''Diplichnites'' are
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
trackways with two parallel rows of blunt to elongate, closely spaced tracks oriented approximately perpendicularly to the mid-line of the trackway. The term is more often used for the
ichnofossils of this description; however, similar trackways from recent arthropods are sometimes given this name as well.
The ''Diplichnites'' makers
This type of trackway was originally based on large fossils from
Pennsylvanian Pennsylvanian may refer to:
* A person or thing from Pennsylvania
* Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timesca ...
strata of Nova Scotia, when Sir J. W. Dawson named it in 1873. Dawson proposed that ''Diplichnites'' were produced by a fish “walking” in shallow water on pectoral or ventral fin spines. Previous to this he had suggested that a large
crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
,
annelid worm
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologi ...
or
myriapod (such as a
millipede) could have made them. Subsequent evidence has supported this earlier interpretation. The fossils on which this
ichnotaxon was based are now thought to be from giant myriapods, such as ''
Arthropleura''. The Scottish ''Diplichnites cuithensis'' could have been the result of a 1 meter-long
arthropleurid walking.
In the decades following Dawson’s work, the trackways of several other arthropods were also included within ''Diplichnites'' – particularly,
trilobites
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...
, which are known from marine
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
deposits around the world. In addition, recent evidence indicates that some ''Diplichnites'' trackways from certain
Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...
intertidal and subaerial deposits of North America, especially the Potsdam and Elk Mound Groups, were produced by
euthycarcinoid
Euthycarcinoidea are an enigmatic group of extinct possibly amphibious arthropods that ranged from Cambrian to Triassic times. Fossils are known from Europe, North America, Argentina, Australia and Antarctica.
Description
The euthycarcinoid body ...
s. In that scenario, the ''Diplichnites'' may have been undertracks that penetrated to the underlying layer of sediment, and the fossil trackways thus produced on the top surface (preserving the impression of the dragging tail) were
Protichnites
''Protichnites'' is an ichnogenus of trace fossil consisting of the imprints made by the walking activity of certain arthropods. It consists of two rows of tracks and a medial furrow between the two rows. This furrow, which may be broken, set at ...
.
[Hoxie, 2005]
References
Further reading
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External links
''Diplichnites:''
Photo--''Diplichnites gouldi'' arthropod trackway--(marine, tidal)
– "Bulletin 241", Kansas Geological Survey
The Kansas Geological Survey (KGS), a research and service division of the University of Kansas, is charged by statute with studying and providing information on the geologic resources of Kansas. The KGS has no regulatory authority and does not t ...
Photo--from ''Arthropleura sp''
– "Nova Scotia, Carboniferous Geology and Paleontology"
Video--Euthycarcinoid animation on ''Diplichnites'' slab (Milwaukee Public Museum)
Trilobite Tracks:
– 3-main types of trilobite trace fossils
{{Taxonbar, from=Q5279813
Arthropod trace fossils
Fossil trackways