Posidonotis Losacco, 1942
LOSACCO, U. 1942. Un nuovo genere aaleniano di Aviculidae della Sabina. Rivista Italiana di Paleontologia e Stratigraphia, 48: 9-16.
Posidonotis dainellii Losacco?; S. E. Damborenea, 1987, Early Jurassic Bivalvia of Argentina; Part 2, Superfamilies Pteriacea, Buchiacea and part of Pectinacea, text figure 30.
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«Genus Posidonotis LOSACCO 1942
Type species: Posidonotis dainellii LOSACCO 1942, from the late early Jurassic of Sabina, Italy, by monotypy.
Synonym: Pectinula A. LEANZA 1943 (type species: Pectinula cancellata A. LEANZA 1943, original designation). Emended diagnosis: Bivalves with discoidal flat shells, thin-shelled, with pectinid auricles in both valves. The dorsal margin of the auricles project above the hinge margin. The posterior auricle has a triangular shape with the posterior margin dipping backwards. The anterior auricle is similar to the posterior one in shape and size in adult specimens, but in young shells has a shallow byssal sinus without a ctenolium in the right valve and is larger than the posterior auricle. The main body of the shell is ornamented with regular concentric folds and radial irregular ribs, that increase in number by intercalation. Both types of folds form a reticulate pattern on the shell surface. This ornamentation does not affect the shell thickness and is thus evident in internal moulds. The auricles are only covered by growth lines. The apical angle is larger than 90°.
Included species: This genus, as here understood, includes the following nominal species: Monotis semiplicata HYATT 1894 (non Pecten semiplicatus ALTH 1850); Monotis symmetrica HYATT 1894; Entolium balteatum CRICKMAY 1928; Posidonotis dainellii LOSACCO 1942 and Pectinula cancellata LEANZA 1943.»
DAMBORENEA, S. E. 1987. Early Jurassic Bivalvia of Argentina; Part 2, Superfamilies Pteriacea, Buchiacea and part of Pectinacea. Palaeontographica, Abteilung, A, Palaeozoologie-Stratigraphie, 199 (4-6): 113-216, pls. 1-14. [p. 190, 191]
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