Nelsonia is a Mexican endemic genus of woodrat and includes only two uncommon species: N. neotomodon and N. goldmani. This genus is of great phylogenetic interest, but has been ignored in most taxonomic studies and revisions due to the scarcity of its representatives in museum collections. The phylogenetic position of this genus is poorly known, and its interspecific and intraspecific relationships are unclear. The aim of this study was to infer the phylogenetic position of Nelsonia within the Cricetidae family, to determine whether the two species are monophyletic groups, and to assess the intraspecific genetic variation of N. goldmani. We amplified two mitochondrial markers: cytochrome b and cytochrome oxidase subunit 1 from specimens collected recently and museum samples from the type locality in 1903 to 1981 sampling half the known individuals reported to date. Sequences were analyzed by Bayesian and maximum likelihood to generate a phylogenetic hypothesis. Divergence time was performed to infer the biogeographic history. The genus Nelsonia was monophyletic and sister group of the current Xenomys, Hodomys, and Neotoma diverging in the middle-late Miocene. Nelsonia goldmani was also monophyletic, diverged from N. neotomodon during the late Miocene, and was formed by four highly divergent lineages. Further evidence may support a rank of full species for each of the four clades. Our results along with fossil data suggest that likely the genus Nelsonia diverged from Repomys or Protorepomys in the region of Californian-Rocky Mountains of the United States of America, and posteriorly invaded the Western Sierra Madre and Transmexican Volcanic Belt in Mexico.

尼尔森氏菌是墨西哥伍德拉特犬的特有属，仅包括两个不常见的物种：新托莫顿猪笼草和戈德曼猪笼草。该属在系统发育上具有很大的意义，但由于在博物馆收藏中缺乏其代表，因此在大多数分类学研究和修订中都被忽略了。该属的系统发生位置知之甚少，其种间和种内关系还不清楚。本研究的目的是推断的系统发育位置Nelsonia的仓鼠家庭内，以确定这两个物种是否单系组，并评估的种内的遗传变异N. goldmani。我们从最近收集的标本中扩增了两个线粒体标记物：细胞色素b和细胞色素氧化酶亚基1，从1903年至1981年从该类型地点收集的博物馆样本中采样了迄今报道的已知个体的一半。通过贝叶斯分析和最大似然分析序列以产生系统发生假说。进行发散时间以推断生物地理历史。属Nelsonia是当前的单系和妹妹组Xenomys，Hodomys和Neotoma在中晚中新世发散。尼尔森氏菌（Nelsonia goldmani）也是单种的，与新烟草猪笼草有所不同。在中新世晚期，由四个高度不同的世系组成。进一步的证据可能支持四个进化枝中每个进化枝的完整物种等级。我们与化石数据一起研究结果表明，可能属Nelsonia从分歧Repomys或Protorepomys在美利坚合众国加利福尼亚州-洛矶山脉的地区，向后侵入西方马德雷山脉和Transmexican火山带在墨西哥。