Jorgechlamys del Río, 2004
DEL RÍO, C. J. 2004. Revision of the large neogene pectinids (Mollusca: Bivalvia) of Eastern Santa Cruz and Chubut Provinces (Patagonia: Argentina). Journal of Paleontology, 78 (4): 690-699, figs. 1-6. [p. 695]
Genus JORGECHLAMYS new genus
Type species.— Jorgechlamys juliana (Ihering, 1907).
Included species.-- Jorgechlamys centralis (Sowerby, 1846) (Early Miocene San Julián and Chenque formations).
Diagnosis.— Shell large, only weakly inflated, higher than long, nearly equivalve or with right valve slightly more inflated than left. Anterior auricle longer than posterior, and free margin of posterior auricles inclined towards anterior; deep byssal notch retained in adults with ctenolium bearing two or three prominent teeth.
Etymology.— From the San Jorge Gulf, the region where this genus is highly abundant and almost restricted.
Occurrence.— San Julián, Monte León, and Chenque formations, Early Miocene, Santa Cruz and Chubut provinces.
Discussion.— The pattern of main plicae and the sculpture of numerous scaly riblets are characters that Jorgechlamys shares with Reticulochlamys n. gen. However, longer anterior auricles, a deep byssal notch retained in adults stage, and development of a functional ctenolium throughout ontogeny differentiate Jorgechlamys from Reticulochlamys. Moreover, shagreen microsculpture is very reduced or even is lacking on most left valves of Jorgechlamys, whereas it is strongly developed on both valves of Reticulochlamys proximus and R. borjasensis n. sp.
Apart from the type species, this new genus includes Pecten centralis Sowerby, 1846. Both species are especially abundant in the San Julián Formation (northern Austral Basin, Early Miocene) and in the basal and middle fossiliferous beds of the Chenque Formation (San Jorge Basin, Early Miocene). CLAUDIA JULIA DEL RÍO, 2004
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Jorgechlamys juliana (Ihering, 1907); C. J. del Río, 2004, Revision of the large neogene pectinids (Mollusca: Bivalvia) of Eastern Santa Cruz and Chubut Provinces (Patagonia: Argentina), figures 5.1-5.5.
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