Members of the Nereites family consist of a median backfilled structure and lateral-worked-areas. The current, senior synonyms (Häntzschel, 1975) are Nereites MacLeay 1839, Helminthoida Schäfhautl 1851, Phyllodocites Geinitz 1867, Scalarituba Weller 1899, Neonereites Seilacher 1960, and Palaeohelminthoida Ruchholz 1967.
The main, fundamental difference between different family members appears to be that in some the backfilled area consists of a continuous fecal string (e.g., Helminthoida) and in others it is a meniscate alternation of coarse and fine (fecal) sediment (e.g., Scalarituba). The second fundamental difference appears to be behavioral (≈environmental); some forms are tight, grazing patterns (most Helminthoida, Palaeohelminthoida, Nereites) and others are loosely-looping grazing patterns (Scalarituba, some Helminthoida and Nereites). The least important difference appears to be preservational; it depends on a top view (Phyllodocites, Nereites), interlaminar views (Scalarituba, Palaeohelminthoida, Neonereites?), or bottom (or low-in-the-structure) view (Neonereites).
Based on the difference in the median structure, Nereites and Scalarituba are probably the only two valid senior synonyms.
Nereites (≈Helminthoida) occurs in shallow shelf through abyssal environments. Scalarituba occurs in shallow shelf to probably no deeper than bathyal.
Nereites (≈Helminthoida) can be confused with simple backfilled tubes (usually fecal ribbons) because even in Nereites, the lateral-worked-areas are not always obvious. The use of Cosmorhaphe for simple fecal ribbons further confuses the nomenclature and is inappropriate because Cosmorhaphe is a hyporelief sand cast of a simple, open tube originally made in a mud substrate. Nereites can be confused with Phycosiphon where lateral-worked-area of the former and the spreite of the latter are not visible.