Park Travis, Marx Felix G, Fitzgerald Erich M G, Evans Alistair R
School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.
Geosciences, Museum Victoria, Melbourne, Victoria, Australia.
J Morphol. 2017 Jun;278(6):801-809. doi: 10.1002/jmor.20674. Epub 2017 Mar 23.
The pygmy right whale, Caperea marginata, is the least understood extant baleen whale (Cetacea, Mysticeti). Knowledge on its basic anatomy, ecology, and fossil record is limited, even though its singular position outside both balaenids (right whales) and balaenopteroids (rorquals + grey whales) gives Caperea a pivotal role in mysticete evolution. Recent investigations of the cetacean cochlea have provided new insights into sensory capabilities and phylogeny. Here, we extend this advance to Caperea by describing, for the first time, the inner ear of this enigmatic species. The cochlea is large and appears to be sensitive to low-frequency sounds, but its hearing limit is relatively high. The presence of a well-developed tympanal recess links Caperea with cetotheriids and balaenopteroids, rather than balaenids, contrary to the traditional morphological view of a close Caperea-balaenid relationship. Nevertheless, a broader sample of the cetotheriid Herpetocetus demonstrates that the presence of a tympanal recess can be variable at the specific and possibly even the intraspecific level.
侏儒露脊鲸（Caperea marginata）是现存了解最少的须鲸（鲸目，须鲸亚目）。尽管它在露脊鲸科（露脊鲸）和须鲸科（座头鲸+灰鲸）之外的独特地位使其在须鲸进化中具有关键作用，但关于其基本解剖结构、生态学和化石记录的知识却很有限。最近对鲸类耳蜗的研究为感官能力和系统发育提供了新的见解。在此，我们首次描述这种神秘物种的内耳，将这一进展扩展到侏儒露脊鲸。其耳蜗很大，似乎对低频声音敏感，但其听力极限相对较高。与传统形态学观点认为侏儒露脊鲸与露脊鲸科关系密切相反，发育良好的鼓室隐窝的存在将侏儒露脊鲸与须鲸科和须鲸科联系起来，而不是与露脊鲸科联系起来。然而，对须鲸科的赫氏须鲸更广泛的样本研究表明，鼓室隐窝的存在在种级甚至可能在种内水平上都是可变的。
