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Ovarian tissue vitrification is a promising method to preserve follicles and gametes, but can be improved with mineral supplementation to the vitrification medium. The objective of this study was to determine the effects of supplementing 0.5 mg/mL zinc chloride to the media during cryopreservation of pig ovarian tissue. After thawing, the following criteria were evaluated: (1) follicular development and damage, (2) in vitro fertilization (IVF) characteristics, and (3) embryonic development. The number of damaged antral follicles (72.0 [+ or -]3.8%) was less (p, INTRODUCTION There is a growing interest and need for cryopreservation techniques to be improved so that ovarian tissue and oocytes can be preserved in biomedical models and endangered species (Mouttham [...]

Lizard activity patterns are restricted by both intrinsic and extrinsic variables. The Mexican Plateau Horned Lizard (Phrynosoma orbiculare) is endemic to México and an ambush forager and viviparous species that becomes dormant during the cooler months. The objective of this study was to determine the spatiotemporal activity patterns of P. orbiculare and the environmental conditions related to its occurrence in the natural protected area Statal Park Sierra Morelos, State of Mexico, México. We conducted samplings during 2018 and 2019. We assessed temporal activity patterns with Watson's U2 test to determine differences in activity hours between age classes, sexes, and seasons, and we evaluated spatial activity patterns through a hotspot analysis. We conducted a logistic regression model by using landsat 8 bands and indices as independent variables. Differences in temporal activity patterns (activity timing) were detected between age classes and seasons (in the juvenile group) but not between sexes. Within the natural protected area, P. orbiculare aggregated in solar glades. There is an important contribution of ultrablue and blue landsat bands to P. orbiculare occurrence. Differences in activity between age classes could be related to the heat acquisition rate of smaller individuals; meanwhile, no differences between sexes suggests that the thermal optima of females are similar to male optima. Hotspot analysis and the distribution model reveal that P. orbiculare appears on the windward slope where sunrise occurs. Solar glades are important for the species occurrence and should be protected in the studied area. These data allow future monitoring studies to help prevent population declines and illegal extraction. [ABSTRACT FROM AUTHOR]

The reproductive activity of reptiles is typically assessed using monthly sampling. The spermatogenic cycle of Sceloporus variabilis was recently assessed using the aforementioned methodology, and only two spermatogenic phases (recrudescence and maximum activity) were observed. The authors hypothesized that quiescence and regression must occur in a short period (less than a month), which was not visualized by their monthly sampling methods. Thus, the entire spermatogenic cycle displayed by this species may have not been adequately represented. The present study assessed the spermatogenic cycle of S. variabilis in those months where the spermatogenic activity passes from maximum activity (July) to recrudescence (August) using weekly sampling to test the hypothesis that quiescence and regression do indeed occur. The results showed a regression period for 2 weeks, whereas quiescence was not observed. These results lead us to two hypotheses: (a) quiescence occurs in a very short period (days/hours) or (b) does not occur in this species. The data generated in this study suggest that species exhibiting rapid changes in spermatogenic activity need to be assessed at more frequent intervals to accurately depict the spermatogenic stages. [ABSTRACT FROM AUTHOR]

Although different mechanisms exist to explain the presence of polymorphism in lizards, one model suggests that multiple morphotypes display the same level of fitness. Three male morphs (grey, yellow and orange) coexist in Sceloporus aeneus, a Mexican endemic oviparous lizard. Using a histological perspective, we test the hypothesis that spermatogenic output does not vary across morphotypes of S. aeneus during its maximum testicular activity. Males of S. aeneus (five grey, five yellow and five orange) were collected in Calimaya, Estado de México, Mexico. Snout‐vent length (SVL), testis mass, diameter and epithelial heights for the seminiferous tubules and epididymis, and the number of layers of germ cells did not vary among morphs; moreover, according to principal component analysis, a high overlap among lateral colour morphs exists. Our results suggest strongly that the lateral colour morphs in S. aeneus have the same spermatogenic output, and natural selection may be a stronger driving force than sexual selection within this species. Further studies into other lizard species with multiple morphotypes are required to determine whether the lack of variation in spermatogenic output observed in this endemic lizard is consistent across polymorphic species which will provide a greater understanding of the selective mechanisms acting on an individual's fitness. [ABSTRACT FROM AUTHOR]

Gaining a deeper understanding of spermatogenic cycles within squamates has aided in our knowledge of the controls of reproduction and has bettered our understanding of reproductive phenology. One of the most studied genera of squamates, Sceloporus, is widely distributed along a latitudinal and elevational gradient in temperate, tropical, low‐elevation and high‐elevation habitats. Due to this wide distribution and varying habitats, Sceloporus exhibit differences in their spermatogenic activity (including both cyclical and acyclical patterns) and may be one of the most useful genera for understanding the abiotic correlations with spermatogenesis. The spermatogenic activity in Sceloporus variabilis was studied histologically (in a population that inhabits a tropical region at Los Tuxtlas, Veracruz, Mexico) and found to exhibit a unique cyclical pattern with an extended period of maximum activity (from November to July) and the absence of regression and quiescence. Furthermore, these data corroborate previous works on the spermatogenic cycles of S. variabilis despite different populations utilised. These data suggest that although abiotic factors may play a role in the timing of spermatogenesis, phylogenetic signal may be equally as important. More data concerning spermatogenic cycles in phylogenetically related taxa from differing habitats will elucidate the patterns of spermatogenic diversity. [ABSTRACT FROM AUTHOR]

We describe the home range and movements of a population of Kinosternon integrum in Tonatico, Estado de México, México, over 3.5 years (during rainy and dry season months) using radiotelemetry in 37 adult turtles. The results showed that the home range of K. integrum was 0.151 ± 0.051 ha using 50% kernel density estimator ( KDE), and 0.657 ± 0.214 ha using 95% KDE; the home range did not vary between sexes. Kinosternon integrum showed low distances traveled 51.44 ± 4.50 m, where 87.3% ( n = 373) of movements were <100 m. The distance traveled differed by season, and movement category (aquatic and terrestrial movements). The shortest distance occurred during the dry season, during which some individuals move to estivation sites, and these movements were shorter than movements to artificial ponds (cattle ponds). In this population, home range and movement are similar to other species of the genus Kinosternon. Overall, the results indicate than K. integrum are highly dependent on aquatic habitats, but also utilize the terrestrial habitats for different biological activities, and to maintain viable populations. Therefore, the conservation of the entire inhabited area is fundamental. This study highlights the need to increase the studies, in Central México, concerning habitat use of freshwater turtles in order to increase the efficiency of conservation strategies. [ABSTRACT FROM AUTHOR]