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Boaz wrote:TABLE 2. A nonexhaustive list of plesiomorphic or primitive characters of A. afarensis'

Occipitomarginal sinus
Shallow mandibular fossa
Postglenoid process anterior to tympanic
Extensively pneumatized temporal squama
Flat shallow palate
Pronounced subnasal prognathism
Weak flexion of cranial base
Lateral concavity of nuchal plane
Posterior temporalis larger than anterior
Temporal lines diverge below lambda
Weak articular eminence
Foramen magnum anterior to tympanic tips
M3-temporomandibular joint distance long
Compound temporonuchal crest
Asterionic notch present
Tubular tympanic
Sagittally oriented petrous temporals
Asymmetric P3 outline
Large relative canine size
Canines project in wear
Mesial and distal contact facets on C-
Low masseteric origin
Canine jugum separate from margin of nasal aperture
Canine jugum prominent
Steeply inclined nuchal plane
Medially inflected mastoid processes
Posterior origin of zygomatic arch
Anterior mandibular corpus receding bulbous partly lateral to nasal aperture margins
Maxillary posterior tooth row convergence
Transverse buttress from canine juga to zygomatic arch
Long pedal phalanges
Curved proximal pedal phalanges

Dentition

Grine (1985) discerned four characters of the deciduous dentition that he considered unique to the Hadar and Laetoli samples, which he assigned to one species, A. afarensis. The deciduous canine in this group has a distal apical edge that is elongated and more steeply inclined than in other australopithecines. Three distinguishing characters give a “nonmolariform” aspect to the A. afarensis deciduous molar dentition: the dml (also termed dp3) has a thin distal marginal ridge, the dml and dm2 (also termed dp4) have strongly beveled lingual surfaces on their protocones (mesiolingual cusps), and the dm2 has a protoconid (mesiobuccal cusp) set strongly mesiad of the level of the metaconid (mesiolingual cusp). Johanson (198513) discussed five traits of the adult dentition that have proven “most diagnostic” for A. afarensis. The canines were generally large, both in absolute dimensions compared to other hominid samples and relative to the teeth in the same jaw.

Yohannes Haile-Selassie wrote:

Dental remains from Woranso-Mille. (a) Occlusal (top row) and mesial (bottom row) views of ARI-VP-3/80g (LM2), ARI-VP-1/90 (LM3), ARI-VP-3/80d (LM2) and ARI-VP-1/462 (LM1). These molars show the lingual slope on upper and buccal slope on lower molars like Au. anamensis. (b) MSD-VP-5/50, ARI-VP-3/80a and ARI-VP-2/95, P3s from the Woranso-Mille showing variation in P3 occlusal crown morphology. (c) Comparison of lower deciduous canine root length relative to crown height. KNM-KP 34 725 (Au. anamensis), ARI-VP-1/190 (Woranso-Mille) and A.L. 333-35 (Au. afarensis). Like Au. anamensis, the Woranso-Mille specimen has longer root relative to the crown height compared with Au. afarensis. Image of the Au. anamensis specimen was obtained from Carol Ward and A.L. 333-35 was made from cast.

John Hawks wrote:Early hominins do not have the same extent of canine size dimorphism as other hominoids, but the males do tend to have larger canines than females. In early hominins like A. afarensis, this dimorphism is marked in both projection and diameter of the canines, and the lower third premolars also vary in shape and orientation between males and females. In later hominins, who accentuate the large chewing teeth, the canines still have some size dimorphism in their diameters, but this loses its utility in the robust australopithecines.