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Species Kitchinites (Kitchinites) darwini Steinmann 1895 | ||||||
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| Diagnosis / Definition: | ||||||
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MACELLARI (1986): SUPPLEMENTARY DESCRIPTION.- Moderately evolute species with a compressed whorl section (Figure 19.1, Table 5). Ribs incised and forwardly projected in the ventral portion of the shell but disappearing towards the umbilicus. The ribs are slightly prorsiradiate to rectiradiate on the inner portion of the flank (when present), but become strongly prorsiradiate on the outer third of the flank. Living chamber with radial ribs preserved across the entire venter. Five deep constrictions observed in the last whorl. The constrictions (which cut two or three previous ribs) are preceded by a raised undulation of the shell, are prorsiradiate to rectiradiate in the lower half of the flank, and become strongly projected forward near the center of the flank. Suture complicated, with saddle E/L almost symmetrically bifid; L deep but not as deep as in Maorites. There is only a slight reduction in size from E/L to L/U, but after this saddle the umbilical elements become much smaller (Figure 18). |
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| Discussion / Comments: | ||||||
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MACELLARI (1986): LECTOTYPE.- Puzosia darwini Steinmann, 1895, P1. 5, figs. 3a, b, by subsequent designation of Howarth, 1966, p. 60. Material.- 20 specimens, mostly well preserved. REMARKS.- The presence of K. (Kitchinites) darwini in the James Ross area was first reported by Howarth (1966) (Vega Island) and then by Del Valle et al. (1976) (Seymour Island). Howarth (1966, p. 60) pointed out that the original specimens of K. (K.) darwini from Quiriquina, described by Steinmann (1895), could not be located in Europe or Chile. I obtained several photographs and a cast of this species from the type locality and, except for a slightly more compressed section (Figure 19, Table 5), other features of the shell are identical to those of the Antarctic specimens. One of the specimens from Vega Island described by Howarth (1966, figs. 3b, 4) (see Figure 19, BM C72791) has a more inflated whorl section, particularly near the dorsal part of the shell. In addition, the ribs are less incised than what is normally found in this species. The other specimen from Vega Island (Howarth, 1966, figs. 2a, b) is identical to specimens from Seymour Island. K. (Kitchinites) darwini is similar to K. (K.) angustus (Marshall) from the Mata Series of New Zealand. According to Henderson (1 970, p. 34-35), K. (K.) angustus differs from K. (K.) darwini by the prorsiradiate inclination of the constrictions as they cross the dorsal flanks, by the presence of umbilical tubercles, and by having more compressed whorls at corresponding stages of growth. K. (K.) darwini differs from K. (K.) angolaensis Howarth from the Campanian of Egito, Angola (in Howarth, 1965, p. 386-387, Pl.2, figs. 4- 6), by the presence of a larger umbilicus and much stronger constrictions. K. (K.) pondicherryanus (Kossmat) from the late Cretaceous of India (in Kossmat, 1897, Pl. 6 (1 7), figs. 6a-c) can be distinguished from this species because its ribs are continuous throughout the flank. Also the constrictions are more rectiradiate than in K. (K.) darwini, but the suture and degree of compression are nearly identical. K. (K.) brevicostatus (Marshall) from the Upper Cretaceous of New Zealand has a more inflated whorl section and ribs that do not disappear in the middle of the flank. K. (K.) spathi Henderson and McNamara (in Henderson and McNamara, 1985, Pl. 4, figs. 5-6, 9-10, 14-1 5) is almost identical to K. (K.) darwini. The minor differences appear to be fewer ribs and a slightly more evolute shell in K. (K.) spathi. LOCALITIES.- E, F, H, 47,49, 107, 142, 143, 173, 174, 175, 382, 383, 384, 385, 394,423, 427, 428, 429, 432, K-84, L-84, M-84. Also present in Vega Island (Howarth, 1966; Del Valle et al., 1982). STRATIGRAPHIC DISTRIBUTION.- Lopez de Bertodano Formation; in Vega Island it is found in the Gunnarites antarcticus Zone (of Olivero, 1981) and in Seymour Island in the Pachydiscus ootacodensis Zone, indicating an age extending possibly from the middle Campanian to the early Maastrichtian. |
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| Systematics: | ||||||
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50 Ordo Ammonoidea Subordo Ammonitina Superfamilia Desmocerataceae Familia Desmoceratidae Subfamilia Puzosiinae Genus Kitchinites Species Kitchinites (Kitchinites) darwini |
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| Synonym list: | ||||||
| MACELLARI (1986): 1895 Puzosia darwini Philippi. - STEINMANN : p. 73-74 pl. 5; fig. 3a, b
1966 Kitchinites darwini Steinmann. - Howarth : p. 59-61 fig. 2a, b, 3b, 4
p 1976 Kitchinites darwini Steinmann. - Valle et al. : p. 5-7 pl. 1;
pl. 4, fig. a, b;
pl. 5, fig. a
1986 Kitchinites (Kitchinites) darwini Steinmann. - MACELLARI : p. 18, 21, 22, 26 fig. 14.2-14.3, 17.1-17.3, 18, 19.1, 22.2
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| Stratigraphy - relative ages: | ||||||
| ? upper Maastrichtian ? middle Campanian: MACELLARI (1986) |
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| References: | ||||||
STEINMANN,G.. (1895): Howarth,M.D.. (1966): Valle,R.D..; Fourcade,N.H.. and Rinaldi,C.A.. (1976): MACELLARI,C.E.. (1986): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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