Walking

Work by Manton (1952 to1977) has allowed work to be carried out on eurypterid locomotion by reconstructing fossil arthropod walking patterns.  Trace fossil evidence and body fossil reconstruction can be used to deduce gait patterns.  Gait tells us the relative proportions of legs that were on and off the ground at any one time.  Each individual track gives the imprint of the particular appendage, a repeat of 2 or more tracks is known as a trackway, while an unrecognised track (due to substrate or behaviour) is known as a trail.  Trackways can be compared to extant taxa, to gain more information on locomotion.

Swimming

For eurypterids, that have paired appendages, swimming underwater has been termed 'subaqueous flying'.  In order to swim the weight and drag of the animal must be overcome, in other words the animal must produce a thrust to overcome drag.  At a low velocity water flows smoothly over the body causing little wake, however, at a higher velocity water will produce a swriling wake behind the animal forming eddies.  The  6th prosomal appendage functions as a stearing or stabilizing paddle.  In some forms the telson was used as a rudder, aiding manuverability.

Swimming can be placed into 2 mechanisms, drag based and lift based.  Drag based swimming means that the animal will use a power stroke, where the drag on the appendage is maximised, and a recovery stroke where it is minimised.  This implies that muscles involved in the power stroke will be much stronger than those used in the recovery stroke.  Lift based swimming uses a hydrofoil or 'wing'.  The basic movement of this appendage will be up and down.  In order to over come gravity, the downward stroke will be longer that the upward stroke, so the animal will not sink.  However, in negatively buoyant animals both strokes will need to be the same.