【作者】 牟迈；

【导师】 龚大洁；

【作者基本信息】 西北师范大学 ， 生态学， 2008， 硕士

【摘要】 文县疣螈(Tylototriton wenxianensis Fei, Ye et Yang, 1984)俗称山娃娃鱼,隶属有尾目(Caudata)、蝾螈科(Salamandridae)、疣螈属(Tylototriton),是我国特有的珍稀有尾两栖动物,因在甘肃文县发现而得名,在四川、重庆、贵州、湖南、安徽等地也有分布。目前,有关文县疣螈的研究报道甚少,仅限于分类、形态描述和生态习性方面,其他方面几乎处于空白。因此,研究文县疣螈的繁殖和种群分布不仅能填补该领域的空白,为其他研究提供基础资料,也能为该物种的保护工作起到一定的指导作用。2006～2007年,在甘肃文县和四川青川县,采用直接计数法、样方法、标志重捕法和访问法,调查了文县疣螈的种群数量和分布。在繁殖场实地观察并记录了其雌雄特征、性比、繁殖行为等,并利用仪器测量了各种生境指标。室内饲养过程中,观察和记录了幼体的生长发育。数据以SPSS和Excel 2003软件统计分析。另外,还利用光学显微镜和透射电子显微镜观察和研究了精子和精巢的微观结构。结果表明,文县疣螈在甘肃、四川的分布主要在文县和青川县,平武县也有分布,其中青川的种群数量最多。调查中,共发现文县疣螈繁殖场3处,其中2处发现成体,而在繁殖场之外仅发现零星个体。共发现成体83尾,幼体141尾,卵302粒。成体雄螈和雌螈的形态量度无明显差异,利用数量性形态学特征鉴定该螈的性别不可行。因此,目前较为常用和可靠的方法仍是雌、雄泄殖腔部差异鉴别和解剖学方法。该螈3月底出蛰,随着气温升高和降雨量增加,开始向繁殖场迁移。通常是雄性先迁入繁殖水塘周围的陆地上占区后,雌性才迁入,但雌性产卵后即迁出,而雄性迁出通常在繁殖末期。繁殖期性比明显偏雄,雌雄性比先逐渐升高,后逐渐下降,在5月中下旬达到最高。求偶时雄螈占主动,并伴有竞争现象。求偶、交配和产卵均在繁殖水塘周围的陆地上进行。产卵环境颇为一致,一般在腐叶间或以腐叶覆盖的泥土上。体内受精,雌螈纳精后即开始选择产卵位点,然后筑巢,产卵多在筑巢后24h开始。从纳精到产下第一粒卵的间隔约为48 h(2d)。产卵时间多在傍晚至次日黎明,集中在20:00~次日4:00,昼时较少见到。每次产卵1粒,雌螈产卵期长达(26.8±1.3)d (n=6),产卵量在(42.8±11.9)粒(n=6)左右。窝卵数与成体大小成正相关,线性回归方程为:Y=-27.27+0.859x,[r=0.924, P<0.001]。刚产出的卵近球形,周围由一层卵外胶次膜包裹,卵外胶次膜在(5.1±1.3)d(n=50)后消失。卵由内层的胚盘和外层的卵胶囊构成。初生卵单粒重0.203(0.098~0.233)g(n=52),卵径为(4.2±1.8)mm(n=52)。动物极浅棕色,植物极乳白色,中央具胚盘,由于地心引力作用胚盘总是向下。精子除可见头部、颈部和尾部外,其他结构不明显。精巢的光镜观察可见曲细精管、精小叶、输出管等结构以及各级生精细胞和精子束。精巢间质为富含血管和淋巴管的疏松结缔组织,除成纤维细胞、血细胞外,还可见间质细胞。电镜下,各级生精细胞及支持细胞、间质细胞核较明显,滤泡细胞除核外,可见明显的线粒体、糙面内质网等细胞器。文县疣螈的致危因素主要为生境退化和丧失、过度采集和环境污染等。其中,生境丧失是最直接的影响因素。生境丧失不仅剥夺了文县疣螈基本的生存条件,更使其繁殖活动受到严重影响。因此,应大力加强该物种生境的保护,在维护现有生境的基础上,开辟新的生境,如新建繁殖场和生境走廊等,保证其繁殖活动正常进行,尤其要避免对产卵场的干扰和破坏。另建议提高保护级别,鼓励国家和当地政府制定保护措施。同时,应加强宣传教育,尽量减少人为捕捉现象和栖息地的环境污染,并积极开展迁地保护和人工繁育。更多还原

【Abstract】 Tylototriton wenxianensis (Fei, Ye et Yang, 1984)also called Shan wa-wa yu, on attachment to Tylototriton, Salamandridae, Caudata, is epidemic to China, first discovered in Wenxian of Gansu Province and also rarely distributed in Sichuan, Guizhou, Hunan, Anhui and Chongqing. Since the species is so rarely known and narrowly distributed, little studies were made on it, and they are limited in classification, morphology and ecology while almost no studies in other field. Therefore, the study on breeding and population distribution could not only fill the gap and provide basic document for other studies, but could also guide the protection of the species.During 2006 to 2007, in Qingchuan of Sichuan province and Wenxian of Gansu province, we investigated into the population and distribution using direct counting method, quadrat sampling method, marking-recapture method and access method. We also observed and recorded the breeding habitat, sex ratio during the breeding season, male and female fetures, breeding behaviors, growth and development of, and captive feeding and measured kinds of habitat index with instruments. The data were analyzed with SPSS and MS Excel 2003. We also observed the microstructure and ultra structure of sperm and spermary through optical microscope and TEM, in contrast with the species of Salamandridae.The result shows that the newts distributed in Gansu and Sichuan are mainly focused in Wenxian and Qingchuan, as well as Pingwu and Qingchuan has the largest population. The investigation has found 3 breeding sites (2 with adults) and no adults were found beyond the breeding sites, along with 83 adults, 141 juveniles and 302 eggs. There are no violent differences in morphological measurement of adult males and females, so it’s not feasible to distinguish between the sexes by quantitative morphology. The sex ratio was obviously desciscent to male in breeding seasons. The ratio of males to females rose at first and then fell. The population reached a peak during mid-May to late may as well as the ratio of females. The newt came out of hibernation in late March and set out to migrate to the breeding sites with the rising temperature and rainfall. The observation showed that at first the males migrated into the land around the pool and occupy the territory, and then the females got in. However, the females migrated out as soon as they finished breeding while the males at the end of breeding season. The breeding habitat looked almost the same. The female finished spawning in a short time without male involved. Spawning lasted 2-3 days smoothly in rainy seasons without interference. They moved to the spawning pools no sooner than they selected the proper sites. Spawning began one day later. The female spawned one a time lasting half a hour, and the whole course 5-6 hours. The course maintained a even pace slowly without a peak. The body size was positively related to the number of eggs per nest. Regression equation: Y=-27.27+0.859x, [r=0.924, P<0.001]. The eggs firstly laid were almost round wrapped by zonated secretion. The secretion was filmy when unfolded which was called meninx secundaria. The secretion disappeared in (5.1±1.3) d (n=50). The egg consisted of blastoderm inside and egg jelly outside. The firstly laid egg weighed 0.203(0.098~0.233) g (n=52) with the diameter of (4.2±1.8) mm (n=52). The animal pole was light brown and vegetate pole milky white. There’s a blastoderm in the center which kept hanging downwards attracted by the gravity from the earth.The sperm consisted of head, neck and tail, which were different from those of reported salamanders. The ultra structure of spermary showed spermatogenous cells, spermatocytes, sustentacular cells, interstitial cell, follicular cells etc., and no spermoblasts and sperms were found.The main factors causing the newt in severe danger are the loss and destruction of habitat, excessive seizure and pollution. The loss of habitat is the most direct factor which could not only deprive the newt of basic life condition but could also seriously affect the breeding behavior. Therefore, the habitat protection should be strengthened and open up such new habitat as new breeding sites and transit corridors when maintaining the current habitat. To guarantee regular breeding behavior and especially to avoid destroying the breeding sites. We suggest upgrading the protection level and encouraging the state and local government to draw up measures for protection. Meanwhile, artificial seizure and pollution in habitat should be reduced and allochthonous protection and artificial breeding should be carried out.更多还原