Phthanoncoceras ellipticurn (Lossen 1860), Lasnamiigian (Late Llanvirn), glacial erratic boulders of Baltic origin, a-b: Lectotype MB C.873 in lateral and ventral views; Żary (Lower Silesia). c: Longitudinally split specimen MB C.869, Platte Nr. 3 of H. PATRUmIY, Bydgoszcz. d-e: Juvenile specimen MB C.872 in lateral and ventral views, same boulder.

Reconstructions of adult conchs of Lasnamigian Baltic oncoceratids - Phthanoncoceras ellipticum (Lossen, 1860).

Diagnoza

Long living chamber, only a little less than half of the whole conch lenght. Conch gently curved, compression index at adult stages is about 0,7.

Porównanie

Autekologia

Występowanie geograficzne

The nautiloid assemblage from this erratic boulder contains also a longiconic species of Clinoceras and the
ellesmeroceratid Cochlioceras,both common in the Lasnamigian.
Along with the erratic boulder material,
some specimens of the species are known
which were collected from in situ outcrops of the Folkeslunda Limestone of
southern Sweden (they are in the  collection of the Naturhistoriska Riksmuseet, Stockholm).
The species seems thus to range from the
early Kundan to late Lasnamigian of at
least the western Baltic area. 

Zasięg czasowy

Materiały muzealne

Literatura

Dzik J.,  Kiselew G.N. 1995. The Baltic nautiloids Cyrtoceras ellipticum LOSSEN 1860, C. priscum Eichwald 1861, and Orthoceras damesi Krause 1877 Palaont. Z 69: 61-71, Stuttgart.