Hoploscaphites indicus Forbes 1846 (TaxonConcept

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Species Hoploscaphites indicus Forbes 1846

Diagnosis / Definition:

Kennedy & Henderson (1992):
DESCRIPTION.- The holotype is a body chamber fragment 52 mm long, with traces of a spear-filled nucleus preserved in the dorsal impressed zone. Coiling appears to have been moderately involute, with the whorls in contact, although the body chamber itself has what might be interpreted as an eccentric umbilical seam. The whorl section is depressed, with a rounded-rectangular cross section, the whorl breadth to height ratio 2.24, the greatest breadth at mid-flank. The umbilicus is deep, with a rounded wall merging with a broadly rounded umbilical shoulder. The flanks are flattened, the ventrolateral shoulders broadly rounded, and the broad venter flattened. Ornament consists of fine, sharp ribs, narrower than the interspaces. Most ribs arise at the umbilical seam, are initially weak, but strengthen to the umbilical shoulder, where a few bifurcate, and at least one bears a tiny tubercle. The ribs are variably prorsiradiate on the flank, and there are rare bifurcations and intercalations low on the flank. Groups of three or four ribs converge on, and are linked at horn-like ventral clavi (of which only two survive on the fragment), with about five nontuberculate ribs between clavi. This bunching of ribs at clavi produces marked irregularities in rib spacing on the outermost flanks and ventrolateral shoulder. The ventral clavi are linked across the venter by four or five looped ribs, the adapical ones being concave, the adapertural ones being convex on the shoulders, before passing straight across the venter. They occasionally bifurcate, and show minor irregularities where they approach the ventral tubercles. Little can be made of the fragmentary inner whorl, other than the outline of a tangential section. This suggests rather more compressed phragmocone whorls, with similar ribs to the body chamber and ventral tubercles. No trace of the suture survives.

Discussion / Comments:

Kennedy & Henderson (1992):
TYPE.- Holotype, by monotypy, is BMNH C51093, the original of Forbes (1846, pl. 8, fig. 9), GSC R10489, from the Valudavur Formation of Pondicherry, south India (ex Kaye and Cunliffe Collection). DISCUSSION.- The fragmentary holotype, with its fine, sharp, looped ribs and depressed whorl section stands apart from the outer scaphitids in the Pondicherry fauna. In general style, the ornament is closest to certain late Campanian Hoploscaphites which, although much older, have the same basic style of ribs and tubercles, as in Hoploscaphites ikorfatensis Birkelund, 1965 (p. 102, pl. 24, figs. 1-4; pl. 25, figs. 1-2; pl. 26, fig. 1; text-fig. 59, 93, 121.3), or various forms illustrated by Schlüter (1871, pl. 27, figs. 5-7). However, the depressed whorls and very distant nodes of H. indicus distinguish it from all of these. OCCURRENCE.- As for type.

Systematics:

41
Subordo Ancyloceratina
  Superfamilia Scaphitaceae
   Familia Scaphitidae
    Subfamilia Scaphitinae
     Genus Hoploscaphites
      Species Hoploscaphites indicus

Synonym list:

Kennedy & Henderson (1992):

1846 Ammonites? indicus Forbes. - Forbes : p.114 pl. 8; fig. 9

1850 Ammonites indicus Forbes. - d'Orbigny : p.213

1898 Holcodiscus indicus Forbes. - Kossmat : 35(142)

1925 Kossmaticeras indicum Forbes. - Diener : p.98

1977 Hoploscaphites indicum Forbes. - Phillips : p.90

1992 Hoploscaphites? indicus Forbes. - Kennedy & Henderson : p.716 pl. 6; fig. 7-8

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. (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

Kossmat,F.. (1898):
Untersuchungen über die Südindische Kreideformation. Dritter Theil. . Beiträge zur Paläontologie Österreich-Ungarns und des Orient Vol. 11 p. 89-152

Diener,C.. (1925):
Ammonoidea neocretacea . Fossilium Cat, (1: Animalia) Vol. 29 p. 244 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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