Hautier Lionel, Billet Guillaume, de Thoisy Benoit, Delsuc Frédéric
Institut des Sciences de l'Evolution, UMR5554, CNRS, IRD, EPHE, Université de Montpellier, Montpellier, France.
Mammal Section, Life Sciences, Vertebrate Division, The Natural History Museum, London, UK.
PeerJ. 2017 Aug 15;5:e3650. doi: 10.7717/peerj.3650. eCollection 2017.
The systematics of long-nosed armadillos (genus ) has been mainly based on a handful of external morphological characters and classical measurements. Here, we studied the pattern of morphological variation in the skull of long-nosed armadillos species, with a focus on the systematics of the widely distributed nine-banded armadillo ().
We present the first exhaustive 3D comparison of the skull morphology within the genus , based on micro-computed tomography. We used geometric morphometric approaches to explore the patterns of the intra- and interspecific morphological variation of the skull with regard to several factors such as taxonomy, geography, allometry, and sexual dimorphism.
We show that the shape and size of the skull vary greatly among species, with representing a clear outlier compared to other long-nosed armadillos. The study of the cranial intraspecific variation in evidences clear links to the geographic distribution and argues in favor of a revision of past taxonomic delimitations. Our detailed morphometric comparisons detected previously overlooked morphotypes of nine-banded armadillos, especially a very distinctive unit restricted to the Guiana Shield.
As our results are congruent with recent molecular data and analyses of the structure of paranasal sinuses, we propose that should be regarded either as a polytypic species (with three to four subspecies) or as a complex of several distinct species.
长鼻犰狳属（ 属）的系统分类主要基于少数外部形态特征和传统测量方法。在此，我们研究了长鼻犰狳物种头骨的形态变异模式，重点关注分布广泛的九带犰狳（ ）的系统分类。
基于微计算机断层扫描，我们首次对 属内的头骨形态进行了详尽的三维比较。我们使用几何形态测量方法，探讨了头骨在种内和种间形态变异的模式，涉及分类学、地理、异速生长和两性异形等多个因素。
我们发现， 属内不同物种的头骨形状和大小差异很大，与其他长鼻犰狳相比， 表现为明显的异常值。对 颅内部种间变异的研究表明，其与地理分布存在明确联系，支持对过去分类界限进行修订。我们详细的形态测量比较发现了九带犰狳先前被忽视的形态类型，特别是一个仅限于圭亚那地盾的非常独特的单元。
由于我们的结果与最近的分子数据以及鼻旁窦结构分析一致，我们建议 应被视为多型种（有三到四个亚种）或几个不同物种的复合体。
