Studies on the Little Toothed Whales in the West Sea Area of Kyusyu―X. About Prodelphinus sp. so-called "HASHINAGA IRUKA" in Japan caught in the Sea Area around Gotō Is. Nagasaki Pref.

• Main Authors: 水江, 一弘, 吉田, 主基, 園田, 成三郎
• Format: Other/Unknown Material
• Language: Japanese
• Published: 長崎大学水産学部 1964
• Subjects: toothed whales
• Online Access: https://nagasaki-u.repo.nii.ac.jp/record/8779/files/suisan17_010.pdf

1. As a result of the investigations of the four little toothed whales which had been caught in the area around Gotō Is., and landed at Nagasaki fish-market in September 1963, they were found to be the same as one sample of head which OGAWA had received from Nagasaki in 1936 and named them "HASHINAGA IRUKA". 2. These samples of ours belong to the genus Prodelphinus. 3. The body colors of our samples are shown in Fig. 2 and Plate I, namely they are black on back, white on ventral and gray on side face and there is no spot on the surface of the body entirely. The characteristic color is shown at the forehead part and around the anus (Fig. 2 & Plate I, 5. 6 and 7). 4. The values of the external proportions are shown in Table 1, one of the greatest characteristic features of body is the longer snout than those of the other Prodelphinus spp. except P. longirostris., and their three fins are larger than those of "MADARA IRUKA" (Prodelphinus sp. in former report). 5. The values of skull measurment are shown in Table2. The long snout of the skull of these specimens is characteristic. The skulls of our specimens resemble to those of Prodelphinus longirostris from the viewpoint of the existence of the tuber on os incisivum at the triangular area in front of nares and the very small and round temporal fossae, but our snout is shorter and wider than those of Prodelphinus longirostris, and our skull itself is wider than other skulls. 6. The number of vertebra is shown in Table 3, is 71～72; mean value is 71.2. 7. The number of teeth is shown in Table 4; namely, 50～52/49～50. 8. The form of scapula and sternum is interesting to see. The number of os castale, two-headed os castale and cartilago, and their connection are shown in Fig. 5. 9. OGAWA had reported one head of this specimen as Prodelphinus longirostris, but from the point of view of the body color, the values of skull measurement and the number of vertebra, it seems that our specimen is the other species from P. longirostris which had reported by TRUE, namely it is ...