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Helminthoidichnites tenuis Fitch, 1850

Taksoni kirjeldused

Schlirf et al., 2001

Diagnosis: Relatively thin, horizontal, irregularly meandering or winding trails with occasional loops.

Buatois et al., 1998c

Emended diagnosis.—Horizontal, small, thin, unbranched, simple, straight or curved to, more rarely, circular trails or bur­rows that commonly display overlap among specimens, but lack self-overcrossing.

Buatois et al., 1996

Description: Slightly curved to straight, non meandering, unbranched, horizontal trails. Smooth surface. Crossing between different individuals is common. Diameter relatively constant within each specimen. Diameter ranges between 1.0-3.0 mm. Length varies between 25-95 mm. Preserved as hypichnial ridges.

Remarks: Although placed in synonymy with Gordia by Häntzschel (1975), Helminthoidichnites was more recently considered as a distinct form by Hofmann and Patel (1989). Helminthoidichnites is not meandering as Helminthopsis and does not show overcrossing as Gordia (Hofmann and Patel, 1989; Buatois and Mângano, 1993a). A single ichnospecies, Helminthoidichnnites tenuis Fitch, is known. It is interpreted as grazing trails (pascichnia) probably produced by arthropods.

Buatois & Mángano, 2012a

Simple, unbranched, straight to gently curved trails, oriented parallel to the bedding plane. Fill is identical to the host rock. Overlapping among different individuals is common. Diameter is 0.8–2.1 mm and may slightly vary along the course of individual trails. Maximum observed length is 17.0 mm. Preserved in full relief on sandstone tops.

Helminthoidichnites tenuis is one of the most common components of Ediacaran and lower Cambrian ichnofaunas (e.g., Hofmann et al., 1994; MacNaughton et al.,2000; Jensen et al., 2006). This ichnotaxon is interpreted as a grazing trace (pascichnion) most likely produced by vermiform animals (Buatois et al., 1998).

 

Sünonüümika
1850     Helminthoidichnites tenuis — Fitch , lk. 866, joon. unnumbered figure
1886     Montfortia rhedonensis — Lebesconte , lk. 782-783, joon. 34:5
1886     Montfortia filiformis — Lebesconte , lk. 782-783, joon. 34:8,9
1989     Helminthoidichnites tenuis Fitch, 1850 — Hofmann and Patel , lk. 141, joon. 2a
1990     Helminthoidichnites tenuis Fitch, 1850 — Narbonne & Aitken , lk. 968, joon. 4:2,3
1997     Helminthoidichnites tenuis Fitch, 1850 — Jensen , lk. 55, joon. 278, 37C
1998     Helminthoidichnites tenuis Fitch, 1850 — Buatois et al. , lk. 157, joon. 4.3, 4.4
1999     Helminthoidichnites tenuis — MacNaughton and Narbonne , lk. 106, joon. 7B
2001     Helminthoidichnites tenuis Fitch, 1850 — Schlirf et al. , lk. 84, joon. 14
2003     Helminthoidichnites tenuis Fitch, 1850 — Aceñolaza & Tortello , lk. 97, joon. 3.7a; 3.8; 3.11
Valik taksonit käsitlevast teaduskirjandusest
Uchman, A., Hanken, N.-M., Binns, R. 2005. Ordovician Bathyal Trace Fossils From Metasiliciclastics in Central Norway and Their Sedimentological and Paleogeographical Implications. Ichnos 12, 2, 105-133. DOI:10.1080/10420940590914534
Jensen, S. 1997. Trace fossils from the Lower Cambrian Mickwitzia sandstone, south-central Sweden. Fossils and Strata 42, 1-110.
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Levik kirjandusandmetel