Cho M R, Robbins R T
J Nematol. 1991 Jan;23(1):134-44.
Morphometrics of 23 United States populations of Xiphinema americanum sensu lato, sharing the characteristics of an offset lip region and conoid tail, were examined and analyzed statistically by canonical discriminant analysis (CDA). Specimens were collected from Arkansas, Georgia, Tennessee, Mississippi, Florida, Oklahoma, California, and North Dakota. Eleven measurements and body ratios obtained from female specimens were used in the analysis. Xiphinema americanum, X. bricolensis, X. californicum, X. citricolum, X, intermedium, X. tarjanense, and X. thornei, and one undescribed species were identified among the 23 populations. Three groups -- X. americanum-group, X. californicum-group, and X. intermedium-group (X. intermedium and X. tarjanense) -- were formed and four populations belonging to four different species were separated consistently from these groups in CDA scatterplots of the 23 populations. Composition of the groups was somewhat related to the geographical origins of the populations in the groups. A population from California had morphometrics intermediate between X. americanum and X. californicum. Separation between the X. americanum-group and X. californicum-group in the CDA scatterplots was not as distinct as that between them and the X. intermedium-group or between any of the three groups and the four single outlying populations.
对23个美国美洲剑线虫复合种群体进行了形态测量分析，这些群体具有偏置唇区和锥形尾的特征，并通过典范判别分析（CDA）进行了统计检验和分析。样本采集自阿肯色州、佐治亚州、田纳西州、密西西比州、佛罗里达州、俄克拉何马州、加利福尼亚州和北达科他州。分析中使用了从雌虫样本获得的11项测量值和体长比。在这23个群体中鉴定出了美洲剑线虫、布里科剑线虫、加利福尼亚剑线虫、柠檬剑线虫、中间剑线虫、塔尔扬剑线虫、索恩剑线虫以及一个未描述的物种。形成了三个类群——美洲剑线虫类群、加利福尼亚剑线虫类群和中间剑线虫类群（中间剑线虫和塔尔扬剑线虫）——在23个群体的CDA散点图中，四个属于四个不同物种的群体始终与这些类群区分开来。类群的组成与类群中群体的地理起源有一定关系。来自加利福尼亚州的一个群体的形态测量特征介于美洲剑线虫和加利福尼亚剑线虫之间。在CDA散点图中，美洲剑线虫类群和加利福尼亚剑线虫类群之间的区分不如它们与中间剑线虫类群之间的区分明显，也不如三个类群中的任何一个与四个单独的外围群体之间的区分明显。
