Hominid Fossil Study Guide

Pre-Australopiths

7 - 4.4 mya

Sahelanthropus tchadensis

Dates: 7-6 mya (late miocene)

Location: Chad, Africa

Key Features:

• Pronounced brow ridge & small cranial capacity (350 cc)

• More anterior foramen magnum (bipedalism) w/ small, less prognathic head

Orrorin tugenensis

Dates: ~6 mya

Location: Tugen Hills, Kenya, Eastern Africa

Key Features:

• Ends of femurs have bipedal traits (long necks & groove for obturator externus)

Ardipithecus ramidus

Dates: 4.4 mya

Location: Middle Awash, Ethiopia (eastern Africa)

Key Features:

• 35 individuals recovered

• Short canines w/ wear on tips

• Small cranial capacity 

• 4ft

• Long arms w/ curved fingers

• Arboreal climbing over suspensory locomotion

• Short/broad pelvis

• Long toes w/ diverged hallux

• Bones of feet more suited for pushing off in bipedal walking

Australopiths

4 mya - 1 mya, early Pliocene to early Pleistocene

Australopithecus anamensis

Dates: 4 mya, Pliocene

Location: Eastern Africa

Key Features:

• Ape-like traits (large canines, parallel upper tooth rows, asymmetrical lower premolars, large outer tooth cusps)

• Post-cranial remains indicate habitual bipedalism with some adaptations for this

• Likely a direct ancestor to Ardipithecus

Australopithecus afarensis

Dates: 3.6 - 3 mya, late Pliocene

Location: Eastern Africa

Key Features:

• 350 - 500 cc cranial capacity (small compared to us)

• More prognathic (protruding) faces than humans but flatter than chimps

• Larger canines than humans but smaller than chimps

• Share direct ancestor-descendant relationship with Au. anamensis

• Equally sized lower premolar cusps

• Arched tooth rows like humans (not parallel)

• Wide range of plant diet (more than living like chimps than Au, anamensis)

• Lucy! & Selam (Dikika site, Ethiopia)

• Angled femurs, short/broad pelvis (not as bowl shaped), diverged hallux, arched feet

• More bipedal with some arboreal traits (broad shoulders, curved fingers)

• Polygynous

Australopithecus africanus

Dates: 3 - 2 mya, late Pliocene to early Pleistocene

Location: Southern Africa

Key Features:

• First species of australopith discovered

• Cranial capacity 450 - 550 cc

• Smaller incisors, canines, and larger premolars + molars

• Flatter face

• Similar diet, postcranial traits (long arms, short/broad pelvis), social structure and degree of sexual dimorphism as Au. afarensis

Australopithecus garhi

Dates: 2.5 mya, end of the Pliocene

Location: Eastern Africa

Key Features:

• ~450 cc cranial capacity

• Prognathic face (protruding)

• Small sagittal crest

• Larger canines, premolars & molars compared to earlier australopiths

• Longer legs (potentially indicating more bipedalism but inconclusive)

• Potentially ancestors of the homo genus

• Suggested earliest users of tool use

Paranthropithecus (Au.) bosei/robustus

Dates: Boisei: 2.3 - 1.2 mya, Pleistocene & Robustus: 2 - 1.5 mya late Pleistocene

Location: Boisei: Eastern Africa & Robustus: Southern Africa

Key Features:

• Boisei:

  • 510 cc cranial capacity

  • Most robust w/ largest molars, sagittal crest, large zygomatic arches

  • Heavy chewing diet (tough vegetation)

• Robustus:

  • 410 - 530 cc cranial capacity

  • Large sagittal crest, molars & zygomatic arches

  • Broader diet than Au. boisei

Early Members of the Genus Homo

2.5 mya - 1.8 mya, early Pleistocene

Homo habilis

Dates: 2.5 - 1.8 mya, early Pleistocene

Location: Eastern & Southern Africa

Key Features:

• “Handy man”

• Less robusticity (small teeth, face), larger brain size

• Probably habitual biped but also believed to be the first obligatory biped (no opposable hallux or longitudinal arch)

• 650 cc cranial capacity

• More gracile cranial & dental features (smaller teeth, mandibles, & zygomatic arches w/ no sagittal crest)

• Diversified diet (wide range of plants in diet)

Homo rudolfensis

Dates: 2 mya, early Pleistocene

Location: East Africa

Key Features:

• Basically H. habilis but with larger cranial capacity & more robust traits (some scientists disagreed w/ this & blamed it on sexual dimophism)

• Koobi Fora, Kenya fossils (smaller H. rudolfensis fossils proving its its own species)

Later Members of the Genus Homo

1.8 mya - present day

Homo ergaster

Dates: 1.8 - 1.3 mya, early Pleistocene

Location: Eastern & Southern Africa

Key Features:

• African group of H. erectus

• Sagittal keel (bone that runs along mid-side of the cranium + less pronounced than a sagittal crest)

• Thinner cranial bones, not as low/long cranium

• Less pronounced brow ridges/occipital torus

• Taller/less stocky

Homo erectus

Dates: 1.8 mya - 300 kya (A + A), late Pleistocene & 1.8 mya - 400 kya (E)

Location: Asia + Africa, Europe

Key Features:

• 950 cc w/ variation between groups (600 cc - 1,200 cc)

• Long/low head like football

• Pronounced brow ridge, flat face, occipital torus (ridge bone along occipital bone that sticks out when seen from the side)

• Smaller premolars & molars than australopiths (more biting & tearing)

• Obligate bipeds (long legs, short arms, barrel shaped rib cage angled femurs)

• Oldowan tools + Acheulean technology

• First species in our genus to leave Africa (environmental shifts & changing food availability)

• Shorter, stockier

Homo antecessor

Dates: 1.2 mya - 780 kya

Location: Gran Dolina site, Atapuerca, Spain

Key Features:

• Debate on whether it should be considered H. erectus (only fragmented juveniles found so no fully mature bones)

• Stone tool use unknown

Homo heidelbergensis

Dates: 600 - 130 kya

Location: Africa, Asia, & Europe

Key Features:

• Shared many traits with H. erectus (long & low crania, large brow ridges, small occipital torus)

• Larger cranial capacity 1,200 - 1,300 cc

• Smaller premolars & molars

• Wear on teeth potentially indicated teeth used as tools 

• Debate on whether they should be classified as their own species or an earlier (archaic) version of the homo sapien

• Diet included meat from large animals

• First members of the genus homo to use Mousterian technology + used Archeulean tools

Homo neanderthalensis

Dates: 130 - 30 kya

Location: Europe & Western Asia

Key Features:

• Similarities with H. heidelbergensis (long & low cranium, large brow ridges, small molars & premolars with wear)

• Large cranial capacity, 1,245 - 1,740 cc

• Large cranial capacity but brain to body ratio is lower than humans

• Occipital bun on back of skull (round bump like thing on back of head)

• Cold weather adaptations (arge nasal openings to help warm inhaled air & stocky bodies to retain heat)

• Built fires, used caves as shelter, rudimentary clothing, buried their dead, created nonfunctional objects

• Diet consisted of large animals hunted by Mousterian tools

• Often injured bc of hunting tendencies

• Potentially used languaged & had complex thinking (shown by them eating non nutritious plants & the fox p2 gene)

• Classified as early (archaic) homo sapiens

Homo sapiens

Dates: 200 - 15 kya

Location: Europe, Asia, Africa, Australia, Americas

Key Features:

• More gracile than earlier homo species but more robust than the modern human

• Small orthognathic (flat) faces with small brow ridges, small front and back teeth

• Pronounced chin on the front of the mandible

• Tall and rounded cranial shape (vertical forehead)

• Large cranial capacity 1,350 cc

• Rounded occipital area (without specialized structures like occipital torus or bun)

• Gracile postcrania were relatively (long and lean body type suitable for many environments)

• Diets with a wider range of prey (medium-sized game animals like deer, & smaller game like birds and fish)

• Complex clothing using needles & shelters that required building (no naturally formed caves)

• Complex thinking, ritualistic burials (buried dead with special tools, jewelry, and other grave goods), symbolic objects, like carved figurines and cave paintings

• Used upper paleolithic technology

• Coexisted w/ neanderthals & likely interbred

• The assimilation model explains that humans spread to other parts of the world & interbred with the species living there creating the modern day human

Unusual members of the genus homo

H. florensis, Denisovans, H. naledi

Denisovans

Dates: 30 - 48 kya

Location: Siberia

Key Features:

• More closely related to H. neanderthalensis than to humans (diverged from the human lineage as long ago as 700 kya)

• Interbred w/ humans (seen in ancient DNA evidence & in our own DNA)

Homo naledi

Dates: 335 - 236 kya

Location: Rising Star Cave in the Republic of South Africa

Key Features:

• Similarities w/ early australopiths (small cranial capacity 465 - 560 cc & arboreal climbing shoulders)

• More similarities w/ homo erectus (sagittal keel, large brow ridge, small teeth & mandible, human like feet for bipedalism)

Homo floresiensis

Dates: 100 - 60 kya

Location: Indonesian island of Flores

Key Features:

• Small teeth & orthognathic faces but w/ more primitive locomotor adaptations like long arms and flat feet

• Used flake tools

• Super short with small cranial capacities of 400 cc

• Probably a lineage of early Homo erectus that became a tiny after settling on the island of Flores

Oldowan Tools

• Named after earliest ones being found in Olduvai Gorge

• Au. garhi potentially used some of these (animal bones with cut marks found in Au. garhi site in Ethiopia + stone tools found dated around the same time as Au. garhi)

• Two main types of tools

  • Choppers → large, heavy tools with a small sharp edges, used to break bones

  • Flakes → bits of rock that are removed from choppers, used to scrape meat

• Produced by “direct percussion” (two stones are hit together to break off flakes)

• Vary in size, shape, & raw material

Archeulean (Acheulian) Tools

• Created by H. erectus

• Named after Saint Acheul, France where these tools were discovered in the mid-1800

• Biface tool (stone tool w/ flakes removed from side)

• Handaxe → biface shaped like a tear drop with a large rounded edge & narrow pointed edge used for butchering/digging up underground plants

  • Less variation than Oldowan tools (roughly same size/shape)

Mousterian Tools

• Named after site in France, Le Moustier

• Mostly associated with Neanderthals

• Core tools < Flake tools

• Core tools → tools left when small flakes are removed

• Flake tools → Flakes are the important part of the tool (modified into certain shapes of specific functions

• Stone tipped spears

• Levallois technique

  • Remove small flakes from core of rock

  • Create a platform on one end of the rock to break off a large flake

  • Flake is modified for a specific function

  • Create multiple flakes from one tool