AATheories

Discussion in 'Health and medical' started by Marc Verhaegen, Feb 13, 2004.

  1. > >IMO the LCA of humans and Gorillas and Chimps had attained certain
    bipedal gait prior to the separation. While some other species can knuckle walk The above are our
    closest relatives in the animal world. And we certainly are bipedal it seems logical to me that the
    most likely scenario that we began our journey together by starting to become at least partially
    bipedal together. Here I follow Algis Kiliukas in that we were in a situation that required a fair
    amount of wading. --Frank

    > If I can jump in on this interesting thread too, I agree that the LCA was
    bipedal and wading/swimming. A couple of pieces of evidence not (I think) mentioned so far is that
    chimps, gorillas and orangs all have less than a full covering of fur; and they have a similar
    distribution of eccrine glands over the body to humans, but they are non-functional (ie, our ape
    cousins do not use them for evaporative sweating).

    These "pieces of evidence"(??) were mentioned in my book :) But the evidence is not strong, of
    course. IMO we first need more exact countings of hair densities & eccrine glands in different
    ape & monkey spp. (BTW, apes, at least gorillas, do use the eccrines to some extent for Tp
    regulation AFAIK.)

    > This suggests (to me) a more-or-less aquatic period covering the LCA and
    probably quite some time afterwards, with chimps, gorillas and orangs drifting away from the water
    (or the water disappearing from their habitat) rather sooner than for humans.

    Yes, not unlikely IMO.

    > >The location for this was most likely in mangrove swamps or the seashore.

    > Personally, I like Marc's idea of flooded forests around the Tethys
    (spelling?) Sea some 20 Mya, which neatly accounts for the large size and loss of tail in the
    apes. --Pauline

    :)

    Well, it's believed that Africa-Arabia & Eurasia made contact c 18 Ma (possibly initially
    interrupted). AFAIK, the first hominoid fossil in coastal sediments is Heliopith 18-17 Ma (probably
    close relative of Afropith) on the southern Tethys coasts, and at the same time or slightlty later a
    Gripopith-like tooth (Griphopith is also believed to be a +-close relative of Afropith) amid marine
    & other fossils on the northern Tethys coasts.

    Elmar PJ Heizmann & David R Begun 2001 "The oldest Eurasian hominoid" JHE
    41:463-481 http://www.idealibrary.com/links/doi/10.1006/jhev.2001.0495 Engelswies is an early
    Miocene vertebrate locality in S-Germany with a rich assemblage of terr.mammals, invertebrates &
    fossil plants. It is dated to
    42.5-17.0 Ma based on magneto-, bio- & litho-stratigraphy , includes among the faunal remains a
    hominoid upper molar fragment, the oldest hominoid so far identified from Europe. The evidence
    from Engelswies suggests : hominoids arrived in Eurasia c.17 Ma, roughly contemporaneously with
    pliopithecoids & Deinotherium , before the last marine transgression to isolate Eurasia from
    Africa. Thick enamel & low dentine penetrance may have been key adaptations that contributed to
    the success of hominoids of dentally modern aspect in W-Eurasia and ultimately to their ability
    to spread to E-Eurasia & Africa in the middle & late Miocene. [email protected]
    cf.Griphopith Devinskà Novà Ves, Kleinhaderdorf, Pasalar . The high number of laurophyllous
    angiosperms indicates a warm, humid, subtropical or even tropical climate . Magnolia . bunodont
    teeth ... Thickly enamelled hominoids with low dentine penetrance first appear in the late early
    to middle Miocene within a rel.short time on 3 continents. [short time: suggests colonisation
    along coasts?? MV]

    Scientists look to Europe as evol.seat - Fossil discoveries suggest that early ancestors of the
    hominids developed in Eurasia, not Africa - David Begun & his Eur.colleagues are re-writing the book
    on the history of great apes & humans, arguing that most of their evol.development took place in
    Eurasia, not Africa. Begun cs. describe 2 fossils, both discovered in Europe: one comes from the
    oldest relative of all living great apes & humans, the other is the most complete skull ever found
    of a close relative of the Afr.apes & humans:
    - In JHE Nov.01, Begun & Elmar Heizmann (Nat.Hist.Mus.Stuttgart) discuss the earliest-known great
    ape fossil, broadly ancestral to all living great apes & humans. Begun: "Found in Germany 20 yrs
    ago, this specimen is c.16.5 Ma, some 1.5 mill.yrs older than similar spp from E.Africa. It
    suggests that the great ape & human lineage first appeared in Eurasia, not Africa."
    - In JHE Dec.01, Begun & László Kordos (Geol.Mus.Hungary) describe the skull of Dryopith, discovered
    in Hungary by their team a couple of yrs ago. The fossil is identical to living gr.apes in brain
    size & very similar to Afr.apes in the shape of the skull & face & in details of the teeth. The
    discoveries suggest : the early ancestors of the hominids migrated to Eurasia from Africa c.17 Ma,
    just before these 2 continents were cut off from each other by an expansion of the Med.Sea. Begun
    says that the great apes flourished in Eurasia ; their lineage leading to the Afr.apes & humans -
    Dryopith - migrated S. from Europe or W-Asia into Africa, where populations diverged into the
    lines leading towards great apes, gorillas & chimps. One of those lines eventually evolved into
    the ancestors of humans c 6 Ma. [email protected]
    http://www.newsandevents.utoronto.ca/bin2/020218a.asp Janet Wong

    P Holec & RJ Emry 2003 "Another Molar of the Miocene Hominid Griphopithecus suessi from the Type
    Locality at Sandberg, Slovakia" Bull.Am.Mus.Nat.Hist.279:625-631 A recently discovered tooth of Gs
    is only the 5th tooth known of the species , the first upper M3. All 5 teeth are from the locality
    Sandberg, near Devínska Nová Ves (=Neudorf-a/d-March), in the NW-suburban part of Bratislava. The
    deposit in which the locality occurs is a transgressive sequence of nearshore marine sediments that
    are Upper Badenian in terms of the Central-Para-Tethyan marine bio-stratigraphy. The locality has
    also yielded a land mammal fauna of modest diversity that corresponds to earliest MN6 of the
    Eur.land mammal bio-chronology. As earliest MN6, Gs is among the earliest known hominids in Europe.
    Since Abel's description, the species has had a peripatetic taxon.& nomenclatural history, but most
    recently was returned to Abel's genus Griphopith, which requires that it also be returned to Abel's
    sp.Gs, the type sp.of the genus. .Badenian, the near-coastal region of the Para-Tethys Sea in the
    N-part of the Vienna basin. Sandberg is an important locality in that it provides unambiguous ties
    among the molluscan bio-stratigraphy, foraminiferal zones & terr.mammal bio-stratigraphy. The
    section at Sandberg is a sequence of transgressive sands & sandstones, with lenses of cross-bedded
    estuarine deposits. These littoral marine sediments contain abundant fossils, predom.of marine
    invertebrates. Less common are marine vertebrates incl.fishes, sharks, Phocidae, sirenians &
    cetaceans, & the remains of terr.vertebrates are also found occasionally ... The Upper Badenian age
    of the Sandberg locality is indicated by several spp, mainly of mollusks, eg, the lamellibranchs
    Pecten aduncus Eichwald; Flabellipecten solarium Lamarck; Chlamys multistriata Poli; Panopea menardi
    Deschayes; & the gastropods Gibulla triangulata Eichwald, Calliostoma trigonum Eichwald, Astraea
    meynardi Michelotti & others. The modest abundance of terr.mammals in marine sediments at Sandberg
    indicates nearshore deposition , this is confirmed by the lithology & deposit.relationships. Within
    a short distance from Sandberg, < 1 km, the transgress.marine sequence can be observed to lap
    directly onto uplifted Mesozoic limestones on the NW.flank of Devínska Kobyla, a highland outlier at
    the SW-end of the Malé Karpaty (Lesser Carpathian) range. During the Badenian, this range was a
    peninsula or archipelago extending into the ParaTethyan Sea.

    Marc Verhaegen

    http://www.onelist.com/community/AAT
     
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