8/2/2019 Kenyanthropus Platyops - Cheatsheet

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Kenyanthropus platyopsTimespan: 3.3 3.5 mya

Region: West Turkana, East Africa

Specimens: 2 individuals

Discovered: Leakey 2001

Holotype: KNM -WT-4000

Lineage: suggested ancestor to

H. rudolfensis

Environment: Woodland

Diet: Unknown

Speculation/theories:

facial features show that orthonagthism evolved earlier than prev assumed;

new genus increases diversity in Pliocene (as expected); diet-driven adaptive radiation

affinity w/ H. rudolfensis strong, some suggest reclassification as K. rudolfensis

taxonomic classification highly controversial, many suggest KNM-WT-4000 too distorted to

diagnose; suggest simplyA. afarensis (White 2003)

D I A G N O S T I C F E AT U R E S

Cranium size w/in A. afarensis & A. africanus range

molar enamel comparable to A. anamensis & A. afarensis

buccolingually narrow M2

thick molar enamel

tepmoral bone w/ more cylindrical

articular eminence

deeper mandibular fossa

similar facial architecture (incl flat orthognathic nasoalveolar clivus)

more primitive nasal and neurocranial morphology

lacks derived shot nasal bones & everted lateral nasal margin

cranial

tall malar region

zygomaticoaveolar crest low & curved

nasal cavity entrance stepped palate roof: thin, flexed anteriorly to incisive foramen

tympanic element mediolaterally long & lacking petrous

crest

transversely flat midface

external acoustic porus small

absence of occipital/marginal venous system

moderate subnasal prognathism

nasoalveolar clivus long & flat w/out marked

juga

maxillary zygomatic process: anterior surface

positioned over premolars & more vertically-

oriented

dentition

M1 & M2 small crowns

I 1 & I2 roots near equal in size

P3 & P4 3-rooted

M1 & M2 thick enamel

incisor alveoli parallel w/ bicanine line

differs from

A. anamensis,A. africanus,

A. garhi

differs from

A. afarensis:more derived

facially but moreprimitive cranial

features

differs from

Ar. ramidus {

}compared to

H. rudolfensis

Lacks derived facial

features of

P. aethiopicus, P. boisei, &

P. robustus

Lacks derived cranial

features ofH. erectus &

H. sapiens

8/2/2019 Kenyanthropus Platyops - Cheatsheet

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K E Y S P E C I M E N S

KNM-WT-4000 cranium, highly distorted. Preserved in 2 pieces (neurocranium w/ superior

& lateral orbital margins but cranial base missing; and face)

Aprox 3.5 mya

Cranial capacity of 350 cc (estimating difficult due to condition of skull)

Found w/ well-preserved temporal bone, two partial maxillae, & isolated teeth (not yet

assigned to K. platyops)

KNM-WT-38350 partial left maxilla, found in 1998

Aprox 3.3 mya

M A J O R S I T E S

Lomekwi, West Turkana, Kenya localities between Lomekwi & Topernawi river drainages in

northern Kenya

KNM-WT-4000 found in Kataboi Member, below Tulu Bor Tuff & above Locochot Tuff

B I B L I O G R A P H Y

Ackerman, R. and R. Smith (2007) The Macroevolution of our Ancient Lineage: What We Know

(or Think We Know) about Early Hominin Diversity, Evolutionary Biology34: 72-85

Begun, D. (2004) The Earliest Hominins Is Less More?, Science 303: 1478-1450

Gee, H. (2001) Return to the planet of the apes, Nature 412: 131-132

Gibbons, Anne (2002) In search of the first hominids, Science 295: 1214-1219

Cameron, D. (2003). Early hominin speciation at the Plio/Pleistocene transition. HOMO-Journal

of Comparative Human Biology, 54(1), 128.

Collard, M, and B. Wood (2007) Hominin homoiology: An assessment of the impact of

phenotypic plasticity on phylogenetic analyses of humans and their fossil relatives,

Journal of Human Evolution 52: 573-584

Leakey, M. G., et al (2001). New hominin genus from eastern Africa shows diverse middle

Pliocene lineages. Nature, 410(6827), 433-40

Lieberman, D. E. (2001). Another face in our family tree, Nature 410

White, T. (2003). Early Hominids Diversity or Distortion?, Science 473(2001), 4-6.