeologist-paleontologist Mary Leakey in 1959. Her husband and fellow scientist Louis Leakey initially classified the hominid as Zinjanthropus boisei and thought that it was an early ancestor of modern humans that lived approximately 2 million years ago. However, this contention was later withdrawn because of its robust australopithecine features and the discovery of Homo habilis soon thereafter.

Contents

Discovery

Mary and Louis Leakey had conducted excavations in Tanzania since the 1930s, though most such work was postponed due to the outbreak of World War II. They returned in 1951, finding mostly ancient tools and fossils of extinct mammals for the next few years.[2] On the morning of July 17, 1959, Louis felt ill and stayed at camp while Mary went out to Bed I's Frida Leakey Korongo (korongo is Swahili for gully; this one was named after Louis's ex-wife).[3] Sometime around 11:00 a.m., she noticed a piece of bone that "seemed to be part of a skull" which had a "hominid look".[4] After dusting some topsoil away and finding "two large teeth set in the curve of a jaw", she drove back to camp exclaiming "I've got him!"[5] They created a pile of stones around the exposed portion of the fossil to protect it from the weather.[6] Active excavation began the following day; they had chosen to wait for photographer Des Bartlett to arrive so that a photographic record of the entire process of removal could be made.[6] A partial cranium was fully unearthed August 6, though it had to be reconstructed from its fragments which were scattered in the scree.[7]

Once he had examined the cranium, Louis determined it to be subadult, or adolescent, based on its dentition, and he and Mary began to call it "Dear Boy".[8] He also believed that it was of a species ancestral to modern humans but a member of the subfamily Australopithecinae.[9] In describing the fossilized hominid in his journal, Louis initially considered the classification Titanohomo mirabilis (wonderful Titan-like man),[10] but he eventually dubbed their find Zinjanthropus boisei (East Africa man). Zinj is an ancient Arabic word for the East African coast; anthropus refers to the fossil's humanlike characteristics; and boisei refers to Charles Boise, who had been making financial contributions to the Leakeys' work since 1948.[11] This classification was eventually revised to Paranthropus boisei, though this remains a matter of contention since the genus Paranthropus is disputed because of morphological similarities to Australopithecus.[12] In either case, OH 5 is the holotype of its species.[13]

Analysis

Louis wrote "A new fossil skull from Olduvai" for Nature the week following the excavation, detailing the titular find and the "living floor" of Bed I which was replete with fossils of other mammalian fauna.[14] "The Newest Link in Human Evolution: The Discovery by L.S.B. Leakey of Zinjanthropus Boisei", his account of the dig, was published in the January 1960 issue of Current Anthropology. It was annotated by anthropologist Francis Clark Howell, who had been allowed to examine the Leakeys' Olduvai findings before public announcements of their discovery.[15] Louis also wrote "Finding the World's Earliest Man" for the September 1960 issue of National Geographic, estimating the fossil's age to be 600,000 years old.[16] University of California, Berkeley, geochemists Garniss Curtis and Jack Evernden used potassium-argon dating to re-assess the site, finding that Olduvai's Bed I was actually about 1.75 million years old.[17] Such an application of geochronology was unprecedented; OH 5 became the first hominin to be dated by that method.[18] The same process was used for OH 7, the holotype of Homo habilis (handy man).[18]

External images
Zinj on display at the National Museum of Tanzania.

After the cranium was reconstructed with a model of the absent mandible, contemporaneous newspapers referred to it as "Nutcracker Man" due to the large posterior teeth and jaws which gave it a resemblance to vintage nutcrackers.[19] Phillip Tobias, a colleague of the Leakeys, has also received attribution for this nickname.[20] Primitive tools fashioned out of rocks and bone were excavated at and around Olduvai's Bed I, sometimes called the FLK Zinjanthropus site since the finding of OH 5.[21] Louis initially believed P. boisei to be a direct ancestor of modern humans (as evident from the title of his National Geographic article) and the maker of those tools found near its remains, but he withdrew this idea once he and Mary unearthed Homo habilis – which had a larger brain[22] – in the same area less than two years later.[23] Despite that, OH 5 made the Leakeys famous and brought more attention to the developing field of paleoanthropology.[24] The cranium was taken to Kenya after its discovery and was there until January 1965 when it was placed on display in the Hall of Man at the National Museum of Tanzania in Dar es Salaam.[25] It remains there as of 2009, still recognized by the name Zinjanthropus, or simply Zinj.[25]

Debate over diet

In a Tuesday, May 3, 2011, online news story article from Washington, D.C. by Randolph E. Schmid, of AOL News and the Huffington Post, it was revealed that "Nutcracker Man didn't eat nuts after all. After a half-century of referring to an ancient pre-human as "Nutcracker Man" because of his large teeth and powerful jaw, scientists now conclude that he actually chewed grasses instead. The study "reminds us that in paleontology, things are not always as they seem," commented Peter Ungar, chairman of anthropology at the University of Arkansas. The new report, by Thure E. Cerling of the University of Utah and colleagues, is published in Tuesday's edition of the National Academy of Sciences. Cerling's team analyzed the carbon in the enamel of 24 teeth from 22 individuals who lived in East Africa between 1.4 million and 1.9 million years ago. One type of carbon is produced from tree leaves, nuts and fruit, another from grasses and grasslike plants called sedges. It turns out that the early human known as Paranthropus boisei did not eat nuts but dined more heavily on grasses than any other human ancestor or human relative studied to date. Only an extinct species of grass-eating baboon ate more, they said."

Notes

  1. ^ Cela-Conde & Ayala, 158; Lewin & Foley, 235; Morrell, 183.
  2. ^ Mary Leakey, My Search, 52–53, 83; Lewin & Foley, 234.
  3. ^ Bowman-Kruhm, 66; Mary Leakey, Excavations, 227; Morrell, 180–181.
  4. ^ Mary Leakey, My Search, 75.
  5. ^ Morrell, 181.
  6. ^ a b Mary Leakey, Excavations, 227.
  7. ^ Cela-Conde & Ayala, 158; Morrell, 183–184.
  8. ^ Cracraft & Donoghue, 524; Deacon, 56; Morrell, 183–184.
  9. ^ Cela-Conde & Ayala, 158; Johanson, Edgar & Brill, 156
  10. ^ Johanson, Edgar & Brill, 156; Morrell, 183.
  11. ^ Louis Leakey, "A new fossil skull from Olduvai", 491; Morrell, 185–186.
  12. ^ Bowman-Kruhm, 67; Cela-Conde & Ayala, 158; Cracraft & Donoghue, 524; Deacon, 56.
  13. ^ Cela-Conde & Ayala, 158.
  14. ^ Louis Leakey, "A new fossil skull from Olduvai", 491–493.
  15. ^ Louis Leakey, "The Newest Link in Human Evolution", 76–77.
  16. ^ Louis Leakey, "Finding the World's Earliest Man", 421–435; Morrell, 196.
  17. ^ Boaz, 17; Cela-Conde & Ayala, 159; Richard Leakey, 49; Morrell, 196.
  18. ^ a b Dunsworth, 79; Lewin & Foley, 235.
  19. ^ Cachel, 48.
  20. ^ Bowman-Kruhm, 66.
  21. ^ Cachel, 48; Mary Leakey, My Search, 52–53, 74; Spencer, 610.
  22. ^ Wilkins & Wakefield, 161–226.
  23. ^ Lewin & Foley, 235; Spencer, 610.
  24. ^ Bowman-Kruhm, 66; Johanson, Edgar & Brill, 158.
  25. ^ a b Staniforth, 155.

References

  • Boaz, Noel (1998). Quarry Closing In On the Missing Link. New York: Simon & Schuster. ISBN 0684863782. 
  • Bowman-Kruhm, Mary (2005). The Leakeys: A Biography. Greenwood Publishing Group. ISBN 0313329850. 
  • Cachel, Susan (2006). Primate and Human Evolution. Cambridge: Cambridge University Press. ISBN 0521829429. 
  • Cela-Conde, Camilo; Francisco Ayala (2007). Human Evolution: Trails from the Past. Oxford: Oxford University Press. ISBN 0198567804. 
  • Cracraft, Joel; Michael Donoghue (2004). Assembling the Tree of Life. Oxford: Oxford University Press. ISBN 0195172345. 
  • Deacon, Jeanette (1999). Human beginnings in South Africa. Rowman Altamira. ISBN 0761990860. 
  • Dunsworth, Holly (2007). Human Origins 101. Greenwood Publishing Group. ISBN 0313336733. 
  • Johanson, Donald; Blake Edgar (1996). From Lucy to Language. Principal photography by David Brill. New York: Simon & Schuster. ISBN 0684810239. 
  • Leakey, Louis (August 1959). "A new fossil skull from Olduvai". Nature 184 (4685). Bibcode 1959Natur.184..491L. doi:10.1038/184491a0. ISSN 00280836. 
  • ——— (September 1960). "Finding the World's Earliest Man". National Geographic 118 (3). ISSN 00279358. 
  • ——— (January 1960). "The Newest Link in Human Evolution: The Discovery by L.S.B. Leakey of Zinjanthropus Boisei". Current Anthropology 1 (1). ISSN 15375382. 
  • Leakey, Mary (1965). Olduvai Gorge. 3: Excavations in Beds I & II, 1960–1963. London: Cambridge University Press. ISBN 0521077230. 
  • ——— (1979). Olduvai Gorge: My Search for Early Man. London: Collins. ISBN 0002116138. 
  • Leakey, Richard (1983). One Life. London: Michael Joseph. ISBN 071812247X. 
  • Lewin, Roger; Robert Foley (2004). Principles of Human Evolution (2 ed.). Wiley-Blackwell. ISBN 0632047046. 
  • Morrell, Virginia (1995). Ancestral Passions: The Leakey family and the Quest for Humankind's Beginnings. New York: Simon & Schuster. ISBN 0684824701. 
  • Spencer, Frank (1997). History of Physical Anthropology. Taylor & Francis. ISBN 0815304900. 
  • Staniforth, Amy (March 2009). "Returning Zinj: curating human origins in twentieth-century Tanzania". Journal of East African Studies 3 (1). ISSN 17531055. 
  • Wilkins, Wendy & Wakefield, Jenny (1995). "Brain evolution and neurolinguistic preconditions". Behavioral and Brain Sciences 18 (1). ISSN 0140525X. 

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