" ... unfortunately for Creationists, evolution is ... not theory but fact.  Let's face the fact:  We are related to the ape and every other form of life on this planet... Today, creationists [reject this view].... Let's let them crawl back into their caves and leave the explanation of life to true scientists.

G. M. Finniss,  USA Today, Aug. 17, 1985, p 28.
 

J. S. Jones and S. Rouhani  Nature  319, 449, (1986).
 

J. Shreeve, Discover, Sept.  1995, pg 70.
 

Bernard Wood, Nature  355, 783, 1992.
 

M. Wolpoff, Amer. Journal of Phys. Anthrop.  89:402, 1992.

Goals

1. Main characteristics of the key fossil species believed to be related to humans

2. Debate variation within groups versus macroevolutionary transformation

3. Creationist interpretations for robust morphologies in humans

4. Evidences of humans coexisting with australopithicines and for recent erectus-like morphologies

5. Current status in this field

Outline
 

1.  Introduction (main issues, viewpoints)

2.  Characteristics of australopithecines

3.  Characteristics of homo erectus, neanderthals, archaic homo sapiens, etc.

4.  Explanations for robust morphologies in humans

5.  Recent erectus-like fossils

6.  Questions regarding homo habilis

7.  Problems with the orthodox evolutionary sequence

8.  Evidences of humans in "old" deposits

1.  Introduction
 
 
 

The Main Issue:
 
 

microevolution within humans, apes, chimpanzees, others

versus

macroevolutionary transformation from nonhuman ape-like ancester to modern humans, apes, and chimpanzees
 

(similar to the horse "series")
 
 
 

               Hominids-2                                   Hominids-3                                   Hominids-4                                Hominids-5
 

Difficulties in resolving this issue:

1.  Morphology varies within all species

 
a).  Wide variation even among existing or recent apes chimps, and humans

b).  What did apes, chimps, humans, etc. look like in the past?

2.  The majority of species have become extinct
 

3.  Morphology changes during growth:  fossils of infants may not show characteristic features of adults
 

3.  Typically, only pieces and fragments are found.  Some reconstruction is required.
 

4. Humans and chimpanzees share many characteristics
 

5.  Tremendous subjectivity in the interpretation of these fossils
 
 
 
 
 
 
 

 

"Orthodox" evolutionary sequence:
 
 

australopithecus afarensis to australopithecus africanus to

homo habilis to

homo erectus to archaic homo sapiens to modern homo sapiens
 
 
 

  Hominids-6

Creationists and evolutionists largely agree:

australopithecines  -  chimp-like or ape-like

homo erectus, archaic homo sapiens, modern homo sapiens  -  human-like
 

Key:  homo habilis  (large gap between australopithecines and homo erectus)

Potential ways to distinguish between the two paradigms (microevol. within groups versus macroevol.):
 
 

1.  transitionals?      (gap between the australopithecines and homo erectus?)
 

2.  descendants existing before ancestors?
 

3.  ancestors and descendants coexisting for long periods of geological time?

2.  Characteristics of australopithecines
 
 

(afarensis "Lucy", africanus, robustus, boisei, etc., field constantly in flux)
 
 

 Hominids-7                       Hominids-8

a)  Features resembling chimps or apes
 
 

-overall size, skull, brain capacity

"In terms of overall body size, brain size, and skull shape, Lucy resembles a chimpanzee."

Washington State University Webpage

-dentition and faces

 "All the australopithecines developed their dentitions quickly, like apes ...  Bromage found that australopithecine faces are built like ape faces, not human faces."
        Leakey & Lewin, Origins Reconsidered, 1992, pg 156.

"The massive build of the face and the huge teeth bespeak something more along the lines of a gorilla than a human."
        N. Eldredge, speaking of a. africanus in The Miner's Canary, Unravelling the Mysteries of Extinction, (1993), pg 184.
 
 

-shoulder socket orientation (cranially-oriented as in apes)

 
Schmidt of the Anthropological Institute of Zurich pointed  out that because the shoulders are important for arm  swinging and balance, this chimp-like feature does not seem  compatible with efficient bipedality.
        Leakey & Lewin, Origins Reconsidered, 1992, pg 194.

"...would certainly be valuable if the arm were held overhead much of the time, as it is when climbing  and hanging in  trees."
        J. Cherfas, New Scientist  97 172, (1983).
 
 

-rib cage and waist
 

"The chest was the problem.  I noticed that the ribs were more round in cross-section, more like what you see in apes.   Human ribs are flatter ..., but the shape of the rib cage itself (in Lucy) was the biggest surprise of all.  The human rib cage is barrell-shaped, and I just couldn't get Lucy's ribs to fit this kind of shape.  But I could get them to make a conical-shaped rib cage, like what you see in apes.
        Schmidt, Anthropological Institute of Zurich, quoted by Leakey & Lewin, Origins Reconsidered, 1992, pg 193.
 

the new reconstruction of Lucy  "...reveals her to be remarkably chimp-like, particularly in the morphology of the rib cage."
        A. Zihlman, New Scientist, 140, 40, (1984).
 

"He examined the whole trunk, the lumbar region, and the shoulders.  (all of these) are important in human running; the shoulders for arm-swinging and balance, the trunk for balance and breathing, and the waist for flexibility and swinging of the hips.  What you see in Australopithecus is not what you'd want in an efficient bipedal running animal...  the shoulders were high, and combined with the funnel shaped chest, would have made improbable arm-swinging in the human sense.  It wouldn't be able to lift its thorax for the kind of deep breathing that we do... "
        Leakey & Lewin, Origins Reconsidered, 1992, pg 194.

 

-arms
 

New finds  "... complete the image of a waddling, forest- dwelling creature with long, powerful arms, the females lighter and more agile than the males...."
        S. Bunney New Scientist  142, 18, (1994).

 

-hands and fingers

 
"Lucy's fingers are slender and curved ... strong grasping muscles ... (this) hominid is very like modern chimpanzees."
        J. Cherfas New Scientist  97 172, (1983).

b)  Evidence used to argue for human ancestry
 
 

 
-hip joint and pelvis

 Hominids-9                        Hominids-10

-position of Foramen Magnum

c)  Australopithicus afarensis has a strong resemblence to Pygmy Chimpanzees
 

Except for the pelvis, the (pygmy chimpanzee) skeleton shows a striking resemblence to fossils of the earliest hominid, Australopithecus.
        A. Zihlman, Nature 359, 786, (1992).
 

...the oldest known hominid fossils, Australopithicus from Africa, are small-brained creatures resembling bipedal  chimpanzees.  Except for having small rather than large teeth, and a quadrupedal rather than a bipedal pelvis, pygmy chimpanzeess are remarkably like early gracile australopithecines in their skeletal dimensions.
        A. Zihlman, New Scientist 15, 39, (1998).

d)  Did the australopithecines walk upright?     (postural vs. locomotive)

 
semicircular canals - three bony tubes which curve through the bone that underlies the external ear.  These canals have a lot to do with balance while locomoting erect.

 
"The combined evidence now suggests that we in fact have before us the remains of a distinctive hominoid from Africa, but of a great ape rather than a hominid.
        Martin, quoted in P. Shipman, New Scientist 143, 26,  (1994).

 "Australopithecines are more similar to chimpanzees than to modern humans in their inner-ear morphology ... Inner ears like those of modern humans first emerged in Homo erectus."]
        B. Bower, Science News, 145, 231, (1994).

e)  other interpretations of the australopithecines
 
 

1. ancestors to modern apes and chimpanzees
 

"...no fossils of ancestors to the modern chimp and gorilla have been found;  so we have two living species, without known ancestors, and two fossil species, without known descendants, and all four are closely related to man... as Holmes said, once you have eliminated the impossible, what remains, however improbable, is the truth."
        J. Cherfas and J. Gribbin, New Scientist 91, 592, (1981)
 

One of the frustrations of paleoanthropology is that the australopithecines are better represented by fossils than are the great apes with which they were, presumably, contemporaries."
        Anonymous, Nature 372, 31, 1994.
 
 

2. extinct primates
 

"...the fossils are indeed uniquely different from these extant hominoids (humans and apes).  It is in this sense that I use the term 'unique'.  ...This uniqueness leads inexorably to the possibility that these fossils (the australopithecines) are not ancestral to either humans or apes'.
        C. Oxnard The Order of Man, (1984), pg 93.
 

"The australopithecines are rapidly sinking back into the status of peculiarly specialized apes ..."
        M. Cartmill, D. Pilbeam, G. Isaac  American Scientist 74, (July-August 1986), 419.

 
 

Trivia Question
 

How did the "Lucy" skeleton get its name?
 

a)  named after Donald Johanson's mother

b)  showed a striking resemblence to Lucille Ball

c)  named after the Beatles' song "Lucy In The Sky With Diamonds"

d)  Donald Johanson's favorite comic strip is Peanuts
 
 
 
 
 
 

        H. Erectus

 
 tall (Turkana Boy  -  6 ft at 1.6 mya)

 walked like modern people (semi-circular canals)

 cranium long and low

 little forehead

 thick skull

 jaws protrude

 ridges above eyes

 

Examples of H. erectus  (fossils found from > 200 individuals):
 

Turkana boy

 Hominids-11               Hominids-12

Java Man

Peking Man

 
 
 

Differences from modern humans:
 

1) smaller brain:

 
 avg:     900 cc (erectus), 1350 cc (modern humans)

 ranges:   750-1250 (erectus), 780 - 2200 (modern humans)

"It is recognized that this spread has virtually nothing to do with intelligence, because human intelligence is more dependent on how the brain is organized than on sheer brain size alone."
    M. Lubenow, Bones of Contention, (1992), pg 138.
 

2) skull morphology
 

3) more heavily muscled
 
 
 

Large difference between H. erectus and Australopithecus

 
Australopithecus:  - ~ 3.5 ft tall

    -nearly all characteristics ape-like except pelvis and hip joints

    -semicircular canals ape-like
 
 

Homo erectus -   -6 ft tall

    -nearly all characteristics human-like except skull

    -semicircular canals like modern humans
 
 
 

Is H. erectus morphologically distinct enough to warrant its classification as a separate species?
 
 

"Does H. erectus exist as a true species or should it be sunk into H. sapiens?"
    Michael Day, citing one of the many questions surrounding H. erectus in Nature348, 688, (1990).
 

H. erectus is distinct from modern man (H. sapiens), but there is a tendancy to exaggerate the differences.  Even if one ignores transitional or otherwise hard to classify specimens and limits consideration to the Java and Peking populations, the range of variation of many features of H. erectus falls within that of modern man.
    G. W. Lasker, Physical Anthropology(1973), pg 284.
 

"In our view there are two alternatives.  We should either admit that the H. erectus/H. sapiens boundary is arbitrary and use nonmorphological (i.e. temporal) criteria for determining it, or H. erectus should be sunk [into H. sapiens].
    M. Wolpoff, W. X. Zhi, A. G. Thorne "The Origins of Modern Humans", (1984), pp 465.
 

His bones were heavier and thicker than a modern man's, and bigger bones require thicker muscles to move them.   These skeletal differences, however, were not particularly noticeable.  "Below the neck", one expert has noted, "the differences between H. erectus and today's man could only be detected by an experienced anatomist."
    E. White and D. Brown, The First Men (Time-Life,1973), pp 14.
 

"changes in locomotor anatomy from H. erectus to modern man were relatively minor and by earliest H. erectus times body size was essentially modern."
    R. Susman, J. T. Stern, M. D. Rose, Amer. Journal of Physical Anthropology60:3, 144,(1983).
 

"Indeed, one may well wonder whether agreement will ever be reached as to which fossils do belong to or represent the taxon, and on what morphological-cum-phylogenetic grounds fossil hominids are or are not to be regarded as H. erectus."
    B. Sigmon and J. Cybulski, Homo Erectus: Papers in Honor of David Black  (1981), 227.
 

"H erectus was clearly a different kind of animal from earlier hominid species, both in anatomy and behavior.  It was much more human in stature and build than earlier species ..."
    Roger Lewin, New Scientist, May 7, 38, (1994).
 

"It would be interesting to know if a modern man and a million-year-old erectus woman could together produce a fertile child.  The strong hunch is that they could; such evolution as has taken place is probably not of the kind that would prevent a successful mating.  But that does not flaw the validity of the species definition given above, because the two cannot mate.  They are reproductively isolated by time."
    D. Johanson and M. Edey, "Lucy: The Beginnings of Humankind", 1981, 144.
 
 
 

Time Frame
 

1.  Origin  (unknown)

"Just how Homo erectus first evolved is one of the major issues in paleoanthropology.  Here the fossils and the stratigraphic record are limited, and many details may never be resolved."
 

H. erectus appears fully formed, in Africa and Java, at ~ 2 mya.  An african rather than asian origin is favored because

"there are no known antecedents of H. erectus in Asia."
    A. Walker, quoted in New Scientist, May 7, 38, (1994).

2.  Duration

Recent papers say erectus lived ~2 x 10⁶ yrs with virtually no change  (ScienceFeb. 25, 1994).

"Populations inhabiting these far-flung regions of the Old World are anatomically similar, and the morphology of the species seems to have changed little over more than a  million years."
    G. P. Rightmire, The Evolution of H. Erectus, (1990), pg 204.
 
 
 

-abrupt appearance and stasis  (does not fit the Darwinian paradigm)
 

-H. erectus coexisted with other humans (extended coexistence does not fit the Dariwian paradigm)

"...they are the earliest fossils of Homo sapiens found in China and are almost as old as some of the latest H. erectus, ...    The dating results of these palaeoanthropological sites... suggest a possible coexistance of two species of Homo [H. sapiens and H. erectus] in China, ..."
 

 
-had larger brains on average than modern humans

1250 cc - 1740 cc

-Neanderthals lived alongside modern humans for 60,000 yrs in Middle East (Israel)
  Discover,Sept. 1995, pg 70.
 
 

"some scholars treat neanderthal as late erectus."
    C. Loring Brace, Creation/Evolution 19, (Winter 1986-1987), 23.
 
 

"when one examines a classic Neanderthal skull, of which there are now a large number, one cannot excape the conviction that its fundamental anatomical formation is an enlarged and developed version of the H. erectus skull."
    Harry L. Shapiro (Amer. Mus. of Nat. Hist.) Peking Man (1974), 125.

 
Non-creationists:

-rickets (due to vitamin D deficiency)

    R. Virchow,  Z. Ethnol. 4, 157, (1872).
    Francis Ivanhoe, Nature 227, 577, (1970).
 

-syphilis

    D. J. M. Wright, "Syphilis and Neanderthal Man", Nature  229 (Feb. 5, 1971), pg 409.
 

-use of jaws and teeth as tools

    R. Klein, The Human Career:  Human Biological and Cultural Origins   (1989), 281.
 

Creationists:

long life spans (before and shortly after flood)

microevol. (due to climate change, ice age after flood)
 
 

5.  Recent erectus-like fossils
 
 

106 individuals more recent than 300,000 y a

62 more recent than 12,000 y a
 
 
 

Australia (3 populations living alongside "modern" humans)

 
 Fossils                                      Dates

 Mossgiel                                   6000 y a

 Kow Swamp (40 individuals)     10000 y a

 Cossack skull                         <  6500 y a
 
 

 Hominids-13

 

Original explanations of recent Erectus-like morphologies  (Nature  238, Aug. 8, 1970, 578.)

 
1.  small inbred community

2.  thicker bones survive longer than thinner bones

3.  nutritional problem

4.  low grade anemia

5.  genetic factors

6.  endocrinal factors

7.  a pathological condition
 
 

More recently

 Cultural practice of head-binding

 
 
 

Summary of Australopithecus and H. erectus
 

Australopithecines
 

apes (in nearly all characteristics) with unusual pelvis and hip joint suggesting some form of bipedalism:

discoverers claimed fully human-like bipedalism (missing link)

other researchers concluded that the bipedalism was postural based on analysis of the limb bones

the latter view is supported by recent study of semicircular canals
 
 

Erectus (and neanderthals, archaic homo sapiens)
 

human (modern in nearly all characteristics) with different cranial morphology

many researchers see no boundary between H. erectus and modern humans

semicircular canals of erectus were fully modern - walked like modern humans

some erectus-like morphologies have been dated to be recent, i.e. within recorded human history  -  indicates that erectus-like morphologies are within the range of genetic variation of modern humans
 
 
 
 
 
 

It is remarkable that the taxonomic ...  relationships of the earliest known representatives of our genus, Homo, remain obscure.  Advances in techniques for absolute dating and reassessments of the fossils themselves have rendered untenable a simple (linear) model of human evolution, in which Homo habilis succeeded the australopithecines and then evolved via H. erectus into H. sapiens - but no clear alternative consensus has yet emerged.
    Bernard Wood, Nature 355, 783, 1992.
 
 

Criticisms
 

a).  Original criticism - combination of australopithicus and H. erectus

"Some thought that H. habilis showed too few advanced features to separate it from Australopithicus, but others complained that some of the fossils were indistinguishable from H. erectus."
    Bernard Wood, Nature  355, 783, 1992.
 

b).  Wide ranges of sizes and morphologies

"it is a species that manifestly embraces an unusually large amount of variation.  ... Those who believe this range to be unacceptable wide, and thus for whom H. habilis  represents more than one species, disagree about how the (collection of fossils) should be apportioned."
    Bernard Wood, Nature 355, 783, 1992.
 

Richard Leakey states that of all the fossils considered to belong to the Homo habilis grouping:

"... at least half probably don't.  But there is no consensus as to which fifty percent should be excluded.
    R. Leakey and R. Lewin, Origins Reconsidered, 1992, pg 112.
 

c).  Many specimens are very similar to australopithecines
 

"habilis turns out to have been only a little over three feet tall - just like the diminutive afarensis named Lucy.  And it still had somewhat curved toes and fingers, long arms, and short legs.  ... Except for its bigger brain and its association with stone tools, habilis is virtually indistinguishable from the earliest australopithecines.  This raises doubts about whether habilis should be regarded as a member of the genus homo"
    M. Harris  Our Kind, (1989), pg 23.
 

Although H. habilis would be expected to be more human-like than its australopithecine ancestors, Sigrid Hartwig-Scherer and Robert Martin of the Anthropological Institute in Zurich found the opposite when they analysed the limbs of OH 62 in 1991.  The limbs have more primitive or ape-like features than does Lucy, the partial skeleton of A. afarensis.
    P. Shipman, New Scientist, July 30, 1994, pg 28.
 

OH 62:  a 'habiline' with body features even more ape-like than Lucy yet dated at roughly 2 mya.  "The first time that postcranial material (from the neck down) had been found in unquestioned association with a H. habilis skull."
    M. Lubenow (Creationist), Bones of Contention, pg 164.
 

One casualty of this process [rearranging the hominid evolutionary tree] may be that the diverse group of fossils from 1 million years or so ago, known as H. Habilis, may be more properly recognized as australopithecines.
    Anonymous, Nature 372, 31, (1994).

 

d).  Time frame

 
"The puzzle is how the form represented in the hominid OH 62 and its male equivalent ... could have evolved in 200,000 years or less, into a hominid as large as H. erectus."
    S. Bunney, "Will the real Homo habilis please stand up?" New Scientist120(1636),  33, 1986.
 

D. Johanson, T. White et al.  -  Punctuated Equilibrium?  (Nature 327, 205, 1987.)
 

H. erectus fossils are contemporaneous with the entire H. habilis material.  Hence, neither H. habilis as a taxon, nor any part of it, could be ancestral to H. erectus.
    M. Lubenow (Creationist), Bones of Contention, pg 166.
 
 
 
 

Best argument for Homo habilis as a transitional taxon - larger brains than australopithecus
 

H. habilis      600-750 cc

australopithecus   350-450 cc
chimpanzee    ~ 400 cc
gorillas        450-750 cc
H. erectus     750-1250 cc
modern humans    780 - 2200 cc
 

 

Reconstruction of KNM-ER 1470 (brain size ~ 750 cc)
 
 

 Hominids-14

 
originally:
 

"You could hold the maxilla (upper jaw) forward and give it a long face, or you could tuck it in, making the face short.  How you held it really depended on your preconceptions.  It was interesting watching what people did with it.

"...if you held it one way, it looked like one thing; if you held it another (way), it looked like something else".

Alan Walker and R. Leakey quoted by R. Lewin in "Bones of Contention", 1987, pg160.
 

more recently:
 

"When it was first reconstructed, the face was fitted to the cranium in an almost vertical position, much like the flat faces of modern humans.  But recent studies of anatomical relationships show that in life the face must have jutted out considerably, creating an ape-like aspect, rather like the faces of australopithecus.
        T. BromageNew Scientist Jan 11, 1992, pg 41.

Also meatus angle and facial development patterns were ape-like

        T. Bromage New Scientist Jan 11, 1992, pg 41.
 
 
 

semicircular canals [one H. habilis specimen so far]

 
"The only thing that the labyrinth suggests is that [H. habilis] is less bipedally adapted than the australopithecines.  It looks much more like gibbons, maybe, or like baboons - certainly not a human pattern....Either this specimen is not H. habilis, or if it is, H. habilis is unlikely to be ancestral to H. erectus, " which, not surprisingly, has entirely human-like labyrinths
        P. Shipman, New Scientist, July 30, 1994, pg 28.
 

"The combined evidence now suggests that we in fact have before us the remains of a distinctive hominoid from Africa, but of a great ape rather than a hominid."
        R. Martin quoted by P. Shipman, New Scientist, July 30,  1994, pg 29.

 
 

Summary of H. habilis
 

- no skeletons of half-man half-ape (but plenty of artists' imaginative pictures)
 

-many bones and fragments from different species lumped into H. habilis, very wide variation in size and morphology
 

- combination of australopithecus-like and H. erectus-like
 

-dated 1 million yrs younger than australopithecus, had larger brains, but some specimens are more ape-like than Lucy in other respects!
 

-H. erectus overlaps H. habilis in geological time
 

-semicircular canals (1 specimen thus far):   more ape-like than Lucy!
 

7.  Other problems with the macroevolutionary sequence
 

 
a)  lack of change over supposedly long times
 

australopithecus  -  over more than 1.7 million years

H. erectus  -  over ~ 2 million years

 

b) reversals - gracile morphology of a. afarensis (Lucy) and a. africanus, then robust morphology of H. erectus, then gracile morphology of modern humans

8.  Evidences of humans in deposits dated very old
 
 

Kanapoi KP 271 (elbow bone)

 
"The humeral fragment from Kanapoi, with a date of about 4.4 million, could not be distinguished from H. sapiens morphologically or by multivariate analysis by Patterson and myself in 1967 (or by much more searching analysis by others since then).  We suggested that it might represent Australopithecus because at that time allocation to Homo seemed preposterous, although it would be the correct one without the time element.

W. Howells, "Homo erectus in human descent: ideas and problems", 1981, pg 79.

Laetoli footprints (dated at 3.7 mya)
 
 

 Hominids-15

 
"..one of the most significant finds in all of paleoanthropology..."
        Curtis and Barnes, Biology, pg 1039.
 

"remarkably similar to those of modern man."
        Mary Leakey, National Geographic, April 1979.
 

"...the footprints are like those of modern man and totally unlike those of the apes."
        Clark, quoted by R. Tuttle in Amer. Journal of Phys.  Anthropology, 85(2), 403, 1991.
 

"...show a total morphological pattern like that seen in modern humans."
        T. White, quoted by R. Tuttle in Amer. Journal of Phys.  Anthropology, 78, 316, 1989.
 

Russel Tuttle was asked by Mary Leakey to analyze the Laetoli footprint trails.  After studying the habitually unshod Machiguenga Indians (Peru):
 

"In discernible features, the Laetoli G prints are indistinguishable from those of habitually barefoot Homo sapiens."
        R. Tuttle and D. Webb, Amer. Journal of Phys.  Anthropology, 78, 316, 1989.
 

"Casts of Laetoli G-1 and of Machiguenga footprints in moist sandy soil further illustrate the remarkable humanness of Laetoli hominid feet in all detectable morphological features."
        R. Tuttle  "Did a. afarensis make the Laetoli G footprint trails?"  Amer. Journal of Phys. Anthropology, 1991  supplement: 175.
 

"it is unlikely that creatures with feet like those at Hadar [Lucy] made the remarkable Laetoli Site G footprint trails."
        R. Tuttle Amer. Journal of Phys. Anthropology, 85(2),  399, 1991.
 

"...the relatively numerous pedal specimens from the Hadar site exhibit features such as long curved toes, which are functionally incompatible with the virtually human footprints at Laetoli.  This came as a surprise to me.  I had studied the Hadar specimens before Mary Leakey invited me to analyze the Laetoli prints.  Despite preliminary reports which stressed their humanness, I thought that some apish features might be found in them.  There are none.  Further, there are no features of gait, exhibited by the trails, that are incompatible with human walking, ....   If the Laetoli prints had been undated, or if they had been dated younger, they probably would be ascribed to Homo."
        R. Tuttle, Amer. Journal of Phys. Anthropology, 85(2),  401, 1991.
 

"In sum, the 3.5-million-year-old footprint trails at Laetoli site G resemble those of habitually unshod modern humans.  None of their features suggest that the Laetoli hominids were less capable bipeds than we are.  If the G footprints were not known to be so old, we would readily conclude that they were made by a member of our genus, Homo.   ...   we should shelve the loose assumption that the Laetoli footprints were made by Lucy's kind, a. afarensis."
        R. Tuttle, Nat. History  Mar. 1990, pp. 60.

 
 

How have macroevolutionists dealt with this finding?
 

Regarding the discovery of the "missing link" i.e. Lucy,

"Many more remains of the species [a. afarensis] have turned up, including beautifully preserved footprints found in the mid-1970's in Tanzania by a team led by the famed archaeologist Mary Leakey.  Set in solidified volcanic ash, the footprints confirmed that Lucy and her kin walked like humans."

"How Man Began", Time March 14, 1994.