Dromopus

{{Short description|Trace fossil}} {{Ichnobox | fossil_range = {{fossil range|Moscovian|Changhsingian|Moscovian-Changhsingian}} | image = Dromopus lacertoides.png | image_caption = Plate of ''D. lacertoides'' tracks, as figured by Hanns Bruno Geinitz | taxon = Dromopus | authority = Marsh, 1894 | type_ichnospecies = {{extinct}}''Saurichnites lacertoides'' | type_ichnospecies_authority = Geinitz, 1861 | subdivision_ranks = Ichnospecies | subdivision = *''Dromopus lacertoides'' (Geinitz, 1861; type) *?''Dromopus agilis'' Marsh, 1894 *?''Dromopus didactylus'' (Moodie, 1930) | synonyms = *''Protritonichnites'' Pohlig, 1892 *''Eumekichnium'' Nopcsa, 1923 *''Gampsodactylum'' Nopcsa, 1923 }}

'''''Dromopus''''' is a reptilian ichnogenus commonly found in assemblages of ichnofossils dating to the late Pennsylvanian (Moscovian stage) to the late Permian (Changhsingian stage). It has been found throughout Europe, as well as in the United States, Canada, and Morocco. Several ichnospecies have been named; only the type ichnospecies '''''D. lacertoides''''' is definitively recognized.<ref name="meade2016">{{cite journal |last1=Meade |first1=L.E. |last2=Jones |first2=A.S. |last3=Butler |first3=R.J. |year=2016 |title=A revision of tetrapod footprints from the late Carboniferous of the West Midlands, UK |journal=PeerJ |volume=4 |article-number=e2718 |doi=10.7717/peerj.2718|pmid=27904809 |pmc=5126627 |doi-access=free }}</ref>

==History== ===Species=== Originally named as an ichnospecies of ''Saurichnites'' by Hanns Bruno Geinitz in 1861, ''S. lacertoides'' was transferred to the newly created genus ''Dromopus'' by Othniel Charles Marsh in 1894, along with a new ichnospecies ''D. agilis'' from the United States.<ref name="gand2006">{{cite book |last1=Gand |first1=G. |last2=Durand |first2=M. |year=2006 |chapter=Tetrapod footprint ichno-associations from French Permian basins: Comparisons with other Euramerican ichnofaunas |title=Non-Marine Permian Biostratigraphy and Biochronology |series=Geological Society, London, Special Publications |volume=265 |page=161 |doi=10.1144/GSL.SP.2006.265.01.07|s2cid=129263187 }}</ref>

In 1929, Roy Moodie described two-digit traces from the Red Beds of Texas under the ichnospecies ''Varanopus palmatus'', ''V. impressus'', ''V. elrodi'', and ''V. didactylus''.<ref name="moodie1929">{{cite journal |last1=Moodie |first1=R.L. |year=1929 |title=Vertebrate footprints from the red beds of Texas |journal=American Journal of Science |volume=17 |issue=100 |pages=352–368 |doi=10.2475/ajs.s5-17.100.352|bibcode=1929AmJS...17..352M }}</ref> However, these were subsequently considered to represent a single ichnospecies of ''Dromopus'' by William Sarjeant. Because the type specimen of ''V. palmatus'' is broken, and ''V. impressus'' and ''V. elrodi'' are incomplete, ''Dromopus didactylus'' is generally the preferred name.<ref name="gand2006"/>

In 1963 and 1964, Paul Ellenberger described many ichnospecies of ''Dromopus'': ''D. neooctavianensis'', ''D. brevidigitatus'', ''D. duidigitatus'', ''D. octavianensis'', ''D. bidigitatus'', ''D. curtidigitus'', ''D. inversidigitulifer'', ''D. rabejacensis'', ''D. rectidigitus'', ''D. rectangulus'', ''D. exsultans'', and ''D. cursor''. Harmut Haubold considered them invalid in a 2000 review.<ref name="haubold2000">{{cite journal |last1=Haubold |first1=H. |title=Tetrapodenfährten aus dem Perm – Kenntnisstand und Progress 2000 |trans-title=The tetrapod tracks of the Permian – state of knowledge and progress 2000 |year=2000 |journal=Hallesches Jahrbuch für Geowissenschaften |volume=22 |pages=1–16 |url=https://www.researchgate.net/publication/239575531}}</ref>

There have been disagreements about whether the North American ''D. agilis'' represents a separate ichnospecies.<ref name="haubold1995"/> More recently, based on the fact that there is no satisfactory anatomical diagnosis distinguishing various ichnospecies of ''Dromopus'', only the type ichnospecies ''D. lacertoides'' has been agreed to be valid.<ref name="meade2016"/><ref name="voigt2015">{{cite journal |last1=Voigt |first1=S. |last2=Lucas |first2=S.G. |year=2015 |title=Permian tetrapod ichnodiversity of the Prehistoric Trackways National Monument (south-central New Mexico, USA) |journal=Bulletin of the New Mexico Museum of Natural History and Science |volume=65 |pages=162–163 |url=https://books.google.com/books?id=MOaoDQAAQBAJ&pg=PA153}}</ref>

===Synonyms=== In 1892, Pohlig used the new ichnogenus ''Protritonichnites'' for the ichnospecies ''Saurichnites lacertoides'', before Marsh had named ''Dromopus''. By the principles of synonymy, ''Protritonichnites'' should have priority over ''Dromopus''. However, in 1970, Haubold argued that this name was largely unused by this point, and it was also based on a less taxonomically sound definition. Although some European researchers during the 1980s persisted in using the name ''Protritonichnites'', ''Dromopus'' has generally found more widespread adoption.<ref name="haubold1995">{{cite journal |last1=Haubold |first1=H. |last2=Lockley |first2=M.G. |last3=Hunt |first3=A.P. |last4=Lucas |first4=S.G. |year=1995 |title=Lacertoid Footprints from Permian Dune Sandstones, Cornberg and DeChelly Sandstones |journal=Bulletin of the New Mexico Museum of Natural History and Science |volume=6 |page=241 |url=https://books.google.com/books?id=aY8ZCgAAQBAJ&pg=PA238}}</ref> Other synonyms include ''Eumekichnium'', named by Franz Nopcsa in 1923, including the type ichnospecies ''E. longipollex'', as well as ''E. gampsodactylum'' and ''E. pachydactylum'' (both formerly ''Ichnium''); and ''Gampsodactylum'', also named by Nopcsa in 1923, including the type ichnospecies ''G. alberdorfense'' as well as ''G. friedrichrodanum'' and ''G. kabarzense''.<ref name="haubold2000"/>

==Description== ''Dromopus lacertoides'' tracks are characterized by five-fingered hand and foot imprints up to {{convert|6|cm}} long, about a third longer than they are wide, with a short palm and long, slender, tapered digits. The length of the digits increases from the first to the fourth, with the fifth having the same length as the second. The hand and foot imprints are not particularly distinct.<ref name="voigt2017">{{cite journal |last1=Voigt |first1=S. |last2=Lucas |first2=S.G. |year=2017 |title=Early Permian Tetrapod Footprints from Central New Mexico |journal=Bulletin of the New Mexico Museum of Natural History and Science |volume=77 |pages=338–339 |url=https://books.google.com/books?id=zMyCDwAAQBAJ&pg=PA333}}</ref> ''D. didactylus'' tracks are based on similar tracks, but where the imprints of all but two digits are faint.<ref name="gand2006"/>

''Dromopus'' tracks have been ascribed to lizard-like reptiles, including the diapsid Araeoscelidia and the parareptilian Bolosauridae.<ref name="meade2016"/><ref name="marchetti2018">{{cite journal |last1=Marchetti |first1=L. |last2=Petti |first2=F.M. |last3=Bernardi |first3=M. |last4=Citton |first4=P. |last5=Rossi |first5=R. |last6=Schirolli |first6=P. |title=On the first description of tetrapod footprints from Italy: Re-analysis of the original specimen after 150 years |journal=Rendiconti Online della Società Geologica Italiana |volume=44 |pages=112–118 |doi=10.3301/ROL.2018.16|year=2018 |hdl=11336/97917 |hdl-access=free }}</ref><ref name="lucas2004">{{cite journal |last1=Lucas |first1=S.G. |last2=Lerner |first2=A.J. |last3=Hunt |first3=A.P. |year=2004 |title=Permian Tetrapod Footprints from the Lucero Uplift, Central New Mexico, and Permian Footprint Biostratigraphy |journal=Bulletin of the New Mexico Museum of Natural History and Science |volume=25 |pages=338–339 |url=https://books.google.com/books?id=7Nb5CQAAQBAJ&pg=PA291}}</ref>

==References== {{Reflist}}

Category:Reptile trace fossils