Flores Deanna, Eldridge Emma I, Elminowski Erin E, Dickinson Edwin, Hartstone-Rose Adam
Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA.
Department of Biological Sciences, Sam Houston State University, Huntsville, Texas, USA.
J Morphol. 2020 Jun;281(6):646-652. doi: 10.1002/jmor.21130. Epub 2020 Apr 17.
The Rancho La Brea (RLB) fossil collection housed at the La Brea Tar Pits and Museum in Los Angeles, California, is one of the richest collections of carnivoran fossils in the world. The collection is also particularly well known for the preservation of rare and understudied bones in the tar, including the small bony apparatus that is of particular interest to this study, the hyoid. The La Brea collection houses hyoids from several extinct carnivoran species, some of the most common being those of Canis dirus (the dire wolf) and Canis latrans (the coyote). In this study, we compare fossilized hyoid elements from these two canids to samples from modern large congeners, namely: Canis lupus (the gray wolf), Canis rufus (the red wolf), and modern C. latrans. Seven or nine measurements were taken on each bone of the hyoid apparatus, and principal component analyses were performed in order to determine statistical significance between species. For most of the bones, the majority of the variation was driven by size. Dire wolves could be clearly differentiated from all other canids for all elements; the hyoid apparatus of C. dirus is larger and more robust than that of C. lupus. Most of the bony elements could not be distinguished between red wolves or modern coyotes. However, there are enough, complete fossil coyote basihyoids to compare with those of their modern relatives, and in several metrics (both PC shapes and overall size), RLB and modern C. latrans are significantly different. As larger hyoids have been associated with a lower vocal frequency, this distinction would have resulted in the vocalizations of C. dirus occurring at a lower frequency than those produced by C. lupus and perhaps lower vocalizations in ice age coyotes than their modern relatives. RESEARCH HIGHLIGHTS: We quantify morphological differences in the hyoid of dire wolves (Canis dirus) relative to extant grey wolves (Canis lupus), and hypothesize that, as larger hyoids have been associated with a lower vocal frequency, the vocalizations of C. dirus might have occurred at a lower frequency than those by C. lupus. Likewise, modern and fossil coyotes (Canis latrans) show a significant difference in basihyoid size and shape, potentially indicating that modern and ancient coyotes might have sounded differently.
收藏于加利福尼亚州洛杉矶拉布雷亚沥青坑博物馆的兰乔拉布雷亚（RLB）化石藏品，是世界上最丰富的食肉动物化石藏品之一。该藏品还因其在沥青中保存了罕见且研究不足的骨骼而特别闻名，包括本研究特别感兴趣的小骨结构——舌骨。拉布雷亚藏品中保存着几种已灭绝食肉动物物种的舌骨，其中一些最常见的是恐狼（Canis dirus）和郊狼（Canis latrans）的舌骨。在本研究中，我们将这两种犬科动物的化石舌骨元素与现代大型同属动物的样本进行比较，即：灰狼（Canis lupus）、红狼（Canis rufus）和现代郊狼。对舌骨结构的每块骨头进行了七次或九次测量，并进行了主成分分析，以确定物种之间的统计显著性。对于大多数骨头来说，大部分变异是由大小驱动的。恐狼的所有元素都能与所有其他犬科动物明显区分开来；恐狼的舌骨结构比灰狼的更大、更粗壮。大多数骨元素在红狼或现代郊狼之间无法区分。然而，有足够多完整的化石郊狼基舌骨可以与它们现代亲属的基舌骨进行比较，并且在几个指标（主成分形状和整体大小）上，RLB的郊狼和现代郊狼有显著差异。由于较大的舌骨与较低的发声频率相关，这种差异可能导致恐狼的发声频率低于灰狼，也许冰河时期郊狼的发声频率也低于它们的现代亲属。研究亮点：我们量化了恐狼（Canis dirus）与现存灰狼（Canis lupus）舌骨的形态差异，并假设，由于较大的舌骨与较低的发声频率相关，恐狼的发声频率可能低于灰狼。同样，现代郊狼和化石郊狼（Canis latrans）在基舌骨大小和形状上存在显著差异，这可能表明现代郊狼和古代郊狼的叫声可能有所不同。
