Revision des Ichnotaxon Tomaculum Groom, 1902

Tomaculum Groom, 1902 was not only designated to typify single fecal pellets of cylindrical outline. An essential part of the protologue is the special mode of accumulation, which took place on the sediment surface, in charactristic patches, strings and/or bands. Thus, Tomaculum ist senior synonym of Syncoprulus Richter & Richter, 1939a, who noticed this synonymy immediately (1939b). "Coprulus n.g." had been established by Richter & Richter (1939a) as informal name only, for single coprogenic pellets of cylindicral shape. This is the reason why Coprulus should not be considered as junior synonym of Tomaculum. Moreover, Coprulus is out of any nomenclatorical state because of missing type species. In contrast to the current use Tomaculum should not serve for "composite trace fossils" with cylindrical or granular Coprulus-like constituents, e.g. pellet-filled burrows similar to Alcyonidiopsis Massalongo, 1856. Burrows of the Alcyonidiopsis type have been originated infaunally whereas Tomaculum pellets and strings are the excrementa of an epibenthic animal comparable to the excremental behaviour of gastropods. Only in this restricted sense Tomaculum is indicative for the Ordovician. Tomaculum can serve as a case study for a critical discussion on the justification of the composite and compound concept in ichnology. The composite/compound concept is an inconsistent amalgamation of an IRZN-nomenclatorical approach combined with elements of an informal-descriptive terminology which is not useful for clarifying the Tomaculum problem.