Ichnotaxonomy

Analysis of variability in /Protichnites/ morphology and a standardized method of identification

by Matt Burton-Kelly

Presented at the Ichnological Applications to Sedimentological and Sequence Stratigraphic Problems, SEPM Research Conference, May 20 - 26, 2007, Price, Utah, USA.

First paragraph:
Morphological characters of described specimens of the ichnogenus _Protichnites_ Owen, 1852, (a... more First paragraph:
Morphological characters of described specimens of the ichnogenus _Protichnites_ Owen, 1852, (a probable arthropod trace fossil) in the literature were identified. For this study, _Protichnites_ was defined as a trackway possessing the following characteristics: paired imprints across the midline, medial structure (groove(s) or ridge(s)), and a countable (i.e., generally unchanging) number of tracks in each repeating trackset. This definition removes certain described specimens and ichnospecies of _Protichnites_ from that ichnogenus (and from this study), due mainly to a lack of ‘countable’ tracks per set, something that Owen (1852) considered an important aspect of these trackways when he named _P. septemnotatus_ (“seven-marked”), _P. octonotatus_ (“eight-marked”) and _P. multinotatus_ (“many-marked”). Specimens that possess this morphology but have not been identified as _Protichnites_ were not included in this study. Many specimens from the literature have been identified only to the level of ichnogenus.

Comment on the draft proposal to emend the Code with respect to trace fossils-reply

by Markus Bertling

(currently no pdf available because of online full text version)

(no abstract existing) (no abstract existing)

Causas de la variabilidad en icnitas de dinosaurios y su aplicación en icnotaxonomía.

by Ignacio Díaz-Martínez

Díaz-Martínez, I., Pérez-Lorente, F., Canudo, J. I. y Pereda-Suberbiola, X. (2009). Causas de la variabilidad en icnitas de dinosaurios y su aplicación en icnotaxonomía. Actas de las IV Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno. Salas de los Infantes, Burgos, 207-220. (In Spanish)

The classification is one of the major problems in the study of dinosaur footprints. The shape of the footprints... more The classification is one of the major problems in the study of dinosaur footprints. The shape of the footprints depends mainly on: the type of dinosaur and his behaviour (intrinsic causes); on the physic properties of the mud, on traces interference, on sedimentary processes and on stone conservation processes (extrinsic causes). It also depends on the relation between the stratigraphic level in which are observed the tracks (undertracks more or less deep) and the stratigraphic level where the dinosaur walked on (real footprints). In this work there are analysed all the factors involved in the formation of the footprints and its importance in ichnotaxonomic studies.

Key words: dinosaur footprints, variability, intrinsic causes, extrinsic causes, kind of footprint, ichnotaxonomy.

Rosselia socialis: a dwelling structure of a probable terebellid polychaete

by Masakazu Nara

Invertebraten Spurenfossilien aus dem Taunusquarzit (Siegen, Unterdevon) von der "Rossel" nahe Rüdesheim

by Masakazu Nara

Reappraisal of Schaubcylindrichnus: a probable dwelling/feeding structure of a solitary funnel feeder

by Masakazu Nara

Morphology, ethology and taxonomy of the ichnogenus Schaubcylindrichnus: notes for clarification

by Masakazu Nara

A new occurrence of /Protichnites/ Owen, 1852, in the Late Cambrian Potsdam Sandstone of the St. Lawrence lowlands

by Matt Burton-Kelly

Co-authored with J. Mark Erickson, published in The Open Paleontology Journal 3:1-13 (2010)

Late Cambrian arthropod trackways from the Potsdam Sandstone have been known since the 1850s. A site in Clinton... more Late Cambrian arthropod trackways from the Potsdam Sandstone have been known since the 1850s. A site in Clinton County, New York, USA, exposes _Protichnites_ in fine-grained, quartz-rich, rippled, micro-laminated Potsdam Sandstone. The study area includes evidence of microbial mat growth on the original surface where the trackways were produced. Ripple marks presumably underlie, and therefore were generated prior to, the microbial mat. Trackway preservation is variable over the outcrop and depositional setting indicates a high intertidal or a low supratidal environment with growth of benthic microbial mats. At least eleven distinguishable trackways of multi-legged, telson- bearing individuals show a range of widths. The trackways consist of repetitive sets of seven pairs of tracks converging in the direction of motion of the organism. A telson impression, either discontinuous or continuous, divides the trackways longitudinally and is nearly centered throughout the lengths of the trackways. The trackways are consistent in number of tracks per series, arrangement, and stride lengths with the ichnospecies holotype from the original description of _Protichnites septemnotatus_ Owen, 1852. Variable preservation probably resulted from varying thickness of the microbial mat and/or varying water depth or wind and wave action in an intertidal pool.

Range of Experimental Dinosaur (Hypsilophodon foxii) Footprints Due to Variation in Sand Consistency: How Wet Was the Track?

by Simon Jackson

Co-authored with Martin A Whyte, Mike Romano

The laboratory-controlled simulations of dinosaur footprints in this study revealed characteristic track features that... more The laboratory-controlled simulations of dinosaur footprints in this study revealed characteristic track features that could be used to identify the consistency of sand substrates and provide an insight into the paleoenvironment. A model foot of Hypsilophodon foxii was indented into three sands of four different moisture (= water) contents. The two intermediate moist states were characterized by shallow tridactyl impressions, in which only digits II-IV were impressed, showing details of padding and claws. Where the foot penetrated more deeply, in the dry and saturated states, the hallux and heel were also impressed; in these cases, the foot detail was not preserved accurately and track morphology deviated significantly from that of the foot. Dry sand tracks were characterized by the outward and upward movement of sediment and tracks in saturated sand by mainly downward displacement. The finer-grained saturated sand was also associated with liquefaction and closure of digit imprints. Tracks from the Middle Jurassic Cleveland Basin of Yorkshire showed features of the saturated state. The range of experimental track morphotypes formed by one foot highlighted the difficulties in assigning a print type to a particular trackmaker and the importance of excluding preservational variants from ichnotaxonomic studies.

Draft Proposal to Emend the Code With Respect to Trace Fossils: Request for Comments

by Markus Bertling

(no pdf avalable because of online full text)

(no abstract existing) (no abstract existing)

Names for Trace Fossils: a Uniform Approach

by Markus Bertling

(let me know if you cannot access the pdf)

The taxonomic treatment of trace fossils needs a uniform approach, independent of the ethologic groups concerned. To... more The taxonomic treatment of trace fossils needs a uniform approach, independent of the ethologic groups concerned. To this aim, trace fossils are rigorously defined with regard to biological taxa and physical sedimentary structures. Potential ichnotaxobases are evaluated, with morphology resulting as the most important criterion. For trace fossils related to bioerosion and herbivory, substrate plays a key role, as well as composition for coprolites. Size, producer, age, facies and preservation are rejected as ichnotaxobases. Separate names for undertracks and other poorly preserved material should gradually be replaced by ichnotaxa based on well-preserved specimens. Recent traces may be identified using established trace fossil taxa but new names can only be based on fossil material, even if the distinction between recent and fossil may frequently remain arbitrary. It is stressed that ichnotaxa must not be incorporated into biological taxa in systematics. Composite trace fossil structures (complex structures made by the combined activity of two or more species) have no chnotaxonomic standing but compound traces (complex structures made by one individual tracemaker) may be named separately under certain provisions. The following emendations are proposed to the International Code of Zoological Nomenclature: The term ‘work of an animal’ should be deleted from the code, and ichnotaxa should be based solely on trace fossils as defined herein.