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Ancient Italian ape had human-like precission grip

15 Jan
Reconstruction of O. bamboli (Pavel Major / ICP)
Oreopithecus bamboli was primate species, surely a hominine (great ape excluding orangutans) that lived in Tuscany and Sardinia some 8.2-6.7 million years ago.
It has great interest regarding human evolution because it is the oldest known ape to have developed a pad-to-pad precision grip, a characteristic otherwise only found in the human genus.
This trait, hotly debated in the last decades, has been recently confirmed by researchers of the Catalan Institute of Paleontology Miquel Crusafont (ICP). It must be said however that this development is considered convergent evolution and not ancestral to our own precision grip.
O. bamboli fossil
(CC by Ghedoghedo)
I guess that much of the controversy is caused by the old hypothesis that argued that it was the precision grip itself which elicited human brain development, something that obviously did not happen with Oreopithecus.
Other traits of this species are quite different from our own or our australopithecine relatives. They probably walked upright but with different gait (unlike the more human-like Sahelanthropus, of similar age) and their feet were very much unlike ours, with a very open angle for the big toe (hallux).
It seems that their environment was swampy and not strictly forestal.
Sources[es/cat/en]: Pileta, Diari de Girona, Wikipedia.
Ref.: Sergio Almécija et al., The morphology of Oreopithecus bambolii pollical distal phalanx. AJPA 2014. Pay per viewLINK [doi:10.1002/ajpa.22458]
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4 responses to “Ancient Italian ape had human-like precission grip

  1. Marc Verhaegen

    January 15, 2014 at 10:06 pm

    Thanks for this interesting paper, which says that Oreop displays a human-like medio-laterally wide tuft & thumb-to-hand length ratio, compatible with pad-to-pad precision grasping & enhanced manipulative skills.
    Common sense says that narrower instruments are better for fine manipulations, but anthropocentric paleo-anthropologists often assume that broad tufts indicate a precision grip: “humans have broad tufts, humans have precision grip, therefore broad tufts indicate precision grip”. They illogically reason A->B & A->C, hence B->C (but logica is A->B & B->C, hence A->C).
    But broadening of the end-phalanges are typically seen in (all?) swimming animals. Oreop lived in swamp forests. We know archaic Homo swam a lot (Pleistocene diaspora along coasts & rivers, google “econiche Homo” & “Laden Verhaegen”). Could Oreop also have swum regularly (parallelism)? It would also explain the “human-like thumb-to-hand length ratio”. OTOH, Oreop's widely divergent big toe suggests arborealism, and “a long tendon of a flexor muscle” in its thumb might suggest frequent vertical climbing & perhaps arm-hanging. Swimming, possibly wading or floating vertically, vertical climbing in the branches above the swamp – all this suggests Oreop spent a lot of time in water, possibly frequently feeding on floating vegetation (google “aquarboreal”).
    Oreop apparently used its hands for swimming & climbing & food collection. Not unexpected for a primate in swamp forests…

     
  2. Maju

    January 15, 2014 at 10:43 pm

    I don't know (have no access to the paper) if the conclusion is reached as you say by assuming that “broad tufts indicate precision grip” or rather not. Considering that this issue has been debated form more than two decades and that there are several full skeletons of Oreopithcus, I would find it naive that they would say just that. The precision grip is granted, I understand, not by “broad tufts” but by long opposable thumbs and, from what I understood from all the articles, that's what they are saying. Am I wrong?

    “We know archaic Homo swam a lot”…

    I wouldn't put my money on it. African rivers are full of dangerous animals (particularly crocodiles) and even today many Africans can't swim, even if they live by rivers and travel through them regularly. It's better to stay on the canoe if possible, you know. Most apes and monkeys are quite phobic to rivers anyhow (for example it is a large river what protects the existence of bonobos vs. their more violent chimpanzee cousins and it's almost certain that neither species ever crossed it at all in almost two million years, i.e. since the formation of the Congo basin).

    Said that, it's possible that Oreopithecus did swim or at least waded deep in the water (no crocs in Europe). I have pondered myself that their very open hallux angle could have helped them to stand on the mud in fact, just the same that many animals have wider or extensible feet to stand on snow. But I doubt they lived all the time in the water, that's most un-apeish, and retired to trees for rest, as chimps and bonobos do.

     
  3. marc verhaegen

    September 9, 2014 at 11:40 pm

    Of course, Maju, archaic Homo swam a lot: they dispersed intercontinentally along coasts & rivers (e.g. Mojokerto, Java 1.8 Ma, found amid barnacles & marine & freshwater molluscs = delta), they had very heavy bones, exclusively seen in shallow water diving mammals (pachyostosis, pachyosteosclerosis), ear exostoses (humans diving in cold water), flat long low skulls, typical of swimming mammals (platycephaly) etc., see my last paper:
    “The aquatic ape evolves: Common misconceptions and unproven assumptions about the so-called Aquatic Ape Hypothesis” Hum.Evol.28:237-266, 2013
    Abstract: While some paleo-anthropologists remain skeptical, data from diverse biological and anthropological disciplines leave little doubt that human ancestors were at some point in our past semi-aquatic: wading, swimming and/or diving in shallow waters in search of waterside or aquatic foods. However, the exact scenario—how, where and when these semi-aquatic adaptations happened, how profound they were, and how they fit into the hominid fossil record—is still disputed, even among anthropologists who assume some semi-aquatic adaptations.
    Here, I argue that the most intense phase(s) of semi-aquatic adaptation in human ancestry occurred when populations belonging to the genus Homo adapted to slow and shallow littoral diving for sessile foods such as shellfish during part(s) of the Pleistocene epoch (Ice Ages), presumably along African or South-Asian coasts.
    Conclusions: Many scientific as well as popular publications on the so-called AAH give incorrect impressions of how, when and where our semi-aquatic ancestors could have evolved. This paper provides arguments from diverse biological subdisciplines for the following 3 hypotheses, which to conservative anthropologists might seem unexpected at first sight, but are based on what is known from other animals: the comparative evidence.
    (1) The aquarboreal theory of Mio-Pliocene hominoids suggests that our Mio-Pliocene more apelike ancestors and relatives, including the australopiths, led an aquarboreal life, living in wet forests such as flooded, mangrove or swamp forests and later in more open wetlands, and fed on hard-shelled and other plant and animal foods at the water surface and the waterside as well as in the trees.
    (2) The littoral theory of Pleistocene Homo (AAH sensu stricto) suggests that early-Pleistocene archaic Homo populations dispersed along the coasts, where they reduced climbing adaptations, but frequently dived and used stone and other tools for feeding on shallow-water and water-side foods including shellfish.
    (3) The wading hypothesis of early Homo sapiens suggests that, later in the Pleistocene, Homo populations gradually ventured inland along the rivers, reduced diving skills, and frequently waded with very long and stretched legs and fully upright body to spot prey in very shallow water and used complex tools to collect different sorts of aquatic and waterside foods.
    marc verhaegen tech.groups.yahoo.com/group/AAT
    http://www.researchgate.net/profile/Marc_Verhaegen
    independent.academia.edu/marcverhaegen
    slideplayer.nl/slide/2120122/

     
    • Maju

      September 10, 2014 at 7:23 am

      I strongly disagree. Why would “aquatic” animals sweat? Why no swimming adaptations whatsoever? How did we face the all-pervading crocodiles before we had weaponry? Actually most Africans do not even practice swimming and that’s largely because of crocodiles. We were never more “aquatic” than elephants, probably less.

       

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