Vidal Nicolas, Hedges S Blair
Service de systématique moléculaire, Institut de systématique (CNRS FR 1541), Muséum national d'histoire naturelle, 43, rue Cuvier, 75231 Paris, France.
C R Biol. 2002 Sep;325(9):977-85. doi: 10.1016/s1631-0691(02)01510-x.
Higher-level snake relationships are inferred from sequence analyses of one nuclear gene (C-mos) and three mitochondrial genes (12S rRNA, 16S rRNA and cytochrome b). Extant snakes belong to two lineages: the fossorial Scolecophidia, which feed on small prey on a frequent basis, and the ecologically diverse Alethinophidia ('typical' snakes), which feed on large prey on an infrequent basis. The vast majority of Alethinophidia, if not all of them, belong to two clades, corresponding to two distinct prey neutralization modes: unimodal constriction for the Henophidia (locomotor and feeding systems coupled) and injection of toxic saliva, in addition (or not) to diverse alternate modes of constriction, for the Caenophidia (locomotor and feeding systems uncoupled). Within Alethinophidia, non-macrostomatan (small gape) Aniliidae (genus Anilius) and macrostomatan (large gape) Tropidophiidae (genera Trachyboa and Tropidophis), both from the Neotropics, are closest relatives. Although our data are insufficient to robustly infer the ancestral mode of life of snakes, we find evidence of plasticity in the basic ecological and trophic modes of snakes. Consequently, the macrostomatan condition should not be treated a priori as a derived character state devoid of homoplasy.
通过对一个核基因（C - mos）和三个线粒体基因（12S rRNA、16S rRNA和细胞色素b）的序列分析推断出更高层次的蛇类关系。现存的蛇类属于两个谱系：穴居的盲蛇亚目，它们频繁捕食小型猎物；以及生态多样的真蛇亚目（“典型”蛇类），它们不频繁地捕食大型猎物。绝大多数真蛇亚目（如果不是全部的话）属于两个进化枝，对应两种不同的猎物中和模式：蟒蚺亚目采用单峰收缩方式（运动和进食系统耦合），而新蛇亚目除了（或不采用）多种不同的收缩方式外，还会注入有毒唾液（运动和进食系统不耦合）。在真蛇亚目内部，来自新热带界的非巨口类（小口裂）的筒蛇科（筒蛇属）和巨口类（大口裂）的美洲闪鳞蛇科（美洲闪鳞蛇属和闪鳞蛇属）是近亲。虽然我们的数据不足以确凿地推断蛇类的原始生活方式，但我们发现了蛇类基本生态和营养模式具有可塑性的证据。因此，巨口类的情况不应被先验地视为一种没有同塑性的衍生性状状态。
