Limits...
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.


Resting trace of P. annectens on moist fine sand.The animal was oriented with anterior at the top of the image. Photo (left), Height map (centre), and ousupptline (right). Scale bar = 10 cm, height map covers 10 mm from low (blue) to high (red).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5037403&req=5

f6: Resting trace of P. annectens on moist fine sand.The animal was oriented with anterior at the top of the image. Photo (left), Height map (centre), and ousupptline (right). Scale bar = 10 cm, height map covers 10 mm from low (blue) to high (red).

Mentions: The lungfish was not always motivated to travel far, and occasionally declined to move at all. In one of these instances, we recorded the resting trace left behind after the animal was removed from the substrate (Fig. 6).


Trackways Produced by Lungfish During Terrestrial Locomotion
Resting trace of P. annectens on moist fine sand.The animal was oriented with anterior at the top of the image. Photo (left), Height map (centre), and ousupptline (right). Scale bar = 10 cm, height map covers 10 mm from low (blue) to high (red).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f6: Resting trace of P. annectens on moist fine sand.The animal was oriented with anterior at the top of the image. Photo (left), Height map (centre), and ousupptline (right). Scale bar = 10 cm, height map covers 10 mm from low (blue) to high (red).
Mentions: The lungfish was not always motivated to travel far, and occasionally declined to move at all. In one of these instances, we recorded the resting trace left behind after the animal was removed from the substrate (Fig. 6).

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.