Vertebrate Ichnopathology: Pathologies Inferred from Dinosaur Tracks and Trackways from the Mesozoic

Abstract

Literature concerning dinosaur footprints or trackways exhibiting abnormal gait or morphology reflecting pathology (ichnopathology) is rare. We report on a number of Jurassic and Cretaceous occurrences of theropod footprints from western North America with unusual morphologies interpreted herein as examples of inferred pathologies, or ichnopathologies. The majority of ichnopathologies are primarily manifested in the digit impressions and include examples of swelling, extreme curvature, dislocation or fracture, and amputation. A number of occurrences are single tracks on ex situ blocks with substantial deformation (inferred dislocation or fracture), or absence of a single digit impression. Two occurrences are from in situ natural mould trackways, one of which is a lengthy trackway of a presumed allosauroid with no noticeable deformation of the digits or feet but with strong inward rotation of the left footprint toward the midline and a pronounced, waddling limp. The other is a tyrannosaurid trackway consisting of three footprints (one right, two left) with the two left prints exhibiting repetitive ichnopathology of a partially missing Digit II impression.Keywords Dinosaur tracks, Amputation, Antalgic gait, Compensated gait, Jurassic, Cretaceous, Ichnopathology, Laterality, Irregular gait, Limping gait, Shuffling gait, Waddling gait INTRODUCTIONOver the course of the past few decades, there has been a marked increase in the literature of pathology of dinosaurs (e.g., Tanke and Rothschild, 2002 and references therein). However, the literature on inferred pathology from dinosaur tracks and trackways (ichnopathology) has not seen a corresponding increase. Reports on ichnopathology in dinosaurs have been infrequent, with perhaps less than one paper published per decade since the beginning of modern studies of dinosaur traces in the early 19th century. It is possible that reports of ichnopathology have not kept pace with reports of pathologies on osteological specimens due to the various influences of track-bearing substrate, the behavior of the trackmaker, as well as a range of taphonomic factors that make such interpretations difficult. The sparse publication record of ichnopathology may also be a reflection of the cautious approach ichnologists employ when interpreting phenomena related to tracks.Even with a restrained approach toward footprint and trackway interpretation, some dinosaur tracks and trackways exhibit morphologies that have defied explanation by conventional behaviors of the trackmaker, or by the physical and dynamic qualities of the track surface, both pre-and post-burial.This article discusses previous reports of dinosaur ichnopathology with reinterpretations where such is warranted. Several recent and new reports of dinosaur ichnopathologies are described, from sites in the Jurassic of China and the Cretaceous of North America. A number of criteria are proposed that will aid in the interpretation of ichnopathologies

Trackways of the American Crocodile (Crocodylus acutus) in Northwestern Costa Rica: Implications for Crocodylian Ichnology

“…18), and the inside of pes prints, and the heel, are (aside from claw marks) the deepest parts of hindfoot prints (cf. some sauropod trackways: Farlow et al, 2015). Webbing between digits II-III, and III-IV, of the pes may register as a shallow region of the print (Figs.…”

Mammalian ichnopathology: A case study of holartic ungulates (Gomphotheriidae, Equidae, Camelidae) of the Late Pleistocene of South America. Ichnotaxomic implications

“…; from the Late Pleistocene (Lujanian Stage/Age) of Pehuen Co (Partido de Coronel Rosales) and Laguna del Monte (Partido de Guaminí) tracksites, Buenos Aires Province, Argentina (Figure 1). The differentiation of pathologic footprints was based on the detection of potential clinical signs (related to any of the limb affections known for modern ungulates); having previously discarded other types of intraspecific variations (intramorphological changes) and/or secondary alterations linked to external factors (extramorphological characters) (e.g., nature of the substrate, mechanical disturbance, presence of foreign objects, infauna influence; see McCrea et al, 2015). The recognition of the ungual diseases has been made indirectly, through interpretation of Owen, 1848(Camelidae Gray, 1821Cervidae Gray, 1821;Bobidae Gray, 1821;Giraffidae Gray, 1821;Hippopotamidae Gray, 1821;Suidae Gray, 1821;Tayassuidae Palmer, 1897), either on wild or captive animals (Fowler, 1978(Fowler, , 1980 (Kuntze, 1972(Kuntze, , 1980Fowler, 1980Fowler, , 2001von Houwald, 2001;Benz, 2005) ( Figure 2A).…”

“…In contrast, the advances in ichnopathology (paleopathology based on the fossil-tracks analysis) are much more restricted and specifically focused on dinosaurs (see Lockley et al, 1994;Tanke and Rothschild, 2002;McCrea et al, 2014McCrea et al, , 2015. In this regard, although this specialty has developed parallel to conventional ichnology since the mid-nineteenth century, its evolution was comparatively lesser, headed by sporadic contributions wherein a scarce number of anomalous records, from the Mesozoic of Northern Hemisphere, were described: Late Triassic-Early Jurassic (Hitchcock, 1844(Hitchcock, , 1858Abel, 1935;Lull, 1953) and Late Cretaceous (McCrea et al, 2014(McCrea et al, , 2015Tanke and Rothschild, 2015) of North America; Triassic s. l. (Tucker and Burchette, 1977) and Late Jurassic (Dantas et al, 1994;Avanzini et al, 2008) of Europe; Middle Jurassic of Africa (Jenny and Josen, 1982;Ishigaki, 1986Ishigaki, , 1988 and Late Cretaceous of Asia (Currie et al, 2003;McCrea et al, 2015). This is probably due to the high difficulty that imply the differentiation of pathological signs in footprints and trails, which reflect the influence of several extrinsic agents (e.g., nature of the track-bearing substrate, behaviour of the trackmaker, taphonomical factors) (see McCrea et al, 2015); made even worse in the cases where there are no modern species for comparison.…”

“…In this regard, although this specialty has developed parallel to conventional ichnology since the mid-nineteenth century, its evolution was comparatively lesser, headed by sporadic contributions wherein a scarce number of anomalous records, from the Mesozoic of Northern Hemisphere, were described: Late Triassic-Early Jurassic (Hitchcock, 1844(Hitchcock, , 1858Abel, 1935;Lull, 1953) and Late Cretaceous (McCrea et al, 2014(McCrea et al, , 2015Tanke and Rothschild, 2015) of North America; Triassic s. l. (Tucker and Burchette, 1977) and Late Jurassic (Dantas et al, 1994;Avanzini et al, 2008) of Europe; Middle Jurassic of Africa (Jenny and Josen, 1982;Ishigaki, 1986Ishigaki, , 1988 and Late Cretaceous of Asia (Currie et al, 2003;McCrea et al, 2015). This is probably due to the high difficulty that imply the differentiation of pathological signs in footprints and trails, which reflect the influence of several extrinsic agents (e.g., nature of the track-bearing substrate, behaviour of the trackmaker, taphonomical factors) (see McCrea et al, 2015); made even worse in the cases where there are no modern species for comparison. In this paper we present the results obtained from the paleopathological study of fossil tracks and trackways related to Holarctic ungulates (equids, camelids and gomphotherids), from the Late Pleistocene of Argentina (South America), and discuss the ichnopathological and ichnotaxonomical implications of these findings.…”

First tetrapod footprints from the Permian of Sardinia and their palaeontological and stratigraphical significance

“…This method, whose practice is explained by several papers (e.g., Falkingham, ; Mallison & Wings, ; Petti et al, ), enables preservation and communication more objectively about ichnological data. Its adoption has greatly increased in recent times, becoming almost a standard taking advantage of a protocol for ichnological studies (Falkingham et al, ) and being used as support of different approaches related to ichnological analysis (e.g., Castanera et al, ; Citton, Carluccio, Nicolosi, & Nicosia, ; Citton, Nicolosi, Carluccio, & Nicosia, ; Citton, Nicosia, Nicolosi, Carluccio, & Romano, ; Citton et al, ; Citton, Romano, Salvador, & Avanzini, ; Lallensack, Sander, Knötschke, & Wings, ; McCrea et al, ; Romano & Citton, ). High‐resolution Digital Photogrammetry is based on Structure from Motion (SfM) (Ullman, ) and Multi View Stereo (MVS; Seitz, Curless, Diebel, Scharstein, & Szeliski, ) algorithms and produces high‐quality dense point clouds.…”