Stephen Munro

Pachyosteosclerosis suggests archaic Homo frequently collected sessile littoral foods

Fossil skeletons of Homo erectus and related specimens typically had heavy cranial and postcranial bones, and it has been hypothesised that these represent adaptations, or are responses, to various physical activities such as endurance running, heavy exertion, and/or aggressive behavior. According to the comparative biological data, however, skeletons that show a combination of disproportionally large diameters, extremely compact bone cortex, and very narrow medullary canals are associated with aquatic or semi-aquatic tetrapods that wade, and/or dive for sessile foods such as hard-shelled invertebrates in shallow waters. These so-called pachyosteosclerotic bones are less supple and more brittle than non-pachyosteosclerotic bones, and marine biologists agree that they function as hydrostatic ballast for buoyancy control. This paper discusses the possibility that heavy skeletons in archaic Homo might be associated with part-time collection of sessile foods in shallow waters.

Possible preadaptations to speech. A preliminary comparative

Human language is a unique phenomenon and its evolutionary origins are uncertain. In this paper we attempt to explore some of the preadaptations that might have contributed to the origin of human speech.The comparative approach we use is based on the assumption that all features of a species are functional, and that all features can be compared with those of other animals and correlated with certain lifestyles. Using this method we attempt to reconstruct the different evolutionary pathways of humans and chimpanzees after they split from a common ancestor. Previous results from comparative studies suggest human ancestors may not have evolved on the open African savannas as was once believed, but more probably were coastal omnivores feeding on plant matter and easy to catch invertebrates such as shellfish from beaches and shallow waters. Fossil and archaeological data suggest this coastal phase occurred at the beginning of the Pleistocene, whenHomo ergaster-erectus dispersed between East-Africa, North-Africa, South-Asia and Indonesia.This paper presents comparative data suggesting the various human speech skills may have had their origins at different times and may originally have had different functions. Possible preadaptations to speech include, for instance, musical skills present in a variety of primate species (sound production); airway closure and breath-hold diving for collecting seafood (voluntary breath control); and suction feeding adaptations for the consumption of fruit juice or certain seafoods (fine control of oropharyngeal movements). The different evolutionary pathways of chimpanzees and humans might explain why chimpanzees lack language skills and why human language is a relatively recent phenomenon.

Reply to John Langdon's review of the eBook: Was Man more aquatic in the past? Fifty years after Alister Hardy, Mario Vaneechoutte, Algis Kuliukas, Marc Verhaegen (Eds.), in: Waterside Hypotheses of Human Evolution. Bentham eBooks (2011), 244 pp., eISBN: 9781608052448

We welcome the opportunity, offered by the editors of HOMO Journal of Comparative Human Biology, to respond to John Langdon’s review (Langdon, 2012) of our recently published eBook, Was Man More Aquatic in the Past? (Vaneechoutte et al., 2011). Langdon’s review, however, is not so much about the eBook itself – as he hardly discusses any of the rich data and hypotheses forwarded by the eBook – but rather represents his critical attitude towards the aquatic hypothesis (AH). His criticisms are largely rhetorical, focusing on philosophical questions about science, rather than substance, and as such they can be applied equally to science in general. Our comments address these reflections, and also highlight the fact that some of Langdon’s statements are based on misinterpretations and misrepresentations, not only of the content of the eBook and of the AH, but also of some of the palaeo-anthropological and comparative biological data.