NMITA: Neogene Marine Biota of Tropical America

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To view the shell in 3 orientations. To view a SEM image of the protoconch.

Photograph: (Jung, 1989, Fig. 289.4) Scale bar is 1 mm. Image is of NMB H17264. NMB locality 17449: La Bomba, Río Banano, Limón Province, Costa Rica; Río Banano fm. Height: 8.3 mm; width: 4.4 mm.

Synonyms: Strombina lloydsmithi Pilsbry & Brown, 1917, p. 33, pl.5, fig. 4.

Morphologic Description: Shell small and stout. Protoconch consists of 3 volutions; its outer lip is sinusigerous. Teleoconch whorls up to 6. Except for the last part of the body whorl all the whorls are sculptured by axial ribs. On early spire whorls these ribs are orthocline, but they gradually become somewhat prosocline on succeeding whorls. There are about 14 axial ribs on early spire whorls and up to 20 ribs on late spire whorls. On late teleoconch whorls there may be a few faint spiral grooves in the spaces between the axial ribs. Dorsal hump of body whorl moderately prominent. Hump to the left of aperture present, but not conspicuous, marked by the 2 or 3 last axial ribs. Dorsal part of body whorl smooth except for spiral cords at its base. Behind the thickened outer lip there are two axial swellings, which are crossed by spiral grooves. Outer lip somewhat extended adapically; its inner surface with elongated denticles. Columellar callus well developed, with denticles. Parietal callus prominent, with a ridge bordering the posterior canal. Anterior canal short, slightly recurved.

Holotype: ANSP 3040 (Near Cartagen, northern Colombia, age uncertain but probably from beds of late Miocene or early Pliocene age).

Distribution: Early Pliocene: Río Banano Formation, Río Banano, Limón Province, Costa Rica; Probably late Miocene or early Pliocene age: Beds near Cartagena, northern Colombia.

Return to the Species Listing of the subgenus Sinaxila.