Glyptoxoceras largesulcatum Forbes 1846 from: Kennedy, W.J..Henderson, R.A.. (1992): Heteromorph ammonites from the Upper Maastrichtian of Pondicherry, south India . Palaeontology Vol. 35 p. 693-731 . |
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Species Glyptoxoceras largesulcatum Forbes 1846 |
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Diagnosis / Definition: |
Kennedy & Henderson (1992):
DESCRIPTION.-
The lectotype (Pl. 3, figs. 4, 8-9), is a straight body chamber fragment 54 mm long, with a maximum preserved whorl height of 23.5 mm. The whorl section is a compressed oval, with a costal and intercostal whorl breadth to height ratio of 0.84. The ribs are in a distance equal to the whorl height. In profile, the interspaces are symmetrically concave, and terminate at the sharp rib crests, a very distinctive ornament indeed. The ribs are slightly weakened and concave on the dorsum, feebly prorsiradiate on the flanks and strengthened slightly and transverse on the venter. BMNH C51095 (Pl. 3, fig. 7) is also a straight body chamber fragment, 54.5 mm long, with a costal whorl breadth to height ratio of 0.91, and an intercostal whorl breadth to height ratio of 0.95. The rib index is 4.5 to 5, BMNH C51096 (Pl. 4, figs. 16-18) is 80 mm long, with a rib index of 5, BMNH C51097 (Pl. 3, fig. 6) is 34.5 mm long with a rib index of 5. A topotype, BMNH C4051, shows the suture (Text-fig. 1D), which is moderately incised, with broad-stemmed bifid lobes and narrower-necked bifid saddles. |
Discussion / Comments: |
Kennedy & Henderson (1992):
TYPES.-
Lectotype, here designated, is BMNH C51094, the original of Forbes (1846, pl. 11, fig. 1); GSC R10498; paralectotype are BMNH C51095-51099 are G. rugatum (Pl. 3, figs. 1-3; Pl. 4, figs. 13-15). All are from the Valudavur Formation of Pondicherry, south India (ex Kaye and Cuncliffe Collection). Topotypes are BMNH C24200 (ex Kaye Collection), and C4051.
DISCUSSION.-
The Geological Society of London catalogue lists only one specimen under Hamites largesulcatus, and this is designated lectotype above. There are, however, five other specimens in The Natural History Museum collections, labelled, in L.F. Spath’s hand, ‘Diplomoceras (cotypes of Ham. Largesulcatus Forbes)’. In the absence of the original boards to which the specimen were glued, as well as the original labels, these are taken to be syntypes, as Forbes refers to both straight and curved specimens, including what is clearly BMNH C51098 (Pl. 3, figs. 1-3) ‘the most curved specimen bearing two oval varices’ (Forbes 1846, p. 117). This specimen and paralectotype C51099 (Pl. 4, figs. 13-15) are referred to G. rugatum.
One of the specimens of Hamites acuticostatus d’Orbigny, 1847a (pl. 3, figs. 9.10) has a circular whorl section, is 27 mm long, with a whorl height of 15 mm, and a rib index of 3. It appears to belong to the present species. The other fragment illustrated as acuticostratus has a compressed whorl section and a rib index of 4, and seems to be G. rugatum.
The distant, sharp ribbing, with symmetrical interspaces distinguishes G. largesulcatum from all other species of the genus.
OCCURRENCE.-
As for types. |
Systematics: |
41 Subordo Ancyloceratina
Superfamilia Turrilitaceae
Familia Diplomoceratidae
Subfamilia Diplomoceratinae
Genus Diplomoceras
Species Glyptoxoceras largesulcatum
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Synonym list: |
Kennedy & Henderson (1992):
non 1966 Neohamites largesulcatus Forbes. - BRUNNSCHWEILER : p.28 pl. 1, fig. 8;
pl. 8, fig. 3-6;
text-fig. 36 [=G. rugatum]
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Was used in synonym list of: |
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References: |
Forbes,E.. (1846): Report on the Cretaceous fossil invertebrates from southern India, collected by Mr. Kaye and Mr. Cunliffe . Transactions of the Geological Society of London Vol. 2(7) p. 97–174
d'Orbigny,A. (1847): Paléontologie, Pls. 1-6 (Geologie Pls. 4-9). In: M. de Dumont D'Urville, 1846-1 854, Voyage au Pole Sud et dans I'Oceanie sur les corvelles L'Astrolabe et la Zelée pendant les années 1837- 1838-1839-1840 sous le commandément de M. Dumont D'Urville Capitaine du Vaisseau. Pls. 1-9 Eds: Baudry, G..
d'Orbigny,A. (1850): Prodrome de Paléontologie. Stratigraphique universelle des animaux mollusques & rayonnés faisant suitre au cours élémentaire de paléontologie et de géologie stratigraphique. , Cours Élémentaire de Paléontologie et de Géologie Stratigraphiques Vol. 2
Stoliczka,F.. (1866): The fossil Cephalopoda of the Cretaceous rocks of southern India. Ammonitidae with revision of the Nautilidae etc. . Memoirs of the Geological Survey of India, (l), Palaeontologica Indica10-13 p. 155-216
Kossmat,F.. (1895): Untersuchungen über die Südindische Kreideformation. Erster Theil . Beiträge zur Paläontologie Österreich-Ungarns und des Orient Vol. 9 p. 97-203
Matsumoto,T.. (1959): Upper Cretaceous ammonites of California, Part I: Introduction and Baculitidae . Memoirs of the Faculty of Science, Kyushu University, Series D, Geology Vol. 8 p. 91-171
BRUNNSCHWEILER,R.o.. (1966): Upper Cretaceous ammonites from the Carnarvon Basin of Western Australia 1: the heteromorph Lytoceratina. . Bulletin of the Bureau of Mineral Resources, Geology and Geophysics Vol. 58 p. 5-58
COLLIGNON,M.. (1969): Atlas des fossiles caracteristiques de Madagascar (Ammonites). (Campanien inferieur). Vol. 15 p. 216 pp
Phillips,D.. (1977): Catalogue of the type andjigured specimens of Mesozoic Ammonoidea in the British Museum (Natural History). , Trustees of the British Museum (Natural History) p. 220 pp.
Kennedy,W.J.. and Henderson,R.A.. (1992): Heteromorph ammonites from the Upper Maastrichtian of Pondicherry, south India . Palaeontology Vol. 35 p. 693-731
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