Nereites (trace fossil) MacLeay, 1839

This trace fossil occurs as irregularly winding hypichnial ribbons, 7 mm wide, forming very deep, irregular meanders with a bulge in the turning area, or running along more loose paths. Locally, the ribbons are rimmed by an indistinct, 2 mm thick, halo-like zone of slightly
different coloor.

This trace fossil is very similar to Scalarituba Weller, which was included in Nereites (MacLeay, 1839) (see Uchman, 1995). The halo represents the reworked zone and the ribbon is the faecal string. Nereites is a typical pascichnion produced by an unknown tracemaker (see discussion by Rindsberg, 1994; Uchman, 1995; M
angano, West, et al., 2002).

Diagnosis: Usually selectively preserved, winding to regularly meandering, more or less horizontal trails, consisting of a median backfilled tunnel enveloped by even to lobate zone of reworked sediment. Commonly, only the external part of the enveloping zone is preserved as a densely packed chain of uni- or multi-serial small depressions or pustules (Uchman, 1995).

Nereites MacLeay is diagnosed as winding to regularly meandering, more or less horizontal trails, consisting of a medianback-filled tunnel (core) enveloped by an even to lobate zone of reworked sediment (mantle). Commonly, only the external part of the mantle is preserved as a densely packed chain of small, uni- or multiserial depressions or pustules (Uchman, 1995). Lists of ichnotaxa included in Nereites, which belong amongst others to Scalarituba Weller, Neonereites Seilacher and Helminthoida Schafhäutl, were presented by Rindsberg (1994) and Uchman (1995), who also discuss the ichnotaxonomic problems of this ichnogenus.

Diagnosis.—Selectively preserved, curved, winding to regularly meandering or spiralling, unbranched, predominantly horizontal trails, consisting of a median backfilled tunnel enveloped by an even to lobate zone of reworked sediment (after Uchman, 1995 and Orr and Pickerill, 1995).