RT Conference Proceedings
T1 MYOCARDIAL STRUCTURE AND VASCULARIZATION OF THE HEART VENTRICLE IN HOLOCEPHALI: IMPLICATIONS FOR HEART EVOLUTION
A1 Durán, Ana C.
A1 López-Unzu, Miguel A.
A1 Rodríguez, Cristina
A1 Lorenzale, Miguel
A1 Fernández, Borja
A1 Sans-Coma, Valentín
K1 Quimeriformes - Anatomía
AB It has been classically assumed that the ventricle of the primitive vertebrate heart iscomposed of spongy myocardium, supplied exclusively by oxygen-poor, luminal blood.This idea is on two facts: (1) extant agnathans have a spongy ventricular myocardium,and (2) in avian and mammalian embryos, the formation of trabeculated myocardiumprecedes the appearance of compact myocardium. Recently, it has been proposed that,like elasmobranchs, the early gnathostomes possess a fully vascularised ventriclecomposed of mixed myocardium. We tested this idea by studying the structure andvascularisation of the ventricular myocardium in four holocephalan species of thefamilies Chimaeridae and Rhinochimaeridae. Chimaera monstrosa, Hidrolagus affinisand Harriotta raleighana have a spongy myocardium covered by a thin layer of cardiacmuscle. In H. raleighana, the compacta is reduced to an extremely fine rim. In all threespecies there is a well-developed coronary artery system consisting of subepicardialvessels which give off branches that penetrate the myocardial trabeculae.Rhinochimaera atlantica has no compacta and its ventricular coronary artery system isreduced to subepicardial vessels that do not enter the spongy layer. This report is thefirst to show that in wild living vertebrates, a coronary artery system supplying the wholemyocardium exists in the absence of a well-developed compacta, which supportsexperimental work that shows that myocardial cell proliferation and coronary vasculargrowth rely on genetically separated programs. We conclude that the mixed ventricularmyocardium is primitive for chondrichthyans, and that the lack of compacta in someholocephalans is a derived character. Moreover our results support the hypotheses thatthe mixed myocardium is the primitive condition in gnathostomes, and that the absenceof a compacta in different actinopterygian taxa is the result of its repeated loss duringevolution.
YR 2013
FD 2013-07-25
LK http://hdl.handle.net/10630/5656
UL http://hdl.handle.net/10630/5656
LA eng
NO El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013. Anatomical Record, Volume 296, Special Feature — 1: P-075.
NO Proyecto CGL2010-16417/BOS; Fondos FEDER
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 13 abr 2026