. Bulletins of American paleontology. 438 Bulletin 216 a). Text-figs. 36a, b. Septal sutures of Tniftocrras kirki, sp. iio-v., from Upper E. hovjclli Zone of Wide Bay. a) T. cf. kirki, complete immature suture at 8 mm. diameter corresponding to septum of Text-fig. 35 b. b) Holotype, at 28 mm. diameter. Both magnified; U„ small and simple. on llie l)ody chamber of Lhe holotype and, remarkably, only on the nucleus oi' another specimen (PI. 72, fig. 10). Constrictions appear to vary strongly and irregularly, possibly with little genetic depend- ence, and are here consequently not regarded as of m
. Bulletins of American paleontology. 438 Bulletin 216 a). Text-figs. 36a, b. Septal sutures of Tniftocrras kirki, sp. iio-v., from Upper E. hovjclli Zone of Wide Bay. a) T. cf. kirki, complete immature suture at 8 mm. diameter corresponding to septum of Text-fig. 35 b. b) Holotype, at 28 mm. diameter. Both magnified; U„ small and simple. on llie l)ody chamber of Lhe holotype and, remarkably, only on the nucleus oi' another specimen (PI. 72, fig. 10). Constrictions appear to vary strongly and irregularly, possibly with little genetic depend- ence, and are here consequently not regarded as of much taxonomic value. The whorl section is moie c<nnpressed and exiernally more narrowly curved than in at least most examples of T. scissuiu. The septal sutures of three sj)ecimens, all Avhich could be obserxed, are simpler than in the complete specimen of T. sdssum and than sutmes figiued by other authors of any Tmctoccras macroconch of comparable size. Tuietoccras kirki is only known from the upper part of the E. Iioxvelli Zone of 'W'ide liay, and two stratigraphical subspecies are distinguished. There is a clear evolutionary trend in the intensification of the specific "diagnostic" characters, away from 7". scissiim-hke ancestralship, ending in T. kirki jlexicostatum, subs p. nov. Tmetoceras (Tmetoceras) kirki kirki Westermann, sp. et subsp. nov. PI. 72, fig. 4-6; Text-figs. 35, 36. Diagnosis.—A subspecies of T. kirki with moderately spaced. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Paleontological Research Institution (Ithaca, N. Y. ); Columbia University. Ithaca, N. Y. , Paleontological Research Institution [etc. ]
Size: 2619px × 954px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorpaleonto, bookcentury1800, bookdecade1890, bookyear1895
