Ciclo ovárico y jerarquía folicular de Peltocephalus dumerilianus (Testudines: Podocnemididae)

Abstract

Resumén se analizaron cuarenta pares de ovarios de hembras adultas de Peltocephalus dumerilianus (schweigger 1812), para establecer los cambios morfológicos mensuales producidos durante un año. se llevaron a cabo exámenes macroscópicos de los oviductos y de los ovarios de especímenes que los habitantes ribereños del municipio de Barcelos, amazonas, Brasil, utilizaron para su consumo, usando metodológicamente la medida del diámetro y conteo de los folículos ováricos y de los cuerpos lúteos. Los resultados muestran la presencia gradual de folículos acorde con la época reproductiva, resaltando que durante el último tercio del proceso, justo antes de la postura se hacen más evidentes; se analiza la relación existente entre el tamaño de la hembra y la masa ovárica, la cual es estadísticamente significativa (F (10,29)=3,655, p < 0,05). se hace evidente la existencia de una jerarquía ovario folicular que demuestra que para esta especie solo es posible fisiológicamente una postura por año. PalabRas-Clave: Ovarios, folículos, ciclo reproductivo, Peltocephalus dumerilianus, Brasil. Ovarian cycle and follicular hierarchy of Peltocephalus dumerilianus (Testudines: Podocnemididae)abstRaCt Forty pairs of ovaries of mature female Peltocephalus dumerilianus (schweigger 1812) were analyzed, to establish the morphologic monthly changes that take place during one year; we examined macroscopically the oviducts and the ovaries of specimens that the riverside inhabitants of the municipality of Barcelos, amazons, Brazil, used for their consumption. We measured the diameter and recorded the number of enlarged ovarian follicles and corpora lutea. The results show the gradual enlargement of follicles in agreement with the reproductive period, observing that during the last third of the process; just before oviposition they become more evident. The positive relationship between the size of the female and the ovarian mass, is statistically significant (F (10.29)=3.655, p <0.05). Follicullar sizes suggest that this species nests only once a year.

Reproductive biology, morphology, and morphometry of ovaries and oviducts of Trachemys scripta elegans in Brazilian Cerrado

“…The significant relationship between female size (body mass and plastron length) and left ovary length suggested that the gonadal growth was concomitant with the body growth, and supported the existence of a positive relationship between brood size and female size as described in other species (Ceriani & Wyneken 2008, Delgado 2006, Velasquez & Vogt 2011, Failla et al 2018), but different from sea turtles (Hamann et al2003) and C. mydas juveniles Rosa (2005Rosa ( , 2009.…”

“…This structure resembles, in some aspects, those of some species of mammals (Guillette Junior et al 1995) and has as their key function, the preservation of the pregnancy or of the eggs which are developing inside the oviducts (Gemmell 1995). For this reason, the higher activity of the corpus luteum coincides with the formation of external membranes in the oviducts (Altland 1951), which explains their regression shortly after (Velasquez & Vogt 2011) or up to three months after spawning in the genera Pseudemys and Graptemys (Webb 1961). In T. scripta elegans corpus luteum were visualized in females with eggs inside the oviducts and were distinguished from the follicles by their translucent white coloration ( Fig.8) as in sea turtles (Owens 1980).…”

“…The presence of follicles of different diameters (<5mm up to >25mm), as well as corpus luteum and eggs in the oviducts, highlighted a similarity of follicular development among specimen of the same species (Perez-Santigosa et al 2008) and other species (Ramo 1982, Velasquez & Vogt 2011 and reflected the ovarian complexity of the analyzed females, which ranged from the beginning of the period of ovarian maturation to the presence of eggs and corpus luteum. These findings denote the presence of ovarian follicular hierarchy (Velasquez & Vogt 2011) characterized by the presence of follicles at all maturation stages, including also not-vitellogenic follicles (Etches & Petitte 1990). This hierarchy can be accepted as a reproductive strategy to keep the highest possible number of follicles available and thus reduce the probability of losses caused by excessive and effective ovulation, making a possible rapid ovarian recovery and ensuring maximum reproduction of females at each station.…”

“…This hierarchy can be accepted as a reproductive strategy to keep the highest possible number of follicles available and thus reduce the probability of losses caused by excessive and effective ovulation, making a possible rapid ovarian recovery and ensuring maximum reproduction of females at each station. In chelonians, these characteristics may increase as a function of the size of the female (Velasquez & Vogt 2011), as observed in G2, which presented a significant number of follicles (Table 2).…”

“…In this species the right ovary was larger than the left due to the higher number of vitellogenic follicles (Chaves et al 2012). The average mass of right and left ovaries in the G1 groups (7.46 and 9.99g, respectively); G2 (13.01 and 18.57g) and G3 (14.58 and 14.45g) were higher than those of K. scorpioides (6.25±4.23g and 2.27±1.42g, respectively) (Chaves et al 2012), while Velasquez & Vogt (2011) observed in Peltocephalus dumerilianus values ranging from 1.31 to 48.25g and 1.21 to 45.66g, respectively. In T. scripta elegans the presence of enlarged or pre-ovulatory follicles, eggs or distended oviducts, suggest recent oviposition (Perez-Santigosa et al 2008) and, after the oviposition period, no eggs or follicles larger than 21mm, but only follicles of 7 to 13mm, and in a small proportion of females, also a few pre-ovulatory follicles of 14-20mm, corroborating with those observed in groups G1 and G2, respectively.…”