Fig. 5 in Early Tremadocian cephalopods from Santa Rosita Formation in NW Argentina: the oldest record for South America

Fig. 5. Ellesmeroceratid cephalopod Ellesmeroceras humahuacaensis sp. nov. from the lower Tremadocian (Ordovician) of Quebrada de Arenal, Trancas section, Cordillera Oriental, Jujuy, Argentina. A. CEGH-UNC 27494a in lateral view (coated with ammonium chloride A1, without coating A2), intermediate view between lateral and dorsal (A3). Note the sutural lateral lobes and the bent apical part of the conch. B. CEGH-UNC 27494c in dorsal view. Note the specimen is crossed by a fracture in the rock that was fixed. C. CEGH-UNC 27501 in dorsal view with the apical part rather deformed. D. CEGHUNC 27496a in dorsal view. E. CEGH-UNC 27496c in dorsal view, partially broken externally. F. CEGH-UNC 27491b in dorsal view, with shell wall. G. CEGH-UNC 27491c in external view, showing the growth lines. Scale bars 2 mm.