Meyer A, Lydeard C
Department of Ecology and Evolution, State University of New York, Stony Brook 11794.
Proc Biol Sci. 1993 Nov 22;254(1340):153-62. doi: 10.1098/rspb.1993.0140.
Cyprinodontiforms are a diverse group of approximately 900 pantropical and temperate fishes, mostly found in freshwater. Whereas the vast majority of fishes lay eggs (i.e. are oviparous), this group is unusual in that four groups of cyprinodont fishes give birth to living young (i.e. are viviparous). A molecular phylogenetic hypothesis was based on partial DNA sequences of the tyrosine kinase gene X-src. The study included the major lineages of fishes of the suborder Cyprinodontoidei, order Cyprinodontiformes. Our phylogeny agrees with some but not all of the conclusions of a previous morphological cladistic analysis (Parenti (Bull. Am. Mus. nat. Hist. 168, 335 (1981)). The differences are: (i) the Profundulidae are the sister group to the Goodeidae, not the sister group to all other cyprinodontoids; (ii) Fundulidae are the sister group to the Profundulidae and Goodeidae; (iii) Cubanichthys and the Cyprinodontinae might not be sister taxa; (iv) Cubanichthys, and not the Profundulidae, might be the most basal member of the cyprinodontoids; and (v) the Anablepinae and Poeciliinae might be sister groups. The molecular phylogeny was used to reconstruct the evolution of major life-history traits such as internal fertilization, copulatory organs, livebearing and placentas. Internal fertilization, modifications of the male's anal fin to form a copulatory organ, and viviparity probably evolved independently three times in cyprinodontiform fishes: in the subfamilies Goodeinae, Anablepinae and Poeciliinae (sensu Parenti 1981). The evolution of bundled sperm, spermatozeugmata, is probably not a prerequisite for internal fertilization because at least one species with internal fertilization has free spermatozoa. Livebearing (viviparity), which takes the form of ovoviviparity (where embryos are nourished by their yolk sac only), evolved only in the subfamily Poeciliinae. Advanced forms of viviparity, in which the mother provides additional nourishment to the embryos through placenta-like structures, apparently evolved at least three times from egg-laying ancestors: in the subfamilies Goodeinae, Anablepinae, and more than once in the Poeciliinae.
鲤齿目鱼类是一个多样化的类群，约有900种，分布于泛热带和温带地区，大多生活在淡水中。绝大多数鱼类产卵（即卵生），而鲤齿目鱼类的不同寻常之处在于，有四类鲤齿鱼是胎生的（即生出活的幼体）。一个分子系统发育假说基于酪氨酸激酶基因X-src的部分DNA序列。该研究涵盖了鲤齿亚目（鲤齿目）鱼类的主要谱系。我们的系统发育结果与之前形态学分支分析（Parenti（《美国自然历史博物馆通报》168, 335 (1981)）的部分结论一致，但并非全部。差异在于：（i）深底鳉科是古鳉科的姐妹群，而非所有其他鲤齿亚目的姐妹群；（ii）底鳉科是深底鳉科和古鳉科的姐妹群；（iii）古巴鳉属和鲤齿亚科可能不是姐妹分类单元；（iv）古巴鳉属而非深底鳉科可能是鲤齿亚目中最基部的成员；以及（v）溪鳉亚科和食蚊鱼亚科可能是姐妹群。分子系统发育被用于重建主要生活史特征的演化，如体内受精、交配器官、胎生和胎盘。体内受精、雄性臀鳍的形态改变以形成交配器官以及胎生在鲤齿目鱼类中可能独立演化了三次：分别在古鳉亚科、溪鳉亚科和食蚊鱼亚科（按照Parenti 1981的分类）。成束精子（精子束）的演化可能不是体内受精的先决条件，因为至少有一种体内受精的物种具有游离的精子。胎生（卵胎生，即胚胎仅由卵黄囊提供营养）仅在食蚊鱼亚科中演化。更高级形式的胎生，即母亲通过类似胎盘的结构为胚胎提供额外营养，显然至少从卵生祖先演化了三次：分别在古鳉亚科、溪鳉亚科，以及在食蚊鱼亚科中演化了不止一次。
