Dear MARMAM subscribers, We are happy to share two new publications listed below: (1) Lillie MA, Piscitelli MA, Vogl AW, Gosline JM, and Shadwick RE. 2013. Cardiovascular design in fin whales: high-stiffness arteries protect against adverse pressure gradients at depth. J Exp Biol 216 : 2548-2563. Abstract Fin whales have an incompliant aorta, which, we hypothesize, represents an adaptation to large, depth-induced variations in arterial transmural pressures. We hypothesize these variations arise from a limited ability of tissues to respond to rapid changes in ambient ocean pressures during a dive. We tested this hypothesis by measuring arterial mechanics experimentally and modeling arterial transmural pressures mathematically. The mechanical properties of mammalian arteries reflect the physiological loads they experience, so we examined a wide range of fin whale arteries. All arteries had abundant adventitial collagen that was usually recruited at very low stretches and inflation pressures (2-3kPa), making arterial diameter largely independent of transmural pressure. Arteries withstood significant negative transmural pressures (-7 to -50kPa) before collapsing. Collapse was resisted by recruitment of adventitial collagen at very low stretches. These findings are compatible with the hypothesis of depth-induced variation of arterial transmural pressure. Because transmural pressures depend on thoracic pressures, we modeled the thorax of a diving fin whale to assess the likelihood of significant variation in transmural pressures. The model predicted that deformation of the thorax body wall and diaphragm could not always equalize thoracic and ambient pressures because of asymmetrical conditions on dive descent and ascent. Redistribution of blood could partially compensate for asymmetrical conditions, but inertial and viscoelastic lag necessarily limits tissue response rates. Without pressure equilibrium, particularly when ambient pressures change rapidly, internal pressure gradients will develop and expose arteries to transient pressure fluctuations, but with minimal hemodynamic consequence due to their low compliance. Article is available online at the Journal of Experimental Biology website or by email from Margo Lillie at lillie@zoology.ubc.ca (2) Piscitelli MA, Raverty SA, Lillie MA, and Shadwick RE. 2013. A review of cetacean lung morphology and mechanics. J Morph *Early View online. *(DOI: 10.1002/jmor.20192) Abstract Cetaceans possess diverse adaptations in respiratory structure and mechanics that are highly specialized for an array of surfacing and diving behaviors. Some of these adaptations and air management strategies are still not completely understood despite over a century of study. We have compiled the historical and contemporary knowledge of cetacean lung anatomy and mechanics in regards to normal lung function during ventilation and air management while diving. New techniques are emerging utilizing pulmonary mechanics to measure lung function in live cetaceans. Given the diversity of respiratory adaptations in cetaceans, interpretations of these results should consider species-specific anatomy, mechanics, and behavior. Article is available online at the Journal of Morphology early view or by email from Marina Piscitelli at piscitellim@gmail.com. Please note there is substantial online supplemental material (appendices) online as well. Best Wishes, Marina ______________________________ Marina A. Piscitelli, Ph.D. Candidate Department of Zoology The University of British Columbia 6270 University Blvd. Vancouver, BC CANADA V6T 1Z4 ________________________________