Karyotypes are described for Micruroides euryxanthus from Arizona and Micrurus tener from Texas. These are compared with karyotypes of other elapids from around the world, which exhibit significant interspecific variation. The largest macrochromosome of M. euryxanthus, which is metacentric, is shared by only two other species of coralsnakes from the New World. This may be a shared ancestral chromosome homologous to the largest macrochromosome that occurs in most other snakes, including some of the Australian elapids. The karyotype of M. tener from Texas has a ZZ:ZW1W2 sex chromosome system, which differs from individuals of this species reported previously from Louisiana. Over the relatively young 35-million-year global history of the Elapidae, karyotypes appear to have varied more than those of most other snakes throughout a 140-million-year history.

中文翻译：

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西半球珊瑚蛇（爬行动物：Elapidae）的核型，以及对染色体的种内变异和中心裂变的评论

描述了来自亚利桑那州的 Micruroides euryxanthus 和来自德克萨斯州的 Micrurus tener 的核型。这些与来自世界各地的其他 elapids 的核型进行了比较，后者表现出显着的种间变异。M. euryxanthus 最大的巨染色体是异中心的，只有来自新世界的另外两种珊瑚蛇物种共享。这可能是与大多数其他蛇类（包括一些澳大利亚蛇类）中最大的巨染色体同源的共享祖先染色体。来自德克萨斯州的 M. tener 的核型具有 ZZ:ZW1W2 性染色体系统，这与先前从路易斯安那州报道的该物种的个体不同。在相对年轻的 3500 万年全球历史上，Elapidae