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Species Kitchinites spengleri Fatmi & Kennedy 1999 | ||||||
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| Diagnosis / Definition: | ||||||
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FATMI & Kennedy (1999): Diagnosis.-Compressed, moderately evolute, early phragmocone whorls smooth but for widely separated straight narrow constrictions and narrow collar-ribs that are markedly strengthened over venter. Later phragmocone whorls and body chamber with strong, widely separated primary ribs with up to eight similar but shorter intercalated ribs between, prominent on outermost flank and venter. Feeble constrictions associated with primary ribs. Ribs and constrictions near-straight and prorsiradiate on flanks, transverse to very feebly convex on venter. Description. -Coiling moderately evolute, umbilicus 21-29 percent of diameter (Table 3), shallow, wall low, flattened, inclined outwards. Whorl section compressed, whorl breadth to height ratio 0.61-0.68, greatest breadth below mid-flank. Inner flanks feebly convex, middle-outer flanks flattened, subparallel, ventrolateral shoulders and venter broadly rounded. First growth stage extends from 33 mm (GSP 1040: Fig. 6.1, 6.2) to 48 rum. Distant, narrow primary ribs, four per half whorl, are feebly concave across ventrolateral shoulder, thickened markedly and transverse to very feebly convex across venter. Primary ribs succeeded by very feeble constrictions. Ill-defined, distant primary ribs may occur between constrictions in some individuals. In second growth stage, primary ribs coarsen markedly, three to seven ribs intercalate between, arising as mere striae on inner to middle flanks, strengthening to match primary ribs over outermost flanks and venter to give total of 30 ribs per half whorl at ventrolateral shoulder. Constrictions persist, but conspicuous only on outer flank and venter. Holotype (Fig. 6.14-6.16) may be incomplete adult; primary ribs crowd, with numbers of intercalated ribs reducing progressively. Suture deeply and intricately subdivided, with narrow-stemmed elements. Etymology.-For Erich Spengler, one of the pioneers of Cretaceous geology and palaeontology in Assam. Types.-Holotype is GSP 1039 (Fig. 6.14-6.16), paratypes GSC 1040-1045, all from the Upper Maastrichtian Korara Shale of Goth Haji Ismail, southern Pab Range, Pakistan. |
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| Discussion / Comments: | ||||||
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FATMI & Kennedy (1999): Discussion.-The distinctive ontogenetic changes are seen in a number of other Maastrichtian Kitchinites, but generally at much greater diameters. Kitchinites angustus (Marshall, 1926) (see Henderson, 1970, p. 34, pl. 14, fig. 1; text-fig. 10a) has a near-smooth stage that extends to 80 mm diameter, and a ribbed stage in which all ribs are deflected strongly forwards on the outermost flank and venter to become markedly concave, crossing the venter in a narrow chevron. Kitchinites brevicostatus (Marshall, 1926) (see Henderson, 1970, p. 32, pl. 13, fig. 4; textfig. 10b) has many long primary ribs in addition to the collar ribs through much of its ontogeny and the ribs project more markedly over the ventrolateral shoulder than in the present species. Kitchinites spathi Henderson and McNamara, 1985 (p. 57, pl. 4, figs. 5, 6, 9, 10, 14; text-figs. 6b, c) has the ribs much more markedly projected and concave on the outermost flanks and ventrolateral shoulders, with much coarser intercalated ribs. Constriction and rib direction, notably the marked projection on outermost flanks and ventrolateral shoulders also serve to separate the Antarctic Peninsula species described by Macellari (1986). Kitchinites pondicherryanus (Kossmat, 1897) (see revision in Kennedy and Henderson, 1992a, p. 407, pl. 3, figs. 1012; text-fig. 4a) from the Upper Maastrichtian of Pondicherry, south India, has the relatively straight ribs of the present species but appears to have been much smaller with many more primaries in the ribbed stage, and fewer secondaries, plus only five constrictions per whorl |
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| Systematics: | ||||||
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40 Ordo Ammonoidea Subordo Ammonitina Superfamilia Desmocerataceae Familia Desmoceratidae Subfamilia Puzosiinae Genus Kitchinites Species Kitchinites spengleri 47 Ordo Ammonoidea Subordo Ammonitina Superfamilia Desmocerataceae Familia Desmoceratidae Species Kitchinites spengleri |
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| Synonym list: | ||||||
| FATMI & Kennedy (1999): 1999 Kitchinites n sp. spengleri Fatmi & Kennedy. - FATMI & Kennedy : figs. 5.3-5.5, 6.1, 6.2, 6.8-6.16, 7.1-7.3, 14.3, 15.1
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| Stratigraphy - relative ages: | ||||||
| upper Maastrichtian: FATMI & Kennedy (1999) |
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| References: | ||||||
FATMI,A.N.. and Kennedy,W.J.. (1999): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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