Category: Neandertals

Six Friday Odds and Ends

10/14/2016

I've now become one of "those people" who fiddles around on his phone in the checkout line or while waiting for water to boil. I save links to interesting things I'd like to explore further and possibly write about, but I usually don't get back to them. The back-up is immense at this point. I'm going to park some of the recent ones here in the hope that others might see something of interest. And maybe I'll circle back around to some of these some day.

Lichen Growth on the Remains of Homo naledi

Discussion and debate about interpretation of the anatomical remains of Homo naledi (i.e., what is it) and the context of those remains (how did they get there) continues in both traditional scientific journals and online. This is fascinating to watch, as the online element adds a new dimension to the "standard model" of paleoanthrnopological discourse (paralleling, perhaps, departures from the "standard model" of fieldwork, publication, and analysis marked by the Rising Star Expedition). I wrote about initial reaction to the Rising Star results here. You can get hooked into the latest debate -- concerned with whether manganese deposits on the bones show that the "chamber" the bones were found in was once open to light -- on John Hawks' blog.

What's in a Name?

Brad Lepper's column in Sunday's Columbus Dispatch discussed the Wyandotte Nation’s Cultural Center (Wyandotte, Oklahoma), describing exhibits that embrace the prehistoric cultural-hisotorical timeline developed by archaeologists but rename the periods with Wyandotte names and incorporate them into a Wyandotte narrative. Lepper writes:

"What I find particularly significant about this exhibit is that the Wyandotte Nation considers the culture history developed by archaeologists to be useful for telling their story. Also, by applying their own names to the various cultural periods, the Wyandotte take ownership of that history."

Very interesting story.

Climate Change Timeline

This climate change timeline lets you graphically scroll through 22,000 years of human-environment interaction. It depicts changes in the mean temperature of the earth at a scale that demonstrates how abnormally sudden and severe the warming trend has been over the last 100 years. The depiction is simple, requires no advanced math or imagination to understand, and nicely makes the point. Bravo.

The Hope for Another Viking Site: Point Rosee, Newfoundland

Many of us are watching for results from excavations at Point Rosee, Newfoundland, a site identified as a possible pre-Columbian Norse habitation site based on analysis of images from satellites. The last I read, nothing that would definitively indicate a Norse presence at the site had been located. That doesn't mean it's not there, of course, and that doesn't mean that there aren't possibly other Norse in other parts of the region. This is a fun story to watch from my perspective because it's got the attention of both academic archaeologists and those on the "fringe" who are hungry for any piece of evidence that they think will legitimize their claims. This is a good demonstration both of how actual archaeology is used to search for empirical evidence to evaluate a claim/interpretation: either the Norse were at the site or they weren't -- so how can we tell? We go and look and do the work properly, that's how.

Another Neanderthal Child

It's not my primary line of work, but I'm very interested in the understanding the deep prehistory of human families. That interest has several dimensions. While I was in graduate school at Michigan I did a project where I collected data on parietal thickness of every Late Pleistocene infant I could find to try say something about birth among those populations. I've done some modeling work (e.g., described here and here) trying to understand the relationships between fertility, mortality, and family size/composition among Middle Paleolithic humans. It's exciting when new infant/child remains are announced, such as the parietal from this 7-9-year-old Neanderthal child from Spain. There have been probably been others in recent years that I'm not aware of, so I'll have to do a drag net again if I'm able to focus on this topic in any serious way.

Knights Fighting Snails

Finally, there's this Smithsonian article about depictions of medieval knights fighting snails. It pretty much speaks for itself.

A Supplemented 1930's Account of a "Giant Skeleton" from Palestine

6/29/2016

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If there is one thing I have conclusively demonstrated to myself over the course of my life, it is my ability to lose track of things even in the presence of an immense set of tools to do exactly the opposite. Go me. This is one of the main reasons why I often write about things as I come across them: saving something for later often means it goes to the bottom of some stack somewhere, never to re-surface.

I ran across the topic of this post while I was searching (unsuccessfully, so far) for a 1960's sermon about giants by a Seventh-Day Adventist preacher. I came across that sermon months ago but never wrote about, and I haven't yet been able to relocate it despite being sure I saved it more than once. I can't recall the name of the preacher, the publication, or the sermon. I'll keep searching for that sermon. In the meantime, I give you this account about of a "giant skeleton" from the Holy Land, described in a paragraph from the January 7, 1933, edition of The Gospel Messenger:

"The mounds and caves of the Near East continue to yield archaeological items of interest. Thus there was recently reported the finding of the skeleton of a giant in a cave at Athlit, Palestine. The find is said to resemble that of Paleanthropus Palestinus found a year ago at Mt. Carmel. These prehistoric men differed from all others in their long limbs, jutting chins, and awninglike ridges over their eyes. Maybe it was the descendants of some of these that the spies saw when they went up to look over the promised land."

The Gospel Messenger (1883-1965) was the official paper of the Church of the Brethren, a Christian denomination that traces its roots to early 1700's Germany.

Several things in the paragraph from The Gospel Messenger caught my attention. First was the use of "Paleanthropus Palestinus," a taxonomic construct that I don't remember seeing before. Second was, of course, the phrase "skeleton of a giant." Third was the connection made between fossil evidence and biblical stories.

Spoiler alert: the "giant skeletons" recovered from the cave were none other than the Neandertals of Skhul Cave, one of the most well-known Paleolithic sites in the Near East. The remains were described in a detail in a 1937 report. The "giants" of Skhul Cave were not giants in all, ranging in estimated stature from about 5'7" to a staggering 5'10." In addition to the formal report ( available online for anyone to see), numerous accounts of the discoveries in the popular media discuss the remains without describing them as those of "giants" That hasn't stopped today's giant "researchers" from uncritically embracing a 1932 article in The Milwaukee Journal that added the word "giant" to the text and headline.

The early 1930's was a time of rapid discovery in the Near East. In 1932, work in the caves of Palestine revealed the first relatively complete remains of Neanderthals outside of Europe (the "Galilee skull," more commonly known to paleoanthropologists today as Zuttiyeh and classified as Homo heidelbergensis was discovered in 1925; the burial of an infant Neanderthal had been reported from Skhul cave in 1931). These discoveries were widely reported in newspapers and magazines: I found nine separate stories about the discoveries printed in The New York Times between May of 1932 and January of 1933. An Associated Press story also made the rounds in the summer of 1932, and an illustrated feature appeared in Every Week Magazine (a Sunday supplement) appeared in the fall.

A portion of the fall 1932 "Every Week" feature about the Skhul Cave skeletons (snipped from the Montana Butte Standard, Sunday, October 9, 1932).

The New York Times articles I located trace the discoveries from three skeletons announced in May of 1932, to the announcement of the discovery of four more in June, to the shipment of eight skeletons to London in January of 1933. In on June 26 of 1932, the New York Times ran a piece by Dorothy Garrod that provided a physical description of the remains Garrod, a professor at Cambridge who was involved in the Skhul fieldwork, described the remains as having "powerfully developed" supraorbital ridges (the ridges of bone over the eyes), high cranial vaults, prognathic faces, and "well-marked" chins. Garrod contrasts these features with those of European Neanderthals, explaining why Sir Arthur Keith proposed that the new taxon of Paleanthropus Palestinus (sic). Garrod says only one thing relevant to the stature of these individuals:

"The limb bones are massive but are markedly longer than those of the dwarfish Neanderthaler."

Theodore McCown, the excavator of the skeletons, was directly quoted in a New York Times piece from August 6, 1932:

"Although they were a tall people, they probably stopped and walked with a shambling gait."

The word "giant" does not appear in the New York Times coverage until a January 11 story (attributed simply to "Wireless") that describes the Skhul remains as "skeletons of eight prehistoric giants" that were shipped "embedded in huge blocks of stone." That story post-dates both the (January 7, 1933) account in The Gospel Messenger that I quoted above and a similar story from The Milwaukee Journal (December 16, 1932) that is reproduced on the websites of several giant enthusiasts (e.g., here, here, and here). Here is a transcript of the Milwaukee Journal article:

"FIND GIANT SKELETON IN CAVE IN PALESTINE

Another Mousterian skeleton, resembling those of the so-called Mount Carmel men discovered last year, has been found in the caves at Athlit, Palestine. The remains of the Mt. Carmel men were first found by Theodore McCown, a young American archaeologist. The men were a race of giants who were contemporary with the Neanderthal men of Europe. They differed from all other prehistoric men in their long limbs, jutting chins, and in the enormous ridges over their eyes."

The Milwaukee Journal story, the earliest I have seen so far to refer to the Skhul skeletons as "giants," is credited to "Special Cable." The Milwaukee Journal story is not the ultimate source of the nonsense claim that the Skhul skeletons were giants -- that honor goes to a story that was apparently written for Christian consumption as a supplemented version of another story that I have yet to locate. The earliest version I have found so far is dated January 5, so there must be an earlier one out there that pre-dates the Milwaukee Journal story. Here is a quote from a story titled "There Were Giants" printed in the January 5, 1933, edition of The Harrisburg Telegraph:

" . . . After the manner of many modern demonstrations of the accuracy of Biblical accounts formerly questioned by doubting Thomases among the "higher critics," it is now reported that there really "were giants in those days."
   News has been received that another Mousterian skeleton, resembling those of the so-called "Mt. Carmel men" discovered last year, has been found in the caves of Athlit, Palestine.
   These men were a race of giants contemporary with the Neadnerthal [sic] men of Europe, but differing in that they had exceptionally long limbs and enormous, awning-like ridges over their eyes.
   Here in America we occasionally hear of the finding of the bones of a giant, but except for the admittedly large stature of our own Susquehannock Indians, there is no evidence that giants inhabited this continent."

Based on the use of the distinctive phrase "awning-like ridges," I'm guessing the account in The Gospel Messenger was drawn from a story similar to the one in the Harrisburg Telegraph. "Awning-like" is also used in the later story in the New York Times story with "giants" in the headline. My guess is that sometime in early-to-mid December, someone, somewhere wrote a story about one of the final skeletons uncovered at Skhul and decided to spice it up a little bit by taking these "taller than Neanderthal" people and turning them into giants. Whether or not that original story was packaged intentionally to interest Christians seeking confirmation of the Bible I don't know, but it seems to have been used that way at the time and continues to be used that way today. Then as now, in the absence of giants you just make hem up.

The normal-sized skull of Skhul IV from the 1937 report: despite being erroneously labeled in the press as the skull of a "giant," it was fully published and continues to be studied today.

So, getting back to reality, you can read the full report of the Skhul remains online if you want to wade through all the nitty gritty and/or don't want to take my word for it that the Milwaukee Journal didn't somehow know something about the remains from Skhul that the original excavators (and The New York Times) did not. If you don't want to read it all yourself, here are some highlights relevant to the size of the skeletons:

"The Skhul men, like the male Cromagnons, were tall; their stature ranged from 5 ft. 6.7 in. (1,700 mm.) to 5 ft. 10.3 in. (1,787 mm)." (pp. 16-17)

"The length of the foot in these fossil people is in no way remarkable." (pg. 20)

"There the longest of the Palestinian tibiae, that of Skhul IV, is set side by side with three others . . . The maximum length in Skhul IV is 430 mm. for the right bone and 434 mm. for the left. If we apply the formula of Pearson (1898) . . . we obtain a mean tibial stature of 1,813 mm. (71.3 in.); using Manouvrier's tables . . . the result is still more, namely 1,875 mm. (73.8 in.)." (pg. 41).

"It is at once apparent that we are dealing with a tall race of men, with a body conformation very different from the Neanderthaliens of Europe -- short and stout men. . . . The statures of the four men run from 1,709 mm. (5 ft. 7.2 in.) to 1,787 mm. (5 ft. 10 in.)." (pg. 58)

Comparison of the tibia of Skhul IV with those of other Paleolithic humans. Yes, it's longer, but it's owner was still less than 6' tall.

That the "giant skeletons" from Palestine were nothing of the sort is plain to see with a little bit of investigation. They weren't giants, and information about them was not suppressed. I will bet that none of the websites using this case as an example, however, will change: the uncritical embrace of any old piece of paper with the word "giant" printed on it is a staple among today's cut-and-paste giant enthusiasts. Systematic scrutiny and culling of nonsense "giant" accounts would leave little if any ammunition available for the "how can all of these accounts be wrong?" baloney cannon. Dumb. What else can you really say about a world where manufactured clay statues are accepted as evidence.

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Fetal Head Molding and Obstetrics in Late Pleistocene Humans

3/15/2015

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Preface: This post presents some work I did as a graduate student at the University of Michigan in 2007. It was a poster for a class called "Evolution of the Genus Homo," taught by Milford Wolpoff. I chose the topic because of my interest in the culture, biology, and social organization of Middle/Late Paleolithic humans (see discussion of my 2014 SAA paper here and here, and my 2015 AJPA paper here). I had hoped to develop this into a paper either alone or with a collaborator, but I have never found the time to follow through. As the information I collected ages and I begin to focus on moving to a new job that will require a lot of attention up front to the archaeology of the southeastern United States, it seems less and less likely that I'll ever get around to turning this into a paper. So I'm going to put my analysis from the poster out there "as is" and hope it useful to someone. If you read this and think it's an interesting idea or one that you'd like to pursue, let me know!

I apologize for the state of the bibliography: there are some formatting errors that I will correct when I have the time.

Fetal Head Molding and Obstetrics in Late Pleistocene Humans

Figure 1. Illustration of changes in head shape that occur during birth (from A.D.A.M).

Introduction

This study compares available data from fetal and neonatal crania from the Late Pleistocene to the mechanics of fetal head molding during birth in recent humans.   The small number of fetal and neonatal remains dating to the Late Pleistocene offer an opportunity to simultaneously explore issues of obstetrics, selection, and early brain growth. Most treatments of birth and obstetrics in Pleistocene humans have focused on pelvic anatomy (e.g., Rak and Arensburg 1987; Rosenberg 1998; Rosenberg and Trevathan 2002; Trinkhaus 1984). Studies of childhood growth and development after birth are limited mainly by the dearth of sub-adult skeletons, particularly those that pre-date Neandertals (see Anton 2002; Dean et al. 1986; Minugh-Purvis 1988, 2002; Nelson and Thompson 2002; Stringer et al. 1990; Tellier 1998; Trinkhaus and Tompkins 1990).   Fetal and neonatal remains, from Neandertals and other Late Pleistocene humans, have been described but have not been the subject of detailed, hypothesis-based research.

Deformation (molding) of the fetal cranium is an important part of successful birth in recent humans. This study examines the hypothesis that thickness of fetal cranial bone would have been an impediment to successful birth in Neandertals and other Late Pleistocene humans. Investigating the possible role of fetal head molding in Pleistocene obstetrics may help shed light on both anatomical trends in human cranium (i.e., the emergence of "modern" cranial morphology) and demographic variables and population genetics that may underlay the spread of anatomical "modernity."   Mortality and trauma during childbirth, acting on the mother and/or the fetus, would be an important selective force.

Two aspects of fetal head molding are emphasized: cranial vault thickness and head dimensions.    Vault thickness affects the response of the cranium to pressure during birth. Head size and shape affect both the degree of molding that is required for the fetal head to pass through the birth canal and the distribution of forces on the fetal cranium.

Hypothesis: Thick fetal cranial bone in Late Pleistocene archaic humans would have caused difficulties during childbirth (relative to recent humans) by inhibiting head molding during delivery.

Assuming uniformity in the size of the birth canal between archaic and recent humans, this hypothesis has two test implications:

1) the increased thickness of Late Pleistocene fetal cranial vaults would have a significant effect on elasticity of the cranium

2) the dimensions of the fetal cranium are such that significant molding is required for delivery

In other words, fetal head molding must be shown to be both necessary (by the dimensions of the cranium) and significantly impeded (by the in-elasticity of the vault) in order to fail to reject the hypothesis. If either one of these test implications is rejected, then the hypothesis can be rejected.

Pleistocene Obstetrics: Previous Research

Much research focused on questions of obstetrics in Pleistocene humans have emphasized the selective constraints between locomation and birth mechanics in the pelvis (Rak and Arensburg 1987; Rosenberg 1998; Rosenberg and Trevathan 2002; Ruff 1995; Trinkhaus 1984). Based on pelvis remains, most researchers conclude that birth in Pleistocene humans was much like birth in recent humans (Rosenberg 1998; Rosenberg and Trevathan 2002). Subsequent to the description of the Kebara 2 pelvis (Rak and Arensburg 1987), most ideas about an unusually long gestation periods (Trinkhaus 1984) and rapid in utero brain growth (Dean et al. 1986) in Neandertals have been rejected (see Stringer et al. 1990:148).

While pelvic inlet size during the Pleistocene appears to be, overall, similar to modern humans, cranial capacity increased. during the Middle and Late Pleistocene. Stasis in pelvic inlet size and increase in head size produces an "obstetric dilemma" where the fetal head is larger than the birth canal. Rosenberg and Trevathan (2002:1205) state that

"Two changes could have allowed an increase in adult brain size to occur: human infants could have been born with a smaller percentage of adult brain size (resulting in greater infant helplessness) and/or there could have been an alteration of the shape of the pelvis concomitant with a change in the mechanism of birth."

There is a third possibility: fetal head molding. The possible importance of fetal head molding in Neandertals is raised by similarities in both pelvic inlet size and adult cranial capacity to recent humans. Minugh-Purvis (1988:260) speculated that the thicker vault bone observed in Neandertal fetal remains would have posed a problem if delivery required a "considerable degree of head molding." The possibility was also discussed by Friedlander and Jorndan (1994).

Figure 2.

Fetal Head Molding in Recent Human Birth

In recent humans, the fetal cranium is a flexible structure that deforms during birth because of pressures between the fetal head and the cervical walls (Lapeer and Prager 2001; McPherson and Kriewall 1980a, 1980b) (Figure 2). Pressures and deformation are greatest at the sub-occipito bregmatic plane (Lapeer and Prager 2001; Rosenberg and Trevthan 2002).

During a normal labor, the parietal bones undergo the most significant changes in shape, being compressed towards each other and elongating in the axial plane (Lapeer and Prager 2001; McPherson and Kriewall 1980b). The occipital bone is relatively rigid and undergoes little change during molding (McPherson and Kriewall 1980b:18; Rosenberg and Trevathan 2002:1201). The frontal, occipital, and parietal bones interlock at the sutures after a certain limit of deformation occurs, preventing excessive molding and protecting the brain within a more rigid structure (McPherson and Kriewall 1980a:15).

The risk of excessive molding is greater in pre-term deliveries, where cranial bone is not sufficiently thick to prevent excessive molding (McPherson and Kriewall 1980a). Clinical studies have shown that excessive molding during birth (i.e., where too much deformation occurs) may be linked to psycho-neurological disorders, mental retardation, cerebral palsy, and death (see McPherson and Kriewall 1980b).

Fetal cranial bone must be thin enough to allow sufficient deformation of the cranium, but thick enough to form a rigid structure to protect the brain. Optimal thickness values would vary for different portions of the fetal cranium depending on the pressures that are exerted and the required responses to those pressures.

Parietal Thickness, Span, and Deformation Under Load

Parietal bones grow outward from a center of ossification that later becomes the parietal eminence (Ohtsuki 1980). The bones are thickest at the eminence, thinning towards their margins (McPherson and Kriewall 1980b). Ohtsuki (1977) reported a mean thickness of 0.54 +/- 0.13 mm for term (9-10 month) fetal parietal bones at the center of ossification and a thickness of 0.40 +/- 0.10 for term fetal frontal bones at the center of ossification (n = 10). McPherson and Kriewall (1980a:10) reported term fetal parietal bones that varied in mean thickness from 0.71-0.86 mm.

In their analysis of the mechanical properties of fetal parietal bone, McPherson and Kriewall (1980a:11) found that differences in thickness and the orientation of the bone fibers affected the elastic modulus (the resistance to deformation when a load is applied). Thicker cranial bone requires more force to deform. Figure 3 shows the relationship between thickness and elastic modulus in the data supplied by McPherson and Kriewall (1980a:10,13), using only the parietal bones with fibers orientated parallel.

Using the formulae provided by McPherson and Kriewall (1980:11), we can use the estimates of elastic modulus to estimate the loads that would be required to bend segments of bone of varying length and thicknesses (Figures 4 and 5). Other things being equal, longer "beams" of bone require less force to bend, while thicker "beams" require more. To have the same resistance to bending force, a longer "beam" must be thicker.

Figure 3. Thickness of fetal cranial bone plotted against elastic modulus (data from McPherson and Kriewall 1980a). The regression (R2 = 0.78) is: 4.13 + 2.86(log of thickness in mm)

Figure 4. Plot of force required to cause a deflection of 1 mm in "beams" of bone of varying thickness (assuming a beam length of 75 mm - approximately that of a modern human term fetus). While the absolute values of these calculations may not be accurate (parietal bones vary in thickness in cross-section and do not behave simply as "beams") the calculations show that the resistance to force changes dramatically when thickness increases from 1 mm to 2 mm.

Figure 5. Plot of force required to cause a deflection of 1 mm in "beams" of bone of varying length (assuming a beam thickness of 1 mm).

Fetal Vault Thickness, Dimensions, and Molding in Late Pleistocene Homo

The Late Pleistocene fossil record contains numerous remains from sub-adult specimens. Of interest here are those remains that preserve portions of the cranial vault, particularly the frontal and parietal bones. Fetal and neonatal remains of Neandertals have been recovered from La Ferrassie (Heim 1982) and Hortus (Lumley-Woodyear 1973). Rremains of two Neandertals less than about a year old have been reported from Shanidar (Trinkhaus 1983) and Krapina (Minugh-Purvis 1988). Neonatal remains attributed to anatomically modern Homo sapiens have been reported from Cro-Magnon (Minugh-Purvis 1988), Qafzeh (Tillier 1999), and Abri Patuad (Minugh-Purvis 1988). Krapina is the earliest site, dating to the late Riss/early Wurm (Wolpoff 1999). La Ferrassie, Shanidar, Qafzeh, and Hortus date to Wurm I/Wurm II. Abri Pataud and Cro-Magnon date to Wurm III/IV (Wolpoff 1999).

Vault Thickness

Data on vault thickness at the parietal and frontal eminences are available for six fetal/neonate skeletons and three young (<1 year) infants from the Late Pleistocene.

Figure 6. Top: Drawing of Neandertal neonatal parietal from Hortus 1b (adapted from Lumley-Woodyear 1973). Bottom: Neandertal fetal and newborn frontal bone fragments from La Ferrassie compared to frontals from recent humans (adapted from Heim 1982).

Figure 7.

The thickness of the frontal and parietal bones in this sample contrasts with the data from the modern sample provided by Ohtsuki (1977) (Figure 7), outside the 2 sigma range of his means for term fetuses. If the Late Pleistocene fetal and neonate remains are aged accurately, fetal parietal bone was generally 1.5 to 2 times thicker than that of modern humans.

Considerably more force would be required to deform these bones, assuming the geometry of the bones was otherwise equivalent (see below).

Test prediction 1 is supported: differences in fetal cranial vault thickness are sufficient to affect molding of the cranium.

Fetal Head Dimensions

The limited data available on very young Late Pleistocene individuals suggests that some aspects of fetal head geometry may have differed from that of more recent humans (Minugh-Purvis 2002; Stringer et al. 1990). Bregma-lambda distance appears to have been shorter in Neandertals than in recent humans throughout life (see Minugh-Purvis 2002:488-489; Gunz and Havarti 2007; Harvarti 2003; Trinkhaus 1983:371). In mature Neandertals, the shorter distance is associated with a lower position of bregma (see Harvarti 2003)

Figure 8.

A shorter bregma-lambda distance would reduce the cross-section of the fetal cranium in a dimension that is key to the necessity for fetal head molding. It appears that this distance may have been about 10 mm less in Neandertals at the time of birth relative to recent humans: perhaps 80 mm rather than 90 mm (see Minugh-Purvis 2002). A difference of ca. 10-12% in the bregma-lambda chord would be sufficient to account for a 3-7% reduction in the sub-occipito-bregmatic diameter (SOBD). Assuming equivalence in other dimensions of the head and pelvic inlet, this difference alone would significantly lessen the degree of fetal head molding that would be required for successful delivery.

Test prediction 2 is not supported: the dimensions of the fetal cranium are such that significant molding was probably not required for delivery.

Conclusions

Significant fetal head molding was probably not critical to successful Neanderthal birth. While thicker cranial bone would have reduced elasticity, a smaller SOBD would have negated or lessened the need for molding during birth.

Reduction in fetal cranial thickness may not have been a reproductive advantage for "modern" humans. Rather, cranial thinness associated with an increase in the SOBD may have increased the risks to the fetus during birth (i.e., though excessive molding) while reducing or maintaining the risk to both mother and fetus (i.e., through arrested labor). In the absence of selection for thinner bone associated with a flexibility requirement, thick fetal cranial bone would have offered protection to the fetal brain during delivery. Apparent stasis in pelvic anatomy suggests that smaller, thicker fetal crania may be the ancestral condition. An increase in SOBD, perhaps reflecting some difference in fetal brain growth, would have preceded selection for thinner cranial bone in this scenario.

The fetal cranium is a complex mechanical structure. Constructing a simulation model (similar to that of Lapeer and Prager 2001) of delivery in Neanderthals is possible with the available data. This model could be used to test hypotheses about obstetrics in a more sophisticated way than is possible by calculating simple ratios of head and pelvic size.

References Cited

Anton, Susan C. 2002. Cranial growth in Homo erectus. In Human evolution through developmental change, edited by Nancy Minugh-Purvis and Kenneth J. McNamara, pp. 349-380. Baltimore: Johns Hopkins University Press.

Dean, M.C., C. B. Stringer, and T. Bromage. 1986.    Age at death of the Neanderthal child from Devil’s Tower, Gibraltar and the implications for studies of general growth and development in Neanderthals. American Journal of Physical Anthropology 70:301-309.

Friedlander, N. J., and D. K. Jordan. 1994. Obstetric implications of Neanderthal robusticity and bone density. Human Evolution 9:331-342.

Gunz, Philipp, and Katerina Havarti. 2007.   The Neanderthal “chignon”: Variation, integration, and homology. Journal of Human Evolution 52:262-274.

Havarti, Katerina. 2003. The Neanderthal taxonomic position: Models of intra- and inter-specific craniofacial variation. Journal of Human Evolution 44:107-132.

Heim, Jean-Louis. 1982. Les enfants nJandertaliens de La Ferrassie. Paris, Masson.

Lapeer, R.J., and R.W. Prager. 2001. Fetal head moulding: Finite element analysis of a fetal skull subjected to uterine pressures during the first stage of labour. Journal of Biomechanics 34:1125-1133.

Lumley-Woodyear, Marie-Antionette de. 1973.    AntenJanderthaliens et NJandertaliens du bassin Mediterraneen occidental europen. Etudes Quaternaires. MJmoire 2, Marseille, UniversitJ de Provence.

McPherson, Gregg K., and Timothy J. Kriewall. 1980a. The elastic modulus of fetal cranial bone: A first step towards an understanding of the biomechanics of fetal head molding. Journal of Biomechanics 13:9-16.

McPherson, Gregg K., and Timothy J. Kriewall. 1980b. Fetal head molding: An investigation utilizing a finite element model of the fetal parietal bone. Journal of Biomechanics 13(1):17-26.

Minugh-Purvis, Nancy. 1988. Patterns of craniofacial growth and development in Upper Pleistocene hominids. PhD dissertation, University of Pennsylvania.

Minugh-Purvis, Nancy. 2002.    Heterochronic change in the neurocranium and the emergence of modern humans. In Human evolution through developmental change, edited by Nancy Minugh-Purvis and Kenneth J. McNamara, pp. 479-498. Baltimore: Johns Hopkins University Press.

Nelson, Andrew J., and Jennifer L. Thompson. 2002.   Adolescent postcranial growth in Homo neanderthalensis. In Human evolution through developmental change, edited by Nancy Minugh-Purvis and Kenneth J. McNamara, pp. 442-463. Baltimore: Johns Hopkins University Press.

Ohtsuki, Fumio. 1977.    Developmental changes of the cranial bone thickness in the human fetal period. American Journal of Physical Anthropology 46:141-154.

Rak, Y., and B. Arensburg. 1987.    Kebara 2 Neandertal pelvis: First look at a complete inlet. American Journal of Physical Anthropology 73:227-231.

Roche, A. F. 1953.    Increase in cranial thickness during growth. Human Biology 25(2):81-92.

Rosenberg, Karen R. 1992.   The evolution of modern human childbirth. Yearbook of Physical Anthropology 35:89-124

Rosenberg, Karen R. 1998. Morphological variation in west Asian postcrania. In Neandertals and modern humans in western Asia, edited by Takeru Akazawa, Kenichi Aoki, and Ofer Bar-Yosef, pp. 367-379. Plenum, New York.

Rosenberg, Karen, and Wenda Trevathan. 2002.    Birth, obstetrics and human evolution. BJOG: an International Journal of Obstetrics and Gynaecology 109:1199-1206.

Ruff, Christopher B. 1995.   Biomechanics of the hip and birth in early Homo. American Journal of Physical Anthropology 98:527-574.

Stringer, Christopher B., M. Chistopher Dean, and Robert D. Martin. 1990.    A comparative study of cranial and dental development within a recent British samples and among Neandertals. In Primate life history and evolution, edited by C. Jean DeRousseau, pp. 115-152. New York: Wiley-Liss.

Tillier, Anne-Marie. 1998. Onotogenetic variation in Late Pleistocene Homo sapiens from the Near East. In Neandertals and modern humans in western Asia, edited by Takeru Akazawa, Kenichi Aoki, and Ofer Bar-Yosef, pp. 381-389. Plenum, New York.

Tillier, Anne-Marie. 1999. Les enfants mousteriens de Qafzeh: Interpretation phylogenetique et paleoauxologique. Cahiers de Paleoanthropologie. Paris, CNRS Editions.

Trinkhaus, E. 1983. The Shanidar Neanderthals. New York: Academic Press.

Trinkhaus, E. 1984    Neandertal pubic morpohology and gestation length. Current Anthropology 25:509-514.

Trinkhaus, Erik, and Robert L. Tompkins. 1990. The Neandertal life cycle: The possibility, probability, and perceptibility of contrasts with recent humans. In Primate Life History and Evolution, edited by C. Jean DeRousseau, pp. 153-180. New York: Wiley-Liss.

Young, Richard W. 1957. Postnatal growth of the frontal and parietal bones in white males. American Journal of Physical Anthropology 15:367-386.

Wolpoff, Milford H. 1999.    Paleoanthropology. 2nd edition. Boston: McGraw-Hill.

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"Slicing the Pie" of Neandertal Family Life

4/11/2014

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Part two of my foray into the Middle Paleolithic . . .

The phrase slicing the pie refers to a tactical method of systematically clearing an area hidden by an obstacle: you move around the obstacle and take care of one slice at a time. That’s often a better option than just jumping right past the obstacle and exposing oneself to whatever unknown terrible things might lurk around the corner. Slicing the pie is a method of breaking a big problem up into several smaller problems with the added stipulation that the problems must be addressed in a specific sequence in order for the method to be successful.

My 2014 SAA presentation is my attempt to work through the first slice of the pie of Neandertal family life (and take a peek around the corner to see what the next couple of slices might look like). As I discussed a little bit in this post, I'm using an agent-based model to explore how the high adult mortality regimes suggested by the Atapuerca-SH and Krapina assemblages might have affected the behavioral conditions under which hunter-gatherer populations were demographically viable. Agent-based modeling lets you create representations of plausible human systems unlike those we can observe ethnographically. It lets you understand how those systems are structured and work, and it provides a basis for developing expectations that can be compared to archaeological and fossil data. We could, of course, jump right past those kinds of nuts and bolts questions and argue about whether or not the symbolic contractual aspects of Neandertal male-female pair bonds were like those of “modern” humans. That’s a great piece of the pie to argue about, and I like those arguments as much as the next person. But I think that’s pretty far around the corner. Developing a basic understanding of the structure, organization, and behaviors of Neandertal domestic groups is a better piece of pie to start with.

I’ve still got some work to do on the presentation, but I thought I’d go ahead and post it here. [Edit: I've removed the draft version of the presentation - the version that I presented at the SAAs is here]. Some of the organization and a few details might change before the meetings, but the basic content and ideas will remain the same. I’m hoping that “pre-posting” this helps me do the things I go to conferences to do: learn something, exchange ideas, and meet people who are interested in similar topics or approaches. Maybe it will mitigate the downsides of both posters (does anyone actually read them?) and talks (how much can you get across in 15 minutes?). I’m betting I can generate more interest in my work by posting it and giving a 15 minute presentation than I can by just giving the 15 minute presentation. Or maybe the real benefit will be that I won’t be sitting in my hotel room the night before still trying to organize my Powerpoint. Even if that’s the only benefit there is . . . I’ll still take it.

I'm not done with this question, and I don't claim to have "solved" anything. But I’m generally happy with what I’ve managed to do so far: getting the presentation in shape has helped me clarify my thinking a bit, and working part of this into a publication will be on my summer agenda. I’m going to try to make the case (by showing rather than assertion) that a complex systems approach gives you a fighting chance to understand the structure and organization of domestic life during the Paleolithic. Paleolithic domestic life is, of course, a really big pie. Understanding the implications of high adult mortality in terms of population viability and family-level behaviors during the Middle Paleolithic is just the first slice. To cover in depth all the ideas that are in this presentation is potentially a dissertation- or book-level project: there's a lot of room here. I’ve already written my dissertation, so that’s out. We’ll see where the rest of this goes. Please let me know if you’re interested in thinking about ways to address domestic life during the Paleolithic -- there may be a conference symposium and/or an edited volume in the future.

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Do You Recognize This Man?

4/11/2014

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I came across this portrait of a Middle Paleolithic father and child. Does anyone know who the artist is? It's a really nice piece of work and I'd like to use it in a presentation if possible. The reward for information leading to the artist is substantial: a line in the acknowledgments of a powerpoint at the 2014 SAAs. That and about $5000 will put you in a mint 1970s AMC Pacer. You're welcome.

Addition: Carline VanSickle identified the artist as Sonia Cabello, earning her a line in my acknowledgements and my best wishes for the wonderful times she will one day have with her 1979 AMC Pacer, should she ever choose to purchase one.

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Neandertal "Families," Mortality, and the OY Ratio: SAA 2014

4/3/2014

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I decided to formally wade into the cloudy waters of the Middle Paleolithic at this year's SAA meetings with a presentation titled Marriage, Mortality, and Middle Paleolithic Families: Implications of a Model-based Analysis (the abstract is here). I'm using an agent-based model (ABM) to probe how the harsh adult mortality regimes suggested for the Middle Paleolithic might have affected the behavioral conditions under which human populations were demographically viable. The model I'm using is the same as the one used in the AJPA paper with the addition of an age-specific mortality schedule that more-or-less mimics that suggested by fossil assemblages from Atapuerca and Krapina. If you're interested in the nitty-gritty of the model, full code and description are available at openABM.org.

I became interested in the OY ratio (the ratio of older to younger adults) after reading Caspari and Lee's (2004) paper and the debate that followed. While my results in the AJPA paper showed that there were clear relationships between the demographic characteristics of living populations (in the model) and the OY ratio of assemblages of dead individuals from those populations, thousands of model runs under widely varying conditions of fertility and mortality did not produce OY ratios nearly as low as those reported by Caspari and Lee for pre-Upper Paleolithic samples. But the representations and parameters in the ABM were based on data from ethnographic hunter-gatherers. What happens if we impose a mortality regime like that suggested by Atapuerca and Krapina?

Under a regime of high mortality (mortality schedule 3; MS 3 in the figures - the dotted lines are following José Maria Bermúdez de Castro & María
Elena Nicolás' 1997 paper), model populations are still "viable" if fertility is high enough. And lower OY ratios (i.e., in the Neandertal range) are associated with higher fertility populations. All things being equal, however, significantly larger population sizes are required for viability when we impose a harsh mortality regime. This makes logical sense, of course, but it also seems possibly at odds with some of the peculiarities of the Neandertal fossil/archaeological record. So I'm using the model to investigate the effects of behavioral differences (in terms of pair-bonding behaviors, "family"-like organization, etc.) on demographic viability.

I'm still working my way through the model data. I hope to be done with the presentation early (wouldn't that be a novel idea) so I can put it up here before the meetings, but I'm not sure I'll get there. The presentation will be in the afternoon session on Paleolithic Europe on 4/26/2014.

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Six Friday Odds and Ends

A Supplemented 1930's Account of a "Giant Skeleton" from Palestine

Fetal Head Molding and Obstetrics in Late Pleistocene Humans

"Slicing the Pie" of Neandertal Family Life

Do You Recognize This Man?

Neandertal "Families," Mortality, and the OY Ratio: SAA 2014

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