title: Early hominin auditory capacities.
abstract: Studies of sensory capacities in past life forms have offered new insights into their adaptations and lifeways. Audition is particularly amenable to study in fossils because it is strongly related to physical properties that can be approached through their skeletal structures. We have studied the anatomy of the outer and middle ear in the early hominin taxa Australopithecus africanus and Paranthropus robustus and estimated their auditory capacities. Compared with chimpanzees, the early hominin taxa are derived toward modern humans in their slightly shorter and wider external auditory canal, smaller tympanic membrane, and lower malleus/incus lever ratio, but they remain primitive in the small size of their stapes footplate. Compared with chimpanzees, both early hominin taxa show a heightened sensitivity to frequencies between 1.5 and 3.5 kHz and an occupied band of maximum sensitivity that is shifted toward slightly higher frequencies. The results have implications for sensory ecology and communication, and suggest that the early hominin auditory pattern may have facilitated an increased emphasis on short-range vocal communication in open habitats.
authors.affiliation: Department of Anthropology, Binghamton University [State University of New York (SUNY)], Binghamton, NY 13902-6000, USA. ; Centro de Investigación (UCM-ISCIII) sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos, 5, 28029 Madrid, Spain. ; Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA.
authors.forename: Rolf
authors.initials: R
authors.lastname: Quam
authors.affiliation: Centro de Investigación (UCM-ISCIII) sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos, 5, 28029 Madrid, Spain. ; Departamento de Ciencias de la Vida, Universidad de Alcalá, Edificio de Ciencias, Campus Universitario, 28805 Alcalá de Henares, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Martínez
authors.affiliation: Departamento de Teoría de la Señal y Comunicaciones, Universidad de Alcalá, Escuela Politécnica Superior, Campus Universitario, 28805 Alcalá de Henares, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Rosa
authors.affiliation: Centro de Investigación (UCM-ISCIII) sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos, 5, 28029 Madrid, Spain. ; Departamento de Paleontología, Universidad Complutense de Madrid, Facultad de Ciencias Geológicas, Ciudad Universitaria s/n, 28040 Madrid, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Bonmatí
authors.affiliation: Área de Prehistoria, Universitat Rovira i Virgili, Avinguda Catalunya 35, 43002 Tarragona, Spain. ; Institut Català de Paleoecologia Humana i Evolució Social (IPHES), Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain. ; Centro de Investigación (UCM-ISCIII) sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos, 5, 28029 Madrid, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Lorenzo
authors.affiliation: Department of Anthropology, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Darryl J
authors.initials: DJ
authors.lastname: de Ruiter
authors.affiliation: Laboratori di Antropologia, Dipartimento di Biologia, Universita' di Firenze, via del Proconsolo, 12 50122 Firenze, Italy.
authors.forename: Jacopo
authors.initials: J
authors.lastname: Moggi-Cecchi
authors.affiliation: Departamento de Ciencias de la Vida, Universidad de Alcalá, Edificio de Ciencias, Campus Universitario, 28805 Alcalá de Henares, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Conde Valverde
authors.affiliation: Departamento de Teoría de la Señal y Comunicaciones, Universidad de Alcalá, Escuela Politécnica Superior, Campus Universitario, 28805 Alcalá de Henares, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Jarabo
authors.affiliation: Centre for Anthropological Research, Humanities Research Village, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa.
authors.forename: Colin G
authors.initials: CG
authors.lastname: Menter
authors.affiliation: Evolutionary Studies Institute, University of the Witwatersrand, PO WITS, Johannesburg 2050, South Africa.
authors.forename: J Francis
authors.initials: JF
authors.lastname: Thackeray
authors.affiliation: Centro de Investigación (UCM-ISCIII) sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos, 5, 28029 Madrid, Spain. ; Departamento de Paleontología, Universidad Complutense de Madrid, Facultad de Ciencias Geológicas, Ciudad Universitaria s/n, 28040 Madrid, Spain.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Arsuaga
keywords: Australopithecus; Paranthropus; audition; communication; ear; evolution; sensory ecology