FERNANDEZ Diana Elizabeth
Analysis of the ichnogenus Herradurichnus in quartzites of the Balcarce Formation (lower Silurian) from the Tandilia System of Argentina
GUTIÉRREZ, CAROLINA; PAZOS, PABLO J.; FERNÁNDEZ, DIANA ELIZABETH
BOLLETTINO DELLA SOCIETA PALEONTOLOGICA ITALIANA
SOC PALEONTOLOGICA ITALIANA
Año: 2017 vol. 56
Herradurichnus Poiré & del Valle, 1996 from the Balcarce Formation (lower Paleozoic of the Tandilia System, Argentina) is an enigmatic ichnogenus previously considered as problematic. In this paper, Herradurichnus is revised and key material from collections is redescribed together with other specimens documented in situ from outcrops and quarries. The diagnosis is emended to include its morphological variability. The revised Herradurichnus includes negative, epichnial, U-shaped, V-shaped and parabolic depressions. The specimens are horizontal, subhorizontal or oblique with respect to the bedding plane, and are recorded in fine-grained to very coarse-grained sandstones. Other characteristics are also described in detail. The holotype of Herradurichnus scagliai (Borrello, 1967) has been recovered. Material previously included in Crescentichnus Romano & Whyte, 2015 is now reassigned to Herradurichnus. Xiphosurans and trilobites are disregarded as possible trace-makers of Herradurichnus. The producers were able to construct structures oriented with the convex side of the arch in an opposite sense to the main paleocurrents. This ichnogenus is now reappraised and found to range from the Cambrian to the Lower Silurian of Gondwana.