|Title:||Tsai and Chang 2019 3D data - Pleistocene right whale||Authors:||CH Tsai 蔡政修||Issue Date:||2019||Abstract:||
Current patterns of biological distribution result from the deep past. Of particular interest, some closely related species appear at high latitudes of both hemispheres, but not in between, a pattern known as antitropical distribution. However, the timing, pathway, and drivers of antitropical distributions remain mostly unanswered. Here we described a new fossil, a left tympanic bulla (part of the earbones), from the Middle/Late Pleistocene (0.78 to 0.01 million years ago) of Taiwan. The tympanic bulla is highly diagnostic in baleen whales, and this specimen shows morphological features that are identical to extant Eubalaena, including: relatively large size – the anteroposterior length is 117 mm; rectangular outline in medial view; short anterior lobe, judging from the remaining of the lateral furrow; squared anterior margin; prominent transverse crease on the involucrum; transversely compressed in anterior view; well-developed and rounded outer lip; and parallel involucral and main ridges. Albeit incomplete, the morphological characters and overall similarity to extant Eubalaena allow a reliable taxonomic assignment to Eubalaena sp. The occurrence of a Pleistocene Eubalaena on the southern margin of the western North Pacific is the first balaenid fossil evidence indicative of the biotic interchange between two hemispheres leading to the origin of antitropical distribution in the Pleistocene. Furthermore, this find suggests that the Eubalaena interchange, being one of the largest species displaying antitropical distribution pairs in the history of Life, likely took place along the western Pacific, supporting the phylogenetic hypothesis that the extant Southern Eubalaena australis is closely related to the North Pacific Eubalaena japonica, not the North Atlantic Eubalaena glacialis.
|Appears in Collections:||生命科學系|
|Tsai and Chang 2019 3D data - Pleistocene right whale.obj||377.31 MB||Unknown||View/Open|
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