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New cranium, same old evolutionary ambiguities

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Editors’ note: this article uses technical anatomical terms. The take-home message is that this new find does not in any way contribute to a believable story of human evolution from the apes.

The media has been drooling over a newly reported australopithecine fossil cranium alleged to be an ‘ape-man’ (i.e., hominin) in our family tree. However, the evidence is strongly against the australopithecines being a human ancestor. This latest find, of a cranium labelled MRD-VP-1/1, and attributed to Australopithecus anamensis, provides no new evidence that the australopithecines were anything more than an extinct apish primate group.

 Ghedoghedo (via Wikimedia) CC-BY-SA 4.0.Australopithecus-anamensis
Figure 1: Casts of some of the fossil remains from Kenya attributed to Australopithecus anamensis, including the humerus KNM-KP 271 (top-center) and the tibia KNM-KP 29285 (bottom).

Background

In 1995, Meave Leakey et al. found a new hominid species they called Australopithecus anamensis. Dental, cranial and postcranial specimens from two separate localities, Kanapoi and Allia Bay, in Kenya, were said to be dated to 3.9–4.2 mya (million years ago).1 Most of the fossil scraps undoubtedly came from an extinct apish primate, but it was claimed that the tibia (i.e. shin bone) (KNM-KP 29285; see Figure 1) showed features indicating bipedalism, and that the distal humerus (i.e. lower end of the upper arm) (KNM-KP 271) had “many derived hominid features”.2 The humerus was actually discovered in 1965, and described by Patterson and Howells in 1967.3 The anamensis KNM-KP 271 humerus is said to lack a deep, oval hollow, used as a locking mechanism between the humerus and ulna (i.e. one of the lower arm bones), which is present in chimpanzees, but not in humans, suggesting anamensis was not a knuckle-walker.4 The anamensis KNM-KP 29285 tibia is described as wide, like in humans, because of extra spongy tissue, and thought to act as shock absorbers during bipedal locomotion.5

Peter LineAustralopithecus-afarensis-skull
Figure 2: A cast of an Australopithecus afarensis skull (AL 444-2; believed to be of a male) from Hadar, Ethiopia.

In 1998 additional finds of fossil scraps (including teeth, cranial pieces, a capitate [the largest of the carpal bones, situated at the base of the palm of the hand], a proximal hand phalanx, pieces of a mandible, and a maxilla) from anamensis were reported.6 Of note, the proximal hand phalanx (KNM-KP 30503) was said to be similar to specimens from the Hadar Australopithecus afarensis sample, exhibiting the same degree of curvature.7 In a 1999 article, co-authored by Meave Leakey, anamensis is said to be very similar to Australopithecus afarensis postcranially, with the humerus, tibia, and radius described as “almost exactly matched in size and morphology to the A. afarensis collections from Hadar.”8 Also, a 2000 analysis of fossil radii attributed to afarensis (AL 288-1) and anamensis (KNM-ER 20419) indicated that they both had “specialized wrist morphology associated with knuckle-walking.”9

Another wave of anamensis fossil scraps were published in 2006, from the Middle Awash region of northeastern Ethiopia, by a long list of authors headed by well-known paleoanthropologist Tim White.10 The fossil bones included craniodental and postcranial remains. White et al. claimed that the Middle Awash anamensis was “anatomically intermediate in many characters between the earlier Ar. [Ardipithecus] ramidus and the later A. afarensis from the same study area”.11 However, it appears not so much the anatomy, but more the timing—that is, fossils are found supposedly ‘dated’ between ramidus and afarensis (see Figure 2) finds, and so they search for ways to describe anatomical characters as ‘intermediate’ between the two species. It is all based on the assumption of evolution and the alleged age-date of the fossils, and so gets back to the fact that a person’s worldview determines how these fossils are interpreted.

Further fossil remains attributed to anamensis were published, without much fanfare, in 2013 and 2017.12,13 However, the most recent find, of a cranium (see Figure 3),14 has really put anamensis on the center stage. In the Nature paper (published 28 August 2019) by Haile-Selassie et al., the anamensis cranium (MRD-VP-1/1; referred to as MRD), discovered in 2016, from Woranso-Mille, Ethiopia, thought to be of an adult male, is described as “nearly complete” and ‘dated’ to 3.8 mya.15 The preliminary estimate of cranial capacity was a smallish 365 to 370 cc (cubic centimeter), with the MRD cranium described as having pronounced postorbital constriction, similar to Sahelanthropus tchadensis and Ardipithecus ramidus.16 According to the authors the MRD cranium is assigned “to A. anamensis on the basis of the taxonomically and phylogenetically informative morphology of the canine, maxilla and temporal bone.”15 They note that the shape of the neurocranium viewed superiorly “has notable similarities to that of S. tchadensis”, but that “aspects of the mid- and upper face show clear affinity to A. afarensis.”16

 Dale Omori, Cleveland Museum of Natural History.MRD-VP-1
Figure 3: The MRD-VP-1/1 cranium was discovered in Ethiopia in 2016 and assigned to the species Australopithecus anamensis.

The authors also stated that they “demonstrate that A. anamensis and Australopithecus afarensis differ more than previously recognized and that these two species overlapped for at least 100,000 years—contradicting the widely accepted hypothesis of anagenesis.”15 That there is a lot of confusion concerning species in the genus Australopithecus is illustrated by the authors statement, as follows:

“Furthermore, the fact that MRD shares some neurocranial and facial morphological features with younger taxa such as A. africanus and Paranthropus—albeit considered here to be more likely to have been caused by parallel evolution—is worth further investigation in the future, as it may have considerable bearing on the origin of A. africanus and its relationship with A. afarensis.”17

Whenever ‘parallel evolution’ is invoked, as above, it indicates serious problems with the evolutionary scenario. On this, paleoanthropologist Fred Spoor comments:

“The new fossil has several features that are assumed by the authors to be derived rather than primitive. Most striking is the forward projection of the cheek bones, which creates a facial appearance reminiscent of much younger Paranthropus hominin species, particularly the 2.5-million-year-old Paranthropus aethiopicus. The authors conclude that this facial characteristic evolved independently in A. anamensis and later species, but the resemblance might inspire alternative interpretations.”18

That evolutionists have little confidence in the supposed hominin (or hominid) family tree is evidenced by some of the reactions to the new find. Writing in Nature, Colin Barras wrote that the “Ancient cranium discovered in Ethiopia suggests early hominin evolutionary tree is messier than we thought.”19 In Science, Michael Price’s article had the headline “Stunning skull shakes human family tree”.20 Michael Marshall commented that “the A. anamensis skull does strengthen the case that several older fossils really are hominins, and not dead-end lineages of apes as has sometimes been suggested.”21 If they were not sure about their ‘hominin’ status before the latest find, which, if anything, appears to have made things even messier, one wonders how the latest cranium could have made them less unsure. Most likely, they were all extinct apish primates.

The question of how bipedal anamensis was, or how bipedal any of the other australopithecines were, is open to debate. Evidence indicates that they were likely better designed for bipedalism than extant apes. However, being capable of limited non-human bipedal locomotion does not indicate it was a hominin (a relative of mankind). Consider that, according to evolutionist Charles Oxnard, the australopithecines were unique and differed “more from both humans and African apes, than do these two living groups from each other.”22 He went on to conclude that:

“For instance, though bipedal, it is likely that their bipedality was mechanically different from that of humans. Though terrestrial, it is further likely that these fossils were accomplished arborealists. The combination of the two functions within the same set of creatures is certainly unique among hominoids.”22

From a creation viewpoint, the simplest explanation may be that the finds labeled Australopithecus anamensis simply represent variation within the genus Australopithecus, and that many of the species included in this genus, like anamensis, Australopithecus afarensis and Australopithecus africanus, as well as many fossil specimens attributed to Homo habilis, represent extinct apish primates derived from the same biblical kind. As indicated by Oxnard above, they were not like extant apes, and had their own unique attributes, including locomotion both different from humans and extant apes. They appear to also have been very diverse in morphology. Whether they represent more than one biblical kind is also an open question.

Writing for the BBC, Pallab Ghosh mentions the irritation of anthropologists, including a senior editor at Nature, when the term "missing link" is used to describe a fossil they believe to be “part-ape and part-human.”23 One of the chief reasons for the editor’s irritation is said to be “the recognition that there are many links in the chain of human evolution and most if not nearly all of them are still missing.”23 Ghosh goes on to state that “Anamensis is the latest in a string of recent discoveries that shows that there was no smooth line of ascent to modern humans.”23

More than that, I would say that anamensis indicates there was no evolutionary ascent at all by these extinct primates.

Published: 6 September 2019

References and notes

  1. Leakey, M.G. et al., New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya. Nature, 376:565-571, 1995. Return to text.
  2. Leakey et al., ref. 1, p. 566. Return to text.
  3. Patterson, B. and Howells, W.W., Hominid humeral fragment from early Pleistocene of Northwest Kenya. Science, 156:64-66, 1967. Return to text.
  4. Leakey, M. and Walker, A., Early hominid fossils from Africa. Scientific American, 276(6):62-63, June 1997. Return to text.
  5. Leakey and Walker, ref. 4, pp. 63-64. Return to text.
  6. Leakey, M.G.et al., New specimens and confirmation of an early age for Australopithecus anamensis. Nature, 393:62-66, 1998. Return to text.
  7. Leakey et al., ref. 6, p. 65. Return to text.
  8. Ward, C., Leakey, M. and Walker, A., The new hominid species Australopithecus anamensis. Evolutionary Anthropology, 9:201, 1999. Return to text.
  9. Richmond, B.G. and Strait, D.S., Evidence that humans evolved from a knuckle-walking ancestor. Nature, 404:382, 2000. Return to text.
  10. White, T.D. et al., Asa Issie, Aramis and the origin of Australopithecus. Natur e, 440:883-889, 2006. Return to text.
  11. White et al., ref. 10, p. 888. Return to text.
  12. Ward, C.V. et al., New fossils of Australopithecus anamensis from Kanapoi, West Turkana, Kenya (2003-2008). Journal of Human Evolution, 65:501-524, 2013. Return to text.
  13. Ward, C.V. et al., New fossils of Australopithecus anamensis from Kanapoi, West Turkana, Kenya (2012-2015). Journal of Human Evolution, 23 August 2017; dx.doi.org/10.1016/j.jhevol.2017.07.008. Return to text.
  14. Haile-Selassie, Y. et al., A 3.8-million-year-old hominin cranium from Woranso-Mille, Ethiopia. Nature, 28 August 2019; doi.org/10.1038/s41586-019-1513-8. Return to text.
  15. Haile-Selassie, Y. et al., ref. 14, p. 1. Return to text.
  16. Haile-Selassie, Y. et al., ref. 14, p. 5. Return to text.
  17. Haile-Selassie, Y. et al., ref. 14, pp. 5-6. Return to text.
  18. Spoor, F., Elusive cranium of early hominin found. Nature, 28 August 2019; doi.org/10.1038/d41586-019-02520-9. Return to text.
  19. Barras, C., Rare 3.8-million-year-old skull recasts origins of iconic ‘Lucy’ fossil. 28 August 2019; nature.com/articles/d41586-019-02573-w. Return to text.
  20. Price, M., Stunning skull shakes human family tree. Science, 365:850, 2019. Return to text.
  21. Marshall, M., We've finally found a skull from one of our most important ancestors. 28 August 2019; newscientist.com/article/2214670-weve-finally-found-a-skull-from-one-of-our-most-important-ancestors/ Return to text.
  22. Oxnard, C. E., Fossils, Teeth and Sex: New Perspectives on Human Evolution. Hong Kong University Press, Hong Kong, p. 227, 1987. Return to text.
  23. Ghosh, P., 'All bets now off' on which ape was humanity's ancestor, 28 August 2019; bbc.com/news/science-environment-49486980. Return to text.