Diaphus cassidiformis (Frost, 1933)

Schwarzhans, Werner, Ohe, Fumio, Tsuchiya, Yuki & Ujihara, Atsushi, 2022, Lanternfish otoliths (Myctophidae, Teleostei) from the Miocene of Japan, Zitteliana 96, pp. 103-134 : 103

Diaphus cassidiformis (Frost, 1933)

Fig. 9A-I

Scopelus cassidiformis 1933 Scopelus cassidiformis - Frost: figs 17, 18.

Diaphus cassidiformis 1980 Diaphus cassidiformis (Frost, 1933) - Schwarzhans: figs 176-177, 597.

Diaphus 1992 Diaphus sp. 6 - Radwanska: pl. 4, figs 1-3, textfig. 33.

Diaphus cassidiformis 2013b Diaphus cassidiformis (Frost, 1933) - Schwarzhans: pl. 4, figs 4-7.

Diaphus cassidiformis 2019 Diaphus cassidiformis (Frost, 1933) - Schwarzhans: figs 58.8-10.

Material.

80 specimens; 20 specimens, Okuna , Mizunami City, Gifu Prefecture, Oidawara FM, early Langhian, diatom zone 4A ; 60 specimens (figured specimens SMF PO 101.138), Kubusu River at Kashio, Toyama City, Toyama Prefecture, Kurosednai FM, level K 5, late Burdigalian, lower part of planktonic foraminifera biozone N8 .

Discussion.

Diaphus cassidiformis is easily recognized by its small, round otoliths. It was widely geographically distributed during the middle Miocene from New Zealand to Gabon (West Africa) and is now also recorded from Japan. It is also here interpreted to be present in the Paratethys based on an ongoing review of the myctophid otoliths originally described by Radwanska (1992). Its occurrence is rather irregular, as it may occur in large numbers at one location and in one formation (e.g., in Japan in the Oidawara and Kurosedani formations), while it may be completely missing from other locations. The reason for this unusual distribution pattern is unknown but most likely has to do with the species' ecological adaptation or with a specific lifestyle (e.g., a pseudoceanic occurrence).

Figures

Figure 9. A-I: Diaphus cassidiformis (Frost, 1933), SMF PO 101.138, Yatsuo, Toyama City, Kurosedani Formation, level K 5; J-AC: Diaphus hataii Ohe & Araki, 1973; J-L: SMF PO 101.139, Mizunami City, Oidawara Formation; M-N, Q-V: SMF PO 101.140, Tsuyama City, Takakura Formation, levels MS 06, MS 07, MS 52, MS 90; O-P: SMF PO 101.141, Fuchu machi, Toyama City, Higashibessho Formation, level H 20; W-AA: SMF PO 101.142, Makino River, Iga City, Makino Formation, level A 1; AB-AC: SMF PO 101.143, Inabacho, Tsu City, Katada Formation, level ML 2305; AD-AG: Diaphus biatlanticus (Weiler, 1959); AD-AF: SMF PO 101.144, Mizunami City, Oidawara Formation; AG: SMF PO 101.145, Tsuyama, Takakura Formation, level h; AH-AJ: Diaphus sp. 2, SMF PO 101.146, Mizunami City, Oidawara Formation.