HUANTRAICONELLA N. GEN. DEL TERCIARIO INFERIOR (OSTRACODA, BUNTONIlNAE) (DANIANO) DE ARGENTINA

Alwine Bertels

Abstract


The new genus Huantraiconella, with rhe species Huantraiconella prima, is described and figured. The new genus shows a similar anatomy with the other taxa included in the subfamily Buntoniinae Apostolescu, 1961. The fol1owing features are typical for the new genus: Carapace of medium to large size, piriform, inflated; surface strongly reticulate, with Iongitudinal ridges strongly developed forming three low and broad longitudinal plications: one dorsal ridge, a second medium plication directed from the antero-ventral to the postero- dorsal region and a third ventral plication or fold; left valve larger than right; eye spots and subcentral tubercule present but slightly developed; strong post-ocular furrow behind the eye tubercule which breacks the continuity from the anterior and dorsal outline; inner lamella wide and -regular.v-with numerous marginal pore-canals, simple, curved and unbranched, no vestibule, selvage subperipheral; hinge holamphidont; central scars forrned by four adductor muscle scars and one frontal U shape scar; sexual dimorphism strong. Huantraiconella n. gen. resembles Buntonia Howe, 1935 in muscle scars and marginal zone characters; it differs in shape, by the presence of eye spots, subeerrtral rubercules and post-ocular furrow and a lack of bar crenuJations; from Cytberetta Mueller, J894 it differs by lacking the wide and sinous marginal area and from Mosaeleberis Deroo, 1966 by differ- ences in outline and hinge-structure, Samples from me Roca Formation, exposed in many outcrops of North Patagonia show that Huantraiconella prima is abundant, distinctive, and can be used as a stratigraphic guide fossil in the Argentina Lower Tertiary (Danian ), since it is restricted to strata from this age.

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