Georgiadis Nicholas J, Kat Pieter W, Oketch Hellen, Patton John
Genetics Section, National Museums of Kenya, P.O. Box 40658, Nairobi, KENYA.
Department of Biology, Washington University, St. Louis, MO, 63130, USA.
Evolution. 1990 Dec;44(8):2135-2149. doi: 10.1111/j.1558-5646.1990.tb04317.x.
We describe a phylogeny of the Bovidae based on 40 allozyme loci in 27 species, representing 10 of the 14 bovid tribes described by Vrba (1985). Giraffe represented a related family (Giraffidae). A phenogram was derived using the unweighted pair-group method with arithmetic means (UPGMA), based on Nei's genetic distances (ND) between species. A tree was also derived using the neighbor-joining technique, also based on ND. To provide a cladistic interpretation, the data were analyzed by a maximum parsimony method (phylogenetic analysis using parsimony, PAUP). We found marked divergence within the Bovidae, consistent with the appearance of the family in the early Miocene. Unexpectedly, the most divergent species was the impala, which occupied a basal position in all trees. Species in the tribe Alcelaphini were the most derived taxa in all trees. These patterns conflict strongly with the previous taxonomic alliance, based on immuno-distance and anatomical evidence, of the impala as a sister group of the Alcelaphini. All trees agreed that tribes described by Vrba (1985) are monophyletic, except the Neotragini, which was polyphyletic, with suni occupying a long branch by itself. The dikdik and klipspringer were consistently placed as sister taxa to species in the Antilopini. Three tribes (Aepycerotini, Tragelaphini and Cephalophini), whose fossils have not been found outside Africa, were basal in all trees, suggesting that bovids originated in Africa. Nodes connecting the remaining tribes were closely clustered, a pattern that agrees with fossil evidence of rapid divergence within the Bovidae in the mid-Miocene (about 15 mybp). The allozyme data suggested a second phase of rapid divergence within tribes during the Plio-Pleistocene, a pattern that also agrees with fossil evidence. Rates of bovid divergence have therefore been far from constant. However, the clustering of nodes imparts considerable uncertainty to the branching order leading to the derived tribes, and to a lesser extent, species within tribes. The classical division of the Bovidae into the Boodontia and Aegeodontia does not agree with the phylogenetic grouping of tribes presented in this analysis. However, the maximum parsimony tree derived using 'local' branch swapping clustered all grazing species into a derived, monophyletic group, suggesting that grazing may have evolved only once in bovid evolution.
我们基于27个物种的40个等位酶位点描述了牛科动物的系统发育，这些物种代表了弗尔巴（1985年）描述的14个牛科族中的10个。长颈鹿代表一个相关的科（长颈鹿科）。使用算术平均的非加权配对组方法（UPGMA），基于物种间的内氏遗传距离（ND）得出了一个聚类图。还使用同样基于ND的邻接法得出了一棵树。为了提供一种分支系统学解释，通过最大简约法（使用简约法的系统发育分析，PAUP）对数据进行了分析。我们发现牛科动物内部存在明显的分化，这与该科在中新世早期出现的情况一致。出乎意料的是，分化最大的物种是黑斑羚，它在所有树中都占据基部位置。牛羚族的物种在所有树中都是最进化的类群。这些模式与基于免疫距离和解剖学证据将黑斑羚作为牛羚族姐妹群的先前分类联盟强烈冲突。所有树都一致认为，弗尔巴（1985年）描述的族是单系的，除了新小羚族是多系的之外，桑岛新小羚独自占据一个长分支。犬羚属和岩羚属一直被置于羚羊族物种的姐妹分类单元位置。三个族（麂羚族、薮羚族和遁羚族），其化石在非洲以外未被发现过，则在所有树中处于基部位置，这表明牛科动物起源于非洲。连接其余族的节点紧密聚集，这一模式与中新世中期（约1500万年前）牛科动物快速分化的化石证据相符一致；等位酶数据表明在上新世 - 更新世期间族内存在第二个快速分化阶段，这一模式也与化石证据相符一致。因此，牛科动物的分化速率远非恒定不变。然而，节点的聚集给导致进化族的分支顺序以及在较小程度上给族内物种带来了相当大的不确定性。牛科传统上分为牛齿亚科和真羚亚科，这与本分析中族的系统发育分组不一致。然而，使用“局部”分支交换得出的最大简约树将所有食草物种聚为一个进化的单系类群，这表明食草行为在牛科动物进化过程中可能只进化了一次。
