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Neogeoceras
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Order:
Prolecanitida
Superfamily:
Medlicottioidea
Family:
Medlicottiidae
Formal Genus Name and Reference:
Neogeoceras RUZHENTSEV, 1947b, p. 641
Type Species:
Medlicottia girtyi Miller & FURNISH, 1940a, p. 59, OD
Images
(Click to enlarge in a new window)
Fig. 129, 1a. *N. girtyi (Miller & Furnish), topotype, SUI 61500, Capitanian, Coahuila, diameter at 70 mm (new).-Fig. 129, 1 b- d. N. smithi Miller & Furnish, b, hypotype, GIUA-B171, Wordian, Basleo, Timor, X 1 (new), c, hypotype, SUI 12707, diameter at 29 mm (new, courtesy of D. M. Work & W. B. Saunders); d, hypotype, SUI 12657, Amarassi beds, Wuchiapingian, Amarassi, Timor, diameter at 35 mm (new).——Fig. 129,1e.
N. thaumastum RuzhentSev, Wuchiapingian ( fide zakhaRov & pavlov, 1986), Maritime Territory, diameter approximately 35 mm (adapted from Ruzhentsev, 1976).——F ig . 129,1f. N. boreale (cheRnyShev in kaRpinSkii, 1926), Wuchiapingian, Novaia Zemlia, diameter approximately 40 mm (Karpinskii, 1926).
Synonyms
Geographic Distribution
Cameron Island), Italy (Sicily), Iraq (Kurdistan), Afghanistan, Oman, Russia (Novaia Zemlia, Maritime Territory), China (Xizang), Japan (Honshu), Indonesia (Timor)
Age Range
Beginning Stage in Treatise Usage:
Guadalupian (Wordian)
Beginning International Stage:
Wordian
Fraction Up In Beginning Stage:
0
Beginning Date:
269.21
Ending Stage in Treatise Usage:
Lopingian (Wuchiapingian)
Ending International Stage:
Wuchiapingian
Fraction Up In Ending Stage:
100
Ending Date:
254.24
Description
Sublenticular medlicottiins with relatively broad, shallowly concave venter (width 0.3 to 0.5 maximum conch width). Angular ventrolateral shoulders bordered by shallowly concave ventrolateral flanks, commonly ribbed. Suture characterized by narrow, complexly subdivided ventrolateral saddle (v3-5 , l4-7 ) in which first adventitious element l 1 is only slightly larger than element l 2 and adjacent subdivisions. Additionally, strongly asymmetrical bidentate dorsal subdivision of primary lateral lobe (L1(d) ) lies beneath general lobe alignment, with ventral prong deeper than dorsal. Ten named species. [Taxonomic position of Neogeoceras within the Medlicottiidae is uncertain. Sutures resemble Medlicottia in general aspect, but small size of l 1 and extreme depth and asymmetry of L 1(d) are unknown in other Medlicottiinae. Neogeoceras resembles Episageceras in all these respects, and assignment to the Episageceratinae could be justified. However, we prefer to define that subfamily primarily on the basis of the anomalously short primary umbilical lobe (U) and consider Neogeoceras as the plausible medlicottiin ancestor of the Episageceratinae.]
References
Museum or Author Information
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Order:
Prolecanitida
Superfamily:
Medlicottioidea
Family:
Medlicottiidae
Formal Genus Name and Reference:
Neogeoceras RUZHENTSEV, 1947b, p. 641
Type Species:
Medlicottia girtyi Miller & FURNISH, 1940a, p. 59, OD
Images
(Click to enlarge in a new window)
Fig. 129, 1a. *N. girtyi (Miller & Furnish), topotype, SUI 61500, Capitanian, Coahuila, diameter at 70 mm (new).-Fig. 129, 1 b- d. N. smithi Miller & Furnish, b, hypotype, GIUA-B171, Wordian, Basleo, Timor, X 1 (new), c, hypotype, SUI 12707, diameter at 29 mm (new, courtesy of D. M. Work & W. B. Saunders); d, hypotype, SUI 12657, Amarassi beds, Wuchiapingian, Amarassi, Timor, diameter at 35 mm (new).——Fig. 129,1e.
N. thaumastum RuzhentSev, Wuchiapingian ( fide zakhaRov & pavlov, 1986), Maritime Territory, diameter approximately 35 mm (adapted from Ruzhentsev, 1976).——F ig . 129,1f. N. boreale (cheRnyShev in kaRpinSkii, 1926), Wuchiapingian, Novaia Zemlia, diameter approximately 40 mm (Karpinskii, 1926).
Synonyms
Geographic Distribution
Cameron Island), Italy (Sicily), Iraq (Kurdistan), Afghanistan, Oman, Russia (Novaia Zemlia, Maritime Territory), China (Xizang), Japan (Honshu), Indonesia (Timor)
Age Range
Beginning Stage in Treatise Usage:
Guadalupian (Wordian)
Beginning International Stage:
Wordian
Fraction Up In Beginning Stage:
0
Beginning Date:
269.21
Ending Stage in Treatise Usage:
Lopingian (Wuchiapingian)
Ending International Stage:
Wuchiapingian
Fraction Up In Ending Stage:
100
Ending Date:
254.24
Description
Sublenticular medlicottiins with relatively broad, shallowly concave venter (width 0.3 to 0.5 maximum conch width). Angular ventrolateral shoulders bordered by shallowly concave ventrolateral flanks, commonly ribbed. Suture characterized by narrow, complexly subdivided ventrolateral saddle (v3-5 , l4-7 ) in which first adventitious element l 1 is only slightly larger than element l 2 and adjacent subdivisions. Additionally, strongly asymmetrical bidentate dorsal subdivision of primary lateral lobe (L1(d) ) lies beneath general lobe alignment, with ventral prong deeper than dorsal. Ten named species. [Taxonomic position of Neogeoceras within the Medlicottiidae is uncertain. Sutures resemble Medlicottia in general aspect, but small size of l 1 and extreme depth and asymmetry of L 1(d) are unknown in other Medlicottiinae. Neogeoceras resembles Episageceras in all these respects, and assignment to the Episageceratinae could be justified. However, we prefer to define that subfamily primarily on the basis of the anomalously short primary umbilical lobe (U) and consider Neogeoceras as the plausible medlicottiin ancestor of the Episageceratinae.]