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 |
