德克萨斯大学的自然人类学家C.Kirk宣布自己发现了新的化石灵长类动物，并将其命名为Mescalerolemur horneri，发现地点为西德克萨期州的“恶魔墓地”（Devil’s Graveyard）。

Mescalerolemur horneri的上颚（左，中）和下颚（右）

梅斯卡勒罗狐猴（Mescalerolemur）生活于4300万年前的始新世，与现代狐猴极其相似。它是已灭绝灵长类兔猴型动物（Adapiforms）中的一种，兔猴型动物在始新世的北半球地层中均有发现。与北美相比，梅斯卡勒罗狐猴与欧亚大陆和非洲大陆的兔猴型动物亲缘关系更近。Krik说，梅斯卡勒罗狐猴与之前发现的始新世灵长类群体很不一样，梅斯卡勒罗狐猴与倭兔猴属（Mghgarita）仅发现于德克萨斯的大拐弯地区（the Big Bend region），出现于广布北美的兔猴型动物之后，它的发现，为中始新世北美与欧亚大陆之间动物交流提供了新的证据。

始新世末期，由于全球变冷，北美的灵长类动物和其他热带属种均逐渐消失。Kirk的发现，显示了北美灵长类的最后一次爆发。西德克萨斯州纬度相对较低，气候更为稳定，为喜暖动物提供了最后的庇护所。2005年M.Butcher在这里发现了一颗梅斯卡勒罗狐猴的牙齿化石，之后，大量灵长类化石在比“恶魔墓地”还要早3至4百万年的一个叫“紫滩”（Purple Bench）的地方被发现，“恶魔墓地”曾产出倭兔猴属化石。

Kirk曾以为发现的只是倭兔猴属的一个新种，但是后来随着化石材料的逐渐增多，他开始意识到，一个新属已经被发现。梅斯卡勒罗狐猴体型极小，仅重370克左右，与现代狐猴极为相似。不过，梅斯卡勒罗狐猴的发现仍表明，兔猴型动物与狐猴和丛猴的亲缘关系较其与人类的亲缘关系更近。比如，梅斯卡勒罗狐猴下颚的左右部分是两块单独的骨骼，靠联接带连接起来。这是狐猴和丛猴的典型特征，而兔猴型动物中的一种Mahgarita stevensi，则拥有与人类相似的融合下颚。但是由于梅斯卡勒罗狐猴与兔猴型动物亲缘极近，融合下颚的特征出现在兔猴型动物与猴和猿类中应该为互相独立的演化过程。

推荐原文：

Journal of Human Evolution    DOI:10.1016/j.jhevol.2011.02.014

New adapiform primate of Old World affinities from the Devil’s Graveyard Formation of Texas

E. Christopher Kirka, , and Blythe A. Williams

Most adapiform primates from North America are members of an endemic radiation of notharctines. North American notharctines flourished during the Early and early Middle Eocene, with only two genera persisting into the late Middle Eocene. Here we describe a new genus of adapiform primate from the Devil’s Graveyard Formation of Texas. Mescalerolemur horneri, gen. et sp. nov., is known only from the late Middle Eocene (Uintan) Purple Bench locality. Phylogenetic analyses reveal that Mescalerolemur is more closely related to Eurasian and African adapiforms than to North American notharctines. In this respect, M. horneri is similar to its sister taxon Mahgarita stevensi from the late Duchesnean of the Devil’s Graveyard Formation. The presence of both genera in the Big Bend region of Texas after notharctines had become locally extinct provides further evidence of faunal interchange between North America and East Asia during the middle Eocene. The fact that Mescalerolemur and Mahgarita are both unknown outside of Texas also supports prior hypotheses that low-latitude faunal assemblages in North America demonstrate increased endemism by the late middle Eocene.

Keywords: Adapidae; Caenopithecinae; Cercamoniinae; Asiadapinae; Notharctinae; Eocene; Uintan; Mescalerolemur; Mahgarita