Thirty-one species of early to middle Spathian (late Olenekian, Early Triassic) ammonoids are reported from the Osawa Formation in the Yamaya, Akaushi–Osawa, Utatsu, Kamiwarizaki and Ozashi areas in the southern part of the South Kitakami Belt, Miyagi Prefecture, Northeast Japan. Four distinct Spathian ammonoid zones (taxon-range zones) are recognized in the upper lower to middle upper parts of the Osawa Formation, in ascending order: the upper lower Spathian Deweveria kovalenkoi Zone, the middle Spathian Subcolumbites perrinismithi Zone, Subfengshanites multiformis Zone and Isculitoides sp. Zone. The Subfengshanites multiformis Zone is characterized by its occurrence in various lithologies in different areas, i.e., alternating beds of mudstone and fine-grained sandstone in the south, and more offshore mudstone in the north, suggesting a northward-deepening setting. Because a primitive ichthyopterygian Utatsusaurus hataii occurs in the Subcolumbites perrinismithi to Isculitoides sp. zones, its age is likely constrained to the middle Spathian. The ammonoid faunas in the Osawa Formation exhibit a great affinity with those of South Primorye as well as the Tethys, and such faunal similarity suggests that the South Kitakami Belt may have been located near South Primorye.
Introduction
The Osawa Formation, which is distributed in the South Kitakami Belt, a geologic feature generally regarded as a fragment of continental origin (Kobayashi, 1999), is famous for its yield of a primitive ichthyopterygian, Utatsusaurus hataii Shikama et al., 1978 as well as rich Spathian (late Olenekian) ammonoid faunas (Bando, 1964, 1970; Bando and Shimoyama, 1974; Ehiro, 1993, 2016, 2022; Ehiro et al., 2016; Shigeta, 2022, revision of early Spathian ammonoids). The formation also contains a wide range of fossil groups, i.e., nautiloids (Niko et al., 2016; Niko and Ehiro, 2024), aulacocerid and belemnitid coleoids (Niko and Ehiro, 2018, 2022), pelecypods (Murata, 1973, 1978), brachiopods (Murata, 1973), thylacocephalans (Ehiro et al., 2015, 2019; Ehiro and Kano, 2024), bony fishes (Nakajima et al., 2017; Nakajima and Komura, 2020), cartilaginous fish (Kato et al., 1995), coprolites (Nakajima and Izumi, 2014) and plants (Kon'no, 1973), which suggests a record of a fairly rapid recovery of a complex Spathian marine ecosystem following the Permian/Triassic boundary mass extinction event, similar to the earliest Spathian Paris Biota in southeastern Idaho, western USA (Brayard et al., 2017).
A biostratigraphic scheme for the Osawa Formation, excluding the uppermost part, was established by Bando and Shimoyama (1974); they recognized the following two ammonoid zones, in ascending order, the Subcolumbites Zone and the Arnautoceltites Zone, in latter of which the lower zone was subdivided into the Columbites parisianus Subzone and Subcolumbites perrinismithi Subzone in ascending order. The biostratigraphy of the Osawa Formation has been updated by recent works that focused on the ammonoid faunas from the lower and uppermost parts. Ehiro (2022) described an ammonoid fauna from the uppermost part and recognized a new zone, the uppermost Spathian Eodanubites Zone. Shigeta (2022) revised the taxonomy of the ammonoids described by Bando and Shimoyama (1974) from the lower part of the formation at Akaushi (see Figure 1 in Bando and Shimoyama, 1974). He concluded that these specimens should be attributed to Hellenites tchernyschewiensis Zakharov, 1968, H. inopinatus Kiparisova, 1961, Neocolumbites grammi Zakharov, 1968, N. insignis Zakharov, 1968, Procolumbites ussuriensis (Zakharov, 1968) and P. subquadratus Zakharov, 1968 rather than their previous designations as Columbites parisianus Hyatt and Smith, 1905, Subcolumbites perrinismithi (Arthaber, 1908) and Eophyllites cf. dieneri (Arthaber, 1908). This new designation of the ammonoid assemblage correlates not only with South Primorye, Russian Far East but also with the upper lower Spathian of South China and western USA, and furthermore, it has resulted in the loss of representation of the Subcolombites Zone and its two subzones (the Columbites parisianus Subzone and Subcolumbites perrinismithi Subzone) proposed by Bando and Shimoyama (1974).
In addition to the revision of ammonoid taxonomy of previous authors, this update of ammonoid biostratigraphy of the Osawa Formation is also based 178 newly collected specimens as well as 11 specimens in the “Suzuki Chisato Collection” donated to the Fukushima Museum. Additionally, the age of a primitive ichthyopterygian, i.e., Utatsusaurus hataii, as well as the paleogeographic positioning of the South Kitakami Belt based on the contained faunal similarity, is discussed.
Notes on stratigraphy
The Lower to Middle Triassic Inai Group is widely distributed in the southern part of the South Kitakami Belt in Miyagi Prefecture, Northeast Japan. Consisting mainly of shallow–shelf marine deposits, the Inai Group unconformably overlies the uppermost Permian Toyoma Formation, and is unconformably overlain by either the Upper Triassic or Jurassic (Kamada and Takizawa, 1992). The Inai Group is divided into the Hiraiso, Osawa, Fukkoshi and Isatomae formations in ascending order (Ichikawa, 1951), with the Hiraiso and Osawa formations correlated with the Spathian (Shigeta and Nakajima, 2017; Ehiro, 2022; Shigeta, 2022; Foster et al., 2022), and the Fukkoshi and Isatomae formations with the Anisian (Mojsisovics, 1888; Shimizu, 1930; Ehiro, 2022), mainly based on ammonoid biostratigraphy. Based on lithological facies and sedimentary structures, it is presumed that the Hiraiso Formation was deposited on the upper shore-face to the inner shelf (Kamada and Takizawa, 1992; Kashitama and Oji, 2004; Foster et al., 2022), the Osawa Formation on the outer shelf (Kamada and Takizawa, 1992; Yoshizawa et al., 2021; Ishizaki and Shiino, 2023), the Fukkoshi Formation on the submarine fan (Kamada and Takizawa, 1992), and the Isatomae Formation on the outer shelf near the inner shelf, respectively (Kamada and Takizawa, 1992).
Osawa Formation
Exposure.—The Osawa Formation is distributed in narrow bands, which run in a north-south direction for a total of ∼25 km along the coast, and this study comprises the following five areas: 1) the Yamaya area, 2) the Akaushi–Osawa area, 3) the Utatsu area, 4) the Kamiwarizaki area, and 5) the Ozashi area (Figures 1, 2). In the Akaishi-Osawa area, these bands strike N30–70° eastward and dip 30–50° westward, in the Utatsu area, they strike N5–45° eastward and dip 20–65° westward, and in the Kamiwarizaki and Ozashi areas, they strike N10–30° eastward and dip 50–70° westward.
Thickness.—210–230 m.
Stratigraphic relationship.—The Osawa Formation conformably overlies the Hiraiso Formation and is conformably overlain by the Fukkoshi Formation.
Lithology.—The Osawa Formation is divided into three informal, lithostratigraphic units, i.e., Os1 unit, Os2 unit and Os3 unit (Figure 3). In the Os1 unit, alternating beds of dark gray, bioturbated mudstone and fine-grained sandstone grade upward into dark gray, laminated mudstone intercalated with fine-grained sandstone beds, and then to dark gray, laminated mudstone. In the Yamaya area, the stratigraphic position of the Osawa Formation is unclear because of poor exposures, but the outcrops of dark gray, laminated mudstone suggest that it is probably the Os1 unit.
The basal part of the Os2 unit consists of a 1–8 m thick fine-grained sandstone bed containing mud clasts. It changes upward to dark gray, laminated mudstone and then to bioturbated mudstone intercalated with 0.3–12 m thick-bedded, fine-grained sandstone beds containing mud clasts. The upper part of the Os2 unit consists of alternating beds of dark gray, laminated mudstone and fine-grained sandstone.
The Os3 unit consists of dark gray, laminated mudstone, which grades upward into dark gray, bioturbated mudstone.
Fossils.—The laminated mudstone beds in the upper part of the Os1 unit are fossiliferous, and the following ammonoids have been reported by other workers or collected by the authors from the Akaushi–Osawa area (Bando and Shimoyama, 1974; Shigeta, 2022; Figure 4): Neocolumbites insignis, N. grammi, Procolumbites ussuriensis, P. subquadratus and Deweveria kovalenkoi at Locs. OS-A01 and A02 and Hellenites inopinatus and H. tchernyschewiensis at Loc. OS-A02. From the Kamiwarizaki and Ozashi areas, H. tchernyschewiensis was collected at Locs. OS-A41, A42 and A31. Fengshanites sp., Procolumbites sp. and Idahocolumbites sp. were also collected at Loc. OS-A41. Deweveria kovalenkoi was collected at Locs. OS-A41 and A42. The ammonoid locality at Yamaya contains D. kovalenkoi, H. tchernyschewiensis, Olenekoceras miroshnikovi (Zakharov, 1968), Khvalynites unicus (Kiparisova, 1961) and Pseudosageceras sp.
Figure 1.
Index maps (A, B) showing distribution of the Lower Triassic Hiraiso and Osawa formations (black areas) as well as study areas, the Yamaya, Akaushi–Osawa, Utatsu, Kamiwarizaki and Ozashi areas, along Sanriku Coast (C).
In the Os2 unit, the weakly bioturbated mudstone in the lower part contains various kind of fossils including ammonoids (Figure 4), thylacocephalans, brachiopods, and ichthyopterygian bones. Numerous ammonoid taxa were collected at Loc. OS-A22, including Subcolumbites perrinismithi, Leiophyllites sp., Stacheites floweri, Epiceltites gentii Arthaber, 1911, Prohungarites sp., Albanites sheldoni (Kummel, 1969), A. cf. triadicus Arthaber, 1908, Chioceras sp., Proptychitoides cf. trigonalis (Arthaber, 1911), Hemilecanites sp. and Pseudosageceras sp. Subcolumbites perrinismithi (Arthaber, 1908) was also collected at Locs. OS-A21, A43 and A44. Ammonoids are rare in the middle part of the Os2 unit, but the alternating beds of dark gray, laminated mudstone and fine-grained sandstone in the upper part are fossiliferous and contain ammonoids (Figure 4), bivalves, coprolites and ichthyopterygian bones. The following ammonoids were collected from the upper part of the Os2 unit: Subfengshanites multiformis (Kiparisova in Voinova et al., 1947) at Locs. OS-A33, 45, A46 and A47, Arnautoceltites sp. at Loc. OS-A46, and Suliotoceras inflatus (Kiparisova, 1961) at Loc. OS-A23.
In the Os3 unit, the laminated mudstone in the lower and middle parts is fossiliferous and contains ammonoids (Figure 4), bivalves, coprolites and ichthyopterygian bones. Numerous ammonoid taxa were collected at Loc. OS-A11, including Subfengshanites multiformis, Prenkites graecoamericanus (Renz and Renz, 1948), Stacheites floweri, Arnautoceltites gracilis (Kiparisova in Voinova et al., 1947) and Pseudosageceras sp. Subfengshanites multiformis was also collected at Loc. OS-A34. The faunal composition changes toward the upper part of the Os3 unit, and the following ammonoids were collected (Figure 4): Isculitoides sp. at Locs. OS-A12, A13, A14, A35 and A48, Leiophyllites praematurus Kiparisova at Locs. OS-A13 and A14; Arnautoceltites gracilis at Locs. OS-A12, A13 and A15 and Pseudosageceras sp. at Locs. OS-A12 and A48. Ammonoids were not found in the bioturbated mudstone in the Os3 unit.
Biostratigraphic subdivisions
Based on our detailed geological survey and carefully controlled bed by bed sampling, we recognized four Spathian ammonoid biozones in the interval ranging from the Os1 unit to the middle part of the Os3 unit in the studied areas. A biozone represents a taxon-range zone of the index species, but the boundary between such zones remains obscure because of intermittent fossil occurrences.
Figure 2.
Geological maps showing localities of ammonoid specimens described from the Osawa Formation and study sections (1 through 4) in the Yamaya and Akaushi–Osawa (A), Utatsu (B), Kamiwarizaki (C) and Ozashi (D) areas.
Figure 3.
Columnar sections showing localities from which ammonoids were collected in study sections. 1, Akaushi–Osawa section; 2A, 2B, Utatsu sections; 3, Kamiwarizaki section; 4, Ozashi section. Each locality number has prefix “OS”.
Deweveria kovalenkoi Zone
This zone is characterized by the occurrence of the index ammonoid Deweveria kovalenkoi as well as Procolumbites ussuriensis, P. subquadratus, Hellenites inopinatus, H. tchernyschewiensis, Neocolumbites insignis, N. grammi, Olenekoceras miroshnikovi and Khvalynites unicus. The zone is well documented at Locs. OS-A01, A02, A31, A41, A42 and at Yamaya in the upper part of the Os1 unit (Figures 4, 5). These ammonoids are characteristic of the N. insignis Zone in South Primorye, Russian Far East (Zakharov, 1968, 1997a). Because Procolumbites is a typical latest early Spathian ammonoid genus, the Deweveria kovalenkoi Zone is correlated with the upper lower Spathian (Tong et al., 2004; Galfetti et al., 2007; Guex et al., 2010; Jenks et al., 2013; Ji et al., 2015; Figure 6). This zone corresponds to the Bando and Shimoyama's (1974) Columbites parisianus Subzone of the Subcolumbites Zone.
Subcolumbites perrinismithi Zone
The index ammonoid Subcolumbites perrinismithi occurs with the following taxa: Stacheites floweri, Epiceltites gentii, Prohungarites sp., Albanites sheldoni, A. cf. triadicus, Chioceras sp., Proptychitoides cf. trigonalis, Hemilecanites sp., Eophyllites sp. and Pseudosageceras sp. at Loc. OS-A22 in the Os2 unit. The zone is also well documented at Locs. OS-A21, A31, A43 and A44 (Figures 4, 5), and its ammonoid assemblage is very similar to the middle Spathian Subcolumbites fauna of Albania, Chios, South China and western USA (Arthaber, 1908, 1911; Renz and Renz, 1948; Chao, 1959; Kummel, 1969; Guex et al., 2010; Figure 6). The zone corresponds to the lower part of Bando and Shimoyama's (1974) Subcolumbites perrinismithi Subzone of the Subcolumbites Zone.
Subfengshanites multiformis Zone
This zone is characterized by the occurrence of the index ammonoid Subfengshanites multiformis and contains Arnautoceltites gracilis and Arnautoceltites sp. as well as Stacheites floweri, Prenkites graecoamericanus, Suliotoceras inflatus and Pseudosageceras sp. at Locs. OS-A11, A23, A33, A34, A45, A46 and A47 (Figures 4, 5). The zone is well documented in the interval ranging from the upper part of the Os2 unit to the middle part of the Os3 unit and corresponds to the lower part of Bando and Shimoyama's (1974) Arnautoceltites Zone. Because the Subfengshanites multiformis fauna, which includes A. gracilis and Suliotoceras inflatus, is known from the middle Spathian of South Primorye (Zakarov, 1997a; Zakharov and Mousavi, 2013; Jenks et al., 2015; Figure 6), the Subfengshanites multiformis Zone is correlated with the middle Spathian.
Isculitoides sp. Zone
This zone contains the index ammonoid Isculitoides sp. as well as Arnautoceltites gracilis, Stacheites floweri and Leiophyllites praematurus at Locs. OS-A12–A14, A35 and A48 in the lower and middle parts of the Os3 unit (Figures 4, 5). Because Isculitoides occurs in the middle Spathian Subcolumbites fauna of Albania, Chios, Afghanistan, South China and western USA (Arthaber, 1908, 1911; Renz and Renz, 1948; Chao, 1959; Kummel, 1968, 1969; Guex et al., 2010; Figure 6), the Isculitoides sp. zone is consideres to be middle Spathian. This zone corresponds to the upper part of Bando and Shimoyama's (1974) Arnautoceltites Zone.
Discussion
Biostratigraphic correlation of the Osawa Formation
The upper part of the Os1 unit, characterized by the Deweveria kovalenkoi Zone, is correlated with the upper lower Spathian (Shigeta, 2022). A change in the ammonoid assemblage in the lower part of the Os2 unit, in which Subcolumbites perrinismithi is common, suggests that this part is the middle Spathian (e.g. Guex et al., 2010). Furthermore, the interval ranging from the upper part of the Os2 unit to the middle part of the Os3 unit, characterized by the Subfengshanites multiformis and Isculitoides sp. zones, is also correlatable with the middle Spathian (e.g. Jenks et al., 2015). According to Ehiro (2022), the uppermost part of Os3 unit, characterized by the Eodanubites Zone, is correlatable with the upper Spathian. In summary, the Osawa Formation ranges from the upper lower to upper Spathian (Figure 6).
The Subfengshanites multiformis Zone clearly occurs within different parts of the Osawa Formation in different areas, e.g. in the Ozashi area, the zone occurs in the upper part of the Os2 unit; in the Kamiwarizaki area, it ranges from the upper part of the Os2 unit to the lower part of the Os3 unit; and in the Osawa area, it occurs in the middle part of the Os3 unit (Figures 3, 5). The upper part of the Os2 unit consists of alternating beds of dark gray, laminated mudstone and fine-grained sandstone and the Os3 unit consists of dark gray, laminated mudstone (Figure 3). Because offshore facies are more predominant in the Osawa area, a northward-deepening setting is inferred. This supposition is supported by the northward directed paleocurrents that are evident in the turbiditic sandstone (Ishizaki and Shiino, 2023).
Age of ichthyopterygians from the Osawa Formation
The Osawa Formation is well known for the occurrence of the primitive ichthyopterygian Utatsusaurus hataii, which is found in the Subcolumbites perrinismithi to Isculitoides sp. zones (middle Spathian) in the Os2 and Os3 units (Shikama et al., 1978; Kamata and Takizawa, 1992). A few “Utatsusaurus” remains have been found in the upper part of the Os1 unit in the Utatsu area (specimen nos. A–C of Shikama et al., 1978), but these specimens have not been described or illustrated. This particular horizon, i.e., the Deweveria kovalenkoi Zone, is correlated with the Procolumbites Zone in South China (Ji et al., 2015), from which the primitive ichthyopterygian Chaohusaurus was described, and with the Neocolumbites insignis Zone in South Primorye, where several bone fragments of ichthyopterygian were reported (Nakajima et al., 2022). A single limb bone reported by Nakajima et al. (2022), which was tentatively identified as an ichthyopterygian humerus, represents one of the largest specimens of early Spathian marine reptiles known to date, suggesting an explosive diversification in size immediately after the end-Permian mass extinction (Sander et al., 2021; Kearl et al., 2023). Nakajima et al. (2022) also revealed that the vertebrae and humeral specimens exhibit an extremely cancellous inner structure, suggesting a high degree of aquatic adaptation in those ichthyopterygians. Recently, Kearl et al. (2023) reported ichthyopterygian remains from the Smithian of Spitsbergen and proposed that these pioneering seagoing tetrapods should now be regarded as mass extinction survivors. The early evolution of ichthyopterygian is still a matter of debate, but the latest early Spathian is an important period for studying the diversification of ichthyopterygians, and future studies of ichthyopterygians in the Os1 unit of the Osawa Formation are of particular importance.
Figure 5.
Biostratigraphic correlation between the studied sections. 1, Akaushi–Osawa section; 2A, 2B, Utatsu sections; 3, Kamiwarizaki section; 4, Ozashi section. Each locality number has prefix “OS”.
Figure 6.
Correlation of ammonoid zones of the Hiraiso and Osawa formations (South Kitakami) with other important Spathian (upper Olenekian, Lower Triassic) ammonoid localities. Zakharov and Mousavi (2013) correlated the Ussuriphyllites amurensis Zone with the lower Anisian of South Primorye, but Shigeta and Kumagae (2016) dispute this stratigraphic assignment and regard it as upper Spathian. Recently, Popov et al. (2019) reported the occurrence of the Prohungarites sp.–Paranorellin parisi Beds between the Subfengshanites multiformis Zone and U. amurensis Zone and correlated it with the upper Spathian. The stratigraphic correlation of the U. amurensis Zone (upper Spathian or lower Anisian) is still a matter of debate.
Aspects of the Spathian ammonoid fauna
Ammonoid specimens from the Osawa Formation are very badly deformed laterally due to compaction and subsequently, their ventral portions and suture lines are poorly preserved. Consequently, relatively few ammonoid taxa can be definitively identified to the species level, but it is obvious that many belong to taxa that have been described from South Primorye, i.e., Procolumbites ussuriensis, P. subquadratus, Hellenites inopinatus, H. tchernyschewiensis, Neocolumbites insignis, N. grammi, Deweveria kovalenkoi, Olenekoceras miroshnikovi, Khvalynites unicus, Subfengshanites multiformis, Suliotoceras inflatus, Arnautoceltites gracilis and Leiophyllites praematurus. Some are from the Tethys (e.g. Albania and Chios), i.e., Subcolumbites perrinismithi, Epiceltites gentii, Albanites triadicus, Proptychitoides trigonalis and Prenkites graecoamericanus. Other genera, such as Fengshanites, Hemilecanites, Stacheites, Prohungarites, Procarnites, Isculitoides and Chioceras, which are not strictly limited to the Tethys, nevertheless, have Tethyan similarities. Thus, it is fairly obvious that the ammonoid faunas in the Osawa Formation exhibit a great affinity with those of South Primorye as well as the Tethys. This new perspective differs somewhat from previous studies such as Brayard et al. (2009) and Ehiro et al. (2016), who stated that the ammonoid fauna of the Osawa Formation is very similar to that of the western USA.
The paleogeographic position of the South Kitakami Belt is a matter of debate (Shigeta, 2022, p. 415), but Isozaki et al. (2014, 2017) suggested that this geologic complex was located at the northeastern tip of South China Block, and both South Primorye and the South Kitakami Belt belonged to “Greater South China”, based on zircon geochronology studies. The similarity in ammonoid faunas between the South Kitakami Belt and South Primorye demonstrated in this paper supports the hypothesis proposed by Isozaki et al. (2014, 2017).
Paleontological description
Systematic descriptions basically follow the classification established by Shevyrev (1968), Tozer (1981) and Guex et al. (2010). Morphological terms are those used in Arkell (1957). Quantifiers used to describe the shape of ammonoid shell replicate those proposed by Matsumoto (1954, p. 246) and modified by Haggart (1989, table 8.1).
Institution abbreviations.—CGM, Central Scientific Research Geological Prospecting Museum (TsNIGR Museum), St. Petersburg; DVGI, Far Eastern Geological Institute, Vladivostok; FM, Fukushima Museum, Aizuwakamatsu; IPPM, Iwate Prefectural Museum, Morioka; IPUW, Department of Palaeontology, University of Vienna, Vienna; MBJ, Natural History Museum Basel, Basel; MCZ, Museum of Comparative Zoology, Harvard University, Cambridge; NIGP, Nanjin Institute of Geology and Palaeontology, Nanjin; NMMNH, New Mexico Museum of Natural History and Science, Albuquerque; NMNS, National Museum of Nature and Science, Tsukuba.
Order Ceratitida Hyatt, 1884
Superfamily Xenodiscoidea Frech, 1902
Family Hemilecanitidae Guex et al., 2010
Genus Hemilecanites Spath, 1934
Type species.—Lecanites discus Arthaber, 1908.
Hemilecanites sp.
Figure 7C–I
Hemilecanites discus Arthaber. Ehiro et al., 2016, p. 93, fig. 2.1–2.3.
Leiophyllites? sp. Ehiro et al., 2016, p. 100, fig. 4.5
Material examined.—Six specimens: NMNS PM 45460–45465 from Loc. OS-A22.
Description.—Specimens are characterized by a very evolute, compressed shell with slightly flattened flanks, indistinct ventral shoulders and an angular venter (Figure 7I). Umbilicus is wide with low, vertical wall and rounded shoulder. Shell surface is nearly smooth with fine growth lines as well as low, fold-type ribs on earlier whorls.
Discussion.—Even though the described specimens are strongly deformed laterally due to compaction, their distinctive features, e.g. very evolute, compressed shell with an angular venter and smooth surface, enable us to assign them with reasonable confidence to the genus Hemilecanites. Their morphology and ornamentation are somewhat similar to H. discus Arthaber, 1908 (Figure 7A, B). Ehiro et al. (2016, fig. 2.1–2.3) assigned specimens form Loc. OS-A22 to H. discus, but a definitive species assignment of our specimens as well as those of Ehiro et al. (2016) cannot be made. One of the specimens identified as Leiophyllites? sp. by Ehiro et al. (2016, fig. 4.5) has an angular venter and we herein assign it to Hemilecanites.
Occurrence.—Described specimens were collected from the middle Spathian Subcolumbites perrinismithi Zone.
Genus Deweveria
Guex et al., 2005a
Type species.—Deweveria dudresnayi Guex et al., 2005a.
Deweveria kovalenkoi
Smyshlyaeva and Zakharov, 2015
Figure 8D–I
Glyptophiceras cf. gracile (Spath). Bando, 1970, p. 343, pl. 37, fig. 1, text-fig. 5.
Deweveria kovalenkoi Smyshlyaeva and Zakharov, 2015, p. 114, pl. 1, fig. 5, text-fig. 3e; Shigeta, 2022, p. 412, fig. 4A–D.
Holotype.—DVGI 100/840, figured by Smyshlyaeva and Zakharov (2015, p. 114, pl. 1, fig. 5), from the Neocolumbites insignis Zone (upper lower Spathian) on Russky Island, South Primorye, Russia (Figure 8D, E).
Material examined.—Five specimens: NMNS PM 45466 from Loc. OS-A41; NMNS PM 45467 from Loc. OS-A42; NMNS PM 45468 from Loc. OS-A01; NMNS PM35874 (= Shigeta, 2022, fig. 4A) from Loc. OS-A02; FM-N202300018 (Suzuki Chisato Collection) from Yamama.
Description.—Specimens are strongly deformed laterally due to compaction and the ventral portions are poorly preserved, but they are characterized by a fairly evolute, compressed shell with indistinct ventral shoulders and slightly flattened flanks. Umbilicus is moderately wide with low, vertical wall and rounded shoulder. Ornamentation consists of fine, sinuous growth lines as well as low, fold-type ribs.
Discussion.—See Shigeta (2022) for a discussion of the synonymy of this taxon. Smyshlyaeva and Zakharov (2015) stated that the fold-type ribs on the outer whorls of the holotype of Deweveria kovalenko are barely noticeable, but the reason for this observation is because the shell material on the venter and outer flank of the last quarter of the outer whorl is missing, hence the fold-type ribs and growth lines appear weaker on the inner mold (Shigeta, 2022, p. 413).
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone. Deweveria kovalenkoi also occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Smyshlyaeva and Zakharov, 2015).
Figure 7.
Hemilecanites from the Osawa Formation and Albania. A, B, Hemilecanites discus (Arthaber, 1908) from Albania, NMNS PM 41725, plaster model of the holotype (= Arthaber, 1908, pl. 11, fig. 5, IPUW unregistered specimen); C–I, Hemilecanites sp. from Loc. OS-A22; C, NMNS PM 45460; D, NMNS PM 45461, silicon rubber cast of the outer mold; E, NMNS PM 45464; F, NMNS PM 45462; G, NMNS PM 45463, silicon rubber cast of the outer mold; H, I, NMNS PM 45465, silicon rubber cast of the outer mold. A, ventral view; B–D, F, G, left lateral views; E, H, I, right lateral views.
Family Xenoceltitidae Spath, 1930
Genus Sulioticeras
Tozer, 1994
Type species.—Xenodiscus sulioticus Arthaber, 1911.
Sulioticeras inflatus (Kiparisova, 1961)
Figure 8A–C
Danubites (Preflorianites) inflatus Kiparisova, 1961, p. 145, pl. 29, figs. 3, 4, text-figs. 109, 110.
Preflorianites aff. sulioticus (Arthaber). Bando and Shimoyama, 1974, p. 298, pl. 40, fig. 7.
Holotype.—CGM 160/4404, figured by Kiparisova (1961, p. 145, pl. 29, fig. 4), from the Subfengshanites multiformis Zone (middle Spathian) in the Zhitkov Cape section on Russky Island, South Primorye, Russian Far East (Figure 8A, B).
Material examined.—One specimen: NMNS PM 45469 from Loc. OS-A23.
Description.—Specimen is strongly deformed laterally due to compaction and the ventral portion is poorly preserved, but it is characterized by a fairly evolute shell with a fairly wide umbilicus. Ornamentation consists of regularly spaced, distant, prorsiradiate rounded ribs arising on umbilical shoulder, becoming most prominent at inner flank and fading at ventral shoulder.
Discussion.—A specimen described as Preflorianites aff. sulioticus by Bando and Shimoyama (1974, pl. 40, fig. 7) is very similar to the present specimens in having distant, prorsiradiate rounded ribs fading at ventral shoulder and is probably conspecific.
Occurrence.—Described specimen was collected from the middle Spathian Subfengshanites multiformis Zone. Sulioticeras inflatus also occurs in the S. multiformis Zone (middle Spathian) of South Primorye, Russia (Kiparisova, 1961).
Figure 8.
Sulioticeras and Deweveria from the Osawa Formation and South Primorye. A–C, Sulioticeras inflatus (Kiparisova, 1961); A, B, NMNS PM 43292, plaster model of the holotype CGM 160/5505 (= Kiparisova, 1961, pl. 29, fig. 4) from South Primorye; C, NMNS PM 45469 from Loc. OS-A23; D–I, Deweveria kovalenkoi Smyshlyaeva and Zakharov, 2015; D, E, NMNS PM 35897, plaster model of the holotype DVGI 100/840 (= Smyshlyaeva and Zakharov, 2015, pl. 1, fig. 5) from South Primorye; F, NMNS PM 45466 from Loc. OS-A41; G, NMNS PM 45467, silicon rubber cast of the outer mold from Loc. OS-A42; H, NMNS PM 45468 from Loc. OS-A01; I, FM-N202300018 (Suzuki Chisato Collection) from Yamaya. A, D, ventral views; B, C, E, F, I, left lateral views; G, H, right lateral views.
Superfamily Meekoceratoidea Waagen, 1895
Family Albanitidae Tozer, 1994
Genus Albanites Arthaber, 1909
Type species.—Pronorites triadicus Arthaber, 1908.
Figure 9.
Albanites sheldoni (Kummel, 1969) from USA and the Osawa Formation. A, B, NMNS PM 42868, plaster model of NMMNH P-85016 (= Jenks et al., 2013, fig. 11A–D) from Idaho, USA; C–E, specimens from Loc. OS-A22; C, NMNS PM 45471; D, NMNS PM 45470; E, NMNS PM 43111, plaster model of IGPS coll. no. 111561 (holotype of Leiophyllites wakoi Ehiro et al., 2016) of Ehiro (2016, fig. 4.4). A, right lateral view; B, ventral view; C–E, left lateral views.
Albanites sheldoni (Kummel, 1969)
Figure 9
Svalbardiceras sheldoni Kummel, 1969, p. 453, pl. 43, fig. 1, text-fig. 28C.
Albanites sheldoni (Kummel). Guex et al., 2010, p. 21, pl. 1, figs. 1–4, pl. 45, fig. 3; Jenks et al., 2013, p. 272, figs. 11A–D.
Leiophyllites wakoi Ehiro et al., 2016, p. 99, fig. 4.4.
non. Albanites sheldoni (Kummel). Ehiro et al., 2016, p. 93, fig. 2.4 [ = Albanites cf. triadicus (Arthaber, 1908)].
Holotype.—MCZ 160/4404, figured by Kummel (1969, p. 453, pl. 43, fig. 1), from the Columbites fauna (lower Spathian) in southeast Idaho, western USA.
Material examined.—Two specimens: NMNS PM 45470, 45471 from Loc. OS-A22.
Description.—Specimens are strongly deformed laterally due to compaction, but they are characterized by a fairly evolute, very compressed shell with nearly flat franks and a narrow, tabulate venter. Umbilicus is a fairly narrow, with low, vertical wall. Ornamentation consists of fine, sinuous ribs that become stronger near ventral shoulders and cross venter.
Discussion.—The specimen assigned to Albanites sheldoni by Ehiro et al. (2016, fig. 2.4) has rib-like radial folds and is very similar to A. triadicus. The holotype of Leiophyllites wakoi Ehiro et al., 2016 (Figure 9E) has a fairly evolute, very compressed shell with nearly flat franks and a narrow, tabulate venter, and the ribs are sinuous and become stronger near ventral shoulders and cross venter. These features are identical to A. sheldoni.
Occurrence.—Described specimens were collected from the middle Spathian Subfengshanites multiformis Zone. Albanites sheldoni occurs in the Columbites Zone (lower Spathian) in southeast Idaho, western USA (Guex et al., 2010; Jenks et al., 2013).
Figure 10.
Albanites from the Osawa Formation and Albania. A, B, Albanites triadicus (Arthaber, 1908), NMNS PM 41921, plaster model of IPUW 1911-4-7 (= paralectotype of Pronorites arbanus Arthaber, 1911, pl. 17, fig. 12; see Kummel, 1969 for a discussion of the synonymy of this taxon) from Albania; C–F, Albanites cf. triadicus (Arthaber, 1908) from Loc. OS-A22; C, NMNS PM 43093, silicon rubber cast of the outer mold of IGPS coll. no. 111541 of Ehiro et al. (2016, fig. 2.4); D–F, NMNS PM 45472, silicon rubber cast of the outer mold (D), inner mold (E), suture line (F). A, C, right lateral views; B, ventral view; D, E, left lateral views. Arrow represents the center of venter, and broken line indicates the position of the umbilical seam.
Albanites cf. triadicus (Arthaber, 1908)
Figure 10C–F
cf. Pronorites triadicus Arthaber, 1908, p. 264, pl. 11, figs. 4a–c.
Albanites sheldoni (Kummel). Ehiro et al., 2016, p. 93, fig. 2.4.
Material examined.—One specimen: NMNS PM 45472 from Loc. OS-A22.
Description.—Specimen is characterized by a fairly evolute shell with a moderately wide umbilicus. Ornamentation consists of regularly spaced, distant, sigmoidal rounded ribs. Suture has lobes with denticulations at the base and saddles that are somewhat phylloid (Figure 10F).
Discussion.—Even though the present specimen is strongly deformed laterally due to compaction, its distinctive ornamentation and suture enable us to assign it with reasonable confidence as Albanites triadicus (Figure 10A, B). The specimen described as A. sheldoni by Ehiro et al. (2016, fig. 2.4) is similar to the present specimen in having sigmoidal rounded ribs and is probably conspecific (Figure 10C).
Occurrence.—Described specimen was collected from the middle Spathian Subfengshanites multiformis Zone. Albanites triadicus occurs in the Subcolumbites fauna (middle Spathian) of Albania, Chios and Afganistan and the Prohungarites fauna (middle Spathian) of Timor (Kummel, 1969).
Figure 11.
Chioceras from the Osawa Formation and Chios. A, B, Chioceras mitzopouloi Renz and Renz, 1948, NMNS PM 41846, plaster model of the holotype MBJ 13626 (= Renz and Renz, 1948, pl. 12, fig. 6) from Chios; C–F, Chioceras sp. from Loc. OS-A22; C, NMNS PM 45473, silicon rubber cast of the outer mold; D, NMNS PM 45474; E, NMNS PM 45475, silicon rubber cast of the outer mold; F, NMNS PM 45476. A, ventral view; B, F, left lateral views; C–E, right lateral views.
Family Paranannitidae Spath, 1934
Genus Chioceras Renz and Renz, 1948
Type species.—Chioceras mitzopouloi Renz and Renz, 1948.
Chioceras sp.
Figure 11C–F
Hellenites elegans Guex et al. Ehiro et al., 2015, fig. 3.4; Ehiro et al., 2016, p. 97, figs. 2.7, 2.8.
Material examined.—Four specimens: NMNS PM 45473–45476 from Loc. OS-A22.
Description.—Specimens are characterized by a fairly evolute shell with a fairly wide umbilicus and a distinct, rounded ventral keel. Ornamentation consists of fine growth lines as well as periodic constrictions, which are concave on the flank and projected forward on the ventrolateral shoulder.
Discussion.—The specimens are strongly deformed laterally due to compaction, but their distinctive features, e.g. distinct rounded ventral keel, enable us to assign them with reasonable confidence to the genus Chioceras. Our specimens and the specimens assigned to Hellenites elegans Guex et al., 2005b by Ehiro et al. (2016, figs. 2.7, 2.8) from Loc. OS-A22 are somewhat similar to the juvenile whorls of Chioceras mitzopouloi Renz and Renz, 1948 (Figure 11A, B), but no definitive assignment can be made.
Occurrence.—Described specimens were collected from the middle Spathian Subfengshanites multiformis Zone.
Figure 12.
Arnautoceltites from the Osawa Formation and South Primorye. A–E, Arnautoceltites gracilis (Kiparisova in Voinova et al., 1947); A, B, NMNS PM 43281, plaster model of the holotype CGM 139/5504 (= Kiparisova in Voinova et al., 1947, pl. 28, fig. 1) from South Primorye; C, NMNS PM 45484 from Loc. OS-A11; D, NMNS PM 45485 from Loc. OS-A12; E, NMNS PM 45486 from Loc. OS-A13; F–L, Arnautoceltites sp. from Loc. OS-A46; F, NMNS PM 45477; G, NMNS PM 45478; H, NMNS PM 45479; I, NMNS PM 45480; J, NMNS PM 45481; K, NMNS PM 45482; L, NMNS PM 45483. A, ventral view; B, H, I, L, left lateral views; C–G, J, K, right lateral views.
Genus Arnautoceltites Diener, 1920
Type species.—Celtites arnauticus Arthaber, 1911.
Arnautoceltites gracilis (Kiparisova in Voinova et al., 1947)
Figure 12A–E
Paranannites gracilis Kiparisova in Voinova et al., 1947, p. 140, pl. 28, fig. 1, text-fig. 25; Kiparisova and Krishtofovich, 1954, p. 21, pl. 12, fig. 1; Kiparisova, 1961, p. 125, pl. 28, figs. 3, 4, text-figs. 92, 93.
Arnautoceltites gracilis (Kiparisova in Voinova et al.). Zakharov, 1997a, pl. 3, fig. 9.
Arnautoceltites sp. Bando and Shimoyama, 1974, p. 299, pl. 41, fig. 6.
Holotype.—CGM 139/5504, figured by Kiparisova in Voinova et al. (1947, p. 140, pl. 28, fig. 1), from the Subfengshanites multiformis Zone in the Zhitkov Cape section of Russky Island, South Primorye, Russian Far East (Figure 12A, B).
Material examined.—Three specimens: NMNS PM 45484 from Loc. OS-A11; NMNS PM 45485 from Loc. OS-A12; NMNS PM 45486 from Loc. OS-A13.
Description.—Specimens are strongly deformed laterally due to compaction, but they are characterized by a very involute shell with an arched venter and a very narrow umbilicus. Ornamentation consists of fine growth lines as well as periodic constrictions, which are concave on the flank and projected forward on the ventrolateral shoulder.
Occurrence.—Described specimens were collected from the middle Spathian Subfengshanites multiformis and Isculitoides sp. zones. Arnautoceltites gracilis also occurs in the S. multiformis Zone (middle Spathian) of South Primorye (Zakharov, 1997b).
Arnautoceltites sp.
Figure 12F–L
Material examined.—Seven specimens: NMNS PM 45477–45483 from Loc. OS-A46.
Description.—Specimens are characterized by a fairly involute shell with an arched venter and a fairly narrow umbilicus. Ornamentation consists of fine growth lines as well as periodic constrictions, which are concave on the flank and projected forward on the ventrolateral shoulder.
Discussion.—The specimens are strongly deformed laterally due to compaction, but their distinctive features, e.g. a fairly involute shell with an arched venter and periodic constrictions, enable us to assign them with reasonable confidence to the genus Arnautoceltites. Our specimens are somewhat similar to A. minor (Kiparisova, 1961), but no definitive assignment can be made.
Occurrence.—Described specimens were collected from the middle Spathian Subfengshanites multiformis Zone.
Genus Isculitoides Spath, 1930
Type species.—Isculites originis Arthaber, 1911.
Isculitoides sp.
Figure 13C–M
Prenkites cf. timorensis Spath. Bando and Shimoyama, 1974, p. 303, pl. 41, figs. 4, 5, 8.
Prenkites sp. Bando and Shimoyama, 1974, p. 304, pl. 41, fig. 11.
Isculitoides aff. originis (Arthaber). Bando and Shimoyama, 1974, p. 300, pl. 42, fig. 5.
Material examined.—Twelve specimens: NMNS PM 45487–45491 from Loc. OS-A35; NMNS PM 45492–45494 from Loc. OS-A12; NMNS PM 45495 from Loc. OS-A13; NMNS PM 45496, 45497 from Loc. OS-A14; NMNS PM 45498 from Loc. OS-A48.
Description.—Specimens are characterized by a fairly involute shell with an arched venter and a fairly narrow umbilicus. Ornamentation consists of fine growth lines, which are rursiradiate and concave on umbilical wall and shoulder, straight and prorsiradiate on the flank, and forward projected on the ventrolateral shoulder.
Discussion.—The specimens are strongly deformed laterally due to compaction, but their distinctive features, e.g. a fairly involute shell with an arched venter, a fairly narrow umbilicus and fine growth lines, enable us assign them with reasonable confidence to the genus Isculitoides. Our specimens and the specimens assigned to Prenkites cf. timorensis, Prenkites sp. and Isculitoides aff. originis from the Osawa Formation by Bando and Shimoyama (1974) are somewhat similar to I. originis (Arthaber, 1911) (Figure 13A, B), but no definitive assignment can be made.
Occurrence.—Described specimens were collected from the middle Spathian Isculitoides sp. Zone.
Family Proptychitidae Waagen, 1895
Genus Proptychitoides Spath, 1930
Type species.—Proptychitoides decipiens Spath, 1930.
Proptychitoides cf. trigonalis (Arthaber, 1911)
Figure 14D
cf. Proptychites trigonalis Arthaber, 1911, p. 225, pl. 19, fig. 4.
Nordophiceratoides bartolinae Guex et al. Ehiro et al., 2016, p. 100, fig. 5.2.
Material examined.—One specimen: NMNS PM 45499 from Loc. OS-A22.
Description.—A fairly involute shell is characterized by a sub-trigonal whorl section with narrowly rounded venter and flanks gradually converging from umbilical shoulders to venter. Maximum whorl width occurs on umbilical shoulders. Umbilicus is fairly narrow with high, vertical wall and rounded shoulders. Ornamentation consists of weak radial folds.
Discussion.—The specimen is strongly deformed laterally due to compaction, but its distinctive shell morphology enables us to assign it with reasonable confidence as Proptychitoides trigonalis (Figure 14A–C). The specimen assigned to Nordophiceratoides bartolinae Guex et al., 2010 from the Osawa Formation by Ehiro et al. (2016, fig. 5.2) is very similar to the present specimen and it is probably assignable to P. cf. trigonalis.
Occurrence.—Described specimen was collected from the middle Spathian Subcolumbites perrinismithi Zone. Proptychitoides trigonalis occurs in the Subcolumbites fauna (middle Spathian) of Albania and Chios (Kummel, 1969).
Figure 13.
Isculitoides from Albania and Isculitoides from the Osawa Formation. A, B, Isculitoides originis (Arthaber, 1911), NMNS PM 41968, plaster model of the lectotype IPUE 1911/4/57 (= Arthaber, 1911, pl. 23, fig. 1) from Albania; C–N, Isculitoides sp.; C, NMNS PM 45487 from OS-A35; D, NMNS PM 45488 from OS-A35; E, NMNS PM 45489 from OS-A35; F, NMNS PM 45490 from OS-A35; G, NMNS PM 45491 from OS-A35; H, NMNS PM 45492 from OS-A12; I, NMNS PM 45493 from OS-A12; J, NMNS PM 45494 from OS-A12; K, NMNS PM 45495 from OS-A13; L, NMNS PM 45496 from OS-A14; M, NMNS PM 45497 from OS-A14; N, NMNS PM 45498 from OS-A48. A, ventral view; B, C, E, F, H, J, K, M, left lateral views; D, G, I, L, N, right lateral views.
Figure 14.
Proptychitoides from the Osawa Formation and Albania. A–C, Proptychitoides trigonalis (Arthaber, 1911), NMNS PM 41930, plaster model of the holotype IPUW 1911-4-18 (= Arthaber, 1911, p. 225, pl. 19, fig. 4) from Albania; D, Proptychitoides cf. trigonalis (Arthaber, 1911), NMNS PM 45499, silicon rubber cast of the outer mold from Loc. OS-A22. A, D, right lateral views; B, ventral view; C, apertural view.
Superfamily Sageceratoidea Hyatt, 1884
Family Hedenstroemiidae Waagen, 1895
Genus Pseudosageceras Diener, 1895
Type species.—Pseudosageceras sp. indet. Diener, 1895.
Pseudosageceras sp.
Figure 15
Pseudosageceras multilobatum Noetling. Ehiro, 2016, p. 2, fig. 2.1.
Pseudosageceras? sp. Ehiro et al., 2016, p. 94, fig. 5.1.
Material examined.—Five specimens: NMNS PM 45503 from Loc. OS-A22; NMNS PM 45501 from Loc. A48; NMNS PM 45502 from loc. OS-A11; NMNS PM 45500 from Loc. OS-A12; IGPS coll. cat. no. 111506 (Ehiro, 2016, fig. 1) from Yamaya.
Description.—Specimens are characterized by a very involute, very compressed shell with a very narrow, tabulate venter, angular ventral shoulders and an occluded umbilicus. Shell surface is smooth, but sinuous growth lines are visible on the body chamber. Suture line has trifid lateral lobe, bifid lobes and many adventitious lobes.
Discussion.—The distinctive shell morphology and suture support its identification with reasonable confidence as Pseudosageceras, but the strongly deformed preservation precludes a definitive species assignment.
Occurrence.—Specimens from Yamaya were collected from the upper lower Spathian Deweveria kovalenkoi Zone. Other described specimens were collected from the middle Spathian Subcolumbites perrinismithi, Subfengshanites multiformis and Isculitoides sp. zones.
Figure 15.
Pseudosageceras sp. from the Osawa Formation. A, B, NMNS PM 45500 from Loc. OS-A12; C, NMNS PM 45501 from Loc. OS-A48; D, NMNS PM 45502 from Loc. OS-A11; E, F, NMNS PM 45503 from Loc. OS-A22. A, E, left lateral views; B–D, right lateral views; F, suture line. Arrow represents the center of venter.
Figure 16.
Stacheites floweri Kummel, 1969 from the Osawa Formation. A, NMNS PM 45504, silicon rubber cast of the outer mold from Loc. OS-A31; B–E, specimens from Loc. OS-A22; B, NMNS PM 45505; C, NMNS PM 45507; D, NMNS PM 45506; E, NMNS PM 43094, silicon rubber cast of the outer mold of IGPS coll. no. 111543 (holotype of Pseudokymatites tabulatus Ehiro et al., 2016) of Ehiro et al. (2016, fig. 2.5). A–C, right lateral views; D, E, left lateral views.
Superfamily Dinaritoidea Mojsisovics, 1882
Family Dinaritidae Mojsisovics, 1882
Genus Stacheites Kittl, 1903
Type species.—Stacheites prionoides Kittl, 1903.
Stacheites floweri Kummel, 1969
Figures 16, 17
Stacheites floweri Kummel, 1969, p. 456, pl. 28, figs. 1–10, text-fig. 29; Guex et al., 2010, p. 26, pl. 3, figs. 3–5, pl. 53, fig. 1.
Stacheites sp. Bando and Shimoyama, 1974, p. 305, pl. 42, fig. 4 (1).
Dalmatites sp. Bando and Shimoyama, 1974, p. 308, pl. 41, fig. 3.
Prohungarites? sp. Bando and Shimoyama, 1974, pl. 42, fig. 4 (2). Pseudokymatites tabulatus Ehiro et al., 2016, p. 94, figs. 2.5, 2.6.
Metadagnoceras sp. Ehiro et al., 2016, p. 97, fig. 2.9.
Holotype.—MCZ 9441, figured by Kummel (1969, p. 456, pl. 28, figs. 3, 4), from the Subcolumbites fauna (middle Spathian) of the Tobin Formation, Nevada.
Material examined.—Twenty specimens: NMNS PM 45504 from Loc. OS-A31; NMNS PM 45505–45507 from Loc. OS-A22; NMNS PM 45508–45519 from Loc. OS-A11; NMNS PM 45520–45523 from Loc. OS-A12.
Description.—Specimens are strongly deformed laterally due to compaction and the ventral portion is poorly preserved, but they are characterized by a very involute, compressed shell with a tabulate venter and angular ventral shoulders. Umbilicus is narrow with abruptly rounded shoulder and vertical wall. Ornamentation consists of weak radial folds and fine, sinuous growth lines. Suture is preserved on only one specimen (NMNS PM 45516; Figure 17I, Q) and it shows a prominent first lateral lobe, a shallow, broad second lateral lobe, a narrow first lateral saddle and a broadly rounded second lateral saddle. Lobes have denticulations at the base.
Discussion.—The shell morphology and ornamentation of the specimens described by Ehiro et al. (2016) as Pseudokymatites tabulatus (Figure 16E = Ehiro et al., 2016, fig. 2.5) and Metadagnoceras sp. (Ehiro et al., 2016, fig. 2.9) are very similar to Stacheites floweri Kummel, 1969 in having a tabulate venter, weak radial folds, and fine, sinuous growth lines; both are regarded as conspecific. Ehiro et al. (2016, fig. 6b) described the suture of P. tabulates as goniatitic, but the suture lines are too poorly preserved for this type of determination.
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone and the middle Spathian Subcolumbites perrinismithi, Subfengshanites multiformis and Isculitoides sp. zones.
Figure 17.
Stacheites floweri Kummel, 1969 from the Osawa Formation. A–L, Q, specimens from Loc. OS-A11; A, NMNS PM 45508; B, NMNS PM 45509; C, NMNS PM 45510; D, NMNS PM 45511; E, NMNS PM 45512; F, NMNS PM 45513; G, NMNS PM 45514; H, NMNS PM 45515; I, Q, NMNS PM 45516; J, NMNS PM 45517; K, NMNS PM 45518; L, NMNS PM 45519; M–P, specimens from Loc. OS-A12; M, NMNS PM 45520, silicon rubber cast of the outer mold; N, NMNS PM 45521; O, NMNS PM 45522; P, NMNS PM 45523, silicon rubber cast of the outer mold. A, B, F–J, L, O, left lateral views; C–E, K, M, N, P, right lateral views; Q, suture line. Arrow represents the center of venter, and broken line indicates the position of the umbilical seam.
Family Khvalynitidae Shevyrev, 1968
Genus Khvalynites Shevyrev, 1968
Type species.—Khvalynites mangyshlakensis Shevyrev, 1968.
Khvalynites unicus (Kiparisova, 1961)
Figures 18, 19
Dagnoceras? unicum Kiparisova, 1961, p. 74, pl. 13, fig. 6, text-fig. 35.
Metadagnoceras? unicum (Kiparisova). Zakharov, 1968, p. 81, pl. 13, figs. 2–5, text-fig. 16f.
Metadagnoceras motoyoshiense Ehiro, 1993, p. 232, figs. 2a, 3.2, 3.3. Khvalynites sp. Ehiro, 2016, p. 4, fig. 2.2.
Holotype.—CGM 70/5504, figured by Kiparisova (1961, p. 74, pl. 13, fig. 6), from the Neocolumbites insignis Zone (upper lower Spathian) in the Schmidt Cape section on Russky Island, South Primorye, Russia.
Material examined.—Three specimens: IPPM 60015, 60032 of Ehiro (1993, figs. 3.2, 3.3) from Yamaya; IGPS coll. cat. no. 111507 of Ehiro (2016, fig. 2.2) from Yamaya.
Description.—Specimens from Yamaya are strongly deformed laterally due to compaction, but they are characterized by a very involute shell with a narrow umbilicus and a narrow rounded venter. Specimen IGPS coll. cat. no. 111507 (Figure 18A) is 30 mm in diameter and has fine, sigmoidal ribs. Specimen IPPM 60015 (Figure 19) is 185 mm in diameter and the body chamber is ornamented with sinuous growth lines as well as indistinct, coarse strigation. Specimens IPPM 60015 and 60032 are fragments of the body chamber and coarse strigation is partly visible on the shell surface.
Discussion.—Specimen (IGPS coll. cat. no. 111507; Figure 18A) described as Khvalynites sp. by Ehiro (2016, fig. 2.2) is a juvenile shell of K. unicus (Figure 18B–E) and two specimens (IPPM 60015 [Figure 19], 60032) described as Metadagnoceras motoyoshiense by Ehiro (1993, figs. 2a, 3.2, 3.3) are larger shells of K. unicus (Figure 18F–H). The presence of strigation on the shell surface is diagnostic of M. motoyoshiense, which is also observed in large shells of K. unicus; both species are conspecific.
Occurrence.—Specimens from Yamaya were collected from the upper lower Spathian Deweveria kovalenkoi Zone. Khvalynites unicus occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Zakharov, 1997b).
Family Columbitidae Spath, 1934
Genus Neocolumbites Zakharov, 1968
Type species.—Neocolumbites grammi Zakharov, 1968.
Neocolumbites grammi Zakharov, 1968
Figure 20A–E
Neocolumbites grammi Zakharov, 1968, p. 111, pl. 21, figs. 6–9, text-fig. 28g; Shigeta, 2022, p. 408, fig. 2A–E.
Eophyllites cf. dieneri (Arthaber). Bando and Shimoyama, 1974, p. 306, pl. 40, fig. 1.
Columbites parisianus Hyatt and Smith. Bando and Shimoyama, 1974, p. 301, pl. 40, figs. 2, 8.
Holotype.—DVGI 469/801, figured by Zakharov (1968, p. 111, pl. 21, fig. 6), from the Neocolumbites insignis Zone (upper lower Spathian) in the Tchernyshev Bay section on Russky Island, South Primorye, Russia (Figure 20A, B).
Material examined.—Five specimens: NMNS PM 45526 from Loc. OS-A01; NMNS PM 45524, 45525 from Loc. OS-A02; IGPS coll. cat. nos. OS-1101-9, OS-1101-4 of Bando and Shimoyama (1974, pl. 40, figs. 1, 2) from Akaushi (= Loc. OS-A01).
Description.—Specimens are strongly deformed laterally due to compaction and the ventral parts are poorly preserved, but they are characterized by a moderately evolute shell with a moderately wide umbilicus. Ornamentation consists of weak radial folds and fine growth lines, which are rursiradiate and concave on umbilical wall and shoulder, straight and prorsiradiate on the flank, and forward projected on ventrolateral shoulder.
Discussion.—See Shigeta (2022) for a discussion of the synonymy of this taxon.
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone. Neocolumbites grammi also occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Zakharov, 1997b).
Figure 18.
Khvalynites unicus (Kiparisova, 1961) from the Osawa Formation and South Primorye. A, NMNS PM 43090, plaster model of IGPS coll. cat. no. 111507 (= Ehiro, 2016, fig. 2.2) from Akaushi; B–H, specimens from Tchernyshev Bay on Rusky Island, South Primorye; B–E, NMNS PM 45638; F–H, NMNS PM 45639. A, B, right lateral views; C, ventral view; D, F, G, left lateral views; E, H, apertural views.
Figure 19.
Khvalynites unicus (Kiparisova, 1961) from the Osawa Formation. NMNS PM43086, plaster model of IPPM 60015 (holotype of Metadagnoceras motoyoshiense Ehiro, 1993) of Ehiro (1993, fig. 3.2), from Yamaya, right lateral view.
Neocolumbites insignis Zakharov, 1968
Figure 20F–I
Neocolumbites insignis Zakharov, 1968, p. 112, pl. 21, figs. 9a, b–11, text-fig. 28h; Shigeta, 2022, p. 411, fig. 2F–J.
Columbites parisianus Hyatt and Smith. Bando and Shimoyama, 1974, p. 301, pl. 40, fig. 2.
Holotype.—DVGI 478/801, figured by Zakharov (1968, p. 112, pl. 21, fig. 9a, b), from the Neocolumbites insignis Zone (upper lower Spathian) in the Tchernyshev Bay section on Russky Island, South Primorye, Russia (Figure 20F, G).
Material examined.—Three specimens: NMNS PM 45527, 45528 from Loc. OS-A01; IGPS coll. cat. no. OS-1108-8 of Bando and Shimoyama (1974, pl. 40, fig. 8) from Akaushi (= Loc. OS-A01).
Description.—Specimens are strongly deformed laterally due to compaction and the ventral parts are poorly preserved, but they are characterized by a fairly evolute shell with a fairly wide umbilicus. Ornamentation consists of weak radial folds and weak ribs as well as fine growth lines which are slightly concave.
Discussion.—See Shigeta (2022) for a discussion of the synonymy of this taxon.
Comparison.—Neocolumbites insignis differs from N. grammi by its wider umbilicus (Zakharov, 1968).
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone. Neocolumbites insignis also occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Zakharov, 1997b).
Figure 20.
Neocolumbites and Idahocolumbites from the Osawa Formation and South Primorye. A–E, Neocolumbites grammi Zakharov, 1968; A, B, NMNS PM 35884, plaster model of the paratype DVI 470/801 (= Zakharov, 1968, pl. 21, fig. 7) from South Primorye; C, NMNS PM 45524 from OS-A02; D, NMNS PM 45525, silicon rubber cast of the outer mold from OS-A02; E, NMNS PM 45526, silicon rubber cast of the outer mold from OS-A01; F–I, Neocolumbites insignis Zakharov, 1968; F, G, NMNS PM 35886, plaster model of the holotype DVI 478/801 (= Zakharov, 1968, pl. 21, fig. 9) from South Primorye; H, NMNS PM 45527, silicon rubber cast of the outer mold from Loc. OS-A01; I, NMNS PM 45528, silicon rubber cast of the outer mold from Loc. OS-A01; J, K, Idahocolumbites sp. from Loc. OS-A41; J, NMNS PM 45529; K, NMNS PM 45530. A, C, D, F, J, K, right lateral views; B, G, ventral views; E, H, I, left lateral views.
Genus Idahocolumbites Guex et al., 2005a
Type species.—Pseudoceltites cheneyi Kummel, 1969.
Idahocolumbites sp.
Figure 20J, K
Material examined.—Two specimens: NMNS PM 45529, 45530 from Loc. OS-A41.
Description.—Specimens are characterized by a fairly evolute shell with moderately wide umbilicus. Ornamentation consists of regularly spaced, distant, prorsiradiate rounded ribs arising on umbilical shoulder, becoming most prominent at middle to upper flank and fading on ventral shoulder.
Discussion.—The distinctive ornamentation, e.g. rounded ribs that completely fade on ventral shoulder, supports their assignment with reasonable confidence to the genus Idahocolumbites, but the crushed and strongly deformed preservation precludes a definitive species assignment.
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone.
Genus Procolumbites Astachova, 1960
Type species.—Procolumbites karataucicus Astachova, 1960.
Procolumbites ussuriensis (Zakharov, 1968)
Figure 21A–C
Columbites sp. Kiparisova, 1961, p. 119, pl. 26, fig. 8, text-fig. 81.
Columbites ussuriensis Zakharov, 1968, p. 107, pl. 20, figs. 6, 7, 9, text-fig. 28b; Zakharov and Rybalka, 1987, pl. 3, fig. 15; Zakharov, 1997a, pl. 2, figs. 3, 4; Smyshlyaeva and Zakharov, 2015, pl. 1, figs. 7–10.
Columbites parisianus Hyatt and Smith. Bando and Shimoyama, 1974, p. 301, pl. 40, figs. 4, 6.
Procolumbites ussuriensis (Zakharov). Shigeta, 2022, p. 411, pl. 20, fig. 3A–H.
Holotype.—CGM 23/8701, figured by Zakharov (1968, p. 107, pl. 20, fig. 6), from the Neocolumbites insignis Zone (upper lower Spathian) in the Golyj (Kom-Pikho-Sakho) Cape section, on the eastern coast of Ussuri Gulf, South Primorye, Russia (Figure 21A).
Material examined.—Four specimens: NMNS PM 45531 from Loc. OS-A02; NMNS PM 45532 from Loc. OS-A01; IGPS coll. cat. nos. OS-1000, OS-1101-11 of Bando and Shimoyama (1974, pl. 40, figs. 4, 6) from Akaushi (= Locs. OS-A01, A02).
Description.—Specimens are strongly deformed laterally due to compaction and the ventral part is poorly preserved, but they are characterized by a moderately evolute shell with a moderately wide umbilicus. Ornamentation consists of constrictions and strong, major ribs, which are rursiradiate and concave on umbilical wall and shoulder, and straight and prorsiradiate on the flank, as well as growth lines and fine ribs between major ribs.
Discussion.—See Shigeta (2022) for a discussion of the synonymy of this taxon.
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone. Procolumbites ussuriensis also occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Zakharov, 1997b).
Procolumbites subquadratus Zakharov, 1968
Figure 21D
Procolumbites subquadratus Zakharov, 1968, p. 110, pl. 21, figs. 4, 5, text-fig. 28f; Shigeta, 2022, p. 412, fig. 3M, N, S–V.
Columbites parisianus Hyatt and Smith. Bando and Shimoyama, 1974, p. 301, pl. 42, figs. 1, 3.
Holotype.—CGM 27/8701, described by Zakharov (1968, p. 110), from the Neocolumbites insignis Zone (upper lower Spathian) in the Tchernyshev Bay section on Russky Island, South Primorye, Russia.
Material examined.—Two specimens: NMNS PM 45533 from Loc. OS-A02; IGPS coll. cat. no. OS-1101-7 of Bando and Shimoyama (1974, p. 42, figs. 1, 3) from Akaushi (= Loc. OS-A01).
Description.—Specimen is strongly deformed laterally due to compaction and the ventral part is poorly preserved, but it is characterized by a very evolute shell with a wide umbilicus. Ornamentation consists of distinct, prorsiradiate ribs, which bend gently forward on ventrolateral shoulders.
Discussion.—See Shigeta (2022) for a discussion of the synonymy of this taxon.
Comparison.—Procolumbites subquadratus differs from P. ussuriensis by its wider umbilicus (Zakharov, 1968).
Occurrence.—Described specimen was collected from the upper lower Spathian Deweveria kovalenkoi Zone. Procolumbites subquadratus also occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Zakharov, 1997b).
Procolumbites sp.
Figure 21E
Material examined.—One specimen: NMNS PM 45534 from Loc. OS-A41.
Description.—Specimen is characterized by a very evolute shell with a wide umbilicus. Ornamentation consists of dense, distinct, prorsiradiate ribs, which bend gently forward on ventrolateral shoulders.
Discussion.—The distinctive ornamentation supports its identification with reasonable confidence to the genus Procolumbites, but the crushed and strongly deformed preservation precludes a definitive species assignment.
Occurrence.—Described specimen was collected from the upper lower Spathian Procolumbites-Hellenites Zone.
Figure 21.
Procolumbites from the Osawa Formation and South Primorye. A–C, Procolumbites ussuriensis (Zakharov, 1968); A, NMNS PM 35891, plaster model of the paratype DVGI 464/801 (= Zakharov, 1968, pl. 20, fig. 7) from South Primorye; B, NMNS PM 45531, silicon rubber cast of the outer mold from Loc. OS-A02; C, NMNS PM 45532 from Loc. OS-A01; D, Procolumbites subquadratus Zakharov, 1968, NMNS PM 45533 from Loc. OS-A02; E, Procolumbites sp., NMNS PM 45534, silicon rubber cast of the outer mold from Loc. OS-A41. A–C, E, right lateral views; D, left lateral view.
Genus Hellenites Renz and Renz, 1948
Type species.—Tropiceltites paraematurus Arthaber, 1911.
Hellenites tchernyschewiensis Zakharov, 1968
Figures 22, 23A–J
Hellenites tchernyschewiensis Zakharov, 1968, p. 150, pl. 30, fig. 1, text-fig. 35b, c; Zakharov, 1997a, pl. 3, figs. 3, 4; Shigeta, 2022, p. 407, fig. 1A–D, I, J. Subcolumbites perrinismithi (Arthaber). Bando and Shimoyama, 1974, p. 302, pl. 41, fig. 9; Ehiro et al., 2015, fig. 3.2.
Columbites parisianus Hyatt and Smith. Ehiro et al., 2015, fig. 3.1.
Holotype.—DVGI 484/801, figured by Zakharov (1968, p. 150, pl. 30, fig. 1), from the Neocolumbites insignis Zone (upper lower Spathian) in the Tchernyshev Bay section on Russky Island, South Primorye, Russia (Figure 22A, B).
Material examined.—Twenty-three specimens: NMNS PM 45545 from Loc. OS-A02; NMNS PM 45546 from Loc. OS-A31; NMNS PM 45544 from Loc. OS-A41; NMNS PM 45535–45543 from Loc. OS-A42; IGPS coll. cat. no. OS-1002-2 of Bando and Shimoyama (1974, pl. 41, fig. 9) from Akaushi (= Loc. OS-A02); FM-N202300008–N202300017 (Suzuki Chisato Collection) from Yamaya.
Description.—Specimens are slightly deformed laterally due to compaction, but they are characterized by a very evolute, compressed shell with a fairly wide umbilicus and a distinct ventral keel. Ornamentation consists of fine, dense, rectiradiate ribs, which strongly project forward on ventrolateral shoulder. Inner whorls are ornamented only by fine, dense ribs, but many radial folds appear as shell grows larger.
Discussion.—See Shigeta (2022) for a discussion of the synonymy of this taxon.
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone. Hellenites tchernyschewiensis also occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Zakharov, 1968).
Figure 22.
Hellenites tchernyschewiensis Zakharov, 1968 from the Osawa Formation and South Primorye. A, B, NMNS PM 35877, plaster model of the holotype DVGI 484/801 (= Zakharov, 1968, pl. 30, fig. 1) from South Primorye; C–K, specimens from Loc. OS-A42; C, NMNS PM 45535; D, NMNS PM 45536; E, NMNS PM 45537; F, NMNS PM 45538; G, NMNS PM 45539; H, NMNS PM 45540; I, NMNS PM 45541; J, NMNS PM 45542; K, NMNS PM 45543; L, NMNS PM 45544 from Loc. OS-A41; M, NMNS PM 45545 from Loc. OS-A02; N, NMNS PM 45546 from Loc. OS-A31. F, I, K, N, silicon rubber casts of the outer molds. A, C–E, G–I, K, M, right lateral views; B, ventral view; F, J, L, N, left lateral views.
Figure 23.
Hellenites from the Osawa Formation. A–J, Hellenites tchernyschewiensis Zakharov, 1968 from the Osawa Formation at Yamaya (Suzuki Chisato Collection); A, FM-N202300009; B, FM-N202300010; C, FM-N202300008; D, FM-N202300012; E, FM-N202300011; F, FM-N202300013; G, FM-N202300014; H, FM-N202300015; I, FM-N202300016; J, FM-N202300017; K, Hellenites inopinatus Kiparisova, 1961 from Loc. OS-A02, NMNS PM 35866, silicon rubber cast of the outer mold of IGPS coll. cat. no. OS-1002-1. A, B, I, J, K, right lateral views; C–H, left lateral views.
Hellenites inopinatus Kiparisova, 1961
Figure 23K
Hellenites? inopinatus Kiparisova, 1958, pl. 13, fig. 9; Kiparisova, 1961, p. 169, pl. 33, fig. 4.
Hellenites inopinatus Kiparisova. Zakharov, 1968, p. 149, pl. 29, figs. 8–11, text-fig. 35d; Zakharov, 1997a, pl. 3, fig. 2; Shigeta, 2022, p. 408, figs. 1E–H.
Columbites parisianus Hyatt and Smith. Bando and Shimoyama, 1974, p. 301, pl. 41, fig. 10.
Holotype.—CGM 185/5504, figured by Kiparisova (1958, pl. 13, fig. 9; 1961, p. 169, pl. 33, fig. 4), from the Neocolumbites insignis Zone (upper lower Spathian) in the Zhitkov Cape section on Russky Island, South Primorye, Russia.
Material examined.—One specimen: IGPS coll. cat. no. OS-1002-1 of Bando and Shimoyama (1974, pl. 41, fig. 10) from Akaushi (= Loc. OS-A02).
Description.—Specimen is characterized by very evolute coiling and a fairly wide umbilicus. Ornamentation consists of distant, strong, slightly rectiradiate ribs on early whorls, which become denser and finer on the later whorls. Ribs strongly project forward on ventrolateral shoulder.
Discussion.—Although the specimen is slightly deformed laterally due to compaction and the ventral part is poorly preserved, its distinctive ornamentation permits its identification with reasonable confidence as Hellenites inopinatus.
See Shigeta (2022) for a discussion of the synonymy of this taxon.
Comparison.—Hellenites inopinatus differs from H. tchernyschewiensis by its distant, strong ribs on earlier whorls.
Occurrence.—Hellenites inopinatus is known from the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia and the lowest part of the Osawa Formation.
Genus Epiceltites Arthaber, 1911
Type species.—Epiceltites gentii Arthaber, 1911.
Epiceltites gentii Arthaber, 1911
Figure 24
Epiceltites gentii Arthaber, 1911, p. 268, pl. 24, fig. 8; Spath, 1934, p. 210, pl. 13, fig. 5, text-fig. 64; Renz and Renz, 1948, p. 43, pl. 1, fig. 9; Kummel, 1969, p. 447, pl. 3, figs. 10, 11, pl. 35, figs. 6, 7, text-fig. 26.
Subcolumbites perrinismithi (Arthaber). Bando and Shimoyama, 1974, p. 302, pl. 40, fig. 3.
Columbites parisianus Hyatt and Smith. Ehiro et al., 2015, fig. 3.3; Ehiro et al., 2016, p. 94, figs. 3.1–3.5.
Yvesgalleticeras sp. Ehiro et al., 2016, p. 97, figs. 3.11, 3.12.
Holotype.—IPUW 1911-4-73, figured by Arthaber (1911, p. 268, pl. 24, fig. 8), from the Subcolumbites fauna of Kcira, Albania (Figure 24A–C).
Material examined.—Thirteen specimens: NMNS PM 45547–45558 from Loc. OS-A22; NMNS PM 45559 from Loc. OS-A43.
Description.—Specimens are strongly deformed laterally due to compaction and the ventral part is poorly preserved, but they are characterized by an evolute, compressed shell with a fairly wide umbilicus. Ornamentation consists of fine, radial ribs as well as periodic constrictions, which are strongly projected forward on the ventrolateral shoulder.
Discussion.—The specimens assigned to Subcolumbites perrinismithi by Bando and Shimoyama (1974, pl. 40, fig. 3) and Columbites parisianus and Yvesgalleticeras sp. by Ehiro et al. (2015, fig. 3.3; 2016, figs. 3.1–3.5, 3.11, 3.12) from the Osawa Formation are conspecific with Epiceltites gentii.
Occurrence.—Described specimens were collected from the middle Spathian Subcolumbites perrinismithi Zone. Epiceltites gentii also occurs in the Subcolumbites fauna (middle Spathian) of Albania, Chios and southern Idaho (Kummel, 1969).
Genus Subcolumbites Spath, 1930
Type species.—Columbites perrinismithi Arthaber, 1908.
Subcolumbites perrinismithi Arthaber, 1908
Figures 25–27
Columbites perrinismithi Arthaber, 1908, p. 277, pl. 12, fig. 1; Arthaber, 1911, p. 262, pl. 23, figs. 19, 20; Renz and Renz, 1948, p. 20, pl. 11, fig. 7.
Columbites europaeus Arthaber, 1908, p. 261, pl. 23, figs. 13–18; Renz and Renz, 1948, p. 19, pl. 11, figs. 3–6.
Columbites mirditensis Arthaber, 1911, p. 263, pl. 24, figs. 2–4.
Columbites europaeus perrinismithi Renz and Renz, 1948, p. 20, pl. 11, figs. 1, 2.
Subcolumbites perrinismithi (Arthaber). Spath, 1934, p. 203, pl. 12, fig. 5; Kummel, 1968, p. 495, pl. 1, figs. 1–3; Kummel. 1969, p. 427, pl. 1, figs. 1–9, pl. 2, figs. 5–8, pl. 3, figs. 1–9, pl. 4, figs. 1–4, text-fig. 24; Bando and Shimoyama, 1974, p. 302, pl. 40, fig. 5; Ehiro et al., 2019, fig. 5; Germani, 1997, p. 273, pl. 1, fig. 1, text-fig. 3.
Subcolumbites europaeus (Arthaber). Spath, 1934, p. 204, pl. 12, fig. 6, text-fig. 62c.
Columbites asymmetricus Chao, 1959, p. 303, pl. 30, figs. 10–13.
Subcolumbites kwangsianus Chao, 1959, p. 304, pl. 30, figs. 14–17, text-fig. 41c.
Subcolumbites cf. perrinismithi (Arthaber). Bando, 1964, p. 99, pl. 3, figs. 18, 19, pl. 4, fig. 3.
Tardicolumbites aff. tardicolumbus Guex et al., 2005a. Ehiro et al., 2016, p. 96, figs. 3.6–3.10.
Subcolumbites sp. Ehiro et al., 2016, p. 97, figs. 4.1, 4.2.
non. Subcolumbites perrinismithi (Arthaber). Bando and Shimoyama, 1974, p. 302, pl. 41, fig. 9; Ehiro et al., 2015, fig. 3.2 (= Hellenites tchernyschewiensis Zakharov, 1968).
Holotype.—IPUW 1911-4-63, figured by Arthaber (1908, p. 277, pl. 12, fig. 1), from the Subcolumbites fauna of Kcira, Albania (Figure 25A, B).
Material examined.—Twenty-two specimens: NMNS PM 45560–45566 from Loc. OS-A21; NMNS PM 45567–45570 from Loc. OS-A22; NMNS PM 45571–45578 from Loc. OS-A43; NMNS PM 45579–45581 from Loc. OS-A44.
Description.—Specimens are strongly deformed laterally due to compaction and the ventral part is poorly preserved, but they are characterized by an evolute, compressed shell with a fairly wide to wide umbilicus. Ornamentation consists of very fine strigation covering entire shell (Figure 25F), and fine, dense ribs, which are arched backward slightly on flanks and projected forward on ventral shoulder. Ribs vary in strength.
Discussion.—See Kummel (1969) for a discussion of the synonymy of this taxon. The specimens assigned to Tardicolumbites aff. tardicolumbus and Subcolumbites sp. from the Osawa Formation by Ehiro et al. (2016, figs. 3.6–3.10, 4.1, 4.2) are conspecific with Subcolumbites perrinismithi. Bando and Shimoyama (1974, pl. 41, fig. 9) assigned a specimen from the lowest part of the Osawa Formation at Akaushi to S. perrinismithi, but as Shigeta (2022) pointed out, the specimen is conspecific with Hellenites tchernyschewiensis. A specimen illustrated as S. perrinismithi by Ehiro et al. (2015, fig. 3.2) should be assigned to Hellenites sp.
Remarks.—Specimen NMNS PM 45578 has a lower jaw in the body chamber (Figure 27). The rostrum of the jaw is slightly broken, but is probably small and pointed. The wing is elongated, with rounded posterior end, and the length is about 6 mm. The lower jaw is similar to “normal type” among the five jaw types of the Ammonoidea (e.g. Tanabe et al., 2015).
Occurrence.—Described specimens were collected from the middle Spathian Subcolumbites perrinismithi Zone. Subcolumbites perrinismithi also occurs in the middle Spathian of Albania, Chios, Afghanistan and South China (Kummel, 1969).
Figure 24.
Epiceltites gentii Arthaber, 1911 from the Osawa Formation and Albania. A–C, NMNS PM 41992, plaster model of the holotype IPUW 1911-4-73 (= Arthaber, 1911, pl. 24, fig. 8) from Albania; D–O, specimens from Loc. OS-A22; D, NMNS PM 45547; E, NMNS PM 45548; F, NMNS PM 45549; G, NMNS PM 45550; H, NMNS PM 45551; I, NMNS PM 45552; J, NMNS PM 45553; K, NMNS PM 45554; L, NMNS PM 45555; M, NMNS PM 45556; N, NMNS PM 45557; O, NMNS PM 45558; P, NMNS PM 45559 from Loc. OS-A43. L–P, silicon rubber casts of the outer molds. A, E, H, I, K, left lateral views, B, D, F, G, J, L–P, right lateral views; C, ventral view.
Figure 25.
Subcolumbites perrinismithi (Arthaber, 1908) from the Osawa Formation and Albania. A, B, NMNS PM 35883, plaster model of IPUW 1911-4-64 (= Arthaber, 1911, pl. 23, fig. 20) from Albania; C–J, specimens from Loc. OS-A21; C, NMNS PM 45560; D, NMNS PM 45561; E, F, NMNS PM 45562; G, NMNS PM 45566; H, NMNS PM 45565; I, NMNS PM 45563; J, NMNS PM 45564; K–N, specimens from Loc. OS-A22; K, NMNS PM 45567; L, NMNS PM 45568; M, NMNS PM 45569; N, NMNS PM 45570. C–J, N, silicon rubber casts of the outer molds. A, C, H–J, L, N, ventral view; B, right lateral views; D, E–G, K, M, left lateral views.
Figure 26.
Subcolumbites perrinismithi (Arthaber, 1908) from the Osawa Formation. A–G, specimens from Loc. OS-A43; A, NMNS PM 45571; B, NMNS PM 45572; C, NMNS PM 45573; D, NMNS PM 45574, silicon rubber cast of the outer mold; E, NMNS PM 45575, silicon rubber cast of the outer mold; F, NMNS PM 45576; G, NMNS PM 45577; H–J, specimens from Loc. OS-A44; H, NMNS PM 45579; I, NMNS PM 45580, silicon rubber cast of the outer mold; J, NMNS PM 45581. A–C, G, H, J, left lateral views; D–F, I; right lateral views.
Figure 27.
Subcolumbites perrinismithi (Arthaber, 1908) from the Osawa Formation. NMNS PM 45578 from Loc. OS-A43. A, right lateral view with a lower jaw in the body chamber; B, enlargement of the lower jaw.
Genus Fengshanites Chao, 1950
Type species.—Fengshanites robustus Chao, 1950.
Figure 28.
Fengshanites from the Osawa Formatioan and South China. A, B, Fengshanites robustus Chao, 1950, NMNS PM 40945, plaster model of the holotype NIGP 12200 (= Chao, 1959, pl. 8, figs. 1, 2) from South China; C–F, Fengshanites sp. from Loc. OS-A41; C, NMNS PM 45582; D, NMNS PM 45583, E, NMNS PM 45584; F, NMNS PM 45585. A, C, D, F, left lateral views; B, ventral view; E, right lateral view.
Fengshanites sp.
Figure 28C–F
Material examined.—Four specimens: NMNS PM 45582–45585 from Loc. OS-A41.
Description.—Specimens are characterized by a moderately evolute shell with a broadly rounded venter and a moderately wide umbilicus. The ornamentation consists of conspicuous, dense strigation covering entire shell, and irregular, weak radial folds and fine ribs which are rursiradiate and concave on umbilical wall and shoulder, slightly sinuous and prorsiradiate on the flank, and forward projected on ventral shoulder.
Discussion.—Even though the present specimens are strongly deformed laterally due to compaction and crushed, their distinctive ornamentation supports their identification with reasonable confidence to the genus Fengshanites. Our specimens are somewhat similar to Fengshanites robustus Chao, 1950 (Figure 28A, B), but a definitive species assignment cannot be made.
Occurrence.—Described specimens were collected from the upper lower Spathian Deweveria kovalenkoi Zone.
Genus Subfengshanites Zakharov et al., 2008
Type species.—Subcolumbites multiformis Kiparisova in Voinova et al., 1947.
Subfengshanites multiformis (Kiparisova in Voinova et al., 1947)
Figures 29–31
Subcolumbites multiformis Kiparisova in Voinova et al., 1947, p. 144, pl. 32, figs. 8–11, text-figs. 31–34; Kiparisova and Krishtofovich, 1954, p. 22, pl. 13, figs. 1–3; Kiparisova, 1961, p. 121, pl. 27, figs. 1–7, text-figs. 82–88; Zakharov, 1968, p. 108, pl. 21, figs. 1–3.
Subfengshanites multiformis (Kiparisova in Voinova et al., 1947). Zakharov et al., 2008, fig. 10.
Holotype.—CGM 126/5504, figured by Kiparisova in Voinova et al. (1947, p. 144, pl. 32, fig. 8), from the Subfengshanites multiformis Zone in the Zhitkov Cape section of Russky Island, South Primorye, Russian Far East.
Material examined.—Fifteen specimens: NMNS PM 45586–45589 from Loc. OS-A11; NMNS PM 45590–45592 from Loc. OS-A33, NMNS PM 45593 from Loc. OS-A34; NMNS PM 45595 from Loc. OS-A45; NMNS PM 45594 from Loc. OS-A46; NMNS PM 45596–45600 from Loc. OS-A47.
Description.—Specimens are strongly deformed laterally due to compaction, but they are characterized by a moderately evolute shell with an arched venter and convex flanks gradually converging from umbilical shoulders to venter. Maximum whorl width occurs on umbilical shoulder. Umbilicus is moderately wide with gently convex umbilical wall and rounded umbilical shoulder. Ornamentation consists of dense, fine strigation covering entire shell, and fine ribs which are rursiradiate and concave on umbilical wall and shoulder, slightly sinuous and prorsiradiate on the flank, and forward projected on ventral shoulder. Strigation disappears in larger shells.
Discussion.—Subfengshanites is very close to Fengshanites, but differs in having denticulated head-like lateral saddles (Zakharov et al., 2008, p. 461). Although suture lines are not preserved on the herein described specimens, their fine strigation and arched venter enable us to attribute them to Subfengshanites multiformis. Kummel (1969, p. 436) synonymized “Subcolumbites” solitus Kiparisova, 1961 and “S.” anomalus Kiparisova, 1961 from the same locality with this taxon. Further studies of intraspecific variation in these taxa are needed.
Occurrence.—Described specimens were collected from the middle Spathian Subfengshanites multiformis Zone. Subfengshanites multiformis also occurs in the middle Spathian of South Primorye (Zakharov, 1968).
Genus Prenkites Arthaber, 1911
Type species.—Prenkites malsorensis Arthaber, 1911.
Prenkites graecoamericanus (Renz and Renz, 1948)
Figure 32
Columbites graecoamericanus Renz and Renz, 1948, p. 27, pl. 10, fig. 4.
Columbites levantinus Renz and Renz, 1948, p. 27, pl. 10, fig. 2.
Columbites huangi Chao, 1950, p. 301, pl. 29, figs. 6–11, text-fig. 41a.
Columbites costatus Chao, 1950, p. 302, pl. 29, figs. 1–3, text-fig. 41b.
Columbites yaliensis Chao, 1950, p. 302, pl. 29, figs. 12–14.
Prenkites kwangsianus Chao, 1950, p. 307, pl. 29, figs. 15–20, text-fig. 42b.
Columbites parisianus Hyatt and Smith. Bando and Shimoyama, 1974, p. 302, pl. 40, fig. 9, pl. 41, fig. 1.
Subcolumbites sp. Bando and Shimoyama, 1974, pl. 42, fig. 4 (3).
Holotype.—MBJ 13564, figured by Renz and Renz (1948, p. 27, pl. 10, fig. 4), from the Subcolumbites fauna of Chios, Greece (Figure 32A, B).
Material examined.—Twelve specimens: NMNS PM 45601–45612 from Loc. OS-A11
Description.—Specimens are strongly deformed laterally due to compaction, but they are characterized by a moderately evolute shell with a moderately wide umbilicus. Ornamentation consists of constrictions and strong, major ribs, which are rursiradiate and concave on umbilical wall and shoulder, and straight and prorsiradiate on the flank, as well as growth lines and fine ribs between major ribs. Degree of ribbing is variable.
Discussion.—The ribbing ornamentation of specimens from Loc. OS-A11 exhibits considerable intraspecific variation in the number, style and strength of ribs. They resemble “Columbites” graecoamericanus and “C”. levantinus described by Renz and Renz (1948) from Chios and “C”. huangi, “C”. costatus, “C”. yaliensis and P. kwangsianus described by Chao (1950) from South China. The character or style of ribbing on these taxa is significantly different from that of Columbites, which usually has strong, prorsiradiate ribs that may be associated with ventrolateral tuberculation, and instead, is consistent with that of Prenkites in having constrictions and strong, prorsiradiate, major ribs. They are clearly conspecific (Kummel, 1969) and are therefore considered synonyms of Prenkites graecoamericanus. Two specimens described as Columbites parisianus and one described as Subcolumbites sp. by Bando and Shimoyama (1974, pl. 40, fig. 9, pl. 41, fig. 1; pl. 42, fig. 4) are very similar to the present specimens in having constrictions and strong, major ribs and are probably conspecific.
Occurrence.—Described specimens were collected from the middle Spathian Subfengshanites multiformis Zone. Prenkites graecoamericanus also occurs in the Subcolumbites fauna (middle Spathian) of Greece and the “Columbites” costatus Zone (middle Spathian) of South China (Kummel, 1969).
Figure 29.
Subfengshanites multiformis (Kiparisova in Voinova et al., 1947) from South Primorye and the Osawa Formation. A, B, NMNS PM 45640 from Zhitkov Cape, South Primorye, collected by H. Maeda; C–F, specimens from Loc. OS-A11; C, NMNS PM 45588; D, NMNS PM 45586; E, NMNS PM 45587; F, NMNS PM 45589; G–I, specimens from Loc. OS-A33; G, NMNS PM 45590; H, NMNS PM 45591; I, NMNS PM 45592; J, NMNS PM 45593 from Loc. OS-A34. E, H, J, silicon rubber casts of the outer molds. A, ventral view; B, D, E, G, I; left lateral views; C, F, H, J, right lateral views.
Figure 30.
Subfengshanites multiformis (Kiparisova in Voinova et al., 1947) from the Osawa Formation. A, NMNS PM 45595 from Loc. OS-A45; B, NMNS PM 45594 from Loc. OS-A46, silicon rubber cast of the outer mold; C–F, specimens from Loc. OS-A47; C, NMNS PM 45595; D, NMNS PM 45599; E, NMNS PM 45596; F, NMNS PM 45598. A, C–E, right lateral views; B, left lateral view; F, ventral view.
Figure 31.
Subfengshanites multiformis (Kiparisova in Voinova et al., 1947), NMNS PM 45600 from Loc. OS-A45, left lateral view.
Superfamily Megaphyllitoidea Mojisovics, 1896
Family Procarnitidae Chao, 1959
Genus Procarnites sp.
Figure 33
Procarnites sp. Ehiro et al., 2016, p. 99, fig. 4.3.
Material examined.—One specimen: IGPS coll. cat. no. 111560 of Ehiro et al. (2016, fig. 4.3) from Loc. OS-A22.
Description.—Specimen is characterized by a very involute, very compressed shell with a narrow rounded venter and a narrow umbilicus. Ornamentation consists of very fine, dense strigation covering entire shell. Suture is ceratitic with subphylloid saddles (Figure 33E).
Discussion.—Even though the present specimen is strongly deformed laterally due to severe compaction, its distinctive shell shape and suture supports its identification with reasonable confidence to the genus Procarnites, but a definitive species assignment of this specimen cannot be made.
Occurrence.—Described specimens were collected from the middle Spathian Subcolumbites perrinismithi Zone.
Figure 32.
Prenkites graecoamericanus (Renz and Renz, 1948) from the Osawa Formation and Chios. A, B, NMNS PM 41826, plaster model of the holotype MBJ 13564 (= Renz and Renz, 1948, pl. 10, fig. 4) from Chios; C–N, specimens from Loc. OS-A11; C, NMNS PM 45601; D, NMNS PM 45602; E, NMNS PM 45603; F, NMNS PM 45604; G, NMNS PM 45605; H, NMNS PM 45606; I, NMNS PM 45607; J, NMNS PM 45608; K, NMNS PM 45609; L, NMNS PM 45610; M, NMNS PM 45611; N, NMNS PM 45612. J, K, M, silicon rubber casts of the outer molds. A, ventral view; B–E, K, left lateral views; F–J, L–N, right lateral views.
Figure 33.
Procarnites sp. from the Osawa Formation at Loc. OS-A22. A, B, NMNS PM 43110a, silicon rubber cast of the outer mold of IGPS 111560 (= Ehiro et al., 2016, fig. 4.3); C–E, NMNS PM 43110b, plaster model of IGPS 111560. A–D, left lateral views; E, suture line.
Superfamily Ceratitoidea Mojsisovics, 1879
Family Keyserlingitidae Zakharov, 1970
Genus Olenekoceras Dagys and Ermakova, 1986
Type species.—Ceratites middendorffi Keyserling, 1845.
Olenekoceras miroshnikovi (Zakharov, 1968)
Figure 34
Keyserlingites miroshnikovi Zakharov, 1968, p. 129, pl. 24, fig. 2, pl. 25, figs. 2, 3.
Keyserlingites cf. middendorffi (Keyserling). Ehiro, 1993, p. 234, figs. 2b, 3.1.
Olenekoceras miroshnikovi (Zakharov). Zakharov, 1997a, pl. 3, fig. 7.
Holotype.—CGM 48/8701, figured by Zakharov (1968, p. 129), from the Neocolumbites insignis Zone (upper lower Spathian) in the Tchernyshev Bay section on Russky Island, South Primorye, Russian Far East.
Material examined.—One specimen: IPPM 60013 of Ehiro (1993, fig. 3.1) from Yamaya.
Description.—Specimen is fragmental and strongly deformed laterally due to compaction, but it is characterized by a moderately evolute shell with a moderately wide umbilicus. Ornamentation consists of robust tubercles on the umbilical shoulder and small ventrolateral tubercles.
Discussion.—Specimen was assigned to Keyserlingites cf. middendorffi by Ehiro (1993, p. 234, figs. 2b, 3.1), but the umbilicus is wider than comparable-sized K. middendorffi specimens (e.g. Dagys and Ermakova, 1988). Three species of Olenekoceras described from the Neocolumbites insignis Zone in South Primorye, i.e., O. meridianus (Zakharov, 1968), O. miroshnikovi and O. tebenkovi (Zharnikova, 1985), are differentiated by their umbilical size and strength of their tubercles. Olenekoceras meridianus has a wider umbilicus and less conspicuous tubercles, but O. miroshnikovi has a narrower umbilicus and much more robust tubercles. Olenekoceras tebenkovi is intermediate between the other two species, which may indicate that these three taxa are in fact the same species that exhibits wide intraspecific variation. Further studies of intraspecific variation are needed.
Occurrence.—Specimen was collected from the upper lower Spathian Deweveria kovalenkoi Zone. Olenekoceras miroshnikovi occurs in the Neocolumbites insignis Zone (upper lower Spathian) of South Primorye, Russia (Zakharov, 1997b).
Figure 34.
Olenekoceras miroshnikovi (Zakharov, 1968) from the Osawa Formation and South Primorye. A, NMNS PM 43085, plaster model of IPPM 60013 (= Ehiro,1993, fig. 3.1) from Yamaya; B–E, NMNS PM 45641 from Tchernyshev Bay on Rusky Island, South Primorye. A, B, right lateral views; C, ventral view; D, left lateral view; E, apertural view.
Family Longobarditidae Spath, 1951
Genus Prohungarites Spath, 1934
Type species.—Prohungarites similis Spath, 1934.
Prohungarites sp.
Figure 35
Material examined.—Ten specimens: NMNS PM 45613–45622 from Loc. OS-A22.
Description.—Specimens are characterized by a fairly involute, compressed shell with an acute venter, rounded ventral shoulder and slightly convex flanks. Umbilicus is fairly narrow with rounded shoulder and low, subvertical wall. Ornamentation consists of fine, prorsiradiate growth lines, which are strongly projected forward on the ventrolateral shoulder.
Discussion.—The distinctive shell morphology, e.g. acute venter, supports their identification with reasonable confidence as Prohungarites, but the strongly deformed preservation and absence of adult features preclude a definitive species assignment.
Occurrence.—Described specimen was collected from the middle Spathian Subcolumbites perrinismithi Zone.
Order Phylloceratidae Zittle, 1884
Superfamily Ussuritoidea Hyatt, 1900
Family Palaeophyllitidae Popov in Luppov and
Drushchits, 1958
Genus Eophyllites Spath, 1930
Type species.—Monophyllites dieneri Arthaber, 1908
Eophyllites sp.
Figure 36
Material examined.—Then specimens: NMNS PM 45623 from Loc. OS-A32; NMNS PM 45624–45632 from Loc. OS-A43.
Description.—Specimens are characterized by a fairly evolute and compressed shell with slightly flattened flanks. Umbilicus is moderately wide with low, gently sloped wall and rounded shoulders. Shell surface is nearly smooth with fine, slightly rursiradiate growth lines and low, fold-type ribs. Suture consists of rounded saddles and strongly denticulated lobes (Figure 36K).
Discussion.—The distinctive shell morphology and suture line support their identification with reasonable confidence to the genus Leiophyllites, but the strongly deformed preservation and absence of adult features preclude a definitive species assignment.
Occurrence.—Described specimens were collected from the middle Spathian Subcolumbites perrinismithi Zones.
Genus Leiophyllites Diener, 1915
Type species.—Monophyllites suessi Mojsisovics, 1882.
Leiophyllites praematurus Kiparisova, 1958
Figure 37
Leiophyllites praematurus Kiparisova, 1958, pl. 7, fig. 13, text-fig. 17b; Kiparisova, 1961, p. 134, pl. 28, figs. 5, 6, text-figs. 101, 102.
Holotype.—CGM 150/5504, figured by Kiparisova (1958, pl. 7, fig. 13), from the Subfengshanites multiformis Zone in the Atlasov Cape section of the western coast of Amur Gulf, South Primorye, Russian Far East (Figure 37A–C).
Material examined.—Five specimens: NMNS PM 45633, 45634 from Loc. OS-A13; NMNS PM 45635–45637 from Loc. OS-A14.
Description.—Specimens are strongly deformed laterally due to compaction, but they are characterized by a very evolute, compressed shell with a rounded venter, rounded ventral shoulders and slightly convex flanks. Umbilicus is wide with low, gently sloped wall and rounded shoulders. Shell surface is nearly smooth with fine, slightly rursiradiate growth lines and constrictions.
Discussion.—Kummel (1969) regarded Leiophyllites praematurus as conspecific with L. variabilis (Spath, 1934), but L. praematurus differs from L. variabilis in having much evolute shell with a wider umbilicus.
Occurrence.—Described specimen was collected from the middle Spathian Isculitoides sp. Zone. Leiophyllites praematurus also occurs in the Ussuriphyllites amurensis Zone (upper Spathian [Shigeta and Kumagae, 2016] or the lower Anisian [Zakharov, 1997a]) of South Primorye.
Figure 35.
Prohungarites sp. from Loc. OS-A22. A, NMNS PM 45613; B, NMNS PM 45614; C, NMNS PM 45615, silicon rubber cast of the outer mold; D, NMNS PM 45616, silicon rubber cast of the outer mold; E, NMNS PM 45617; F, NMNS PM 45618; G, NMNS PM 45619; H, NMNS PM 45620; I, NMNS PM 45621; J, NMNS PM 45622. A–D, G, H, left lateral views; E, F, I, J, right lateral views.
Figure 36.
Eophyllites sp. from the Osawa Formation. A, NMNS PM 45623 from Loc. OS-A32; B–K, specimens from Loc. OS-A43; B, NMNS PM 45624; C, NMNS PM 45625; D, NMNS PM 45626, silicon rubber cast of the outer mold; E, NMNS PM 45627; F, NMNS PM 45628; G, NMNS PM 45629, silicon rubber cast of the outer mold; H, NMNS PM 45630; I, NMNS PM 45631, silicon rubber cast of the outer mold; J, K, NMNS PM 45632. A, E, F–H, J, left lateral views; B–D, I, right lateral views; K, suture line. Arrow represents the center of venter, and broken line indicates the position of the umbilical seam.
Conclusions
Thirty-one species of early to middle Spathian (late Olenekian, Early Triassic) ammonoids are reported from the Osawa Formation in the Yamaya, Akaushi–Osawa, Utatsu, Kamiwarizaki and Ozashi areas in the southern part of the South Kitakami Belt, Miyagi Prefecture, Northeast Japan.
Four distinct Spathian ammonoid zones (taxon-range zones) are recognized in the upper lower to middle upper parts of the Osawa Formation as follows, in ascending order: the upper lower Spathian Deweveria kovalenkoi Zone, middle Spathian Subcolumbites perrinismithi Zone, Subfengshanites multiformis Zone and Isculitoides sp. Zone.
The Subcolumbites perrinismithi Zone is clearly characterized by differing lithologies in different areas, alternating beds of dark gray, laminated mudstone, and fine-grained sandstone in the south and more offshore, dark gray, laminated mudstone in the north, suggesting a northward-deepening setting.
A primitive ichthyopterygian Utatsusaurus hataii occurs in the Subcolumbites perrinismithi to Isculitoides sp. zones of the middle and upper parts of the Osawa Formation, which likely constrains its age to the middle Spathian.
The ammonoid faunas in the Osawa Formation exhibit a great affinity with those of South Primorye as well as the Tethys, and such faunal similarity suggests that the South Kitakami Belt may have been located near South Primorye.
A taxonomic revision of the ammonoids previously reported from the Osawa Formation by Bando (1964, 1970), Bando and Shimoyama (1974) and Ehiro et al. (2016, 2019) is summarized in Appendix.
Figure 37.
Leiophyllites praematurus Kiparisova, 1958 from the Osawa Formation and South Primorye. A–C, NMNS PM 43282, plaster model of the holotype CGM 150/5504 (= Kiparisova, 1958, pl. 7, fig. 13) from South Primorye; D, E, specimens from Loc. OS-A13; D, NMNS PM 45633; E, NMNS PM 45634; F–H, specimens from Loc. OS-A14; F, NMNS PM 45635, silicon rubber cast of the outer mold; G, NMNS PM 45636; H, NMNS PM 45637. A, D, E, H, left lateral views; B, apertural view; C, F, G, right lateral views.
Acknowledgments
We are deeply indebted to the Central Scientific Research Geological Prospecting Museum (TsNIGR Museum, St. Petersburg), Far Eastern Geological Institute (DVGI, Vladivostok), Nanjin Institute of Geology and Palaeontology (Nanjin), Department of Palaeontology, University of Vienna (Vienna), Natural History Museum Basel (Basel), Iwate Prefectural Museum (Morioka) and Tohoku University Museum (Sendai) for kindly providing the opportunity to examine curated specimens including type specimens. We are grateful to Yasuhisa Nakajima (Tokyo City University, Tokyo) and Chisato Suzuki (Iwaki, Fukushima) for donating the specimens and providing locality information. We thank Arnaud Brayard (Université de Bourgogne, Dijon) and an anonymous reviewer for valuable comments on the first draft. Thanks are extended to Tohoku Regional Environment Office, Naoya Takahashi (Minamisanriku, Miyagi) and Ryosuke Amano (University of Tsukuba) in Miyagi Prefecture and Yuri D. Zakharov and Alexander M. Popov (DVGI, Vladivostok) in South Primorye for their cooperation in the field and to Jim Jenks (West Jordan, Utah) for his helpful suggestions and improvement of the English text.
© by the Palaeontological Society of Japan
Locality information
Collecting fossils and rocks requires permission from the Tohoku Regional Environment Office at the following localites, which are located within Sanriku Fukko (Reconstruction) National Park, except for the privately owned Locs. OS-A22 and Yamaya, where landowner permission is required.
Yamaya
Area.—Yamayaarea(Yamaya,Motoyoshi,Kesennuma, Miyagi Prefecture).
Locality.—38°48′40″N, 141°32′54″E, the same locality of Ehiro (1993, 2016), about 750 m west of Hikada Port.
Stratigraphic position.—The Os1 unit of the Osawa Formation.
Fossils.—Ammonoids: Deweveria kovalenkoi, Khvalynites unicus (= Metadagnoceras motoyoshiense), Olenekoceras miroshnikovi, Hellenites tchernyschewiensis and Pseudosageceras sp., which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Deweveria kovalenkoi Zone.
Age.—Late early Spathian.
OS-A01
Area.—Akaushi–Osawa area (Akaushi, Motoyoshi, Kesennuma, Miyagi Prefecture).
Locality.—38°47′53.92″N, 141°32′22.26″E, about 135 m northeast of Akaushi Port. Accessible only at low tide.
Stratigraphic position.—The Os1 unit of the Osawa Formation.
Fossils.—Ammonoids: Deweveria kovalenkoi, Procolumbites ussuriensis, P. subquadratus, Neocolumbites insignis and N. grammi, which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Deweveria kovalenkoi Zone.
Age.—Late early Spathian.
OS-A02
Area.—Akaushi–Osawa area (Akaushi, Motoyoshi, Kesennuma, Miyagi Prefecture).
Locality.—38°47′44.53″N, 141°32′13.50″E, outside the south harbor wall of Akaushi Port. Accessible only at low tide.
Stratigraphic position.—The Os1 unit of the Osawa Formation.
Fossils.—Ammonoids: Deweveria kovalenkoi, Procolumbites ussuriensis, P. subquadratus, Neocolumbites grammi, Hellenites tchernyschewiensis and H. inopinatus, which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Deweveria kovalenkoi Zone.
Age.—Late early Spathian.
OS-A11
Area.—Akaushi–Osawa area (Osawa, Motoyoshi, Kesennuma, Miyagi Prefecture).
Locality.—38°47′30.18″N, 141°31′43.56″E, outside the south harbor wall of Osawa Port. Accessible only at low tide.
Stratigraphic position.—The Os3 unit of the Osawa Formation.
Fossils.—Ammonoids: Subfengshanites multiformis, Arnautoceltites gracilis, Prenkites graecoamericanus, Stacheites floweri and Pseudosageceras sp., which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Subfengshanites multiformis Zone.
Age.—Middle Spathian.
OS-A12
Area.—Akaushi–Osawa area (Osawa, Motoyoshi, Kesennuma, Miyagi Prefecture).
Locality.—38°47′30.18″N, 141°31′43.56″E, outside the south harbor wall of Osawa Port.
Stratigraphic position.—The Os3 unit of the Osawa Formation, 5 m above OS-11.
Fossils.—Ammonoids: Isculitoides sp., Arnautoceltites gracilis, Stacheites floweri and Pseudosageceras sp., which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Isculitoides sp. Zone.
Age.—Middle Spathian.
OS-A13
Area.—Akaushi–Osawa area (Osawa, Motoyoshi, Kesennuma, Miyagi Prefecture).
Locality.—38°47′30.18″N, 141°31′43.56″E, outside the south harbor wall of Osawa Port.
Stratigraphic position.—The Os3 unit of the Osawa Formation, 5 m above OS-12.
Fossils.—Ammonoids: Isculitoides sp., Arnautoceltites gracilis and Leiophyllites praematurus, which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Isculitoides sp. Zone.
Age.—Middle Spathian.
OS-A14
Area.—Akaushi–Osawa area (Osawa, Motoyoshi, Kesennuma, Miyagi Prefecture).
Locality.—38°47′30.18″N, 141°31′43.56″E, outside the south harbor wall of Osawa Port.
Stratigraphic position.—The Os3 unit of the Osawa Formation, 3 m above OS-13.
Fossils.—Ammonoids: Isculitoides sp. and Leiophyllites praematurus, which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Isculitoides sp. Zone.
Age.—Middle Spathian.
OS-A21
Area.—Utatsu area (Tatezaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°42′32.05″N, 141°32′08.29″E, 40 m east of the ichthyosaur monument, south of Tatehama Port.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoid: Subcolumbites perrinismithi, which occurs in the weakly bioturbated mudstone.
Ammonoid Zone.—Subcolumbites perrinismithi. Zone.
Age.—Middle Spathian.
OS-A22
Area.—Utatsu area (Tatezaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°42′49.86″N, 141°32′06.96″E, the same locality of Ehiro et al. (2015, 2016, 2019), about 300 m north of Tatehama Port.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoids: Subcolumbites perrinismithi, Hemilecanites sp., Epiceltites gentii, Prohungarites sp., Albanites sheldoni (= Leiophyllites wakoi), A. cf. triadicus, Chioceras sp., Proptychitoides cf. trigonalis, Procarnites sp., Stacheites floweri (= Pseudokymatites tabulates) and Pseudosageceras sp. Thylacocephalans: Kitakamicaris utatsuensis, Miyagicaris costata, Ankitokazocaris bandoi, A. tatensis, Concavicaris parva and Ostenocaris sp. Small bivalves. All fossils occur in the weakly bioturbated mudstone.
Ammonoid Zone.—Subcolumbites perrinismithi. Zone.
Age.—Middle Spathian.
OS-A23
Area.—Utatsu area (Tatezaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°42′48.40″N, 141°32′02.96″E, 280 m northwest of Tatehama Port.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoid: Sulioticeras inflatus, which occurs in the dark gray, laminated mudstone of the alternating beds of laminated mudstone and fine-grained sandstone.
Ammonoid Zone.—Subfengshanites multiformis Zone.
Age.—Middle Spathian.
OS-A31
Area.—Kamiwarizaki area (Kamiwarizaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°38′10.17″N, 141°31′46.69″E, east coast of Kamiwarizaki campsite.
Stratigraphic position.—The Os1 unit of the Osawa Formation.
Fossils.—Ammonoids: Hellenites tchernyschewiensis and Stacheites floweri, which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Deweveria kovalenkoi Zone.
Age.—Late early Spathian.
OS-A32
Area.—Kamiwarizaki area (Kamiwarizaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°38′12.12″N, 141°31′45.75″E, north coast of Kamiwarizaki campsite.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoid: Eophyllites sp. Lingulid brachiopods: Lingula sp. and Orbiculoidea sp. All fossils occur in the weakly bioturbated mudstone.
Ammonoid Zone.—Subcolumbites perrinismithi Zone.
Age.—Late early Spathian.
OS-A33
Area.—Kamiwarizaki area (Kamiwarizaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°38′14.48″N, 141°31′42.04″E, north coast of Kamiwarizaki campsite.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoid: Subfengshanites multiformis. Ichthyopterygian skeletons. All fossils occur in the dark gray, laminated mudstone of the alternating beds of laminated mudstone and fine-grained sandstone.
Ammonoid Zone.—Subfengshanites multiformis Zone.
Age.—Middle Spathian.
OS-A34
Area.—Kamiwarizaki area (Kamiwarizaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°38′14.55″N, 141°31′41.44″E, north coast of Kamiwarizaki campsite.
Stratigraphic position.—The Os3 unit of the Osawa Formation.
Fossils.—Ammonoid: Subfengshanites multiformis, which occurs in the dark gray, laminated mudstone.
Ammonoid Zone.—Subfengshanites multiformis Zone.
Age.—Middle Spathian.
OS-A35
Area.—Kamiwarizaki area (Kamiwarizaki, Minamisanriku, Miyagi Prefecture).
Locality.—38°38′14.20″N, 141°31′41.20″E, north coast of Kamiwarizaki campsite. Accessible only at low tide.
Stratigraphic position.—The Os3 unit of the Osawa Formation.
Fossils.—Ammonoid: Isculitoides sp., which occurs in the dark gray, laminated mudstone.
Ammonoid Zone.— Isculitoides sp. Zone.
Age.—Middle Spathian.
OS-A41
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′34.18″N, 141°31′24.00″E, 150 m northeast of Ozashi Port. Accessible only at low tide.
Stratigraphic position.—The Os1 unit of the Osawa Formation.
Fossils.—Ammonoids: Deweveria kovalenkoi, Hellenites tchernyschewiensis, Idahocolumbites sp., Procolumbites sp. and Fengshanites sp., which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Deweveria kovalenkoi Zone.
Age.—Late early Spathian.
OS-A42
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′34.12″N, 141°31′23.58″E, 150 m northeast of Ozashi Port. Accessible only at low tide.
Stratigraphic position.—The Os1 unit of the Osawa Formation, 4 m above OS-41.
Fossils.—Ammonoids: Deweveria kovalenkoi and Hellenites tchernyschewiensis, which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Deweveria kovalenkoi Zone.
Age.—Late early Spathian.
OS-A43
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′33.45″N, 141°31′22.74″E, 150 m northeast of Ozashi Port. Accessible only at low tide.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoids: Subcolumbites perrinismithi, Epiceltites gentii and Eophyllites sp. Thylacocephalans: Kitakamicaris utatsuensis, Miyagicaris costata, and Ostenocaris sp. Lingulid brachiopods: Lingula sp. and Orbiculoidea sp. Ichthyopterygian skeletons. All fossils occur in the weakly bioturbated mudstone.
Ammonoid Zone.—Subcolumbites perrinismithi Zone.
Age.—Middle Spathian.
OS-A44
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′31.60″N, 141°31′19.86″E, Ozashi Port.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoid: Subcolumbites perrinismithi, which occurs in the weakly bioturbated mudstone.
Ammonoid Zone.—Subcolumbites perrinismithi Zone.
Age.—Middle Spathian.
OS-A45
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′32.35″N, 141°31′18.01″E, Ozashi Port.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoid: Subfengshanites multiformis, which occurs in the weakly bioturbated mudstone.
Ammonoid Zone.—Subcolumbites perrinismithi Zone.
Age.—Middle Spathian.
OS-A46
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′27.70″N, 141°31′14.73″E, a small island south of Ozashi Port. Accessible only at low tide.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoids: Subfengshanites multiformis and Arnautoceltites sp. Ichthyopterygian skeletons. All fossils occur in the dark gray, laminated mudstone of the alternating beds of laminated mudstone and fine-grained sandstone.
Ammonoid Zone.—Subfengshanites multiformis Zone.
Age.—Middle Spathian.
OS-A47
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′27.68″N, 141°31′14.13″E, a small island south of Ozashi Port. Accessible only at low tide.
Stratigraphic position.—The Os2 unit of the Osawa Formation.
Fossils.—Ammonoid: Subfengshanites multiformis, which occurs in the dark gray, laminated mudstone of the alternating beds of laminated mudstone and fine-grained sandstone.
Ammonoid Zone.—Subfengshanites multiformis Zone.
Age.—Middle Spathian.
OS-A48
Area.—Ozashi area (Ozashi, Ishinomaki, Miyagi Prefecture).
Locality.—38°36′27.53″N, 141°31′13.47″E, a small island south of Ozashi Port. Accessible only at low tide.
Stratigraphic position.—The Os3 unit of the Osawa Formation.
Fossils.—Ammonoids: Isculitoides sp. and Pseudosageceras sp., which occur in the dark gray, laminated mudstone.
Ammonoid Zone.—Isculitoides sp. Zone.
Age.—Middle Spathian.
