NMITA: Neogene Marine Biota of Tropical America

Strombina (Lirastrombina) musanica Olsson, 1922

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

Photograph: (Jung, 1989, Fig. 156.7) Scale bar is 1.6 mm. Image is of USNM 412965. USGS locality 5882g: Río Banano, Limón Province, Costa Rica; Río Banano fm. Height: 18.6 mm; width: 7.8 mm.

Synonyms: Strombina costaricensis musanica Olsson, 1922, pl 129, pl. 10, figs. 26, 27.

Morphologic Descriptions: Of small size, moderately slender. Protoconch consists of 1 1/2 volutions; outer lip is somewhat sigmoid. Teleoconch whorls up to 8 1/2. The first 4 or 5 teleoconch whorls are smooth except for faint, othocline to slightly prosocline growth lines. Their profile is convex. The succeeding sculptured whorls are slightly shouldered. The sculpture consists of narrow, orthocline to slightly prosocline axial ribs extending from suture to suture. There are 15 to 19 axial ribs per whorl. After one or two whorls sculptured only by axial ribs, spiral threads are introduced which become more and more prominent on the adapical part of the whorl, but they may cover the entire height of the whorl. On the body whorl the axial ribs are restricted to the adapical part and are crossed by spiral threads. Near the base of the body whorl there are prominent spiral cords. The central portion of the body whorl is smooth and constricted thus producing a concave spiral belt. Dorsal hump of body whorl not conspicuous. Sometimes the body whorl and one or two earlier whorls are covered by a rhombic pattern of incised lines. Outer lip thickened, only slightly extended adapically, with heavy denticles on its inner surface. Columellar callus well developed, without denticles. Parietal callus thin. Anterior canal fairly long, only slightly recurved.

Lectotype: PRI 21064 Height: 15.0 mm width: 6.6 mm. (Locality: NMB 17454, Río Banano, Limón Province, Costa Rica. Río Banano Formation. early Pliocene.)

Distribution: early Pliocene: Río Banano Formation, Costa Rica.

Return to the Species Listing of the subgenus Lirastrombina.