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Trackways Produced by Lungfish During Terrestrial Locomotion

View Article: PubMed Central - PubMed

ABSTRACT

Some primarily aquatic vertebrates make brief forays onto land, creating traces as they do. A lack of studies on aquatic trackmakers raises the possibility that such traces may be ignored or misidentified in the fossil record. Several terrestrial Actinopterygian and Sarcopterygian species have previously been proposed as possible models for ancestral tetrapod locomotion, despite extant fishes being quite distinct from Devonian fishes, both morphologically and phylogenetically. Although locomotion has been well-studied in some of these taxa, trackway production has not. We recorded terrestrial locomotion of a 35 cm African lungfish (Protopterus annectens; Dipnoi: Sarcopterygii) on compliant sediment. Terrestrial movement in the lungfish is accomplished by planting the head and then pivoting the trunk. Impressions are formed where the head impacts the substrate, while the body and fins produce few traces. The head leaves a series of alternating left-right impressions, where each impact can appear as two separate semi-circular impressions created by the upper and lower jaws, bearing some similarity to fossil traces interpreted as footprints. Further studies of trackways of extant terrestrial fishes are necessary to understand the behavioural repertoire that may be represented in the fossil track record.

No MeSH data available.


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Devonian trace fossils bearing various similarities with lungfish traces; (A) Photo textured and height-mapped digital models of lungfish traces (top, scale bar 1 cm) and tetrapod traces from Valencia Island (bottom, scale bar 10 cm). While the traces differ substantially in size, the overall form of double impressions is highly similar morphologically. (B) Trace attributed to a eurypterid trackmaker by46 – Note the double impression is highly similar to those in Figs 4 and 7A, though orientation of the individual traces is different with respect to the trackway. (C) trace assigned to a tetrapod trackmaker by58 – The paired impressions are interpreted as manus-pes imprints. The sinuous central mark was interpreted as a coincidental horizontal burrow. (D) A trackway from Poland described by49, consisting of alternating circular, paired, impressions. While the regularity of the impressions is unlike those produced by the lungfish here, the general form of the individual tracks is not dissimilar (e.g. Figs 2 and 3).
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f7: Devonian trace fossils bearing various similarities with lungfish traces; (A) Photo textured and height-mapped digital models of lungfish traces (top, scale bar 1 cm) and tetrapod traces from Valencia Island (bottom, scale bar 10 cm). While the traces differ substantially in size, the overall form of double impressions is highly similar morphologically. (B) Trace attributed to a eurypterid trackmaker by46 – Note the double impression is highly similar to those in Figs 4 and 7A, though orientation of the individual traces is different with respect to the trackway. (C) trace assigned to a tetrapod trackmaker by58 – The paired impressions are interpreted as manus-pes imprints. The sinuous central mark was interpreted as a coincidental horizontal burrow. (D) A trackway from Poland described by49, consisting of alternating circular, paired, impressions. While the regularity of the impressions is unlike those produced by the lungfish here, the general form of the individual tracks is not dissimilar (e.g. Figs 2 and 3).

Mentions: Devonian trackways consisting of rounded or paired impressions are generally attributed to tetrapods42434445, but in some cases are interpreted as being made by other organisms, including invertebrates46. We present four reported trackways from the Devonian in Fig. 7, from tetrapods and invertebrates, that display (to greater or lesser degrees) morphological similarities with the lungfish traces we report. We also note a similarity with extant tetrapod traces, specifically those previously recorded from salamanders moving over certain substrates (Fig. 5 of Ref. 14).


Trackways Produced by Lungfish During Terrestrial Locomotion
Devonian trace fossils bearing various similarities with lungfish traces; (A) Photo textured and height-mapped digital models of lungfish traces (top, scale bar 1 cm) and tetrapod traces from Valencia Island (bottom, scale bar 10 cm). While the traces differ substantially in size, the overall form of double impressions is highly similar morphologically. (B) Trace attributed to a eurypterid trackmaker by46 – Note the double impression is highly similar to those in Figs 4 and 7A, though orientation of the individual traces is different with respect to the trackway. (C) trace assigned to a tetrapod trackmaker by58 – The paired impressions are interpreted as manus-pes imprints. The sinuous central mark was interpreted as a coincidental horizontal burrow. (D) A trackway from Poland described by49, consisting of alternating circular, paired, impressions. While the regularity of the impressions is unlike those produced by the lungfish here, the general form of the individual tracks is not dissimilar (e.g. Figs 2 and 3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037403&req=5

f7: Devonian trace fossils bearing various similarities with lungfish traces; (A) Photo textured and height-mapped digital models of lungfish traces (top, scale bar 1 cm) and tetrapod traces from Valencia Island (bottom, scale bar 10 cm). While the traces differ substantially in size, the overall form of double impressions is highly similar morphologically. (B) Trace attributed to a eurypterid trackmaker by46 – Note the double impression is highly similar to those in Figs 4 and 7A, though orientation of the individual traces is different with respect to the trackway. (C) trace assigned to a tetrapod trackmaker by58 – The paired impressions are interpreted as manus-pes imprints. The sinuous central mark was interpreted as a coincidental horizontal burrow. (D) A trackway from Poland described by49, consisting of alternating circular, paired, impressions. While the regularity of the impressions is unlike those produced by the lungfish here, the general form of the individual tracks is not dissimilar (e.g. Figs 2 and 3).
Mentions: Devonian trackways consisting of rounded or paired impressions are generally attributed to tetrapods42434445, but in some cases are interpreted as being made by other organisms, including invertebrates46. We present four reported trackways from the Devonian in Fig. 7, from tetrapods and invertebrates, that display (to greater or lesser degrees) morphological similarities with the lungfish traces we report. We also note a similarity with extant tetrapod traces, specifically those previously recorded from salamanders moving over certain substrates (Fig. 5 of Ref. 14).

View Article: PubMed Central - PubMed

ABSTRACT

Some primarily aquatic vertebrates make brief forays onto land, creating traces as they do. A lack of studies on aquatic trackmakers raises the possibility that such traces may be ignored or misidentified in the fossil record. Several terrestrial Actinopterygian and Sarcopterygian species have previously been proposed as possible models for ancestral tetrapod locomotion, despite extant fishes being quite distinct from Devonian fishes, both morphologically and phylogenetically. Although locomotion has been well-studied in some of these taxa, trackway production has not. We recorded terrestrial locomotion of a 35 cm African lungfish (Protopterus annectens; Dipnoi: Sarcopterygii) on compliant sediment. Terrestrial movement in the lungfish is accomplished by planting the head and then pivoting the trunk. Impressions are formed where the head impacts the substrate, while the body and fins produce few traces. The head leaves a series of alternating left-right impressions, where each impact can appear as two separate semi-circular impressions created by the upper and lower jaws, bearing some similarity to fossil traces interpreted as footprints. Further studies of trackways of extant terrestrial fishes are necessary to understand the behavioural repertoire that may be represented in the fossil track record.

No MeSH data available.


Related in: MedlinePlus