Helicerina, Bronnimann and Masse, 1968
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publication ID |
https://doi.org/ 10.4202/app.2009.0094 |
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persistent identifier |
https://treatment.plazi.org/id/A2018795-2146-FFB3-FCEE-F9149192FD1A |
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treatment provided by |
Felipe |
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scientific name |
Helicerina |
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Helicerina isp. B
Fig. 2D View Fig .
Material.— Four specimens in thin section CPBA−N ° 20675, 20676, Rahue creek ( Fig. 1 View Fig , 36 ° 01.762'S, 69 ° 59.393'W) GoogleMaps .
Description.—Microcoprolite with circular outline and a cross section of 500 to 800 µm in diameter. Due to the poor state of preservation it is not possible to accurately determine the exact shape and number of canals. However, it is possible to notice three canals in the symmetry plane interconnected by doi: 10.4202/app.2009.0094
a pronounced dorsal groove; and some canals interconnected by thinner grooves, two of them joined to the first angular canal at each side of the symmetry plane ( Fig. 2D View Fig ).
Comparisons.— Helicerina isp. B shares similarities with H. kainachensis Fenninger and Hubmann, 1994 from the Santonian–Campanian and with H. ruttei Schweigert, 1997 (see Fig. 3 View Fig ) from the Miocene. Even when the preservation of the samples does not allow their proper classification, the ichnospecies from the Vaca Muerta Formation presents a circular canal joined to the first angular canal at each side of the symmetry plane, which permits to assure that it is a possible new ichnospecies.
Stratigraphic and geographic range.— Helicerina isp. B was recognised in levels corresponding to the Lissonia riveroi and Olcostephanus (Olcostephanus) atherstoni zones (early Valanginian) of the Vaca Muerta Formation ( Fig. 1 View Fig ).
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