Lanternfish otoliths (Myctophidae, Teleostei) from the Miocene of Japan

Abstract

Lanternfishes (Myctophidae) are one of the most common groups of fishes in the mesopelagic zone of the world ocean, and their otoliths have been dominant in pelagic sediments since at least Miocene times. Many species have a wide geographic distribution, with several being circumglobal. This wide distribution makes myctophid otoliths potentially useful for supraregional stratigraphic purposes. The Sea of Japan and the Northwest Pacific is an important region for investigations into the diversity and evolution of the Myctophidae. Here, we describe a large collection of myctophid otoliths from the late early to early middle Miocene (late Burdigalian to early Langhian) from six localities on western and central Honshu, which were under warm water influence during that time. A total of 22 species are recognized, of which eight are new. In the order in which they are described, the new species are Bolinichthys higashibesshoensissp. nov., Ceratoscopelus brevissp. nov., Lampadena eximasp. nov., Lampanyctus lenticularissp. nov., Lampanyctus tsuyamaensissp. nov., Stenobrachius ohashiisp. nov., Diaphus epipedussp. nov., and Diaphus watatsumisp. nov. At least nine species are also known from coeval sediments outside of Japan, most notably New Zealand and Europe. This distribution reflects the extraordinary geographic spread of myctophid species already in the early Miocene and indicates the potential for their future use for biostratigraphic purposes. The paleoecological and paleobiogeographical implications of the studied myctophid otolith assemblages are discussed. Furthermore, the stratigraphic ranges of the observed species are discussed and compared with data from other regions of the world in an attempt to outline the potential future application of myctophid otoliths for supraregional biostratigraphic purposes.

A proposal for an updated and revised stratigraphical framework of the Miocene in the Achterhoek (eastern Netherlands)

“…Several species, however, are known from Middle Miocene deposits of the Aquitaine Basin and some from the Paratethys Basin (Janssen, 1984). This is also seen in the fish-otolith faunas from the same Miocene beds (Schwarzhans, 2010).…”

“…The Neogene strata of the Achterhoek have yielded exceptionally rich and internationally important vertebrate and invertebrate faunal assemblages that have been subject of extensive studies (e.g. Janssen, 1984; Bor et al, 2012; Schwarzhans, 2010). They have also provided important insights into regional ecosystem and biotic development during the Miocene.…”

Ocean temperature drove changes in the mesopelagic fish community at the edge of the Pacific Warm Pool over the past 460,000 years

“…When similar-sized left or right otoliths of the same taxon were present in a single subsample, they were counted only once to avoid overestimation from the same individual. The otoliths of mesopelagic fishes, both extant species (9,10) and their fossil records (11,51), are well known at the global scale at least at the generic level and thus can be identified with confidence to genus or even to species by specialists (9,10). However, because of the large number of juvenile otoliths that lack characteristic features (13)(14)(15), our identifications are conservative and most specimens were recognized to genus or above.…”

Figure 16 from: Schwarzhans W, Ohe F, Tsuchiya Y, Ujihara A (2022) Lanternfish otoliths (Myctophidae, Teleostei) from the Miocene of Japan. Zitteliana 96: 103-134. https://doi.org/10.3897/zitteliana.96.83571

“…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).…”