Adaptive morphology of the heart of Southern‐Fur‐Seal (Arctocephalus australis– Zimmermamm, 1783)

Abstract

The Southern‐fur‐seal belongs to the order Carnivora, suborder Pinnipedia, and Otariidae family. This species inhabits aquatic and terrestrial environments, thus presenting important morphophysiological adaptive changes, especially in the cardiac system. For this purpose, Southern‐fur‐seal (Arctocephalus australis) hearts were used from animals that died from natural causes. Gross morphology observations were supported by light, scanning and transmission electron microscopy. The heart was long and flat; it was lined by pericardium and partly covered by lungs. Structurally, atrium and ventricle muscle fibers exhibit typical features of cardiac fibers revealing myofibrils bundles, mitochondria, plate‐shaped junctions, anastomosis between myofibrils bundles, and electron‐dense granule natriuretic around the nucleus and mitochondria of atrium muscle cells. The Southern‐fur‐seal heart was structurally similar to other mammals; however, it presented morphological changes that assist in their adaptation to their environment.

Comparative electrocardiogram in two anesthetized pinnipeds, the South American fur seal (Arctocephalus australis) and the Southern sea lion (Otaria byronia), with analysis of ECG parameters allometry

“…The Southern sea lion (SSL, Otaria byronia a ) and the South American fur seal (SAFS, Arctocephalus australis ) are the most common species of Pinnipedia in South America. The cardiac morphology of SAFS is structurally similar to other mammals, with some changes that may be associated with their adaptation for breath‐hold diving (Guimarães et al, 2014; Pérez et al, 2008), but there are no similar anatomical studies for the SSL. In previous reports, our research group has provided one echocardiographic description of the left ventricular structure and function in the SSL (Castro et al, 2018) and detailed ECG descriptions of anesthetized SSL and SAFS adult females (Dassis et al, 2016, 2019).…”

Angioarchitecture of collateral arteries of the aortic arch of Antillean manatee (Trichechus manatus manatus Linnaeus, 1758)

“…The right common carotid artery and left and right subclavian arteries emerge from the brachiocephalic trunk. This arrangement was reported in the southern‐fur‐seal ( Arctocephalus australis ; Guimarães, Mari, Le Bas, & Watanabe, ), while in the majority of terrestrial species studied, it predominated in rodents such as the paca ( Agouti paca ; Oliveira, Machado, Miglino, & Nogueira, ), long‐tailed chinchilla ( Chinchilla lanigera ; Araújo, Oliveira, & Campos, ; Özdemir, Çevik‐Demirkan, & Türkmenoğlu, ), guinea‐pig ( Cavia porcellus ; Kabak & Haziroglu, ), rock cavy ( Kerodon rupestris ; Magalhães, Albuquerque, Oliveira, Papa, & Moura, ), coypu ( Myocastor coypus ; Campos, Araújo, & Azambuja, ) and the spix's yellow‐toothed cavy ( Galea spixii ; Oliveira et al, ).…”

Morphology of aortic arch branching patterns in the Eurasian Otter (<i>Lutra lutra</i>, Linnaeus, 1758)

“…Many species, such as rabbits [ 3 ], monkeys [ 11 ], and pigs [ 42 ], are AA-type 2. Most carnivores, such as the dog [ 1 , 15 ], cat [ 27 ], sea otter [ 44 ], crab-eating raccoon [ 39 ], red fox [ 31 ], ocelot [ 25 ], and southern-fur-seal [ 13 ], are also AA-type 2. In AA-type 3, the three branches of the BCT, LCC, and LSB arise from the AA.…”