A STRANDING OF MESOPLODON STEJNEGERI IN
THE MAIZURU BAY, SEA OF JAPAN*NOBUYUKI MIYAZAKI**, IZUMI NAKAMURA***, SHINSUKE TANABE****,AND RYO TATSUKAWA****

ABSTRACTOn 13 June 1984 a Stejneger's beaked whale, Mesoplodon stejnegeri, wasfound to have stranded on the beach of Maizuru Bay (35° 31'N,135°24'£),the Sea of Japan. This whale was probably one of two unidentified whales
occasionally sighted in the bay since eight months before the stranding.
The animal was a juvenile male having testes of 34 g and measuring396.5 cm in body length. It had 44 vertebrae, composed of 7 cervical (first
three cervical bones were fused into one unit), 9 dorsal, 11 lumbar and 17
caudal vertebrae. Only vertebral epiphyses of the 3rd-7th cervicals andthe l 6- l 7th caudals were fused with the centrum. The external, cranial
and vertebral measurements, and organ weights were presented. The
PCBs and p,p'-DDE levels in blubber were 7.0 and 44 µ,g/g on wet weightbasis, respectively. The distribution of the five species of Mesoplodon known
from the North Pacific Ocean was discussed.
INTRODUCTION

In the Sea of Japan, there have been reported four Mesoplodon stejnegeri True,
1885 and one Mesoplodon ginkgodens Nishiwaki and Kamiya, 1958. A strandingof Mesoplodon bowdoini (Andrews, 1908) reported by Nishiwaki (1962b) was
reidentified by Moore ( 1963) as M. stejnegeri. This was the first record of thespecies in the Sea of Japan. Later, Nishimura and Nishiwaki (1964) reported
two additional specimens of M. stejnegeri incidentally taken by the salmon drift
gill net fishery in the Sea of Japan. They were a 520 cm male taken in 39°32'N,
137°03'E on 23 April 1963 and a 238 cm female taken in 39°08'N, 135°16'E
on 10 May 1963. The species was identified based on the external characters,
and the skulls were later lost by an earthquake in the Niigata area on 16 June
1964. The fourth specimen was a male (body length: 490 cm) found on thebeach of Niigata Prefecture on 10 May 1984 (Ikehara, Shimizu, Hiyama, Ito,
* This work was partly supported by the Grant-in-Aid for Scientific Research from the Ministry of Education,
Japan (grant no. 61560224).

** Department of Zoology, National Science Museum, 3-23-1 Shinjuku-ku, Tokyo, 160 Japan.
*** Fisheries Research Station, Kyoto University, Nagahama, Maizuru-shi, Kyoto, 625 Japan.
**** Department of Environment Conservation, Ehime University, 3-5-7 Matsuyama, Ehime, 790 Japan.
Sci. Rep. Whales Res. Inst.,
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MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA

Ogawa and Kamiya, 1985). Only record of M. ginkgodens is a juvenile femaleof 344 cm in body length. It was captured in a set net off Hiyoriyama in the
Sea of Japan on 16 March 1984 (Hiyoriyama Aquarium, 1984) and was identified to the species by Dr T. Tobayama (T. Tobayama, pers. comm.). These
five records (M. stejnegeri and M. ginkgodens) were obtained during March toJune when the oceanographic condition changes from the winter type to thesummer.
Present study is to describe the M. stejnegeri found on the beach of Maizuru
Bay on 13 June 1984, and to describe the ontogenetic change of cranium, thesexual dimorphism and the level of organochlorine pollutant. The distribution of the species is briefly discussed in comparison with other species ofMesoplodon in the North Pacific.
MATERIAL AND METHODSOn 13 June 1984, a male beaked whale of 396.5 cm in body length was foundon the beach of Taira (35°3l'N, 135°24'£), coast of the Maizuru Bay, Sea ofJapan. The first observer told to one of the authors (Nakamura) that the
animal had been already dead at his first sighting. After identifying thespecimen as Mesoplodon on 15 June, Nakamura transported it to the Fisheries
Research Station of Kyoto University for further examination. In the station,
Nakamura recorded the pigmentation, dissected the specimen and weighed
the organs with cooperation of Messrs H. Tanaka and Y. Yamamoto ofEhime
University. The measurements of external proportion and photographs werealso taken. The cranial and vertebral bones were measured by Miyazaki after
cleaning and deposited at the Fisheries Research Station, Kyoto University(FAKU M851). Other bones were lost during preparation. As the major
portion of the teeth of the specimen were embedded in the alveoli, only right
tooth was removed from the alveolus for examination after cutting a part of
the right mandible.
PCBs and p,p'-DDE were extracted using the alkaline alcohol digestion
method of Wakimoto, Tatsukawa and Ogawa (1971). The organochlorines in
the final extracts were quantified by a gas chromatograph with electron
capture detection (Tanabe, Tatsukawa, Tanaka, Maruyama, Miyazaki andFujiyama, 1981). Values of p,p'-DDE reported here also include those ofp,p'-DDT, because p,p'-DDT is converted to p,p'-DDE during alkaline alcohol
digestion.
RESULTS

External morphology
The body shape was typical of beaked whales, characterized by a relatively
large thorax and small head, flippers and tail (Plate I). The body proportionof the specimen is shown in Table 1. The dorsal fin was placed well posterior
Sci. Rep. Whales Res. Inst.,
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STRANDING RECORD OF MESOPLODON STE]NEGERITABLE 1. EXTERNAL MEASUREMENTS OF MESOPLODON STEJNEGERISTRANDED ON THE BEACH OF MAIZURU BAY KYOTO, 1984
Measurments*cm%

1. Body length
2. Tip of rostrum to apex of melon
3. Tip of rostrum to angle of gape
4. Tip of rostrum to blowhole
5. Tip of rostrum to center of eye
6. Tip of rostrm to ear
7. Tip of rostrum to an~erior insertion of flipper
8. Tip of rostrum to anterior insertion of dorsal fin
9. Tip of rostrum to umbilicus
10. Tip of rostrum to center of genital aperture
11. Tip of rostrum to anus
12. Width of flipper at the base
13. Anterior insertion of flipper to tip
14. Posterior insertion of flipper to tip
15. Basal length of dorsal fin
16. Anterior insertion of dorsal fin to tip
17. Posterior insertion of dorsal fin to tip
18. Height of dorsal fin
19. Width of tail flukes
20. Anterior insertion of fluke to tip (left)
21. Anterior insertion of fluke to notch (left)
22. Center of flukes to tip (left)

396.5
13.0
19.5
33.0
35.0
45.0
78.0
244.0
188.0
249.0
290.0
18.5
41.0
25.5
37.5
33.0
18.5
8.8
94.0
54.5
34.0
48.5

100
3.3
4.9
8.3
8.8
11.3
19.7
61.5
47.4
62.8
73.l
4.7
10.3
6.4
9.5
8.3
4.7
2.2
23.7
13.7
8.6
12.2

* Measurements parallel to the body axis.

to the middle of body (tip of rostrum to anterior insertion of dorsal fin :61.5% of body length) and nearly at the level of genital aperture (tip of rostrum to genital aperture : 62.8%). The length of visceral cavity represented
by the proportion of anterior insertion of flipper to anus (55.4%) was longer
than the head (tip of snout to ear : 11.3%), the tail (anus to the center of posterior margin of tail flukes : 26.9%) or the remaining portion (ear to anterior
insertion of flipper : 8.4%). The height of dorsal fin (2.2%) and the flipper
length (anterior insertion of flipper to the tip: 10.3%) were relatively small.
Other characteristic features of the specimen were long and narrow snout,
forehead smoothly tapering to the rostrum, absence of demarcation between
the melon and the rostrum, a pair of prominent throat grooves (left: 24.5 cm
in length, right: 26.0 cm), and absence of a median notch on the posterior
margin of tail flukes (Plate I).
The color of the animal was black on the dorsal side and lighter on themandible and the ventral side of the body. The flippers and tail flukes were
pigmented black on both sides. In the adult male of Mesoplodon carlhubbsi, therostrum and anterior portion of the mandible back to the posterior edge ofthe tooth are a brilliant white (Orr, 1953; Mead, Walker and Houck, 1982).
This pigmentation was absent on the present specimen of M. stejnegeri.
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MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWATABLE 2. BODY AND ORGAN WEIGHT OF MESOPLODON STEJNEGERISTRANDED ON THE BEACH OF MAIZURU BAY, KYOTO, 1984
Measurments
Body weightBrain
MuscleBlubber
BoneVisceraOthersInternal organs (included in viscera)
Heart
Lungs
Liver
Diaphragm
Pancreas
Kidney (left)(right)SpleenTestis (left)(right)g%

544,973783
343,780
112,659
50,93435,258
1,559

100
0.14
63.l
20.7
9.35
6.47
0.29

2,530
6,480
5,100
2,730
255
1,200
1,480
76
15
19

0.46
1.19
0.94
0.50
0.05
0.22
0.27
0.01

Body and organ weights
Body weight of the animal was calculated at 544.973 kg as the total of theweights of muscle, blubber, bone, viscera, brain and other miscellaneous
tissues. This value seemed to be underestimation of the true body weightbecause some of the blood and body fluid were not included. This will causesome inaccuracy in the proportional weights of organs and tissues in Table 2.
Brain weight was 0.14% of the body weight, which was smaller than those of
seven delphinid species, ranging from 0.53% in Stenella coeruleoalba to 1.48%
in Delphinus delphis (Bryden, 1972; Miyazaki, Fujise and Fujiyama, 1981).
Muscle (63.1 % of body weight) was the largest and followed by blubber(20.7%), bone (9.3%) and viscera (6.5%). Among internal organs, lungs(1.2%) were the heaviest organ, and followed by liver (0.94%), diaphragm(0.50%), kidneys (0.49%), heart (0.45%), pancreas (0.05%) and spleen(0.01 %). Testis weight was 15 gin the left and 19 gin the right.
Osteology
The cranial and vertebral measurements are shown in Appendix Tables 1
and 2, respectively. It is noted that this specimen had a pair of antorbital
notches, but no prominental notches which are characteristics for M. carlhubbsi(Plate II).
This specimen had the following characters of M. stejnegeri described by
Moore ( 1963): ( 1) Each antorbital notch opened with an obtuse angle of more
Sci. Rep. Whales Res. Inst.,
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STRANDING RECORD OF MESOPLODON STEJNEGERI

95

than go 0 • (2) The profile of the premaxillary crest above the superior nares
showed an abrupt turn forward, forming about 90° turn in dorsoanterior faceof each premaxillary. (3) In the anterior view, this go 0 turn showed a deep
crease across the premaxillary on the portion of its greatest width and descended laterally about 20° below the horizontal. (4) Both the dorsal andventral profiles of beak were virtually straight. These points are characteristic
to M. stejnegeri (Moore, 1963). The alveolus of the mandible was entirely
posterior to the symphysis. This separates M. stejnegeri from M. carlhubbsi
having alveolus overlapped with the symphysis. The tooth was a triangularshape and was laterally compressed. The ratio of the greatest thickness to thegreatest antero-posterior width of the right tooth was 0.15 in the present
specimen and was within the range (0.13-0.20) of M. stejnegeri (Moore, lg63).
The mesirostral canal was not filled with bone. The anterior margin of the
tooth was not of a straight line and the apex of the tooth was not found to lie
on that line (Plate III). Apex of the teeth was not worn becaus.e the teeth were
not erupted. The pulp cavity was widely open. These characters were virtuallydifferent from those of adult male of the species described by Moore ( 1963).
The thyrohyals were not fused with the basihyal. Vertebral formula was
C:7+D:g+L:ll+Ca:l7=44. The first to third cervicals were fused on bothneural arches and centra, and formed one unit. Only posterior epiphysis of
the third cervical and all epiphyses of the 4-7th cervicals were fused with
their centrum as well as those of the 16th and l 7th caudal vertebrae. These
indicate that this animal is juvenile and physically immature.

Organochlorine residues
Concentrations of PCBs and p, p'-DDE in some organs and tissues weres]f n in Table 3. Among the tissues, the concentration was highest in the
blubber on wet weight basis. This is because, the blubber contains larger
quantity of fat and these pollutants have high lipophilicity. The p, p'-DDE
concentration was higher than that of PCBs in all parts of the body analyzed.
M. stejnegeri showed higher burdens of both PCBs and p, p'-DDE in blubber
than other tissues as seen in other marine mammals (dolphin and seal) having
higher fat content in the blubber (Tanabe et al., 1981; Hidaka, Tanabe andTatsukawa, lg83).
DISCUSSION

Since October l g83, several staffs of the Fisheries Research Station of Kyoto
University sometimes observed a pair of medium-sized whales during theirown investigations in the Maizuru Bay, but they were not able to identify the
species because the whales were very shy against the vessel and didn't comewithin about 100 m of the R/V Ryouyomaru (g.8 tons) of the station or didn't
jump from the surface. Then in February 1984, a 4-5 m whale was strandedin the Maizuru Bay at the almost same position as that of the present strandSci. Rep. Whales Res. Inst.,
No. 38, 1987

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MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWATABLE 3. CONCENTRATIONS OF PCBS AND p,p'-DDE IN THE TISSUESAND ORGANS OF MESOPLODON STEJNEGERI STRANDEDON THE BEACH OF MAIZURU BAY, KYOTO, 1984
Tissue
and
organ

Fat
content(%)

Wet weight basis(µ,gig)
PCB p,p'-DDE*

Blubber
MuscleLiver
Kidneys

90
1.2
8.9
3.6

7.0
0.048
0.29
0.086

44
0.21
0.82
0.31

Fat weight basis(µ,gig)
PCB p,p'-DDE*
7.8
4.0
3.2
2.4

49
17
9.1
8.7

Burden(mg)
PCB p,p'-DDE*
790
4900
16
72
1.5
4.2
0.14
0.52

• p,p'-DDE includes p,p'-DDT (See text).

ing. This animal was buried under the ground without scientific examination.
Since there were no sightings of whales in the Maizuru Bay after these two
strandings, there is a high possibility that the present specimen is one of thepair of the medium-sized whales sighted since October 1983.
The detailed cranial measurements of the present specimen are shown inAppendix Table 1, and selected measurements of five available M. stejnegeri
specimens in Table 4. The proportion of rostrum length (measurement no. 2)
to skull length (no. 1) is higher in the larger individuals in both sexes. The
same tendency is observed in the following four measurements (measurement
nos 3, 5, 6 and 8) related with rostrum length.
The relative and absolute sizes of tooth (nos 56, 57 and 59) and the lengthof alveolus (no. 53), are obviously larger in adult males than adult females as
described by Moore (1963). The ratio of the skull width (nos 17, 18 and 19) toskull length (no. 1) is larger in males than females. The same tendency isobserved in the ratio of the premaxillary width at midlength of rostrum(no. 32), the span of premaxillary crests (no. 29) and the nasal breadth onvertex (no. 26) to skull length. The absolute values of both superior nares
width (no. 39) and inferior nares width (no. 40) are larger in males thanfemales as well as their proportional values to skull length. The ratios of
occipital condyle measurements (nos 21, 22 and 23) to skull length, are larger
in males than females as well as that of breadth of foramen magnum (no. 24).
Fig. 1 shows the reported positions of the catches or strandings of the fivespecies of Mesoplodon (M. stejnegeri, M. carlhubbsi, M. ginkgodens, M. densirostrisand M. hectori) from the Sea of Japan, the Bering Sea and the North Pacific
Ocean (Ogawa, 1938; Jellison, 1953; Nishiwaki and Kamiya, 1958, 1959;
Nishiwaki, 1962a, 1962b; Moore, 1963; Galbreath, 1963; Yang, 1964;
Nishimura and Nishiwaki, 1964; Fiscus, Rice and Johnson, 1969; Kasuya andNishiwaki, 1971; Nishiwaki, Kasuya, Kureha and Oguro, 1972; Mead, 1981;
Mead, et al., 1982; Loughlin, Fiscus, Johnson and Rugh, 1982; Leatherwood,
Reeves, Perrin and Evans, 1982; Nakajima, 1984). Present record extends therange of M. stejnegeri in the Sea of Japan to the south by about 1.5 degree inSci. Rep. Whales Res. Inst.,
No. 38, 1987

97

STRANDING RECORD OF MESOPLODON STE]NEGERITABLE 4. COMPARISON OF SKULL MEASUREMENTS (mm) OF 6 SPECIMENSOF MESOPLODON STEJNEGERJ*
Measurements
1. Condylobasal length
2. Rostrum length
3. Rostrum tip to post.
margin of pterygoid
4. Rostrum tip to post. ext.
of pterygoid wing
6. Rostrum tip to post. ext.
of max. on palate
8. Rostrum tip to ant.
margin of sup. nares
17. Breadth across frontals
18. Breadth across zygomatic proc.
19. Breadth across orbits
21. Span of occipital
condyles
22. Width of occipital
condyles
23. Length of occipital
condyle26. Breadth acrossexoccipitals
29. Pmx. crest to right nasal
32. Pmx. width at midrostrum
39. Width of sup. nares
40. Width ofinf. nares
53. Alveolus length
56. Mandibular tip toalveolus
57. Length of tooth
59. Thickness of toothPresent
specimenuuv. d1 ) (ad. d1 )Nushagak**Akita***(ad. d1 )Kasilof**(im. 9 )Tofino**(ad. 9 )Cedros ls.**(im. no sex)612 ( 100)
327 (53.4)
446 (72.9)

686 ( 100)

682 ( 100)
403 (59.1)
560 (82.1)

708 ( 100)
405 (57.2)
540 (76.3)

782 ( 100)474 (60.6)
625 (79.9)

631 ( 100)
323 (51.2)

270 (44.1)

335 (48.8)

313 (44.1)

395 (50.5)

277 (43.9)

351 (57.4)

426 (62.1)

429 (62.9)

412 (58.2)

500 (63.9)

368 (58.3)

404 (66.0)

480 (70.0)502 (73.6)

482 (68.1)

572 (73.1)

422 (66.9)346 (50.7) 336 (47.5)
333+(48.8+) 329 (45.6)

355 (45.4).337 (43.1)

277+(43.9+)340 (49.9)
118 (17.3)

323 (45.6)
108 (15.3)

335 (42.8)
111 (14.2)

277 (43.9)
103 (16.3)

39 ( 5.5)42 ( 5.4)

40 ( 6.3)

63 ( 8.9)70 ( 9.0)62 ( 9.8)270 (38.1)

278 (35.5)

247 (39.1)

41 ( 6.0)

42 ( 5.9)29 ( 4.1)

30 ( 3.8)
26 ( 3.3)

36 ( 5.7)
31 ( 4.9)
52 ( 8.2)
85 (13.5)302 (49.8)
289 (47.2)
289 (47.2)
95 (15.5)

115 (16.8)

36 ( 5.9)42 ( 6.1)

63 (10.3)

72 (10.5)80 (11.7)

252 (41.2)
26 (12.7)30 ( 4.9)
49 ( 8.0)
101 (16.5)
20 ( 3.3)
147 (24.0)

55 ( 8.0)
94 (13.7)
119 (17.3)
145 (21.l)

52
116
121
149

( 7.6)(17.0)(17,.7)(21.8)

53 ( 7.5)
87 (12.3)30 ( 4.2)
165 (23.3)

55 ( 7.0)
88 (11.3)
26 ( 3.3)
211 (27.0)

51 ( 8.3)
8 ( 1.3)

153 (22.3)
18 ( 2.6)

164 (24.0)
24 ( 3.5)

56 ( 7.9)9 ( 1.3)

61 ( 7.8)
9 ( 1.3)• Figures in parentheses indicate the percentage to the condylobasal length. For details of measurements
see Appendix Table I.
•• Measurements from Moore (1963) .
*** Measurements from Nishiwaki (1962a).

latitude, but does not require to alter the current knowledge of the distribution that it is distributed in the colder waters of the North Pacific Ocean, theSea of Japan, and deep waters of the southwest Bering Sea (Tomilin, 1967;
Leatherwood and Reeves, 1983; Loughlin and Perez, 1985). Comparison of
the sightings among the five species of Mesoplodon in the North Pacific indicates that M. stejnegeri was found in the coldest waters and M. densirostris in thewarmest waters. M. carlhubbsi was found in the colder waters than M. ginkgodens
and M. hectori.
Sci. Rep. Whales Res. Inst.,
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98

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA

QPresent specimen• M. stejnPgeri
o M. carlhubbsi

so•• M. ginkgodens.&M. hectori
OM. densirostris

50°

40°
30°
20°
10°

Fig. I. Locations of the present specimen and the five species of Mesoplodon that have been reported fromthe North Pacific and adjacent seas.

The organochlorine concentrations in the present specimen (7 .0 µ,gig of
PCBs and 44 µ,gig of p, p'-DDE in wet blubber) are within the range of theconcentrations represented by two males M. densirostris (PCBs: 14 and 29 µ,gig,
DDT: 38 and 65 µ,gig) from northwestern Atlantic (Taruski, Olney and Winn,
1975), a female M. densirostris (PCBs: 4.8 µ,gig, DDT: 11 µ,gig) from Mediterranian Sea (Aguilar, Jover and Nadal, 1982), and one female and three malesof Ziphius cavirostris (PCBs: 7.9 to 12 µ,gig, DDT: 12 to 45 µ,gig) from Bermuda(Knap and Jickells, 1983).
ACKNOWLEDGEMENTS

I wish to thank Mr M. Ueno of Kyoto University, and Messrs H. Tanaka,
K. Yamamoto and S. Watanabe of Ehime University for their invaluable assistance in the examination of this study. Mr K. Kameda of the Fishermen's
Cooperative Union of Kyoto Prefecture helpfully gave us the stranding information of the present Stejneger's beaked whale. Dr T. Tobayama of the
Kamogawa Sea World kindly permitted us to use the stranding record of
M. ginkgodens as his personal information. Drs Toshia Kasuya of Far Seas
Fisheries Research Laboratory, Japan and James Mead of Smithsonian
Institution, U.S.A. reviewed the manuscript and made helpful suggestions.
Sci. Rep. Whales Res. Inst.,
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STRANDING RECORD OF MESOPLODON STEJNEGERI99

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N1smwAKI, M. and T. KAMIYA, 1958. A beaked whale Mesoplodon stranded on Oiso beach, Japan. Sci. Rep.
Whales Res. Inst., 13: 53-83.
NISHIWAKI, M. and T. KAMIYA, 1959. Mesoplodon stejnegeri from the coast of Japan. Sci. Rep. Whales Res. Inst.,
14: 35-48.
NISHIWAKI, M., T. KASUYA, K. KuREHA and N. 0GURO, 1972. Further comments on Mesoplodon ginkgodens.
· Sci. Rep. Whales Res. Inst., 24: 43-56.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

100

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA

OGAWA, T., 1938. Studien uber die· Zahnwhale in Japan, insbesondere uber die vier bei uns bisher
unbekannten Gattungen Tursiops, Steno, Pseudorca and Mesoplodon. Arb. Anat. Inst., Kaiser!. Japan.
Univ. Sendai., 21: 173-218.
ORR, R.T., 1953. Beaked whale (Mesoplodon) from California, with comments on taxonomy.]. Mamm.,
34(2): 239-249.
TANABE, s., R. TATSUKAWA, H. TANAKA, K. MARUYAMA, N. MIYAZAKI and T. FUJIYAMA, 1981. Distribution andtotal burdens of chlorinated hydrocarbons in bodies of striped dolphins (Stene/la coeruleoalba). Agric.
Biol. Chem., 45(11): 2569-2578.
TARUSKI, A.G., C.E. OLNEY and H.E. WINN, 1975. Chlorinated hydrocarbons in cetaceans.]. Fish. Res. Board
Can., 32(11): 2205-2209.
ToMILIN, A.G., 1967. Mammals of the U.S.S.R. and adjacent countries, Vol. IX. Cetacea. (Translated from
Russian). The Israel Program for scientific translations, Jerusalem. 717pp.
WAKIMOTO, T., R. TATSUKAWA and T. OGAWA, 1971. Analytical method of PCBs. j. Environ. Pollut. Control,
7: 517-522 (in Japanese).
YANG, H.C., 1964. Whaling and Whales of Taiwan. Geikentsushin, 157: 5-122 (in Japanese).

EXPLANATIONS OF PLATESPLATE I
External features of the present Mesoplodon stejnegeri found on the beach of Maizuru Bay (35°31 'N,
135°24'E) on 13 June 1984. The male, 396.5 cm in body length (Photographs by H. Tanaka).
Fig. 1. Lateral view of head.
Fig. 2. Dorsal fin.
Fig. 3. Left flipper.
Fig. 4. Throat region of head.
Fig. 5. Ventral view.
Fig. 6. Dorsal view of tail flukes (dorsal).
PLATE II
Skull of the present specimen, M. stejnegeri.
Fig. 1. Dorsal view.
Fig. 2. Ventral view.
Fig. 3. Lateral view.
PLATE III
Skull and skeleton of the present specimen, M. stejnegeri.
Fig. 1. Lingual aspect of the right tooth.
Fig. 2. Buccal aspect of the right tooth.
Fig. 3. Mesia! aspect of the right mandible.
Fig. 4. Mesia! aspect of the mandibles.
Fig. 5. Hyoid bones.
Fig. 6. Dorsal view of the cervical vertebrae.
Fig. 7. Lateral view of the cervical vertebrae.
Fig. 8. Lateral view of the dorsal vertebrae. The eight and 9th dorsal vertebrae have been used for pollutant
analysis, and are missing from the figure.
Fig. 9. Lateral view of the lumbar vertebrae.
Fig. 10. Lateral view of the anterior segment of caudal vertebrae.
Fig. 11. Lateral view of the posterior segment of caudal vertebrae.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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104

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA
APPENDIX TABLE 1. SKULL MEASUREMENTS OF THE PRESENT SPECIMEN
OF MESOPLODON STEJNEGERIMeasurements
1. Condylobasal length*
2. Rostrum length*
3. Tip of rostrum to posterior margin of pterygoid nearest mid-sagittal plane*
4. Tip of rostrum to most posterior extension of wing of pterygoid (L)
5. Tip of rostrum to most anterior extension of pterygoid (L)
6. Tip of rostrum to most posterior extension of maxillaries between the pterygoids on the palate*
7. Tip of rostrum to most posterior extension of maxillary plate (L)
8. Tip of rostrum to anterior margin of superior nares*
9. Tip of rostrum to most anterior point of premaxillary crest
10. Tip of rostrum to most posterior extension of temporal fossa (L)
11. Tip of rostrum to most posterior extension oflateral tip of premaxillary crest (L)
12. Tip of rostrum to most anterior extension of pterygoid sinus (L)
13. Greatest length of temporal fossa (L)
14. Greatest length of orbit (L)15. Greatest length of right nasal on vertex of skull
16. Length of nasal suture
17. Greatest breadth of skull across postorbital process of frontals
18. Greatest breadth of skull across zygomatic processes of squamosals
19. Greatest breadth of skull across centers of orbits
20. Least breadth of skull across posterior margins of temporal fossae
21. Greatest span of occipital condyles
22. Greatest width of occipital condyle (L)
23. Greatest length of occipital condyle (L)24. Greatest breadth of foramen magnum
25. Greatest height of foramen magnum
26. Greatest breadth of skull across exoccipitals
27. Greatest breadth of nasals on vertex
28. Least distance between premaxillary crests
29. Distance from anterior process of premaxillary crest to posterior to right nasal on vertex
30. Greatest span of premaxillary crests
31. Width of rostrum at midrostral length
32. Width of premaxillae at midlength of rostrum
33. Width of rostrum at 1/4 rostral length from the tip
34. Width of premaxillae at 1/4 rostral length from the tip
35. Width of rostrum at 3/4 rostral length from the tip
36. Width of premaxillae at 3/4 rostral length from the tip
3 7. Greatest depth of rostrum at midrostral length
38. Width of rostrum in apices of antorbital notches
39. Greatest width of superior nares
40. Greatest width of inferior nares, at apices of pterygoid notches, on the pterygoids
41. Height of skull, distance between vertex of skull and most ventral point on pterygoids
42. Greatest width of temporal fossa approximately at right angles to greatest length (L)43. Least distance between maxillary foramina
44. Least distance between premaxillary foramina
45. Greatest length of vomer visible on palate
46. Greatest condylar length of mandibular ramus (L)4 7. Greatest length of mandibular symphysis
48. Greatest height of mandible at coronoid process (L)49. Height of mandible at midlength of alveolus (measured from lingual margin of alveolus) (L)50. Height of mandible at midlength of alveolus (measured from buccal margin of alveolus) (L)51. Length from most posterior extension of mandibular symphysis to most posterior extention of condyle (L)52. Length from posterior margin of alveolus to condyle (L)53. Length of alveolus (L)54. Width of alveolus (L)55. Tip of mandible to anterior margin of alveolus (L)56. Tip of i:nandible to center of alveolus (L)5 7. Greatest length of tooth (R)58. Greate~t antero-posterior width of tooth at approximately right angles to long axis of tooth (R)59. Greates·t thickness of tooth (R)

mm

%

612
327
446
472
270
351
557
404
436
574
469
311
101
89
41
42
302
289
289
199
95
36
63
40
42
252
37
21
26
116
39
30
24
24
48
32
38
156
49
101
214
60
63
36
65
518
94
105
46
45
426
365
20
9
136
147
51
55
8

100
53.4
72.9
77.1
44.1
57.4
91.0
66.0
71.2
93.8
76.6
50.8
16.5
14.5
6.7
6.9
49.8
47.2
47.2
32.5
15.5
5.9
10.3
6.5
6.9
41.2
6.0
3.4
12.7
19.0
6.4
4.9
3.9
3.9
7.8
5.2
6.2
25.5
8.0
16.5
35.0
9.8
10.3
5.9
10.6
84.6
15.4
17.2
7.5
7.4
69.6
59.6
3.3
1.5
22.2
24.0
8.3
9.0
1.3

* These characters were measured parallel to the condylobasal length while the others by distance between points.
L and R indicate left and right, respectively.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

105

STRANDING RECORD OF MESOPLODON STEJNEGERIAPPENDIX TABLE 2. MEASUREMENTS OF VERTEBRAE (mm) OF MESOPLODONSTEJNEGERI STRANDED ON THE BEACH OF MAIZURU BAY, KYOTO, 1984
Serialno.

Segment
no.

I

Cl

2

2

3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

3

4
5
6
7
DI
2
3
4
5
6
7
8*
9*
LI
2
3
4
5
6
7
8
9
10
11
Cal
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

Greatest
B
H

B

Centrum
H

L

14.3
13.9
11.8
10.1
9.1
8.6
12.8
15.2
15.2
15.0
14.8
14.8
14.9
11.6

13.0
13.0
12.1
10.7
10.5
14.5
19.4
22.5
24.5
24.9
25.7
26.7
27.4
27.5

5.9
5.6
5.4
5.4
6.0
5.3
5.4
5.5
5.4
5.7
5.9
6.2

4.1
3.8
4.1
4.3
4.3
4.3
4.3
4.2
4.1
4.3
4.5
4.7

1.1
1.0
1.2
1.5
2.3
3.5
4.4
5.0
5.6
6.3
6.7

27.1
27.5
27.8
28.2
27.7
27.8
27.7
27.8
27.9
27.2
26.4
24.9
22.4
20.1
17.9
15.4
12.5
10.1
8.7
7.7
7.2
6.7
5.8
5.1
4.6
4.0
3.3
2.1

30.7
31.9
32.8
34.3
35.0
35.3
35.1
34.4
35.2
34.2
33.7
33.2
30.8
28.3
24.6
21.6
18.7
16.3
14.2
11.8
9.1
6.5
5.1
4.0
3.5
2.8
2.0
1.4

7.4
7.7
7.9
8.1
8.3
8.4
8.6
9.0
9.2
9.4
9.4
9.7
9.8
9.5
9.4
9.6
9.6
9.9
8.7
7.7
7.2
6.7
5.8
5.1
4.6
4.0
3.3
2.1

5.5
5.9
6.2
6.3
6.7
6.9
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.6
8.5
8.7
9.1
9.1
9.0
8.8
7.7
6.4
5.0
3.8
3.3
2.7
2.0
1.4

8.4
8.8
9.3
9.4
9.7
10.1
10.5
11.1
11.2
11.7
11.6
11.5
11.0
10.4
9.7
9.2
8.9
8.2
7.4
6.6
5.3
4.0
3.6
3.3
2.9
2.6
2.0
1.3

Neural canal
B
H
5.1

3.7

4.4
4.2
4.3
4.6
5.1
5.2
5.0
4.7
4.4
4.2
4.0
3.7

4.0
4.2
4.5
4.8
5.0
5.1
5.3
5.5
5.6
5.6
5.5

3.4
3.1
3.0
3.0
3.0
3.2
2.9
2.9
2.5
2.3

2.2
1.8
1.6
1.4
1.4
1.4
1.4
1.3
0.9
0.8
0.6

5.4
5.3
5.2
5.1
5.0
5.1
4.6
4.2
3.6
3.2
2.4
2.6
2.3
1.9
1.8
1.6
1.2
1.0
1.0
0.7
0.5

Fusion of
epiphyses
yes
yes
yes
yes
yes
yes
yes
no
no
no
no
no
no
no

no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
yes
yes

44
* These two vertebral bones were used for analysis of organochlorine compounds without making
measurement.
B: breadth, H: height, L: length.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987