A new ichnospecies of Nereites from Carboniferous tidal-flat facies of eastern Kansas, USA: Implications for the Nereites-neonereites debate

Citation
Mg. Mangano et al., A new ichnospecies of Nereites from Carboniferous tidal-flat facies of eastern Kansas, USA: Implications for the Nereites-neonereites debate, J PALEONTOL, 74(1), 2000, pp. 149-157
Citations number
67
Categorie Soggetti
Earth Sciences
Journal title
JOURNAL OF PALEONTOLOGY
ISSN journal
00223360 → ACNP
Volume
74
Issue
1
Year of publication
2000
Pages
149 - 157
Database
ISI
SICI code
0022-3360(200001)74:1<149:ANIONF>2.0.ZU;2-X
Abstract
Predominantly horizontal, gently curved to slightly sinuous traces constitu ting uniserial rows of imbricated, subspherical sediment pads occur in Penn sylvanian tidal-flat facies of eastern Kansas. These traces exhibit a compl ex, actively filled internal structure. The presence of a median tunnel env eloped by overlapping pads of reworked sediment indicates that these biogen ic structures should be included in the ichnogenus Nereites MacLeay in Murc hison, 1839. A new ichnospecies, N. imbricata, is erected. Externally, Nere ites imbricata differs from the other Nereites ichnospecies by the large, t ightly packed, imbricated pads that commonly result in an annulated appeara nce on bedding-planes. Internally, obliquely arranged, arcuate laminae enve lope the median tunnel and tend to follow the outline of the external semis pherical pads. Additionally, the behavioral pattern reflected by N. imbrica ta is less specialized than that of the other Nereites ichnospecies. Eione monoliformis Tate, 1859 resembles N. imbricata in general appearance, but l ack the diagnostic Nereites internal structure, and is invariably preserved as positive epireliefs. Occurrence of Nereites imbricata as both median tu nnels surrounded by reworked sediment (Nereites preservation) and uniserial rows of imbricated sediment pads (Neonereites preservation) supports the n otion that Neonereites Seilacher, 1960 is a preservational variant of Nerei tes. The ichnogenus Nereites is an eurybathic form and is a common componen t of Paleozoic shallow-marine facies.