Phosphatized bromalites from the lower Paleozoic of NW Argentina

 

Authors: Voldman GG, Zeballo FJ, Vaccari NE, Carrera MG, Knaust D, Hunt AP

Article in press: Received 4 February 2025; Accepted in revised form 15 September 2025; Online 9 November 2025

Keywords: feces, trace fossil, paleoecology, Cambrian, Ordovician,

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Abstract

Bromalites, the fossilized remains of material sourced from the digestive system of organisms, are often overlooked in micropaleontological samples, but offer valuable insights into the paleoecology of ancient ecosystems. This study focuses on Furongian (upper Cambrian) to Floian (Lower Ordovician) bromalites from the Central Andean Basin of the Eastern Cordillera, NW Argentina. In many samples, bromalites dominate as the primary organic residue after acid treatment. The recovered assemblage consists of 276 coprolites and cololites, including Anfractuosocoprolithus aphelus Bischoff, A. cf. aphelus Bischoff, Coprulus oblongus Mayer, Hyperocoprolithus levigatus Bischoff, Isvilina kanygini Schallreuter, Rhizocorallites articularis Müller, Transmeristocoprus multifidus Bischoff, Transmeristocoprus? isp., and three unidentified ichnospecies (A, B, and C). Furthermore, a new ichnogenus, Helicobromites, is established, with the description of a new ichnospecies, H. andinus. These ichnospecies may reflect the activity of mollusks as well as that of poorly documented organisms such as ascidian tunicates, polychaetes, holothurians, and perhaps nektonic vertebrates. In this way, the coprolites and cololites from the Eastern Cordillera significantly enhanced the reconstruction of lower Paleozoic ecosystems in the southwestern Gondwanan seas