Conus macneili

Conus macneili (Kanno, O’hara, Caagusan, 1982)

Conus aff. djarianensis by Macneil 1960, p. 121, pl. 6, figs. 17 and 22 is similar ⁽¹⁾.

Descrizione.

Shell medium-sized, rather slender in shape, with spire of medium height. Protoconch missing on the type except for a small fragment of the last whorl which is smooth. Aperture rather narrow, but slightly broader at siphonal end than at anal end. Anal notch very deep. Spire sculptured by four incised spiral lines on the subsutural slope, of which the first and fourth are rather weak compared with the others ; periphery of each whorl of spire consists of a distinct cord which is sculptured by very wide nodes on the young whorls, but these disappear on the last whorl. Sculpture on the body whorl consists of depressed spiral grooves which covers almost the lower half of the body whorl, and are made semipunctate by fine lattice-like crossbars ; spiral grooves are narrower than the smooth, fiat-topped interspaces on the upper part of the whorl, but the interspaces gradually become narrow near the base ; finally it becomes as wide as or wider than the spiral grooves at the base of the whorl where the interspaces change

from fiat-topped to rounded⁽¹⁾.

Remarks: This species is more or less similar to C. djarianensis MARTIN ( 1895, p. 20, pl. 3, figs. 45-50) in general features, but the former differs from the latter in having the acute periphery of whorls, crescent-shaped sculptures on the subsutural slope, and more developed spiral grooves on the body whorl⁽¹⁾.

C. tessulatus BORN (POPENOE and KLEINPELL, 1 778, pl. II , figs. 137 and 141), from the Vigo Formation in Luzon is also somewhat related to this species, but the more developed spiral grooves on the body whorl serve to distinguish it from the present new species⁽¹⁾.

This specific name is dedicated to Dr. Stearns F. MACNEIL, who dedicated himself to study the Tertiary molluscan fauna of Okinawa Island, which is an important keystone between the temperate and tropical molluscan fauna⁽¹⁾.

Geographic distribution :shinzato Pliocene in Okinawa, and the Tartaro Formation in Luzon Island.

Geologic range:-Upper Miocene, Pliocene.

Reg. No : JUE 10061 (holotype) ; JUE 10062 (paratype)

Conus macneili ⁽¹⁾

JUE 10061 (holotype)

p. 120. pl. XVIII. figs. 8a-c

Conus aff. djarianensis ⁽²⁾

Macneil 1960, p. 121; pl. 6, figs. 17 and 22

?Conus djarianensis Martin, 1895, Samml. Geol., Reichsmus. Leiden, v. 1, no. 5, p. 20, pl. 3, figs. 45-50.

Conus djarianensis. Nomura, 1935, Tohoku Imp. Univ. Sci. Repts., 2d ser., v. 18, no. 2, p. 105, pl. 7, figs. 13a, b, 14a, b.

Whether or not the species figured by Nomura is identical with the form described by Martin from the Miocene of Java the writer is not prepared to say. The Okinawan species appears to be identical with the Formosan species, however. Nomura described another species, C. bonus, which compares closely with the Okinawan form in shape, but C. bonus is stated to have fine spiral lines all over, a character that is not evident from the figures. The Okinawan species has only coarse spirals and those only on the lower part of the whorl, the condition described for C. djarianensis.

Distribution: Miocene, ?Java, (Yonabaru clay member) Okinawa; Pliocene, (Byoritzu beds) Formosa.

Localities: Yonabaru clay member, 17451 (figured) ⁽²⁾.

All the photographic material illustrated has been inserted thanks to the work of Takuma Haga and with his consent:

Takuma Haga

Division of Paleoenvironment and Paleoecology,
Department of Geology and Paleontology,
National Museum of Nature and Science, Tokyo
Principal Researcher,
Senior curator of invertebrate fossils
Takuma HAGA Ph.D.
(associate editor, Venus / Molluscan Research / Molluscan Diversity)

Conus macneili

National Museum of Nature and Science PM 16295

Tartaro Formation (Middle Pliocene)

Bulacan, Luzon (Philippine)

Conus macneili

National Museum of Nature and Science PM 16295

Tartaro Formation (Middle Pliocene)

Bulacan, Luzon (Philippine)

Note by Takuma Haga:

Regarding identification, I am not perfectly sure these specimens are safely identified as Conus macneili. The form and sculptures on siphon somewhat differ from what of the holotype depicted in Kanno et al. (1982).

The UV-reconstructed colour pattern shows that the specimens of PM 16295 are very close to, or even identifiable with a Recent species Conus voluminalis (Reeve, 1843).