Conus yuleianus (Noetling, 1901)

The shell is of small size, double conical in shape consisting of an elevated turreted spire and a large accuminate body whorl. Embryonic whorls not observed. The spire consist of about seven flat whorls, separated by a sharp suture; the surface of the whorls forms a steep angle with the suture which becomes only slightly flatter on the later ones; the profile line is slightly curved but sharply step-like because each succeeding whorl does not reach up to the keel of the preceding one. The surface is covered with numerous exceedingly fine revolving lines ⁽²⁾.

The body whorl is high, broad at the posterior, acuminate at the anterior end, divided by a sharp keel into a small posterior part, gently sloping towards the suture and a long anterior one, sloping in opposite direction. The profile line of the body whorl forms, therefore, an obtuse angle having two straight sides, a shorter posterior and larger anterior one. Surface perfectly smooth except for numerous striae of growth; there appear, however, a few indistinct spiral lines on the anterior end ⁽²⁾.

Aperture narrow, anteriorly apparently not expanded ⁽²⁾.

Bemarks ⁽²⁾. I hesitated for a long time before I distinguished this species under a separate name, but on examining and comparing its features with those of the other species hero described, I found that it would be impossible to unite it with any one of them. In shape Conus yuleianus is almost the same as Conus hanza except that the spire is certainly a little lower, the difference in the apical angle being about 10°; a more distinctive feature is, however, the ornamentation of the body whorl which is covered with engraved lines in Conus hanza, while it is perfectly smooth except for a few spiral lines on the anterior end in Conus yuleianus. On the other hand, it bears by the latter character a great similarity to Cunus malaccanus, but the spire of this species is much lower and the apical angle larger than in Conus yuleianus; the spire of this species is also much less step-like than in Conust malaccanus ⁽²⁾.

From Conus avaensis it differs by a higher spire, composed of step-like whorls, covered with much finer revolving striae ⁽²⁾.

The specimen is too ill-preserved to allow of a comparison with either living or fossil species ⁽²⁾.

There is some doubt as to whether this beautiful shell should be classified as a Leptoconus or Lithoconus. The specific identity of one of the specimens figured in Noetling’s monograph (pl. xxiii, fig. ‘21) is doubtful ⁽¹⁾.

The fairly well preserved specimen shown in fig. 22, which must be regarded as the type, is from Kama. The incomplete specimen shown in fig. 21, of which the specific identity is doubtful, is from the so-called “ zone of Aricia humerosa ” presumably near Thayetmyo ⁽¹⁾.

Found only at Kama (Kama stage) (Miocene of Myanmar).

Conus yuleianus Plate XXIII fig. 21 Zone of Aricia humerosa ” presumably near Thayetmyo. Lower Miocene	Conus yuleianus Plate XXIII fig. 22 Kama Lower Miocene

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Bibliografia

· (1) - E. Vredenburg. (1921). Results of a revision of some portions of Dr Noetling's second monograph on the Tertiary fauna of Burma. Records of the Geological Survey of India 51:224-302 pag. 283

· (2) - Noetling, Pal. Ind., new ser., Vol. I, part 3, p, 363, pl. xxiii fig. 22

· (3) - Original Publication: The Annals and magazine of natural history; zoology, botany, and geology

· (4) - H.H. Hayden (1920)