A new early tetrapod, Mesanerpeton woodi gen. et sp. nov., collected by Stan Wood from the Ballagan Formation, Tournaisian CM palynozone, at Willie's Hole, Scottish Borders, is described. It includes vertebrae like those of Crassigyrinus, with poorly developed neural arches, a well ossified ulna with a large olecranon, and a humerus that is structurally intermediate between the pleisiomorphic condition of Devonian taxa and that of all later forms. A comparative analysis of this new material and other tetrapodomorph humeri revealed how an increase in humeral torsion transformed the course of the brachial artery and median nerve through the bone, from an entirely ventral path to one in which the blood vessel and nerve passed through the entepicondyle from the dorsal to the ventral surface. Increasing humeral torsion is suggested to improve walking in early tetrapods by potentially contributing to an increase in stride length, and is one of a number of changes to limb morphology during the Early Carboniferous that led to the development of terrestrial locomotion.

Twelve mature and six 2-year-old Arabian horses were used to determine the effect of dietary long-chain polyunsaturated omega-3 fatty acid supplementation on plasma fatty acids and lameness. Lameness scores and stride lengths were measured on day 0. Horses were striated and pair-matched according to age, gender, stride length and, for mature horses, lameness score, and each horse was fed either a treatment diet containing 5.95 g of stabilized omega-3 fatty acids plus a fat carrier (FA), for a total of 19.4 g fat, or a control diet containing 49 g of corn oil (CO) for 75 days. Horses were exercised 5 d week− 1, and blood samples were drawn and body weights recorded on days 0, 25, 50 and 75. Lameness scores and stride lengths were recorded again on day 75. Total plasma omega-3 fatty acid concentrations were higher on all days in FA horses than in CO horses. Total plasma omega-6 fatty acids increased from days 0 to 25, remained elevated through day 50 and returned to baseline on day 75 in all horses. The ratio of plasma omega-6:omega-3 fatty acids was lower in FA horses. Horses on FA had increased plasma docosahexaenoic acid (DHA) on days 25, 50 and 75. No difference in walk stride length was noted; however, FA horses tended to have a longer trot stride after supplementation when compared with CO horses. No differences were seen in prostaglandin E2 (PGE2) metabolite or tumour necrosis factor-α as measured in blood serum. In summary, supplementing omega-3 fatty acids increases plasma DHA, although there was no overall increase in omega-3 in FA horses. While a trend to increase trot stride length was seen, no differences in lameness scores between treatments were noted.