Notoscopelus kuboensis (Ohe & Araki, 1973)

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

Notoscopelus kuboensis (Ohe & Araki, 1973)

Fig. 10A-N

Lampanyctus kuboensis 1973 Lampanyctus kuboensis - Ohe & Araki: pl. 49, figs 7-11.

Lampanyctus 1977 Lampanyctus sp. - Takahashi: pl. 25, fig. 4.

Lampanyctus parvicauda 1981 Lampanyctus parvicauda Parr, 1931 - Ohe: pl. 3, fig. 12.

Notoscopelus kuboensis 2019 Notoscopelus kuboensis (Ohe & Araki, 1973) - Schwarzhans and Ohe: fig. 13K-M.

Material.

40 specimens (figured specimens SMF PO 101.147-148): 36 specimens, Miya River at Oda and Numa, Tsuyama City, Okayama Prefecture, Takakura FM, levels MS 04.5, MS 05, MS 05.5. MS 06, MS 15, MS 22, MS 27, MS 36, MS 70, MS 80, MS 90, f10, f40, gh, h, j, late Burdigalian, diatom zone 3A-3B ; 1 specimen, Nagano River at Inabacho, Tsu City, Mie Prefecture, Katada FM, level I 2, late Burdigalian, lower part of planktonic foraminifera biozone N8 ; 3 specimens Okuna , Mizunami City, Gifu Prefecture, Oidawara FM, early Langhian, diatom zone 4A ; 2 specimens, Osedani , Toyama City, Toyama Prefecture, Higashibessho FM, level H 20, late Burdigalian to early Langhian, diatom zone 3A-4A .

Discussion.

Notoscopelus kuboensis is a wide-ranging species in the late early and middle Miocene to early Pleistocene of Japan and belongs to the lineage leading to the extant N. japonicus (Tanaka, 1908) (see Schwarzhans and Ohe 2019). The new data document a rather large variability of the ratio OL:OH ranging from 1.65 to 1.9, with a single large specimen reaching a ratio of 2.0 (corrected for erosion along the central portion of the ventral rim). This wide range appears to be mostly ontogenetically driven, with specimens up to 3 mm in length having a ratio OL:OH of 1.65-1.7 (Fig. 10J, K, M ), those of 3 to 4 mm in length a ratio OL:OH of 1.75-1.85 (Fig. 10E, G, H ), and the largest specimens reaching 4.85 mm in length with a ratio OL:OH of 1.9-2.0 (Fig. 10A, B ). The specimens described from the Pliocene and early Pleistocene by Schwarzhans and Ohe (2019) are of larger size (4.4-5.0 mm in length) and show a similar ratio of 1.85-1.95. Notoscopelus kuboensis differs from the middle Pleistocene N. praejaponicus Schwarzhans & Ohe, 2019 and the extant N. japonicus (Tanaka, 1908) primarily by the not extended posterior tip of the otolith, the postdorsal angle being positioned further backward on the dorsal rim in comparison to the two other species, and the lack of the distinctive and long postdorsal concavity developed in N. praejaponicus and N. japonicus .

Figures

Figure 10. A-N: Notoscopelus kuboensis (Ohe & Araki, 1973); A: SMF PO 101.147, Inabacho, Tsu City, Katada FM, level ML 2305; B-N: SMF PO 101.148, Tsuyama City, Takakura Formation, levels MS 15, MS 36, MS 80, MS 90, j.