Cátedra de Otoacústica Evolutiva y Paleoantropología (HM Hospitales-Universidad de Alcalá), Área de Antropología Física, Departamento de Ciencias de la Vida, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
Cátedra de Otoacústica Evolutiva y Paleoantropología (HM Hospitales-Universidad de Alcalá), Área de Antropología Física, Departamento de Ciencias de la Vida, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain; Centro Mixto (UCM-ISCIII) de Evolución y Comportamiento Humanos, Av. Monforte de Lemos 5, 28029 Madrid, Spain.
J Hum Evol. 2019 Nov;136:102641. doi: 10.1016/j.jhevol.2019.102641. Epub 2019 Sep 27.
The cochlea contains taxonomic and phylogenetic information and its morphology is related with hearing abilities among fossil hominins. Data for the genus Homo is presently limited to early Homo and the early Neandertals from Krapina. The present study of the middle Pleistocene hominins from the Sima de los Huesos (SH) provides new evidence on cochlear evolution in the genus Homo. We compared the absolute length, proportional lengths of each turn, number of turns, size and shape of the cross-section of the basal turn, volume, curvature gradient, and thickness of the cochlea between extant Pan troglodytes, extant Homo sapiens, Homo neanderthalensis and the SH hominins. The SH hominins resemble P. troglodytes in the proportionally long basal turn, the small size and round shape of the cross-section of the basal turn, the small cochlear volume and the low cochlear thickness. The SH hominins resemble Neandertals and H. sapiens in their long cochlear length and in the proportionally short third turn. Homo neanderthalensis and H. sapiens share several features, not present in the SH hominins, and that likely represent homoplasies: a larger volume, larger size and oval shape of the cross-section of the basal turn and higher cochlear thickness. Later Neandertals show a derived proportionally shorter apical turn. Changes in cochlear volume in Homo cannot be fully explained by variation in body mass or cochlear length but are more directly related to changes in the cross-sectional area of the basal turn. Based on previous studies of the outer and middle ear in SH hominins, changes in the outer and middle ear preceded changes in the inner ear, and the cochlea and semicircular canals seem to have evolved independently in the Neandertal clade. Finally, the small cochlear volume in the SH hominins suggests a slightly higher upper limit of hearing compared with modern humans.
耳蜗包含分类学和系统发生学信息，其形态与化石人类的听力能力有关。目前关于智人物种的数据仅限于来自克拉皮纳的早期智人和早期尼安德特人。本研究对来自西玛·德洛斯·休斯（Sima de los Huesos，简称 SH）的中更新世人类进行了研究，为智人物种的耳蜗进化提供了新的证据。我们比较了现生黑猩猩、现生智人、尼安德特人和 SH 人类的耳蜗绝对长度、各圈的比例长度、圈数、基底圈横截面的大小和形状、体积、曲率梯度和厚度。SH 人类的基底圈比例较长、基底圈横截面较小且呈圆形、横截面较小、耳蜗体积较小、耳蜗厚度较低，与现生黑猩猩相似。SH 人类的耳蜗长度较长，第三圈比例较短，与尼安德特人和智人相似。尼安德特人和智人有几个特征是 SH 人类所没有的，这些特征可能是同型特征：基底圈横截面的体积较大、尺寸较大且呈椭圆形、耳蜗厚度较高。晚期尼安德特人表现出更衍生的、相对较短的顶部圈。在智人中，耳蜗体积的变化不能完全用体重或耳蜗长度的变化来解释，而与基底圈横截面面积的变化有更直接的关系。根据 SH 人类中耳和外耳的先前研究，中耳和外耳的变化先于内耳的变化，而且耳蜗和半规管似乎在尼安德特人分支中独立进化。最后，SH 人类较小的耳蜗体积表明其听力上限略高于现代人。
