Stromboidea

• Rostellariidae
  • Amplogladius
    • Amplogladius morgani (Cossmann & Pissarro, 1909)

Original Description of Rostellaria (Amplogladius) Morgani, Cossmann, M. & Pissarro, G. 1909, p. 43:

• “Large, slender, ovoid-fusiform; spire elongated, regularly conical; spire whorls flat, their height equal to two-fifth of their width, separated by linear sutures bordered by a thin depressed swelling; they bear straight, axial ribs, most clearly visible anteriorly, rather irregular, constricted towards the anterior suture, interspersed with coarse varices which do not coincide from whorl to whorl. Body-whorl very large, ventricose, compressed, gibbous opposite the outer lip, so that its width exceeds its thickness; its whole surface is smooth. Aperture terminated at its posterior angle by a long channel, which extends almost as far as the penultimate whorl; columella excavated; columellar margin forming a thin, callous swelling, almost detached from the base; outer lip sinuous, externally bordered by a broad callus.”

Locus typicus: “Lower fossifilerous band in zone 2; three miles east of the old coal-pit near Leilan” (Lainyan), Pakistan

Stratum typicum: Danian, lower Paleocene

pl. IV, figs. 24, 25:

Comments by Cossmann & Pissarro, p. 44:

• “Although the solitary specimen of this species has its aperture half broken, yet its generic attribution gives rise to no hesitation. It is of considerable interest as it indicates the presence in India of a section that hitherto seemed restricted to the Paris basin, the Loíre-Inférieure, and the Switzerland. The prolongation of the outer lip recalls that of the bartonian R. athleta, d’Orb., though with a lesser degree of curvature; moreover, the spire bears obsolete ribs and shallow varices that do not exist in the generic type; but the general shape of R. Morgani is quite identical with that of the Parisian species, and not nearly so slender as that of Rostellaria, sensu stricto, whose spire is slightly extraconical. The feeble development of the wing, which does not even reach the total height of the penultimate whorl, readily distinguishes R. Morgani from the species belonging to the sub-genus Hippochrene which is characterised by a widely expanded wing. The fragmentary cast doubtfully referred by d’Archiac and Haime to Rostellaria columbina (loc. cit., Pl. XXX, fig. 12 a) might possibly represent an Ampullogladius [sic]. But it probably was obtained from a different geological horizon, that of Laki or Khirtar limestones in which some at least of these fossils certainly belong to the genus Hippochrene, and are therefore closely related to Rostellaria columbaria. Mr. Vredenburg informs us that in the “Laki limestone” which he regards as Lutetian and which is newer than the Ranikot, he has observed a similar cast bearing the impression of a very large Hippocrene-shaped wing, which speaks in favour of the accuracy of d’Archiac and Haime’s interpretation.”

References

• Cossmann, Pissarro & Vredenburg, 1909