Biología reproductiva y placentotrofía en lagartijas del género Mabuya

Abstract

ResumenPresento una revisión de los trabajos que desde mi laboratorio se han venido realizando sobre la biología reproductiva y la placentotrofía en varias poblaciones de lagartijas vivíparas placentotróficas del género Mabuya. En este grupo la ovogénesis produce huevos microlecitos y en relación a ello se encuentra la mayor complejidad placentaria conocida hasta ahora entre Reptilia que converge en muchos aspectos morfológicos y fisiológicos con la que se conoce en mamíferos euterios; sin embargo, también muestra características exclusivas muy interesantes. Esta complejidad placentaria permite una masiva transferencia desde el oviducto materno de todos los nutrientes necesarios para el desarrollo de los embriones durante los 9 a 10 meses que dura su gestación. En esta revisión muestro la manera como una pregunta de investigación inicialmente sencilla ha permitido ahondar en la biología de este particular clado y cómo las nuevas herramientas que están ahora disponibles a las ciencias biológicas nos permitirán responder preguntas fundamentales en un futuro próximo. Palabras clave: lecitotrofía, matrotrofía, oogenesis, placentación, reptiles escamados, viviparidad Reproductive biology and placentotrophy in lizards of the genus Mabuya AbstractI present a review of the studies that have been made from my laboratory about the reproductive biology and placentotrophy of populations of the viviparous and placentotrophic lizards of Mabuya genus. In this group the oogenesis produces microlecithal eggs and related to that, it is found the highest degree of placental complexity yet known among Reptilia, which converge in several morphological and physiological aspects with those known in eutherian mammals; however, it also shows very interesting exclusive features. This placental complexity allows the transfer from the maternal oviduct of all the needed nutrients for embryo development during the 9 to 10 months of gestation. In this review I demonstrate the manner in which a research question initially simple has permitted get deeper in the biology of this particular clade and how the new tools that are now available to the biological sciences will enable us to answer fundamental questions in the near future.Key words: Lecitotrophy, matrotrophy, oogenesis, placentation, squamate reptiles, viviparity Dentro de las varias especies en las que se han hecho estudios desde mi laboratorio, en los últimos 15 años hemos estado trabajando junto con otros investigadores y estudiantes en la biología reproductiva de poblaciones de la lagartija vivípara del género Mabuya (Figura 1a). De las lagartijas presentes en Colombia, tan sólo dos clados distantes tienen la viviparidad como modo de paridad (dos especies del género Diploglossus, familia Anguidae y las poblaciones del género Mabuya, familia Scincidae), todas las demás lagartijas son especies ovíparas. Las lagartijas del género Mabuya estaban agrupadas para ese entonces (1998) como Mabuya mabouya, nominación que se aplicaba para todas las poblaciones del territorio continental colombi...

Evolution of viviparity in squamate reptiles: Reversibility reconsidered

“…Variation in placental morphology also is consistent with independent origins of viviparity. Detailed interspecific comparisons have been made in five distinct lineages: thamnophine snakes (Stewart, ; Blackburn et al, , ; Blackburn and Lorenz, ,; Stewart and Brasch, ); South American Mabuya (Scincidae) (Blackburn et al, ; Blackburn and Vitt, , 2002; Jerez and Ramírez‐Pinilla, ; Ramírez‐Pinilla, , ; Leal and Ramírez‐Pinilla, ; Ramírez‐Pinilla et al, , ); a clade of North American Sceloporus (Phrynosomatidae) (Villagrán et al, ; Blackburn et al, ; Anderson et al, ); and two distantly related clades of Australian skinks (Stewart et al, 2000; Stewart and Thompson, , 2000, 2009a,b; Thompson et al, ; Adams et al, ). In each case, placental features are similar or identical in species within a lineage but vary extensively between clades.…”

Viviparous placentotrophy in reptiles and the parent–offspring conflict

“…Mabuya from Central and South America show very unusual specializations for histotrophic nutrient transfer. Placental morphology is similar in those species of the genus that have been studied (Blackburn and Vitt, '92, 2002;Ram ırez-Pinilla, 2001, 2003;Ram ırez-Pinilla et al, 2006;Leal and Ram ırez-Pinilla, 2008;Ram ırez-Pinilla, 2014). The yolk sac placenta regresses very early and the eggshell vestige disappears.…”

Reproductive biology of a viviparous lizard (Mabuya dorsivittata) from the subtropical Wet Chaco of Argentina: geographical variations in response to local environmental pressures

“…However, during the pre-ovulatory phase (follicular growth) a large mobilization of lipids would not be necessary to produce microlecithal oocytes, hence the cycle of fat-body mass in Mabuya species seems to be strongly associated with placentotrophy (gómez and Ramírez-Pinilla 2004). In this sense, the small diameter of oocytes at ovulation in M. dorsivittata, as throughout the clade Mabuya (Ramírez-Pinilla 2014), indicates the microlecithal character. The small size of the eggs results from a vitellogenic phase reduction as a consequence of the placental matrotrophy present in this group (Ramírez-Pinilla 2010, 2014.…”

“…In this sense, the small diameter of oocytes at ovulation in M. dorsivittata, as throughout the clade Mabuya (Ramírez-Pinilla 2014), indicates the microlecithal character. The small size of the eggs results from a vitellogenic phase reduction as a consequence of the placental matrotrophy present in this group (Ramírez-Pinilla 2010, 2014.…”