Open access article in JHE:

The game of models: Dietary reconstruction in human evolution

Abstract

Despite substantial additions to the paleontological record and
unanticipated improvements in analytical techniques since the Journal
of Human Evolution was first published, consensus on the diet of early
hominin species remains elusive. For instance, the notable advances in
the analyses of hominin dental microwear and stable isotopes have
provided a plethora of data that have in some instances clouded what
was once ostensibly a clear picture of dietary differentiation between
and within hominin taxa. In the present study, we explore the reasons
why the retrodiction of diet in human evolution has proven vexing over
the last half century from the perspective of both ecological and functional-mechanical models. Such models continue to be indispensable
for paleobiological reconstructions, but they often contain rigid or
unstated assumptions about how primary paleontological data, such as
fossils and their geological and taphonomic contexts, allow
unambiguous insight into the evolutionary processes that produced
them. In theoretical discussions of paleobiology, it has long been
recognized that a mapping function of morphology to adaptation is not one-to-one, in the sense that a particular trait cannot necessarily be attributed to a specific selective pressure and/or behavior. This
article explores how the intrinsic variability within biological
systems has often been underappreciated in paleoanthropological
research. For instance, to claim that derived anatomical traits
represent adaptations related to stereotypical behaviors largely
ignores the importance of biological roles (i.e., how anatomical
traits function in the environment), a concept that depends on
behavioral flexibility for its potency. Similarly, in the
paleoecological context, the underrepresentation of variability within
the �edible landscapes� our hominin ancestors occupied has inhibited
an adequate appreciation of early hominin dietary flexibility.
Incorporating the reality of variation at organismal and ecological
scales makes the practice of paleobiological reconstruction more
challenging, but in return, allows for a better appreciation of the evolutionary possibilities that were open to early hominins. https://www.sciencedirect.com/science/article/pii/S0047248422001555

See also Daeglings recently published book on functional inference in paleoanthropology: https://www.press.jhu.edu/books/title/12388/functional-inference-paleoanthropology

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Op woensdag 14 december 2022 om 15:47:31 UTC+1 schreef Pandora:

Open access article in JHE:
The game of models: Dietary reconstruction in human evolution
Abstract ... https://www.sciencedirect.com/science/article/pii/S0047248422001555

Rarely seen such an empty abstract,
but the text in the article itself is sometimes a bit more concrete, e.g.
"the diets of P.boisei & P.robustus are dissimilar based on isotopic & dental microwear proxies, despite a shared, derived masticatory morphology that reached its peak expression among the E.African form."

Of course, obviously.
But
1) this assumed incorrectly that boisei & robustus belonged to the same genus - obviously not the case, see below,
2) this has 0 to do with *human* evolution, of course:
- Praeanthropus boisei was a fossil relative of Gorilla,
- Australopithecus robustus, of Pan, e.g.

E.Afr. Praeanthropus afarensis->boisei = fossil Gorilla
• “Incisal dental microwear in A.afarensis is most similar to that observed in Gorilla” Ryan & Johanson 1989
• The composite skull reconstructed mostly from A.L.333 spms “looked very much like a small female gorilla” Johanson & Edey 1981
• “Other primitive [in fact, advanced gorilla-like! mv] features found in KNM-WT 17000, but not know or much discussed for A.afarensis, are: very small cranial capacity; low posterior profile of the calvaria; nasals extended far above the
frontomaxillar suture and well onto an uninflated glabella; and extremely convex inferolateral margins of the orbits such as found in some gorillas” Walker cs 1986
• As for the maximum parietal breadth & the biauriculare in O.H.5 & KNM-ER 406 “the robust australopithecines have values near the Gorilla mean: both the pongids and the robust australopithecines have highly pneumatized bases” Kennedy 1991
• In O.H.5, “the curious and characteristic features of the Paranthropus skull... parallel some of those of the gorilla” Robinson 1960
• The boisei “lineage has been characterized by sexual dimorphism of the degree seen in modern Gorilla for the length of its known history” Leakey & Walker 1988
• P.boisei teeth showed “a relative absence of prism decussation”; among extant hominoids, “Gorilla enamel showed relatively little decussation ...” Beynon & Wood 1986

S.Afr. Australopithecus africanus->robustus = fossil Pan:
• “Alan [Walker] has analysed a number of Australopithecus robustus teeth and they fall into the fruit-eating category. More precisely, their teeth patterns look like those of chimpanzees... Then, when be looked at some Homo erectus teeth, be found
that the pattern changed” Leakey 1981
• “The ‘keystone’ nasal bone arrangement suggested as a derived diagnostic of Paranthropus [robustus] is found in an appreciable number of pongids, particularly clearly in some chimpanzees” Eckhardt 1987
• “P.paniscus provides a suitable comparison for Australopithecus [Sts.5]; they are similar in body size, postcranial dimensions and... even in cranial and facial features” Zihlman cs 1978
• “A.africanus Sts.5, which... falls well within the range of Pan troglodytes, is markedly prognathous or hyperprognathous” Ferguson 1989
• In Taung, “I see nothing in the orbits, nasal bones, and canine teeth definitely nearer to the human condition than the corresponding parts of the skull of a modern young chimpanzee” Woodward 1925
• “The Taung juvenile seems to resemble a young chimpanzee more closely than it resembles L338y-6”, a juvenile boisei. Rak & Howell, 1978.
• “In addition to similarities in facial remodeling it appears that Taung and Australopithecus in general, had maturation periods similar to those of the extant chimpanzee” Bromage 1985
• “I estimate an adult capacity for Taung ranging from 404-420 cm2, with a mean of 412 cm2. Application of Passingham’s curve for brain development in Pan is preferable to that for humans because (a) brain size of early hominids approximates that
of chimpanzees, and (b) the curves for brain volume relative to body weight are essentially parallel in pongids and australopithecines, leading Hofman to conclude that ‘as with pongids, the australopithecines probably differed only in size, not in
design’” Falk 1987
• In Taung, “pneumatization has also extended into the zygoma and hard palate. This is intriguing because an intrapalatal extension of the maxillary sinus has only been reported in chimpanzees and robust australopithecines among higher primates”
Bromage & Dean 1985
• “That the fossil ape Australopithecus [Taung] ‘is distinguished from all living apes by the... unfused nasal bones…’ as claimed by Dart (1940), cannot be maintained in view of the very considerable number of cases of separate nasal bones
among orang-utans and chimpanzees of ages corresponding to that of Australopithecus” Schultz 1941

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