[MARMAM] New publication - Tsai and Chang 2019 Pleistocene Eubalaena

Tsai, CH craniata at gmail.com
Sun Dec 29 00:42:44 PST 2019


Dear colleagues

We are very pleased to announce a new paper - describing a Pleistocene
*Eubalaena* (right whale) from Taiwan.

Tsai C.-H. and Chang C.-H. 2019. A right whale (Mysticeti, Balaenidae) from
the Pleistocene of Taiwan. Zoological Letters 5:37
doi:10.1186/s40851-019-0153-z

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 unknown. Here we describe a new fossil, a left
tympanic bulla (part of the ear bones), from the Middle/Late Pleistocene
(0.78–0.01 mya, but not excluding the possibility of Holocene in age, as
the specimen was dredged from the sea bottom and the geological horizon
remains uncertain) of Taiwan. The tympanic bulla is 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. Although 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; alternatively, this specimen might merely represent an
extra-limital record of the North Pacific *Eubalaena*. 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. Notably, this does not
preclude the *Eubalaena* interchange from other routes, such as the eastern
Pacific or the Atlantic Ocean, and future finds should test the scenario
for the biotic interchange between Northern and Southern Hemispheres of
*Eubalaena*.

The paper is freely accessible:

https://zoologicalletters.biomedcentral.com/articles/10.1186/s40851-019-0153-z

Alternatively, feel free to email me for a pdf copy or further discussion:

whaletsai at ntu.edu.tw or craniata at gmail.com

Happy holidays and happy new year.

Regards
Tsai

蔡政修(Cheng-Hsiu Tsai  さい まさのぶ)
Lab of evolution and diversity of fossil vertebrates(古脊椎動物演化及多樣性實驗室)
Department of Life Science, National Taiwan University(台灣大學生命科學系)
No. 1, Sec. 4, Roosevelt Rd., Taipei, 106-17, Taiwan(台灣 106-17 台北市羅斯福路 4 段
1 號)
Email: whaletsai at ntu.edu.tw; craniata at gmail.com; cheng-hsiu.tsai at otago.ac.nz
https://www.facebook.com/NTUWhaleTsai/?modal=admin_todo_tour
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