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Author Topic:   New Species of Homo Discovered: Homo naledi
jar
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Message 121 of 163 (768820)
09-14-2015 10:32 AM
Reply to: Message 120 by NosyNed
09-14-2015 10:30 AM


Re: So that's the difference
If you count an equal number of joints from the tip of a digit what lengths are found?

Anyone so limited that they can only spell a word one way is severely handicapped!

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NosyNed
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Message 122 of 163 (768825)
09-14-2015 11:10 AM
Reply to: Message 121 by jar
09-14-2015 10:32 AM


Re: So that's the difference
If you count an equal number of joints from the tip of a digit what lengths are found?

Well, if I start at the tip of each digit and stop at the 3rd joint (the top of the palm for fingers and the wrist for the thumb) then my thumb is close in length to my middle finger. I wasn't counting the bones of the palm which I guess Faith is so we legitimately end up with different answers both of which are right but depend on how you define "finger".

I don't know what the correct anatomical definition is.


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RAZD
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Message 123 of 163 (768847)
09-14-2015 12:39 PM
Reply to: Message 122 by NosyNed
09-14-2015 11:10 AM


Yes, that's the hand difference, now let's look at the foot?
This is the picture that Malcolm posted previously of a modern human hand:

Note that the thumb is missing an Intermediate Phalange, a trait common to hominids (includes apes).

If you compare bone lengths you can see that the thumb bones compare to the little finger bone lengths.

This is the previously posted Homo naledi hand:

As you can see it has traits very similar to the modern human hand diagram.

As noted in a previous post though, when you look at the fine detail (hard to see from these pictures), there are differences that the scientists find significant: the naledi bones have more curvature (intermediate between australopiths and later homos) and the joint structure is different.

Faith says that these minor differences fall within the normal variation of our species, based on her well documented knowledge of human hand bones

Thus she says it is human.

Now let's look at the foot, and see how similar that is:

quote:
Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa

Abstract
Homo naledi ... also exhibits a humanlike foot and lower limb. ...

Holotype
... Dinaledi foot 1 (F1) is a partial foot skeleton missing only the medial cuneiform and the phalanges of rays II–V. Foot 1 is composed of specimens U.W. 101-1322, −1417 to −1419, −1439, −1443, −1456 to −1458, −1551, −1553, −1562, and −1698.

Figure 9. Foot 1 in (A) dorsal view; and (B) medial view.

(C) Proximal articular surfaces of the metatarsals of Foot 1, shown in articulation to illustrate transverse arch structure. Scale bar = 10 cm.

Differential diagnosis
Foot (F1)
The foot of H. naledi differs from the pedal remains of Au. afarensis, Au. africanus, and Au. sediba in having a calcaneus with a weakly developed peroneal trochlea. F1 also differs from Au. afarensis in having a higher orientation of the calcaneal sustentaculum tali. F1 can be further distinguished from pedal remains attributed to Au. africanus in having a higher talar head and neck torsion, a narrower Mt1 base, a dorsally expanded Mt1 head, and greater proximolateral to distomedial orientation of the lateral metatarsals. The H. naledi foot can be further differentiated from the foot of Au. sediba in having a proximodistally flatter talar trochlea, a flat subtalar joint, a diagonally oriented retrotrochlear eminence and a plantar position of the lateral plantar process of the calcaneous, and dorsoplantarly flat articular surface for the cuboid on the Mt4 (Zipfel et al., 2011). Pedal remains of Au. garhi are currently unknown, and those of P. robustus are too poorly known to allow for comparison.

The H. naledi foot can be distinguished from the foot of H. habilis by the presence of a flatter, non-sloping trochlea with equally elevated medial and lateral margins, a narrower Mt1 base, greater proximolateral to distomedial orientation of the lateral metatarsals, and a metatarsal robusticity ratio of 1 > 5 > 4 > 3 > 2. Pedal morphology in H. rudolfensis is currently unknown, and that of H. erectus is too poorly known to allow for comparison. The H. naledi foot can be distinguished from the foot of H. floresiensis by a longer hallux and shorter second through fifth metacarpals relative to hindfoot length, and higher torsion of the talar head and neck.

The foot of H. naledi can be distinguished from the foot of H. sapiens only by its flatter lateral and medial malleolar facets on the talus, its low angle of plantar declination of the talar head, its lower orientation of the calcaneal sustentaculum tali, and its gracile calcaneal tuber.


It would appear that the naledi foot is also very similar to modern human, maybe even more similar than the hand.

And it looks like hands (adapted for tool use?) and feet (adapted for bipedal upright locomotion) were well established in the early Homo evolution.

Perhaps for comparison we could have some australopith and modern human feet images posted?

Enjoy

Edited by RAZD, : clrty


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Diomedes
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Message 124 of 163 (768862)
09-14-2015 3:18 PM
Reply to: Message 123 by RAZD
09-14-2015 12:39 PM


Re: Yes, that's the hand difference, now let's look at the foot?
FYI folks, there is a Nova special on this Wednesday (check your local stations) called 'Dawn of Humanity'. It will be discussing this recent South African find along with other discoveries.
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RAZD
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Message 125 of 163 (768892)
09-14-2015 6:44 PM
Reply to: Message 124 by Diomedes
09-14-2015 3:18 PM


Re: Yes, that's the hand difference, now let's look at the foot?
... there is a Nova special on this Wednesday (check your local stations) called 'Dawn of Humanity'. It will be discussing this recent South African find along with other discoveries.

Including the discovery of Au. sediba.

And as mentioned in Message 68 it can be watched on-line at

The NOVA/National Geographic Special, “Dawn of Humanity,” ... is streaming online now (click this link).

It's an hour, and a very well spent hour.

Enjoy
(I did)


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RAZD
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Message 126 of 163 (768893)
09-14-2015 6:51 PM
Reply to: Message 125 by RAZD
09-14-2015 6:44 PM


Another source of information from NCSE
Another source:

Homo naledi—Another Awesome Twig on the Human Family Tree, Part 1

This find is a real treasure trove.

More to come.

Enjoy


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RAZD
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Message 127 of 163 (768964)
09-15-2015 10:40 AM
Reply to: Message 123 by RAZD
09-14-2015 12:39 PM


Now here's an interesting exercise -- comparing hand and foot bones ...
Here's a diagram of a foot's bone structure beside the hand picture from Malcolm:

Curiously I notice several things:

  • metatarsals instead of metacarpals
  • proximal phalanges and distal phalanges on both on all toes\thumb\fingers
  • intermediate phalanges only on little toes\fingers, missing on both thumb and big toe
  • the carpal bones also match up to the cuniform and cuboid bones, with two toes meeting at the cuboid bone in similar fashion to the two fingers that meet and a single carpal

In older hominid fossils the big toe is slightly separated from the other toes -- intermediate between the hand like foot of an ape and the modern human foot, as demonstrated by the bones.

Enjoy

ps - iirc there was a discussion of australopithicus feet on one of the 'Lucy' threads, complete with matching it to the Laetoli footprints. I'll try to find it later.

Edited by RAZD, : clrty

Edited by RAZD, : sp


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RAZD
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Message 128 of 163 (769140)
09-16-2015 9:11 PM
Reply to: Message 127 by RAZD
09-15-2015 10:40 AM


Re: Now here's an interesting exercise -- comparing hand and foot bones ...
ps - iirc there was a discussion of australopithicus feet on one of the 'Lucy' threads, complete with matching it to the Laetoli footprints. I'll try to find it later.

So I looked through {composite\Lucy\Little-Foot\Australopithicus} was bipedal and found

Message 20: But if you think "little foot" was an unexpected find, then compare this 1935 prediction with "little foot" (same article):

quote:

A find that matches a prediction based on evolution.

The clearest pictures of the Laetoli footprints that I could find are:

Another article on matching footprints to fossils is

The Laetoli Footprint Trail: 3D reconstruction from texture; archiving, and reverse engineering of early hominin gait ...

Unfortunately that last link is broken.

The important thing to observe though is that the critical alignment of the big toe metacarpal onto the cuneiform bone is written in the fossil and it shows the slight splay of the big toe angled away from the other bones in a position intermediate between that of later hominids and that of apes.

Now some may think that the "Little Foot" fossil evidence is a little scant to extrapolate to the full footprint, but there are others ... it will take a little more digging to find them.

Enjoy


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NoNukes
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Message 129 of 163 (769187)
09-17-2015 6:05 AM
Reply to: Message 123 by RAZD
09-14-2015 12:39 PM


Re: Yes, that's the hand difference, now let's look at the foot?
Thus [because of the hand] she says it is human.

Now let's look at the foot, and see how similar that is

Now that everyone is on the same page about the hand, and possibly even about the foot, the interesting thing is how different much of the rest of the skeleton is from modern humans. Because this is clearly a finding of a formerly living being with human-like hands that was not a homo sapiens.


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RAZD
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Message 130 of 163 (769204)
09-17-2015 8:27 AM
Reply to: Message 129 by NoNukes
09-17-2015 6:05 AM


Getting ahead?
Now that everyone is on the same page about the hand, and possibly even about the foot, the interesting thing is how different much of the rest of the skeleton is from modern humans.

It is fascinating to me how "modern" the foot is, that there has been so little further development of this part of the skeleton. This with the hand shows how macroevolution is not an all-at-once change, but an accumulation of changes over generations. The intermediates are a mosaic of ancestral traits and new derived traits.

... Because this is clearly a finding of a formerly living being with human-like hands that was not a homo sapiens.

I had hoped to get to the pelvic girdle next as that would tie back to discussions on Australopithicus but I did not see a reconstructed pelvis in the paper. Perhaps when they go back and dig further they might find one. We do have femurs, an abundance of femurs, but I don't think those will be as convincing.

That pretty well leaves us with the head\skull\cranial reconstruction:

quote:
Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa

Abstract

Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology.

... the skull had several unique features, it had a small braincase that was most similar in size to other early hominin species that lived between four million and two million years ago. ...

Holotype

Dinaledi Hominin 1 (DH1) comprises the partial calvaria, partial maxilla, and nearly complete mandible of a presumed male individual, ...

Figure 2. Holotype specimen of Homo naledi, Dinaledi Hominin 1 (DH1).

U.W. 101-1473 cranium in (A) posterior and (B) frontal views (frontal view minus the frontal fragment to show calvaria interior). U.W. 101-1277 maxilla in (C) medial, (D) frontal, (E) superior, and (F) occlusal views. (G) U.W. 101-1473 cranium in anatomical alignment with occluded U.W. 101-1277 maxilla and U.W. 101-1261 mandible in left lateral view. U.W. 101-1277 mandible in (H) occlusal, (I) basal, (J) right lateral, and (K) anterior views. Scale bar = 10 cm.

Paratypes

Dinaledi Hominin 2 (DH2) is a partial calvaria that preserves parts of the frontal, left and right parietals, right temporal, and occipital (Figure 3; Supplementary file 1). Dinaledi Hominin 3 (DH3) is a partial calvaria of a presumed female individual that preserves parts of the frontal, left parietal, left temporal, and sphenoid (Figure 4, Supplementary file 1). Dinaledi Hominin 4 (DH4) is a partial calvaria that preserves parts of the right temporal, right parietal, and occipital (Figure 3; Supplementary file 1). Dinaledi Hominin 5 (DH5) is a partial calvaria that preserves part of the left temporal and occipital (Figure 3; Supplementary file 1). U.W. 101-377 is a mandibular fragment that preserves dental anatomy in an unworn state; at present it cannot be definitively associated with any of these Dinaledi Hominin (DH) individuals, and indeed might represent another individual (Figure 5; Supplementary file 1). These cranial specimens agree closely in nearly all morphological details where they overlap in areas preserved except those we interpret as related to sex.

Figure 3. Cranial paratypes.

(A) DH2, right lateral view. (B) DH5, left lateral view. (C) DH4, right lateral view. (D) DH4, posterior view. Scale bar = 10 cm.

Figure 4. Paratype DH3.

(A) Frontal view. (B) Left lateral view, with calvaria in articulation with the mandible (U.W. 101-361). (C) Basal view. Mandible in (D) medial view; (E) occlusal view; (F) basal view. DH3 was a relatively old individual at time of death, with extreme tooth wear. Scale bar = 10 cm.

Figure 5. U.W. 101-377 mandible.

(A) Lateral view; (B) medial view; (C) basal view; (D) occlusal view. (D) The distinctive mandibular premolar morphology with elongated talonids in unworn state. Scale bar = 2 cm.


That is the fossil evidence.

Due to the volume of information I am going to break this into three posts -- the fossil evidence (here), the comparison to other fossils, and the reconstruction of the skull.

Enjoy


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RAZD
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Posts: 18472
From: the other end of the sidewalk
Joined: 03-14-2004
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(1)
Message 131 of 163 (769217)
09-17-2015 12:12 PM
Reply to: Message 130 by RAZD
09-17-2015 8:27 AM


Re: Getting ahead? (pt 2)
Moving on to the comparisons then:

quote:
Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa

Differential diagnosis

This comprehensive differential diagnosis is based upon cranial, dental and postcranial characters. The hypodigms used for other species are detailed in the ‘Materials and methods’. ...

Cranium, mandible, and dentition (DH1, DH2, DH3, DH4, DH5, U.W. 101-377)

The cranium of H. naledi does not have the well-developed crest patterns that characterize Australopithecus garhi (Asfaw et al., 1999) and species of the genus Paranthropus, nor the derived facial morphology seen in the latter genus. The mandible of H. naledi is notably more gracile than those of Paranthropus. Although maxillary and mandibular incisors and canines of H. naledi overlap in size with those of Paranthropus, the post-canine teeth are notably smaller than those of Paranthropus and Au. garhi, with mandibular molars that are buccolingually narrow.

H. naledi differs from Australopithecus afarensis and Australopithecus africanus in having a pentagonal-shaped cranial vault in posterior view, sagittal keeling, widely spaced temporal lines, an angular torus, a deep and narrow digastric fossa, an external occipital protuberance, an anteriorly positioned root of the zygomatic process of the maxilla, a broad palate, and a small canine jugum lacking anterior pillars. The anterior and lateral vault of H. naledi differs from Au. afarensis and Au. africanus in exhibiting only slight post-orbital constriction, frontal bossing, a well-developed supraorbital torus with a well-defined supratoral sulcus, temporal lines that are positioned on the posterior rather than the superior aspect of the supraorbital torus, a root of the zygomatic process of the temporal that is angled downwards approximately 30° relative to the Frankfort Horizontal (FH) and which begins its lateral expansion above the mandibular fossa rather than the EAM, a mandibular fossa that is positioned medial to the wall of the temporal squame, a small postglenoid process that contacts the tympanic, a coronally oriented petrous, and a small and obliquely oriented EAM. The H. naledi mandible exhibits a more gracile symphysis and corpus, a more vertically inclined symphysis, a slight mandibular incurvation delineating a faint mental trigon, and a steeply inclined posterior face of the mandibular symphysis without a post incisive planum. The incisors of H. naledi overlap in size with some specimens of Au. africanus, though the canines and post-canine dentition are notably smaller, with relatively narrow buccolingual dimensions of the mandibular molars. The maxillary I1 lacks a median lingual ridge and exhibits a broad and uninflated lingual cervical prominence, the lingual mesial and distal marginal ridges do not merge onto the cervical prominence in the maxillary I2, the mandibular canine exhibits only a weak lingual median ridge and a broad and uninflated lingual cervical prominence, and the buccal grooves on the maxillary premolars are only weakly developed. H. naledi exhibits a small and isolated Carabelli's feature in the maxillary molars, unlike the more prominent and extensive Carabelli's feature of Australopithecus. Moreover, the H. naledi mandibular molars possess small, mesiobuccally restricted protostylids that do not intersect the buccal groove, differing from the typically enlarged, centrally positioned protostylids that intersect the buccal groove in Australopithecus.

The cranium of H. naledi differs from Australopithecus sediba (Berger et al., 2010) in exhibiting sagittal keeling, a more pronounced supraorbital torus and supratoral sulcus, a weakly arched supraorbital contour with rounded lateral corners, an angular torus, a well-defined supramastoid crest, a curved superior margin of the temporal squama, a root of the zygomatic process of the temporal that is angled downwards approximately 30° relative to FH, a flattened nasoalveolar clivus, weak canine juga, an anteriorly positioned root of the zygomatic process of the maxilla, and a relatively broad palate that is anteriorly shallow. The H. naledi mandible (DH1) has a mental foramen positioned superiorly on the corpus that opens posteriorly, unlike the mid-corpus height, more laterally opening mental foramen of Au. sediba. The maxillary and mandibular teeth of H. naledi are smaller than those of Au. sediba, with mandibular molars that are buccolingually narrow. The lingual mesial and distal marginal ridges do not merge onto the cervical prominence in the maxillary I2, the paracone of the maxillary P3 is equal in size to the protocone, the protoconid and metaconid of the mandibular molars are equally mesially positioned, and the lingual cusps of the molars are positioned at the occlusobuccal margin while the buccal cusps are positioned slightly lingual to the occlusobuccal margin. Also, Au. sediba shares with other australopiths a protostylid that is centrally located and which intersects the buccal groove of the lower molars, unlike the small and mesiobuccally restricted protostylid that does not intersect the buccal groove in H. naledi.

The cranium of H. naledi differs from Homo habilis in exhibiting sagittal keeling, a weakly arched supraorbital contour, temporal lines that are positioned on the posterior rather than the superior aspect of the supraorbital torus, an angular torus, an occipital torus, only slight post-orbital constriction, a curved superior margin of the temporal squama, a suprameatal spine, a weak crista petrosa, a prominent Eustachian process, a small EAM, weak canine juga, and an anteriorly positioned root of the zygomatic process of the maxilla. Mandibles attributed to H. habilis show a weakly inclined, shelf-like post incisive planum with a variably developed superior transverse torus, unlike the steeply inclined posterior face of the mandibular symphysis of H. naledi, which lacks both a post incisive planum or superior transverse torus. The H. naledi mandible (DH1) has a mental foramen positioned superiorly on the corpus that opens posteriorly, while the mental foramen of H. habilis is at mid-corpus height and opens more laterally. The maxillary and mandibular dentitions of DH1 are smaller than typical for H. habilis. The mandibular P3 of H. naledi is more molarized and lacks the occlusal simplification seen in H. habilis; it has a symmetrical occlusal outline, and multiple roots (two roots: mesiobuccal and distal) not seen in H. habilis. The molars of H. naledi lack crenulation, secondary fissures, and supernumerary cusps that are common to H. habilis. The protoconid and metaconid of the mandibular molars are equally mesially positioned.

The cranium of H. naledi differs from Homo rudolfensis by its smaller cranial capacity, and by exhibiting frontal bossing, a post-bregmatic depression, sagittal keeling, a well-developed supraorbital torus delineated by a distinct supratoral sulcus, temporal lines that are positioned on the posterior rather than the superior aspect of the supraorbital torus, an occipital torus, an external occipital protuberance, only slight post-orbital constriction, a small postglenoid process, a weak crista petrosa, a laterally inflated mastoid process, a canine fossa, incisors that project anteriorly beyond the bi-canine line, and a shallow anterior palate. As in H. habilis, mandibles attributed to H. rudolfensis show a weakly inclined, shelf-like post incisive planum with a variably developed superior transverse torus, unlike the steeply inclined posterior face of the mandibular symphysis of DH1, the latter of which lacks either a post incisive planum or superior transverse torus. The mandibular symphysis and corpus of H. naledi are more gracile than those attributed to H. rudolfensis, and the H. naledi mandible (DH1) has a mental foramen positioned superiorly on the corpus that opens posteriorly, unlike the mid-corpus height, more laterally opening mental foramen of H. rudolfensis. The maxillary and mandibular dentition of H. naledi is smaller than that of most specimens of H. rudolfensis, with only KNM-ER 60000 and KNM-ER 62000 appearing similar in size for some teeth (Leakey et al., 2012). The molars of H. naledi lack crenulation, secondary fissures, or supernumerary cusps common in H. rudolfensis. The buccal grooves of the maxillary premolars are weak in H. naledi, and the protoconid and metaconid of the mandibular molars are equally mesially positioned.

H. naledi lacks the typically distinctive long and low cranial vault of Homo erectus, as well as the metopic keeling that is typically present in the latter species. H. naledi also differs from H. erectus in having a distinct external occipital protuberance in addition to the tuberculum linearum, a laterally inflated mastoid process, a flat and squared nasoalveolar clivus, and an anteriorly shallow palate. The parasagittal keeling that is present between bregma and lambda in H. naledi (DH1 and DH3) is less marked than often occurs in H. erectus, including in small specimens such as KNM-ER 42700 and the Dmanisi cranial sample. Also unlike most specimens of H. erectus, H. naledi has a small vaginal process, a weak crista petrosa, a marked Eustachian process, and a small EAM. The mandible of H. erectus shows a moderately inclined, shelf-like post incisive planum terminating in a variably developed superior transverse torus, differing from the steeply inclined posterior face of the H. naledi mandibular symphysis, which lacks both a post incisive planum or a superior transverse torus. The mental foramen is positioned superiorly and opens posteriorly in DH1, unlike the mid-corpus height, more laterally opening mental foramen of H. erectus. The maxillary and mandibular incisors and canines of H. naledi are smaller than typical of H. erectus. The mandibular P3 of H. naledi is more molarized and lacks the occlusal simplification seen in H. erectus, they reveal a symmetrical occlusal outline, and multiple roots (2R: MB+D) not typically seen in H. erectus. Furthermore, the molars of H. naledi lack crenulation, secondary fissures, or supernumerary cusps common in H. erectus.

H. naledi lacks the reduced cranial height of Homo floresiensis, and displays a marked angular torus and parasagittal keeling between bregma and lambda that is absent in the latter species. H. naledi further has a flat and squared nasoalveolar clivus, unlike the pronounced maxillary canine juga and prominent pillars of H. floresiensis. The mandible of H. floresiensis shows a posteriorly inclined post incisive planum with superior and inferior transverse tori, differing from the steeply inclined posterior face of the H. naledi mandibular symphysis, which lacks both a post incisive planum or a superior transverse torus. Dentally, H. naledi is distinguishable from H. floresiensis by the mesiodistal elongation and extensive talonid of the mandibular P4, and the lack of Tomes' root on the mandibular premolars. The molar size gradient of H. naledi follows the M1 < M2 < M3 pattern, unlike the M3 < M2 < M1 pattern in H. floresiensis, and the mandibular molars are relatively mesiodistally long and buccolingually narrow compared to those of H. floresiensis.

H. naledi differs from Middle Pleistocene (MP) and Late Pleistocene (LP) Homo (here we include specimens sometimes attributed to the putative Early Pleistocene taxon Homo antecessor, and MP Homo heidelbergensis, Homo rhodesiensis, as well as archaic Homo sapiens and Neandertals) in exhibiting a smaller cranial capacity. H. naledi has its maximum cranial width in the supramastoid region, rather than in the parietal region. It has a clearly defined canine fossa (similar to H. antecessor), a shallow anterior palate, and a flat and a squared nasoalveolar clivus. H. naledi lacks the bilaterally arched and vertically thickened supraorbital tori found in MP and LP Homo. H. naledi also differs in exhibiting a root of the zygomatic process of the temporal that is angled downwards approximately 30° relative to FH, a projecting entoglenoid process, a weak vaginal process, a weak crista petrosa, a prominent Eustachian process, a laterally inflated mastoid process, and a small EAM. The H. naledi mandible tends to be more gracile than specimens of MP Homo. The mandibular canine retains a distinct accessory distal cuspulid not seen in MP and LP Homo. Molar cuspal proportions for H. naledi do not show the derived reduction of the entoconid and hypoconid that characterizes MP and LP Homo. The mandibular M3 is not reduced in DH1, thus revealing an increasing molar size gradient that contrasts with reduction of the M3 in MP and LP Homo.

H. naledi differs from H. sapiens in exhibiting small cranial capacity, a well-defined supraorbital torus and supratoral sulcus, a root of the zygomatic process of the temporal that is angled downwards approximately 30° relative to FH, a large and laterally inflated mastoid with well-developed supramastoid crest, an angular torus, a small vaginal process, a weak crista petrosa, a prominent Eustachian process, a small EAM, a flat and squared nasoalveolar clivus, and a more posteriorly positioned incisive foramen. The H. naledi mandible shows a weaker, less well-defined mentum osseum than H. sapiens, as well as a slight inferior transverse torus that is absent in humans. The mental foramen is positioned superiorly in H. naledi, unlike the mid-corpus height mental foramen of H. sapiens. The mandibular canine possesses a distinct accessory distal cuspulid not seen in H. sapiens. Molar cuspal proportions for H. naledi do not show the derived reduction of the entoconid and hypoconid that characterizes H. sapiens. The mandibular M3 is not reduced in H. naledi, thus revealing an increasing molar size gradient that contrasts with reduction of the M3 in H. sapiens.


Again, this is a lot of detail, and difficult to follow if you are not into anatomy.

Suffice it to say, that this kind of detail is there, and that it -- especially the head\brain -- is what distinguishes one species from another.

In the next post we can look at the reconstructed skull and what it means for the brain inside.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


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This message is a reply to:
 Message 130 by RAZD, posted 09-17-2015 8:27 AM RAZD has responded

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ringo
Member
Posts: 13026
From: frozen wasteland
Joined: 03-23-2005
Member Rating: 3.5


(2)
Message 132 of 163 (769219)
09-17-2015 12:20 PM
Reply to: Message 130 by RAZD
09-17-2015 8:27 AM


Re: Getting ahead?
RAZD writes:

It is fascinating to me how "modern" the foot is, that there has been so little further development of this part of the skeleton.


It isn't our brains that make us distinct from the other apes. It's our feet.
This message is a reply to:
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Replies to this message:
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 Message 136 by Taq, posted 09-18-2015 4:59 PM ringo has acknowledged this reply

  
Omnivorous
Member (Idle past 380 days)
Posts: 3808
From: Adirondackia
Joined: 07-21-2005


(3)
Message 133 of 163 (769222)
09-17-2015 12:59 PM
Reply to: Message 132 by ringo
09-17-2015 12:20 PM


Re: Getting ahead?
ringo writes:

It isn't our brains that make us distinct from the other apes. It's our feet.

With apologies to Sam & Dave:

quote:
I was brought up on a side street, yes mam
I learned how to love before I could eat
I was educated at woodstock
When I start loving, oh I can't stop

I'm a sole man...



"If you can keep your head while those around you are losing theirs, you can collect a lot of heads."

Homo sum, humani nihil a me alienum puto.
-Terence


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NoNukes
Member
Posts: 9550
From: Central NC USA
Joined: 08-13-2010
Member Rating: 3.1


Message 134 of 163 (769236)
09-18-2015 1:28 AM
Reply to: Message 133 by Omnivorous
09-17-2015 12:59 PM


Re: Getting ahead?
I'm a sole man...

That's freaking awful. Your pun is quite likely the worst thing done to Sam and Dave's hit since the Blues Brothers rendition of the song...


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King

If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? Scott Adams


This message is a reply to:
 Message 133 by Omnivorous, posted 09-17-2015 12:59 PM Omnivorous has acknowledged this reply

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 Message 135 by RAZD, posted 09-18-2015 9:55 AM NoNukes has acknowledged this reply

    
RAZD
Member
Posts: 18472
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.7


Message 135 of 163 (769242)
09-18-2015 9:55 AM
Reply to: Message 134 by NoNukes
09-18-2015 1:28 AM


Re: Getting ahead?
Can we get back to the topic? You can take your sole complaint to the complaint thread ...

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
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