Kent's Cavern 4: chronology and taxonomy questioned???

[Daryl Habel]

John Hawks has managed to obtain a copy of Sir Arthur Keith's 1927 report in the Proceedings of the Torquay Natural History Society, and has posted a brief summary of what is mentioned in the report on his weblog at:
CLICK HERE

Relative to the issue of taxonomy, the most informative information repeated from Keith's paper is that concerned with the measurements of the teeth, but this data does not decide the issue since the measurements of the teeth fall within the range of both late Neanderthals and modern humans.

Hawks' concluding paragraph raises another interesting issue: "...Without a strong anatomical case, what is to dispute the hypothesis that this specimen belonged to a population with a mixture of Neandertal and modern morphologies?...

Indeed, there seems (to me) no strong case to dispute this and it also could be said there are other specimens of fragmentary dentition from the MP/UP 'transitional' period [e.g. Bacho Kiro level 11, and the specimens associated with the Szeletian (Mariaremete) and Uluzzian industries] with pre-Gravettian dates (>30 kyr ago) which also might be rendered subject to the same question.
 
Dar      

[rich]

i presume the teeth have been x rayed for any evidence of taurodontism ?
this a condition seen in the nean dentition.
perhaps someone knows one way or the other
rich

[lagarvelho]

rich and all:

Isn't taurodontism also found among some "modern" people?
Anne G

[Daryl Habel]

Hi rich,

According to John Hawks' weblog summary of Keith's 1927 paper, the Kent's Cavern molar is not taurodont.  Taurodontism does occur in some modern humans, but it is very rare.  In Neanderthals, taurodontism is considered nearly diagnostic, but there is a small but significant percentage of Neanderthals who have non-taurodont molars.  I'm not sure of the percentages.

Lack of molar taurodontism is a likely reason the KC4 maxilla fragment has always been seen as AMH.  Chris Stringer and Eric Trinkaus are planning another examination of KC4 but we'll have to wait and see what they report.

Dar  

[Daryl Habel]

To all,

I've been digging through the literature I have on Neanderthal dental morphology and found that three isolated adult permanent molars were recovered from the latest finds at the Neanderthal (Feldhofer) type site:

Schmitz R.W., Serre D., Bonani G., Feine S., Hillgruber F., Krainitzki H.,  Pääbo S., & Smith F. (2002). The Neandertal type site revisited: Interdisciplinary investigations of skeletal remains from the Neander Valley, Germany. Proc Natl Acad Sci U S A. 99(20): 13342-13347.

This says: “Radiological analysis of the three permanent molars showed no unusual expansion of the pulp cavities (taurodontism), but the presence of this feature is highly variable in Neandertals, especially in maxillary teeth. “
The reference given for this is: Skinner, M F.; Sperber, G H. Atlas of the Radiographs of Early Man. New York: Liss; 1992.

Since KC4 is maxillary, if the above is true, the absence of taurodontism might not necessarily 'prove' the specimen is AMH.  On the other hand, in my lit-dig I've come across:

Bailey, S.E. (2002). A closer look at Neanderthal postcanine dental morphology: the mandibular dentition.  The Anatomical Record (New Anat.). 269: 148-156.

This has some things to say about dental traits that are (as I read it) more Neanderthal-diagnostic than molar taurodontism, but this study (which I hadn't read before and need to read more closely) is focused on characters of mandibular dentition and, in any case, most, if not all, these characters are tooth crown relief contours (which appear to be absent in the worn-down teeth of KC4).

I'm still looking for potential diagnostic maxillary traits.  I think I remember reading somewhere that the position of the zygomatic base relative to the upper molars might be a candidate.  But that's a foggy memory and I'm not sure about this.

Dar  

[rich]

just a few notes taken from my records re present subject and regarding nean dentition:

effective slower maturaton  & eruption time correlates to increase in brain/body size ratio. This could have occurred earlier in ancestral history.                     
enamel hypoplsia common through nean tooth development suggests times of stress through lifetime of tooth   formation.

large anterior lower teeth  maent alveolus large and * no chin obvious on mandible.               
 slow growth trajectory  & thick enamel                     
dental autapormorphies.- high incidence of mid trigonid crest in lower molars,
a unique morphology of lower PM but note these are not seen in the Maur mandible thought to be an ancestor of nean.                     
also their anterior teeth are worn down because of probable use of their teeth in some labour technique where they used their teeth as a third hand so to speak.         

then to mh            
the first would have been robust          45% increase in EQ cf erectus.            
Slow growth trajectory.         
 prominent chin appears            
earliest enamel formation of EDJ deposited in smaller increments * longer formation time * later eruption ages for individual. Eg M1 @ 6  * later maturation of individual and slower growth in person                      
enamel hypoplasia common around weaning but not a lot after                     

[rich]

on reading my last post it does not make clear the implications.
the differing ages and amounts of hypoplastic activity within the enamel of the tooth should be an indication of sorts.
ie there are far more lines of under calcification and activity visible under the micro seen throughout the thichkness of the nean enamel and only ones associated with the age of weaning in amh.
as dar pointed out the cusps of the teeth are worn away so that makes one of the points nul and void, also it refers to lower and not upper though there are differnces i am sure in upper molars.
the third point alludes to a new and different construction and prismatic formation of the first layers of enamel layed down at the enamel/dentine border, seen in amh. under the micro this prism formation and amount of calcification is different to what went on in the teeth of pops before amh.
rich

[Daryl Habel]

Rich,

There is the question in my mind of whether the Kent's Cavern 4 maxilla fragment and teeth has ever been examined for the traits you mention.  Since most of these traits have been published in the recent past (?20 years?) and were AFAIK not known when Sir Arthur Keith made his examination in 1927, it seems (to me) doubtful he even looked for such traits in KC4.  I haven't been able to locate any reference for a more recent published examination of KC4 than Keith's.  Perhaps  the new physical examination that is scheduled to be conducted by Chris Stringer and Eric Trinkaus will answer some of these questions.

Dar