Conus sp. 1-4

Late Eocene Pagat Member of the Tanjung Formation in the Asem Asem Basin near Satui, Kalimantan
Cross-section through the northern part of the Asem Asem Basin, from the Meratus complex to the north to the Java Sea coast. The Pagat Member is shown in light green. The Late Eocene Conus discovered in the Pagat Member lived in a mud-dominated coastal environment, characterized by bioclasts and low-relief reefs (biostromes). The coexistence of these diverse morphotypes suggests that the modern marine biodiversity hotspot of the central Indo-Pacific began to form much earlier than previously thought, as early as the Late Eocene.

Conus sp. 1, long and slender with narrow shoulders and a bi-concave spire and a pointed spire tip, UA-P1841	Conus kutaiensis Plate 4 figs. 8-10 mm. 76 Miocene Sungai Kari Orang, Kalimantan, E. Borneo

Conus sp. 2, with broad shoulders and a flat spire, UA-P1837	Conus gracilispira SMF 12-529b (Boettger, 1875) - Eocene – Pengaron (Borneo)

Conus sp. 3, obconical, exhibiting a low conical (bi-convex) spire and a cyrtoconoid spire, UA-P1844

Conus sp. 4, with a narrow base, broad shoulders, and a low turbinate spire, UA-P1847	Conus djarianensis Miocene

Conus sp.

This specimen consists of a very rough natural cast of a Conus probably related to C. deperditus of Bruguiére, which is found in Eocene areas. It is of broadly conical form, exhibiting the last three volutions, and furnished with a suture which, in the cast, is deeply canaliculated or concave. There are no sculpture-markings of any kind preserved, nor is the anterior end complete, although its general contour and facies would suggest its connection with a form like C. deperditus. Dimensions. Maximum diameter 35 mm. Loc. Garadimi. Collector. Captain Lelean ⁽²⁾.

In 1905, British malacologist Hugh C. Fulton published a scientific paper entitled "On new Species of Helicarion, ...". In this publication, he documented the discovery of a fossil of Conus sp. from Eocene sediments of Borneo. The fossil examined by Fulton was not an intact shell, but rather a very crude natural cast. Fulton hypothesized that this Bornean specimen was closely related to Conus deperditus (originally described by Bruguière), a typical Eocene species. The crude fossil cast of Conus sp. described by Hugh C. Fulton in 1905 was originally part of the Keppel Collection. Much of this historic collection, which includes malacological specimens and types described by Fulton and other British scholars of the time (such as Sowerby), has since been incorporated into and is now housed at the Natural History Museum, London (NHMUK)⁽²⁾.

Bibliografia