44 Yasunari Shigeta et al. (eds.) Systematic Paleontology Triassic (Olenekian) of Paris Bay, Russian Island, in South Primorye, Russia. Cephalopods (by Y. Shigeta and Y. D. Za- Material examined: Three specimens, NSM kharov) PM23100–23102, from AB1022. Systematic descriptions basically follow the Description: Moderately expanding ortho- classification established by Sweet (1964) for conic shell with 4–5 degree adoral angle of ex- orthocerids, Kummel (1964) for nautilids, and pansion and circular whorl cross-section. Juve- Tozer (1981, 1994) for ceratitids. Morphologi- nile shell ornamented with network lirae con- cal terms are those used in the Treatise on In- sisting of fine longitudinal ridges and fine vertebrate Paleontology (Moore, 1957, 1964). transverse lirae, while larger shells exhibit fine Quantifiers used to describe the size and shape transverse lirae. Centrally located siphuncle of ammonoid shells replicate that proposed by with cylindrical connecting ring, and short, or- Matsumoto (1954, p. 246) and modified by thochoanitic septal neck. Suture simple and Haggart (1989, Table 8.1). straight. Cameral deposits not observed. ϭ Abbreviations for shell dimensions: D Occurrence: Described specimens from ϭ ϭ shell diameter; U umbilical diameter; H AB1022 within the Clypeoceras timorense ϭ whorl height; W whorl width. Zone (early Early Olenekianϭearly Smithian) ϭ Institution abbreviations: NSM National in the main part of the Zhitkov Formation, Museum of Nature and Science, Tokyo; Abrek Bay area, South Primorye. This species ϭ CGM Central Research Geological Prospect- occurs abundantly in Olenekian deposits at ing Museum (CNIGR Museum), St. Peters- many localities in South Primorye (Kiparisova, ϭ burg; DVGI Far Eastern Geological Institute, 1961) ϭ Vladivostok; GSC Geological Survey of Discussion: Trematoceras subcampanile ϭ Canada, Ottawa; GSI Geological Survey of (Kiparisova, 1954) is morphologically very India, Kolkata. close to T. campanile (Mojsisovics, 1882, p. 291), T. vulgare Schastlivtceva, (1981, p. 77), Class Cephalopoda Leach, 1817 T. ciarum Schastlivtceva, (1986, p. 125) and T. Order Orthocerida Kuhn, 1940 boreale Schastlivtceva, (1986, p. 125), but dif- Superfamily Orthoceratoidea M’Coy, 1844 fers in that its juvenile shell is ornamented Family Orthoceratidae M’Coy, 1844 with network lirae. It differs from T. mangish- Genus Trematoceras Eichwald, 1851 lakense Schastlivtceva, (1981, p. 79) and T. in- Type species: Orthoceras elegans Münster, speratum Schastlivtceva, (1988, p. 67) by its 1841. smaller angle of shell expansion. Trematoceras subcampanile Order Nautilida Agassiz, 1847 (Kiparisova, 1954) Superfamily Trigonoceratoidea Hyatt, 1884 Fig. 27 Family Grypoceratidae Hyatt, 1900 Genus Gyronautilus Zakharov and Orthoceras sp. indet. ex aff. campanile Mojsisovics. Di- ener, 1895, p. 10, pl. 4, fig. 5. Shigeta, 2000 Orthoceras subcampabile Kiparisova, 1954, p. 20, pl. 11, figs. 1, 2. Type species: Syringoceras praevolutum Trematoceras subcampanile (Kiparisova). Kiparisova, Kiparisova, 1961. 1961, p. 14, pl. 1, figs. 1, 2. Discussion: Gyronautilus was placed within Holotype: CGM 596, figured by Diener the family Grypoceratidae because of its (1895, p. 10, pl. 4, fig. 5), from the Lower flattened venter and its suture, which displays distinct ventral and lateral lobes (Zakharov & Lower Triassic System in the Abrek Bay area, South Primorye 45 Fig. 27. Trematoceras subcampanile Kiparisova, 1954 from AB1022. 1, NSM PM23100, ϫ1.0. 2, NSM PM23101, ϫ1.0. 3, NSM PM23102, ϫ2.0. Shigeta, 2000). Shimansky (1962) recognized from AB1008; paratype, NSM PM23103, four subfamilies within the family Grypocer- from AB1008. atidae: Domatoceratinae, Grypoceratinae, Sy- Diagnosis: Gyronautilus with evolute inner ringonautilinae and Clymenonautilinae. Za- whorls and gyroconic outer whorls. kharov and Shigeta (2000) proposed an addi- Etymology: Named for Alexander M. Popov, tional subfamily Gyronautilinae, and placed who collected the specimens. Gyronautilus in it. Description: Gyroconic shell characterized by evolute inner whorls, subquadratic to sub- Gyronautilus popovi Shigeta and Zakharov trapezoidal whorl section, broadly rounded to sp. nov. subtabulate venter, rounded ventral shoulders, Figs. 28, 29 fairly concave dorsum and nearly parallel to slightly convex flanks with maximum whorl Type specimens: Holotype, NSM PM23104, width just above umbilical shoulder. Umbili- 46 Yasunari Shigeta et al. (eds.) Fig. 28. Gyronautilus popovi Shigeta and Zakharov sp. nov. from AB1008. 1–4, NSM PM23103, paratype, ϫ2.0. 5–8, NSM PM23104, holotype, ϫ1.0. White arrows indicate position of the embryonic constriction. cus exhibits moderately high, vertical wall 1961, p. 25) by its evolute inner whorls, but with rounded shoulders and fairly small both species probably belong to the same evo- (2–3 mm) umbilical perforation. Embryonic lutionary lineage. shell 7.5 mm in length and consists of one half Among the previously described Early Ind- whorl. Body chamber length unknown. Si- uan (Griesbachian) species, Gy. popovi sp. phuncle located at two thirds of whorl height. nov. more closely resembles Nautilus quad- Ornamentation consists of sinuous growth rangulus var. brahmanicus Griesbach (1880, p. lines with deep, U-shaped hyponomic sinus on 104) (assigned to Grypoceras Hyatt, 1883 by venter. Suture simple with shallow ventral lobe Kummel in 1953a) from the Himalayan area, and shallow, wide lateral lobe. in terms of whorl cross-section, siphuncle po- Measurements (mm): sition, ornamentation and suture line. Gy. Specimen no. D U H W U/D W/H popovi sp. nov. is somewhat similar to Nau- NSM PM23104 52.0 14.7 23.3 23.3 0.28 1.00 tilus brahmanicus var. hexagonalis Diener NSM PM23103 17.4 4.8 8.4 8.0 0.28 0.95 (1897, p. 11) from the Early Induan (Gries- Occurrence: Described specimens from bachian) of the Himalayan area, but differs in AB1008 within the Lytophiceras sp. Zone whorl cross-section. It seems best to consider (Early InduanϭGriesbachian) in the middle Gy. popovi sp. nov. to be an offshoot of a part of the Lazurnaya Bay Formation, Abrek species of the early Induan genus Grypoceras, Bay area, South Primorye. such as Gr. brahmanicum. Discussion: Gyronautilus popovi sp. nov. differs from Gy. praevolutus (Kiparisova, Lower Triassic System in the Abrek Bay area, South Primorye 47 Fig. 29. Suture line of Gyronautilus popovi Fig. 30. Suture line of Gyronautilus praevolutus Shigeta and Zakharov sp. nov., NSM (Kiparisova, 1961), NSM PM23105, from PM23104, holotype, from AB1008, at Hϭ AB1010, at Hϭ33 mm. V: venter, D: dorsum. 17 mm. Gyronautilus praevolutus (Kiparisova, 1961) AB1010 within the Gyronites subdharmus Figs. 30–35 Zone (late Early Induanϭlate Griesbachian) in the upper part of the Lazurnaya Bay Forma- Syringoceras praevolutum Kiparisova, 1961, p. 25, pl. 4, fig. 2, text-fig. 26. tion, Abrek Bay area, South Primorye. Gyronautilus praevolutus (Kiparisova). Zakharov and Discussion: Gyronautilus praevolutus Shigeta, 2000, p. 232, figs. 2–4. (Kiparisova, 1961) differs from Gy. popovi sp. nov. in that its shell is gyroconic throughout Holotype: CGM 12/5504, figured by ontogeny. Kiparisova (1961, p. 25, pl. 4, fig. 2), from the Kiparisova (1961) proposed Syringoceras Lower Triassic (Olenekian?) in the Abrek Bay praevolutum on the basis of a single small area in South Primorye, Russia. specimen (Fig. 31.1–31.3) collected in 1948 Material examined: Three specimens, NSM by N. K. Trifonov from the Lower Triassic PM16132, 23105, 23106, from AB1010. (Olenekian?) in the Abrek Bay area. Although Description: Gyroconic shell distinguished the exact locality and horizon of the specimen by subquadratic whorl section, broadly round- were not documented, Zakharov and Shigeta ed to subtabulate venter, rounded ventral (2000) later found a large specimen, NSM shoulders, slightly concave dorsum and nearly PM16132 (Fig. 35), at the type locality, which parallel to slightly convex flanks. Umbilicus they identified as S. praevolutum. They care- characterized by moderately high, subvertical fully described its shell features throughout wall with rounded shoulders and small ontogeny, and proposed Gyronautilus as a (4–6 mm) umbilical perforation. Embryonic new genus of Grypoceratidae. They collected shell 11.3 mm in length, exogastrically curved the specimen from a horizon represented by and consists of one half whorl. Body chamber AB1010 in the Lazurnaya Bay Formation, and represents about 130° in spiral length. Orna- interpreted its occurrence as Early Olenekian, mentation consists of sinuous growth lines based on previous biostratigraphical work by with deep, U-shaped hyponomic sinus on ven- Zakharov and Popov (1999). However, the ter. Siphuncle located near venter at one fifth horizon of AB1010 is now correlated with the of whorl height. Suture simple with shallow late Early Induan (late Griesbachian). ventral lobe, shallow, wide lateral lobe and deep dorsal lobe. Measurements (mm): Genus Xiaohenautilus Xu, 1988 Specimen no. D U H W U/D W/H NSM PM16132 92.6 31.5 41.5 37.1 0.34 0.89 Type species: Xiaohenautilus sinensis Xu, NSM PM23106 135.0 48.0 54.0 55.0 0.36 1.02 1988. NSM PM23105 – 30.0 35.5 30.3 – 0.85 Occurrence: Described specimens from 48 Yasunari Shigeta et al. (eds.) Fig. 31. Gyronautilus praevolutus (Kiparisova, 1961). 1–3, CGM 12/5504, holotype, ϫ1.0. 4–7, NSM PM23105, from AB1010, ϫ1.0. → Fig. 32. Gyronautilus praevolutus (Kiparisova, 1961), NSM PM23106, from AB1010. 1–9, ϫ2.0. 10–12, ϫ1.0. White arrows indicate position of the embryonic constriction. Lower Triassic System