A Complete Embryonic Developmental Table of Microhyla fissipes(Amphibia,Anura,Microhylidae)

Access to embryonic developmental stages is essential basic work for understanding how organisms develop. In this study, seven egg clutches（range 209–564 eggs） of ornamented pygmy frog Microhyla fissipes（Amphibia, Anura, Microhylidae） were obtained from seven breeding pairs in laboratory. One egg clutch of them was observed for the embryonic development, and the staging table of normal development was constructed based on morphological and physiological characteristics. Forty-five developmental stages were defined for M. fissipes, and two major developmental periods were designated： 1） early embryonic development period（stages 1–28）, from fertilization to operculum completion stage, lasted for 82.6 hours at water temperature（WT） 23–25℃; 2） larval development period（stages 29–45）, from operculum completion to tail complete absorption stage, took 38 days at WT 22–26.5℃, showing that the embryos of this species develop rapidly. In addition, the tadpoles were transparent, which is similar to those in field. These characteristics suggest that M. fissipes would be a good model to study developmental biology, adaptive mechanisms from aquatic to terrestrial phases, environmental toxicology, and human disease.

Early embryonic development and transplantation in tree shrews

As a novel experimental animal model, tree shrews have received increasing attention in recent years. Despite this, little is known in regards to the time phases of their embryonic development. In this study, surveillance systems were used to record the behavior and timing of copulations; embryos at different post-copulation stages were collected and cultured in vitro; and the developmental characteristics of both early-stage and in vitro cultured embryos were determined. A total of 163 females were collected following effective copulation, and 150 were used in either unilateral or bilateral oviduct embryo collections, with 307 embryos from 111 females obtained （conception rate=74%）. Among them, 237 embryos were collected from 78 females, bilaterally, i.e., the average embryo number per female was 3.04; 172 fertilized eggs collected from 55 females, bilaterally, were cultured for 24-108 h in vitro for developmental observations; finally, 65 embryos from 23 bilateral cases and 70 embryos from 33 unilateral cases were used in embryo transplantation.

Effect of Incubation Temperature on the Somatic Development of the Snail-Eating Turtle Malayemys macrocephala

The rising average global temperature can lead to changes both in the physical and biological environments and affect the survival of organisms. Freshwater turtles are considered to be susceptible species since their development is dependent on incubation temperature. In Thailand, although several species of freshwater turtle are present, the extent of their susceptibility to temperature change is unknown due to the lack of information on their developmental patterns. This research, therefore, is aimed at examining the effects of temperature on somatic development in Malayemys macrocephala, a native species and the most common freshwater turtle in Thailand. Turtle eggs were collected from rice fields in the central part of Thailand during December 2011 to February 2012 inclusive. Eggs （237-238 per condition） were incubated in microprocessor-controlled incubators at three different temperatures （26 ℃, 29℃ and 32℃） with a relative humidity in excess of 80%. Each week, until the remaining eggs hatched, eggs were randomly selected, removed and dissected to reveal the developing embryo to screen for developmental stage and any abnormalities. The incubation period （lay to hatch） was not significantly different among the three temperatures （115 ±11.3 d, 115 ±20.3 d and 109±17.8 d, respectively）, but the growth patterns, as indicated by the stages of development and carapace lengths, were significantly different. At a high temperature （32℃）, turtle embryos showed a significantly faster growth rate than at the intermediate and low temperatures （29 ℃and 26 ℃）, but had a significantly （over 3.3-fold） higher incidence of developmental abnormalities （especially deformed bodies） than at the lower temperatures. Overall, the results indicate that incubation temperature is an important variable affecting the somatic development of this tropical freshwater turtle species, whilst abnormalities in the embryonic body may be a sensitive indicator of extreme thermal stress.