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Balaenoptera edeni skull from the Holocene (Quaternary) of Osaka City, Japan

Yoshihiro Tanaka and Hiroyuki Taruno

Plain Language Abstract

Skull remains of Balaenoptera edeni from the Holocene (about 8800 to 4000 years before present; a transgressive period) of Osaka City, Japan, was previously identified as B. acutorostrata (Minke whale). Here, we describe in detail and reidentify it based on skull shape. The specimen adds a new record to the not well-known species. The specimen suggests that the modern distribution probably had already established about 8800 to 4000 years around Osaka, Japan. But, more remains of B. edeni will help to further identify their distributional history.

日本語要旨

大阪市の完新統(第四紀)から産出したBalaenoptera edeni(カツオクジラ)の頭蓋骨

 大阪市の完新統(およそ8800-4000年前;海進期)の地層から産出したBalaenoptera edeni(カツオクジラ)の頭蓋骨は過去B. acutrostrata(ミンククジラ)と同定されていた。本研究はこの頭蓋骨を詳細に記載し、再同定し、この良く知られていない種の新しい記録を追加した。それによって、カツオクジラの現代の分布は8800-4000年前の大阪周辺ですでに確立されていた可能性が示唆された。さらに多くのカツオクジラが発掘されれば、彼等の分布がどのように変わってきたか明らかになるだろう。

キィワード:ニタリクジラ;Balaenoptera brydei; 翼蝶形骨;Balaenoptera acutorostrata; ミンククジラ; 縄文時代

 

Resumen en Español

Cráneo de Balaenoptera edeni del Holoceno (Cuaternario) de la ciudad de Osaka, Japón

Los restos del cráneo de Balaenoptera edeni del Holoceno (unos 8800 a 4000 años antes del Presente, un período de transgresión marina) de la ciudad de Osaka, Japón, habían sido identificados anteriormente como B. acutorostrata. Aquí, lo describimos en detalle y lo reidentificamos en función de su alisfenoides grande, que contacta ampliamente con el escamoso, y por presentar un rostro más amplio que B. acutorostrata. El espécimen implica un registro cronológica y geográficamente nuevo para las especies no bien conocidas. El espécimen sugiere que la distribución moderna probablemente ya se había establecido hace alrededor de 8800 a 4000 años, que fue el período de la transgresión de Jomon que creó la Bahía de Kawachi, la antigua condición de la llanura de Osaka. Más restos de B. edeni proporcionarían una mejor resolución de su historia de distribución.

Palabras clave: Ballena de Bryde; Balaenoptera brydei; Alisfenoides; Balaenoptera acutorostrata; Rorcual aliblanco; Período de Jomon

Traducción: Enrique Peñalver (Sociedad Española de Paleontología)

Résumé en Français

in progress

Translator: Antoine Souron

Deutsche Zusammenfassung

Ein Schädel von Balaenoptera edeni aus dem Holozän (Quartär) von Osaka, Japan

Überreste eines Schädels von Balaenoptera edeni aus dem Holozän (vor ca. 8800 bis 4000 Jahren; eine transgressive Phase) von Osaka, Japan, wurden bislang als B. acutorostrata identifiziert. Hier beschreiben wir das Stück im Detail und nehmen eine Neubeschreibung vor, da das Stück ein großes Alisphenoid aufweist, welches das Squamosum umfassend kontaktiert und das Rostrum breiter ist als bei B. acutorostrata. Das Stück ergänzt die wenig bekannte Art mit neuen chronologischen und geographischen Daten. Es legt nahe, dass die moderne Verbreitung möglicherweise schon vor 8800 bis 4000 Jahren etabliert war, in der Zeit der Jomon Transgression als die Kwachi Bucht entstand, die einstige Osaka Ebene. Weitere Funde von B. edeni werden eine bessere Kenntnis der Verbreitungsgeschichte liefern.

Schlüsselwörter: Brydewal; Balaenoptera brydei; Alisphenoid; Balaenoptera acutorostrata; Minkwal; Jomon Periode

Translator: Eva Gebauer

Arabic

Translator: Ashraf M.T. Elewa

 

 

TABLE 1. Measurements in mm of OMNH-QV4816 skull and periotic. For skull and mandible, distances are either horizontal or vertical.

Skull Measure
(mm)
Preserved length of skull 537
Bizygomatic width 1170
Bicondylar width 195
Preserved frontal length 352
Preserved frontal width 565
Posterior process of periotic maximum mediolateral length 226
Posterior process of periotic maximum anteroposterior length 26

 

TABLE 2. Records of Balaenoptera edeni and B. brydei with molecular data and/or morphological specimens around Japan, and in the Seto Inland Sea including the Osaka Bay. These data are taken from Marine Mammal Stranding Database of the National Museum of Nature and Science (www.kahaku.go.jp/research/db/zoology/marmam/drift/index.php) and IDs in this table are the ones in the database.

  Identification Age or date Locality Specimen Reference ID and specimen number
1 B. edeni 8000 to 4400 years before Osaka City Fossil skull This study OMNH-QV4816
2 B. edeni 11 Nov 1995 Shimotsu Port, Wakayama City, Wakayama Prefecture Skeleton Oishi et al 2009 1794, WMNH 1998-ver-3
3 B. edeni 22 Oct 2001 3.6 km southwest to Inge Island, Awaji City, Hyogo Prefecture DNA sample   3006
4 B. edeni 27 Aug 1978 8 km off Aki Town, Ooita Prefecture Skull at Kisuki City Museum   498
5 B. edeni 17 Jan 2007 Hitachinaka Port, Hitachinaka City, Ibaraki Prefecture DNA sample   5253
6 B. edeni 12 May 1994 Imouto Island OgasawaraVillage, Tokyo DNA sample   1678
7 B. edeni 21 Jun 2000 Off Daio Cape, Shima City, Mie Prefecture DNA sample   2638
8 B. edeni 27 Dec 2002 Fukumitsu, Ooda City, Shimane Prefecture DNA sample, Skeleton at Shimane AQUAS Aquarium   3455
9 B. edeni 20 Aug 1998 Tsunoshima, Shimonoseki City, Yamaguchi Prefecture DNA sample   2235
10 B. edeni 8 Nov 1994 Nase, Kitaura Town, Miyazaki Prefecture Skeleton at Kitaura Town   1707
11 B. edeni 31 Jan 2002 Fukue Island, Gotou City, Nagasaki Prefecture DNA sample   3107
12 B. edeni 7 Jun 2006 Takado Beach, Amakusa City, Kumamoto Prefecture Skull at Kumamoto City Museum   5068
13 B. edeni 24 May 2004 Marushima Port, Minamata City, Kumamoto Prefecture DNA, Skeleton   4128, NSMT-M 33622
1 B. brydei 5 Oct 2002 Natori City, Miyagi Prefecture DNA sample, Skeleton   3392, NSMT-M33072
2 B. brydei 15 May 2007 Nakasode, Sodegaura City, Chiba Prefecture DNA sample, Skeleton   5400
3 B. brydei 1953 No record Skeleton   NSMT-M03538

 

TABLE 3. Measurements in mm of Balaenoptera spp. skulls, distances are either horizontal or vertical. Having high alisphenoid is a diagnositic feature for B. edeni.

Scientific name Specimen
number
Bizygomatic width Zygomatic process maximum height Zygomatic process maximum length Alisphenoid maximum height Alisphenoid maximum length Occipital condyle width
B. edeni OMNH-QV4816 120.0 24.5 50.0 6.5 9.0 24.0
B. edeni NSMT-M33622 77.0 23.5 30.0 4.0 8.5 20.0
B. brydei NSMT-M33072 86.5 26.5 30.0 1.0 5.0 19.0
B. brydei NSMT-M03538 140.0 26.0 50.5 1.5 10.0 23.0
B. omurai NSMT-M32505 143.5 37.5 55.5 1.5 3.0 20.5
B. omurai NSMT-M32992 88.5 26.0 28.5 1.5 3.0 18.0
B. acutorostrata NSMT-M52713 117.5 40.5 42.0 3.0 9.0 21.0
B. acutorostrata NSMT-M42450 88.0 28.0 30.5 1.5 6.0 18.0
B. acutorostrata OMNH M3400 62.0 24.0 23.0 1.5 6.5 15.5
 

tanakaYoshihiro Tanaka. Osaka Museum of Natural History, Nagai Park 1-23, Higashi-Sumiyoshi-ku, Osaka, 546-0034, Japan This email address is being protected from spambots. You need JavaScript enabled to view it. and Division of Academic Resources and Specimens, Hokkaido University Museum, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810 Japan and Numata Fossil Museum, 2-7-49, 1 Minami, Numata Town, Hokkaido, 078-2202 Japan

Yoshi Tanaka is a curator at Osaka Museum of Natural History, Japan and also a researcher at Hokkaido University Museum. He works on the morphology and phylogeny of marine mammals (dolphins, porpoises, whales and walruses) from Japan, Ecuador and New Zealand. This paper is a part of his research project of an ancient bay in Osaka.

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Hiroyuki Taruno. Osaka Museum of Natural History, Nagai Park 1-23, Higashi-Sumiyoshi-ku, Osaka, 546-0034, Japan This email address is being protected from spambots. You need JavaScript enabled to view it.

Hiroyuki Taruno is a former curator and currently a researcher of Osaka Museum of Natural History, Japan. He has researched on local geology, vertebrate paleontology and osteology for half a century. His long-term research activities have expanded his interests on taxonomy, paleogeography and evolution of elephants, deers, carnivoras and crocodiles from the Pliocene to Holocene. 

 

FIGURE 1. Locality maps and a stratigraphic section at the locality. 2, restoration of the Kawachi Bay following Osaka City Cultural Properties Association (2008). 3, the columnar section at OMNH-QV4816 locality, which was modified from a boring survey report in 1965.

figure 1 

FIGURE 2. Skull, OMNH-QV4816 in dorsal view. 1, Restoration of the skull based on a photo, which was taken just before specimen was damaged by pulling up from the locality. 2, Line art was made from the photo. The outline of the skull is anteroposteriorly extended at the level of the antorbital process (arrow), result of a slide between the lose frontal and maxilla.

 figure 2

FIGURE 3. Maxilla, premaxilla and vomer, OMNH-QV4816. 1, left anterior part of maxilla and premaxilla. 2, left middle part of maxilla. 3, left preorbital region of maxilla. 4, right anterior part of maxilla. 5, right preorbital region of maxilla. 1-5, in dorsal view. 6, right anterior part of maxilla. 7, right preorbital region of maxilla. 8, left anterior part of maxilla and premaxilla. 9, left middle part of maxilla. 10, left preorbital region of maxilla. 6-10, in ventral view. 11 to 13, vomer. 11, in dorsal view. 12, in left lateral view. 13, in posterior view.

figure 3

FIGURE 4. Frontals, OMNH-QV4816. 1, left in dorsal view. 2 and 3, right in dorsal view. 2, line art. 3, photo. 4 and 5, right in ventral view. 4, photo. 5, line art. 6. right in ventral view. 7 and 8, in right lateral view. 7, photo. 8, line art.

 figure 4

FIGURE 5. Posterior part of skull, OMNH-QV4816 in dorsal view. Top, photo. Bottom, line art.

figure 5 

FIGURE 6. Posterior part of skull, OMNH-QV4816 in ventral view. Top, photo. Bottom, line art.

 figure 6

FIGURE 7. Posterior part of skull, OMNH-QV4816 in anterior view. Top, photo. Bottom, line art.

figure 7 

FIGURE 8. Posterior part of skull, OMNH-QV4816 in posterior view. Top, photo. Bottom, line art.

 figure 8

FIGURE 9. Posterior part of skull, OMNH-QV4816 in right lateral view. Top, photo. Bottom, line art.

figure 9 

FIGURE 10. Map showing records of Balaenoptera edeni and B. brydei. 1, around Japan. 2, in the Seto Inland Sea including the Osaka Bay. See Table 2.

figure 10