Sensory Anatomy and Sensory Ecology of <i>Vintana Sertichi</i> (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar

ABSTRACT—Living mammals are distinguished from other extant tetrapods by adaptations for improved senses of hearing, touch, and smell. These adaptations, and concomitant reductions in visual anatomy, evolved during the Mesozoic in the mammalian and therian stem lineages. Here, we present a comparative study of the sensory anatomy of the Late Cretaceous gondwanatherian mammaliaform <i>Vintana sertichi</i> in order to draw inferences regarding its sensory abilities and sensory ecology. Our analyses demonstrate that <i>Vintana</i> has relatively large orbits that may have accommodated large eyes. <i>Vintana</i> also possessed cochlear primary and secondary osseous laminae and a cochlear canal that was relatively longer than in non-mammaliaform cynodonts but shorter than in extant therians. These features suggest that <i>Vintana</i> had some capacity for high-frequency hearing (i.e., &gt;20 kHz), but that its cochlea may have encoded a more limited range of frequencies than the cochleas of most extant therians. The semicircular canals of <i>Vintana</i> have large radii of curvature and are nearly orthogonal, suggesting high sensitivity to angular head accelerations. These vestibular features may have evolved in order to stabilize large eyes during rapid and/or agile locomotion. Combined with evidence for large olfactory bulbs and a large trigeminal endocast, these data reveal that <i>Vintana</i> possessed a unique suite of sensory adaptations that distinguish it from other Mesozoic mammaliaforms. If these inferences are correct, then <i>Vintana</i> was probably a large-eyed and agile species, with a keen sense of smell and better high-frequency hearing than most other Mesozoic mammaliaforms.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP摘要—现生哺乳类与其他现存四足类（extant tetrapods）的区别，在于其为提升听觉、触觉与嗅觉感知能力演化出的适应性特征。这些适应性特征，以及随之而来的视觉结构退化，是在中生代（Mesozoic）哺乳类及兽类干群谱系（therian stem lineages）中演化形成的。本研究针对晚白垩世冈瓦纳兽类哺乳形类（gondwanatherian mammaliaform）*Vintana sertichi*的感官解剖结构开展比较分析，以期推断其感官能力与感官生态位。 本研究的分析结果显示，*Vintana sertichi*拥有相对较大的眶腔，或可容纳尺寸更大的眼球。该物种还具备耳蜗（cochlear）初级骨板与次级骨板，且其耳蜗管长度相较于非哺乳形类犬齿兽类（non-mammaliaform cynodonts）更长，但短于现生兽类（extant therians）。上述特征表明，*Vintana sertichi*具备一定的高频听觉能力（即大于20千赫兹），但相较于多数现生兽类的耳蜗，其耳蜗所能编码的频率范围更为有限。 *Vintana sertichi*的半规管（semicircular canals）拥有较大的曲率半径，且近乎相互正交，这意味着其对头角加速度具备较高的感知灵敏度。这类前庭系统特征的演化，或可用于在快速或灵活运动过程中稳定其硕大的眼球。 结合其拥有较大嗅球（olfactory bulbs）与大型三叉神经颅内铸型（trigeminal endocast）的证据，上述研究数据表明，*Vintana sertichi*具备一套独特的感官适应性特征组合，使其区别于其他所有中生代哺乳形类。若上述推断均成立，则*Vintana sertichi*大概率是一种眼球硕大、行动灵活的物种，其嗅觉敏锐，且高频听觉能力优于多数其他中生代哺乳形类。 补充数据—本文可通过www.tandfonline.com/UJVP免费获取补充材料。