Mandibular Premolar Orientation

This character helps define the general shape of the mandible by the orientation of the premolar tooth row. The primitive condition is defined by a U-shaped post canine tooth row ( 0), as a result of a near-parallel orientation of each premolar tooth row that is observed only in Kenyapithecus, Dryopithecus, Pongo, Gorilla, Pan, Sahelanthropus, and Praeanthropus (Begun, 2002 Brunet et al., 2002). Next is the dental arcade being V-shaped as the post canine tooth rows diverge laterally ( 1), as...

The Emergence of H ergaster

Homo habilis and H. ergaster were sympatric for approximately 400,000 years. This means that either a proto-ergaster population split away from an earlier population of H. habilis or they share a common ancestor around 2.3 Ma. The first hypothesis appears more likely, for H. ergaster does not appear in the fossil record until around 300,000 years after the earliest representatives of H. habilis H. ergaster has a temporal range of between 2.0 and 1.5 Ma, while H. habilis has a range of between...

The Early Miocene of Africa

During the Eocene, forest vegetation, increased rainfall, and hotter conditions spread from the equator to the poles. The earth's ecology was relatively homogeneous. With the Eocene Oligocene transition, however, ecological stability started to break down, and the world was thrown into the big chill (Prothero, 1994). By 25 million years ago, the position and shape of the continents where beginning to look something like they do today, though North and South America remained separated, the...

The Emergence of Ardipithecus and Early Australopithecines

By 5 Ma, the hominid populations had split into those that began to walk erect and those that continued to be knuckle-walkers. The adaptation to bipedal walking appears to have occurred over a long period of time, because the earliest hominin fossils with preserved wrist joints, from Ethiopia and Kenya, indicate they retained knuckle-walking adaptations (Richmond & Strait, 2000), like gorillas and chimpanzees. Because gorillas and chimpanzees are both knuckle-walkers, but chimpanzees are...

Mandibular Corpus Robusticity Breadth Height

This character measures the robusticity of the corpus at M2. This feature is of functional and developmental interests because it relates to bone deposition associated with tensile and compressive stress during the masticatory cycle (see Hylander, 1984, 1988 Hylander & Johnson, 1994 Hylander et al., 2000 B. Brown, 1997). All data for the hominins has been taken from B.A. Wood (1991), while all extant hominid data is from DWC (unpublished). Most of the values for the Miocene hominids have...

Frontal Sinus Development

Three character states are recognized large (0), intermediate to small (1), and absent (2). The frontal sinus in Dryopithecus is developed because it extends below nasion (Begun, 2002). A well-developed frontal sinus is observed in P. boisei (Tobias, 1967), P. robustus (Tobias, 1991), K. rudolfensis as defined by KNM-ER 1470 (B.A. Wood, 1991), and H. ergaster specimen KNM-WT15000 (Walker & Leakey, 1993b). Gorilla, Pan, and H. sapiens share a similar development (Spoor & Zonneveld, 1999),...

The Original Miocene Out of Africa

The paleobiogeography of the earliest representatives of our own family, the Hominidae, during the Middle and Late Miocene has recently been discussed by a number of researchers (Andrews, 1992 Ciochon & Etler, 1994 de Bonis & Koufos, 1994 Andrews et al, 1996 Pilbeam, 1996, 2002 Begun et al., 1997 Begun & Gulec, 1998 Stewart & Disotell, 1998 Andrews & Bernor, 1999 Agusti et al., 1996, 2001 Begun, 2001, 2002 Heizmann & Begun, 2001 Kohler et al, 2001 Kelley, 2002 Cameron, in...

The Fate of Homo neanderthalensis

All the available paleoanthropological, archeological, and molecular evidence strongly supports the displacement of more primitive endemic human populations by modern humans who recently arrived from Africa. In the case of the Neanderthals at least, it appears to have been displacement by rapid extinction. The correlation in western and central Europe between the disappearance of Neanderthals from both the paleontological and archeological records, around 27,000 years ago, and the appearance of...

Vaginal Process Size

The vaginal process forms part of the tympanic plate, basal to the styloid process. The position and orientation of the styloid-vaginal process are of functional significance in vocalization patterns, because it will influence the position of the hyoid bone and associated soft tissues (Aiello & Dean, 1990). The process is absent to small ( 0) in Pongo, Gorilla, Pan, Praeanthropus, P. walkeri, Australopithecus, and H. habilis, while being moderate to large ( 1) in P. robustus, P. boisei, H....

Palate Breadth

Palate breadth is defined by an index of external palate breadth at M2 divided by orbital height. The method used for defining the three character states used here is described earlier (see character 2). All data for the fossil hominins have been taken from B.A. Wood (1991), and data for the extant and Miocene hominids are unpublished data collected by Cameron. The mean index for the extant hominids (n 124) is 1.66, with one standard deviation equal to 0.13. Thus, a narrow palate is defined by...

Temporal Fossa Size

This character is used to measure independently the relative degree of temporalis development, regardless of parietal temporal bone size. It is distinct from sagittal crest development, which will be correlated directly with the size of these bones, relative to muscle development. For example, a small cranium with moderate to strong temporalis development e.g., species of P. robustus will require the formation of a temporal crest to help expand the attachment space requirements of the...

The Earliest Tool Users and Toolmakers and Early Hominin Behavior

Recognizable stone tools first appear in the archaeological record around 2.5 Ma in east Africa they are associated with two hominin groups, Paranthropus and early Homo see Susman, 1988 Schick amp Toth, 1993 Kimbel et al., 1997 Deacon amp Deacon, 1999 Pickering, 2001 Figure 4.8 . These early stone tools are referred to as the Oldowan industry because they were first recognized from localities within Olduvai Gorge. So far the earliest stone tools are those found at the Gona and Bouri sites,...

Palate Prognathism Relative to Sellion

This is calculated as an index of palate length divided by plate protrusion relative to sellion as defined by Rak 1983 see his Plate 34 and Table 3 . A prognathic premaxilla is defined by an index greater than 0.57 intermediate prognathism is between 0.30 and 0.57, and weak prognathism is an index less than 0.30. The mean indices for hominin taxa have been taken from Rak 1983 . All hominin and extant African ape allocations follow Strait et al. 1997 and Strait amp Grine 2001 , except for...

The Rise of Homo heidelbergensis

Homo Heidelbergensis

The earliest widely accepted appearance of H. heidelbergensis is around 600,000 years ago, as represented by the Bodo skull from Ethiopia Figure 7.2 . There appears to be a continuum of this African deme, to at least 260,000 years ago Gr n et al., 1996 , when the South African Florisbad specimen begins to show real changes, or perhaps to even later if one accepts that the Jebel Irhoud specimens from Morocco represent members of this species Howell, 1998 F.H. Smith, 2002 which we decidedly do...

Evolution of the Miocene Great Apes

The small-bodied ape ran across the top of a tree branch, away from the anger of the dominant male of the group. In haste to get away, however, it had underestimated the thickness and strength of the branch, which gave way. The ape fell to the ground, breaking a forelimb it yelled in pain. Above, the other apes started a commotion and ran across the branches in anxious movements. The yelling would surely bring carnivores to the small patch of tree cover, which was an island of refuge in the...

The Emergence of Kenyanthropus and Australopithecus

Kenyanthropus platyops originates from geological deposits dating to around 3.5 million years ago M.G. Leakey et al., 2001 . Its discovery so recently, with its unique anatomical features so unexpected, sent shockwaves through the anthropological world and started a flurry of speculation. Indeed, recently T.D. White 2003 has suggested that the cranium of the type specimen of Kenyanthropus platyops specimen KNM-WT 40000 may actually represent a specimen of Praeanthropus, for he suggests that the...

Glenoid Fossa Depth

Four character states are defined deep, variable, intermediate between deep and shallow , and a shallow fossa. The depth of the glenoid process is clearly associated with the requirements of the masticatory apparatus temporomandibular joint and is of functional significance. This is also aligned to developmental processes associated with osteoclast osteoblast activity and bone drift, which will affect mandibular and lower facial form Enlow amp Hans, 1996 . This character is measured as an index...

Canine Fossa Development

A canine fossa is defined by a distinct depression or hollow of the bone table posterior to the canine within the lateral maxillary wall. In the extant hominids it is usually associated with a developed transverse buttress, located immediately above the infraorbital foramen see Rak, 1983 . While this feature in some taxa may be associated with sexual dimorphism i.e., greater development in males , there is evidence that it can also be well defined in extant hominid females personal observation...

Info

Sahelanthropus K. platyops K. rudolfensis H. habilis H. ergaster H. sapiens Australopithecus P. walkeri P. boisei P. robustus Garhi Figure 5.3 Majority-rule typology, two steps beyond consensus see text for details . 3 steps i.e., 390 , resulting in the tree shown in Figure 5.4, from 2,096 possible trees. This tree confirms the previous topologies, the only exception being that Praeanthropus is now shown to share a last common ancestor with Sahelanthropus, the garhi group, and more derived...

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Digastric Muscle Insertion

The digastric fossa is the site of origin for the digastric muscle. This muscle is responsible for raising the hyoid bone as well as the opening action of the mandible Aiello amp Dean, 1990 . As such, it is of functional significance, especially in terms of the masticatory apparatus. A broad and shallow fossa is observed in Pongo which is very broad , Gorilla, Pan, Praeanthropus, Australopithecus, and P boisei 0 . A deep and narrow notch is observed in Ardipithecus, K. platyops, P. robustus, H....

Incisor Alveoli Prognathism

This character is defined by the prognathism of the incisor complex relative to the bi-canine line this is distinct from the previous character subnasal prognathism-angle because this character measures the degree of anterior migration of the incisor complex, while the previous character measures degree of subnasal prognathism, relative to height of the nasal clivus. As such, this feature helps measure degrees of incisor crowding as well as the anterior or posterior migration of the incisor...

Inferior Mandibular Transverse Torus

A developed inferior transverse torus helps withstand stresses associated with mastication, related to medial and lateral wishboning of the mandible, as well as increasing resistance to dorsoventral shear Hylander, 1984, 1988 Hylander amp Johnson, 1994 Hylander et al, 2000 . This character is distinct from the previous character, because a deep symphysis may or may not have a developed inferior transverse torus. Thus, there is no clear association between these features, even though they both...

Infraorbital Foramenina Location

This character is likely of developmental interest in terms of its inferior migration and implications for differential patterns in the hominin capsular system. Three states are recognized. The infraorbital foramen is located within the top 50 of the malar 0 , observed in Pongo, Gorilla, Pan, Praeanthropus, H. habilis, H. ergaster, and H. sapiens. Also, Andrews amp Walker 1976 suggest that the infraorbital foramen in Kenyapithecus specimen KNM-FT 46 must have been high set, given that it, and...

The Original Out of Africa

The earliest fossil hominins so far found outside of the African continent are from Dmanisi, in Georgia. Archaeologists digging a medieval site found the first specimen, a mandible, in association with Oldowan-like tools it was dated to between 1.96 and 1.77 Ma and allocated to H. erectus Gabunia amp Vekua, 1995 . Recently three skulls have been discovered from the same locality, and most now consider them to represent members of a European deme of H. ergaster Gabunia et al., 2000a Vekua et...

Interorbital Breadth

The character is generated from metric data and is defined by an index of mid-interorbital breadth divided by orbital height see earlier . A narrow interorbital has often been argued to by a synapomorphy of the Ponginae and is associated with patterns of airorynchy see Shea, 1985, 1988 Andrews, 1992 Cameron, 2002 . As such, this character is of developmental and phylogenetic interest. The extant hominid mean is 0.45 n 123 , with one standard deviation of 0.11. Thus, the intermediate range is...

Early Hominin Social Dynamics

Three main archaeological interpretations of Plio- Pleistocene hominid in behavior have been proposed. While the models emphasize the behavioral repertoire of early Homo for they focus on stone tool technologies and their distribution over the landscape they are probably relevant to the behavioral features of the australopithecines too. The first was proposed by the Harvard archaeologist Glynn Isaac, who became famous for his archaeological excavations and interpretations of the localities...

Mandibular Extramolar Sulcus Width

This feature has been related to a more parabolic shape in the dental arcade, resulting in an M3 placed more medially then the M2, and will result in a large space between the M3 and the ramus, which is said to be essential in accommodating transverse movements of the M3, both of which lie posterior to the ramus see Aiello amp Dean, 1990 . The character state definitions and most species allocations as provided by Strait et al. 1997 and Strait and Grine 2001 are followed here, with only one...

Subnasal Length

This is a chord distance from nasospinale to prosthion, so it is not a measure of subnasal prognathism. Subnasal prognathism is measured in character 49. Subnasal length is defined as an index against orbital height. The mean extant hominid value for this index is 0.72, with 1 standard deviation of 0.13. Thus, an intermediate range is defined by values falling between 0.59 and 0.85. Data for fossil hominins has been taken from B.A. Wood 1991 , while all other values have been constructed from...

Inferior Orbital Margin

This feature helps define the depth of the face Cameron, 1997a . It is defined by the horizontal position of the inferior orbital margins against the superior nasal aperture margin viewed anteriorly . Three states are recognized. The first is defined by inferior orbital margins that are positioned well above the superior nasal aperture margin, indicating a tall mid-face 0 next is the intermediate condition 1 and finally, the inferior orbital margins are aligned to or below the superior nasal...

The Earliest Members of the Neanderthal Lineage

Homo Bergensis Skull Diagram

Another group of mainly European specimens, which some believe represent the basal stock from which the Neanderthal ultimately evolved, have been allocated to a species H. steinheimensis for the moment we partly following Howell, 1998 will use this name. This species is best represented by its type specimen, the Steinheim skull near Stuttgart in Germany Figure 7.6 , the Sima de los Huesos specimens from Atapuerca in northern Spain, the Swanscombe cranium from England, and the Narmada cranium...

The First African Exodus The Emergence of Early Homo in Europe and Asia

The sabertooth big cat had been dead for only a few minutes and had not yet attracted attention from the roaming scavengers of the sky and savanna plains. Quietly the hominin approached the cat. It was most unusual to be the first on the scene of such a prize, a large cache of fresh meat. Looking around she picked up a number of large volcanic rock fragments and begun to hammer out a number of crude but very sharp flakes. She looked around to make sure that no other carnivores were approaching....

External Cranial Base Flexion

This feature is developmentally significant because it relates to a number of mosaic influences that will affect a number of morphological patterns, including facial orientation, neuro-orbital disjunction, postorbital constriction and thus indirectly influencing the development of the tempo-ralis through the size of the temporal fossae , and development of the supraorbital torus, to mention just a few see main text for further details . Given the usually poor preservation of the phenotypic...

Mid FacialUpper Facial Breadth

This is defined by an index of bijugal bi-frontomalare temporale, using the same method described for character 2, to construct the character states. This feature is distinct from character 44, because it describes the breadth of the upper face relative to the mid-face, while the previous character measures the relative breadth of the upper face between hominid taxa. This feature is likely to be of developmental and functional interest because it relates to musculature development e.g.,...

Foramen Magnum Shape

Unlike Strait et al. 1997 , only two character states are recognized oval round 0 and heart shaped 1 . Strait et al. 1997 and Strait and Grine 2001 recognize a variable state, as described for H. ergaster, because the sub-adult specimen KNM-WT 15000 is said to have a heart-shaped foramen Walker et al., 1986 , while adult specimens of this same species, KNM-ER 3733 and KNM-ER 3883, have an oval foramen. Because of the specimens sub-adult status, the condition observed in KNM-WT 15000 is not...

Inferred Phylogenetic Relationships

The analyses conducted here consistently support certain phylogenetic relationships. The most consistent result is that the australopithecines are paraphyletic. Next, Australopithecus africanus is more derived in the Kenyapithecus Dryopithecus Graecopithecus Pongo Gorilla Pan Sahelanthropus Ardipithecus Anamensis Praeanthropus K. platyops K. rudolfensis H. habilis H. ergaster H. sapiens Australopithecus P. walkeri P. boisei P. robustus Garhi Figure 5.9 Majority-rule typology, three extra steps...

Hollowing at the Mental Foramen

This feature is clearly the result of differential patterns of bone growth e.g., increased osteoblast activity in the region of the foramen and or increased osteoblast activity anterior to it and is likely associated with mandibular robusticity requirements. The same character definitions and character state allocations provided by Strait et al. 1997 and Strait and Grine 2001 are followed for the fossil hominins. The primitive character state is seen in Kenyapithecus, Dryopithecus,...

Postglenoid Process Development

This feature is associated with the requirements of the masticatory apparatus. While it might be thought that this feature should be integrated with glenoid fossa depth, this is not the case, for the depth of the fossa and the development of the process are clearly not coupled. For example, both Gorilla and Pan have a similar development of the postglenoid process large and anteriorly set , yet while Gorilla has intermediate depth of the glenoid fossa, it is shallow in Pan. Differential...

The Grisly Folk The Emergence of the Neanderthals

Prominent Frontal Ridge

Most of the group had left the cave earlier that day. Only one elderly male was left behind. In his youth he had been attacked by a saber-tooth when part of a hunting group with the help of his clan he had just managed to survive, his right arm torn off, his right leg crippled, his left eye put out as he fell heavily in the attack. He was now a cripple and depended on the generosity of his group to survive. It was midafternoon when the valley and the surrounding region were rocked by a massive...

Anterior Nasal Pillars

Rak 1983 has discussed this feature extensively. He associates this feature with P. robustus, arguing that it evolved as a functional response to help absorb stresses associated with the anterior dental complex. This feature, however, should not be confused with canine jugum, which is merely the result of a large robust canine. A true nasal pillar is composed of a column-like buttress that extends well beyond the canine root, helping to define the lateral nasal aperture borders Rak, 1983 . Only...

Homo antecessor

The earliest non-ergaster georgicus erectus hominins in Europe are the specimens from Gran Dolina Cave, Level TD-6, in the Atapuerca Hills of northern Spain, allocated to their own species, Homo antecessor Berm dez de Castro et al., 1997 and dating to around 780,000 years ago Par s amp P rez-Gonz lez, 1995 Falgueres, 1999 Figure 7.1 . Berm dez de Castro et al. 1997 argue that the new species evolved from H. ergaster and represents the likely stem species that gave rise to the Neanderthal...

Nuchal Plane Orientation

This feature will obviously be affected by the development of the nuchal muscles, including the rectus capitis posterior major and minor and the obliquus capitis superior. These muscles are involved in head rotation and elevation. As in the inflation of the mastoid, this character may also be influenced by differential patterns of locomotion see earlier . Of secondary importance in the development of this feature will be the degree pattern of cranial base angulation. Following Kimbel et al....

Male Sagittal Crest Development

The formation of a sagittal crest is clearly associated with masticatory considerations related to temporalis development relative to cranial size. In contrast with Skelton et al. 1986 , Skelton and McHenry 1992 suggest phenotypic features associated with function should not automatically be dismissed as phylogenetically informative, given the concept of phylogenetic niche conservatism see main text . While some may consider character 5 to be correlated with this character, an examination of...

Inferior Orbital Margin Is Rounded Laterally

The inferior orbital margin is considered either rounded laterally or not rounded that is, the inferolateral orbital margin is blunted, with a shallow bend posteriorly into the orbit. The overall significance of this feature in terms of function, development, and phylogeny remains obscure. But given that Strait et al. 1997 and Strait and Grine 2001 have included it in their detailed studies, this feature is retained here. Rounded corners in the taxa preserving this region are present in...

Supraorbital Torus Form

The condition in Dryopithecus Begun, 1992, 1995 Moya-Sola amp Kohler, 1993 , Kenyanthropus M.G. Leakey et al., 2001 , Australopithecus Rak, 1983 , the garhi group Asfaw et al., 1999 , H. habilis Tobias, 1991 , K. rudolfensis, and H. ergaster Wood, 1991 is developed laterally, but is weaker medially 0 . The supraorbital torus in Graecopithecus specimen XIR-1 is developed, but not bridge-like thus, it has a developed torus above each orbit 1 de Bonis et al., 1990 de Bonis amp Koufos, 1993 Dean...

Supraorbital Torus Thickness

This feature is distinct from supraorbital torus form because it measures the thickness of the torus from its midpoint inferosuperior chord distance . This value is divided by orbital height to give an index value. The extant hominoid mean of 0.22 and one standard deviation of 0.07 gives an intermediate range of 0.15-0.29. Data for the extant and fossil Miocene homi-noids is unpublished data held by Cameron unless stated otherwise , while all data of the fossil hominins has been calculated from...

Mandibular Mental Foramen Opening

This character is retained in this analysis because it relates to the vascular system and is thus likely to be of developmental and functional interest. The same character states and species allocations provided by Strait et al. 1997 have been retained. Four states are recognized. The primitive condition is defined by the foramen opening anterosuperiorly 0 as seen in Kenyapithecus Andrews amp Walker, 1976 , Pan, and Ardipithecus Strait amp Grine, 2001 . This is followed by some intra-species...

Mandibular Symphysis Robusticity Breadth Height

This feature measures the general robusticity of the mandibular symph-ysis. That is, a high index means the symphysis is robust, while a lower index means it is more gracile. As suggested by Hylander 1984, 1988 , Hylander and Johnson 1994 , and Hylander et al. 2000 , the thickness of the symphysis has important implications associated with wishboning and its impact on the symphyseal region. All data for the fossil hominins have been taken from B.A. Wood 1991 , and data for the extant hominids...

Subnasal Prognathism Nasal Clivus

This character has been taken from M.G. Leakey et al. 2001 . Their Figure 3 indicates three patterns of subnasal prognathism as measured by the angulation of the nasal clivus prosthion-nasospinale . This character is of interest not only because it relates to subnasal prognathism, but this itself is associated with the requirements of the anterior dentition as well as palate depth, which may be associated with differential patterns of cranial base flexure see D.E. Lieberman et al., 2001 ....

Diagonal Length of the Malar

Malar length is defined as an index of orbitale-zygomaxillare divided by orbital height. The mean for the extant hominids is 1.05, with one standard deviation of 0.15 n 122 specimens . Thus, the intermediate range falls between 0.90 and 1.20. All data for the fossil hominins was taken from B.A. Wood 1991 . The minimum extant hominid value is 0.75 and the maximum value is 1.56. A long malar 0 is observed in P. walkeri specimen KNM-WT 17000 with an index of 1.23, P. boisei with a mean index of...

The Gracile and Robust Australians of the Pleistocene and Holocene

There is no morphological evidence to support a Chinese origin for the Pleistocene Australians e.g., Mungo and Keilor specimens or Indonesians e.g., Wajak cranium . And let us remember that the very Keilor specimen that is said by Thorne 1976 to be an important part of the gracile population is actually shown by Thorne and Wilson 1977 to be within the modern comparative Murray Valley population in shape, but larger Indeed, the only truly gracile Australian specimen is LM 1. A single specimen...

Supraglenoid Gutter Development

This feature is defined by an index of supraglenoid gutter width divided by bi-supramastoid breadth. Pongo has a mean index of 19.8 n 3 , Gorilla has a mean of 28.3 n 3 , and Pan has a mean of 19.4 n 2 . Three states are recognized here. The first is defined as wide 0 in Gorilla and P walkeri with an index of 27.9 an intermediate stage 1 is defined by Pongo, Pan, P. robustus SK 48 24.2 , and P boisei KNM-ER 406 22.9, KNM-ER 732 21.4, and OH 5 24.3 . A narrow gutter 2 defines Australopithecus...

Interpretations of the Australian Paleoanthropological Evidence

Mechanical Means Cranial Deformation

Some of the Mungo individuals represent the oldest Australian human fossils so far discovered. It is one of these, Lake Mungo 3 LM 3 Figure 10.1 , that has now been dated at either 60,000 years ago Thorne et al., 1999 or 40,000 years ago Bowler et al., 2003 . They are described as having a high frontal and relatively thin cranial walls. The cranium is spherical in shape, the frontal lacks much of a supraorbital torus, and the face is relatively flat and lies immediately below the frontal Webb,...

The Emergence of Sahelanthropus Orrorin and the Lothagam Hominids

Sahelanthropus And Orrorin

The recent significant discovery and description of Sahelanthropus tchadensis from Chad by a joint French and Chadian paleoanthropological team, dating to between 6 and 7 million years ago Brunet et al., 2002 Vignaud et al., 2002 see also B.A. Wood, 2002 , has done much to refocus our attention on the divergences of the hominins from other hominids. One of the key differences of the hominins from most other hominids is the development of a primitive form of bipedal locomotion, which would...

Postorbital Constriction

This character state is defined by an index of minimum frontal breadth just posterior to the supraorbital torus divided by maximum upper facial breadth bi-frontomalare temporale . The extant hominids have a mean index value of 0.66, with one standard deviation of 0.08 n 122 . This gives an intermediate range of 0.58-0.74. Thus, any value below 0.58 suggests increased postorbital constriction, while any value above 0.74 is reduced. The minimum extant hominid value is 0.46 and the maximum value...

Mastoid Process Inflation

The overall inflation of the mastoid process will be associated with the development of the sternocleidomastoideus muscle, which is responsible for bending the neck laterally, head rotation as well as flexing the neck, and drawing the head ventrally. As such, this feature is likely to be influenced to some degree by differing patterns of locomotion, for it relates directly to the positioning of the head in relation to the clavicle and sternum points of muscle origin . Two patterns are...

Supraorbital Sulcus Development

The frontal bone is defined by one of the following sulcus is absent 0 mid sulcus 1 intermediate development of sulcus 2 or developed and deep sulcus 3 . While it might be thought that the development of supraorbital sulcus may be correlated with supraorbital development reflecting the same feature , this need not always be the case. For example, while Praeanthropus specimen A.L. 444-2 has the primitive hominid development in its supraorbital development e.g., Gorilla and Pan , its supraorbital...

Later Hominid Phylogenies and Paleobiogeography

Dryopithecine Apes

During the later parts of the middle Miocene, there was an expansion of continental ice sheets and increasing ice buildup in Antarctica, ultimately the result of the earlier separation of Australia from Antarctica, which had so significantly changed ocean currents and their circulation that it lead in time to a direct effect on world climate, producing global cooling Williams et al., 1998 Denton, 1999 . Significant cooling in the northern high latitudes is also indicated by seasonal ice-rafting...

The Emergence of the Rudolfensis Group

In the 1970s, a remarkable skull, KNM-ER 1470 Figure 4.6 known to the general public simply as skull 1470 was discovered at Koobi Fora, in northern Kenya, in deposits we now know to be from 1.89 Ma R.E.F. Leakey, 1973a, 1973b, 1974 Day et al., 1975 B.A. Wood, 1976, 1991 . It was originally allocated to Homo habilis, the earliest and most primitive species of our own genus. Doubts began to grow in the 1980s that 1470 really was Homo habilis it was just too different from the acknowledged...

The Evidence from Africa and the Levant

Skhul Qafzeh

The earliest evidence for the emergence of truly modern humans is from Africa, with the discoveries of H. sapiens from Herto in the Middle Awash of Ethiopia T.D. White et al., 2003 Figure 9.1 . These fossil specimens and stone artifacts have been dated to between 160,000 and 154,000 years ago by precise age determinations based on the argon isotope method Clark et al., 2003 . They are truly significant because they predate the classic Neanderthals and lack any of the Neanderthal derived...