Marado Luís Miguel, Silva Ana Maria
Lab2PT - Landscape, Heritage and Territory Laboratory, Unit of Archaeology, University of Minho, Portugal.
Prehistory Laboratory, CIAS, University of Coimbra, Portugal; UNIARQ - WAPS, University of Lisbon Archaeology Center, Portugal; Laboratory of Forensic Anthropology, Center for Functional Ecology, University of Coimbra, Portugal.
Homo. 2016 Dec;67(6):462-470. doi: 10.1016/j.jchb.2016.09.003. Epub 2016 Sep 20.
Dental nonmetric traits are quasicontinous variables, mostly of genetic origin. Thus, sets of such traits allow biological distance estimation between samples. Mandibular molar pit-tubercle (MMPT) is a buccal trait defined by Weets (2009) in Irish samples. This study aims to analyze (a) trait frequencies, (b) grade definitions, (c) intraobserver error, (d) sexual dimorphism, (e) asymmetry, and (f) trait associations for MMPT in a Portuguese sample. The first (LM1), second (LM2) and third (LM3) lower molars of 600 identified individuals from the Coimbra collections were scored for MMPT in three scoring sessions. Intraobserver error, bilateral asymmetry and trait correlations were tested using Kendall's τ-b, while sexual dimorphism was verified using Pearson's χ. Frequencies (LM1: 2.1%; LM2: 3.5%; LM3: 30.3%) were similar to previous reports. However, a new free apex cusp form (grade 3+) was detected. Considering three scoring sessions, intraobserver precision was above 85%, and correlation coefficients between observations were positive and moderate to very strong (0.291<τ-b<0.835). Intrasample variation was low, since only LM3 showed sexual dimorphism (female: 30.2%; males: 16.2%; χ=15.512; p<0.001; df=1; n=556) and large asymmetry (27.1%). There were no strong (τ-b>0.3) intertrait associations involving MMPT. MMPT shows low trait presence, sexual dimorphism and asymmetry in stable teeth (LM1 and LM2). Intraobserver precision is high, so scoring should be reliable, although a plaque and better threshold grade definition is needed. After further research on non-European samples, MMPT can be useful in biodistance research.
牙齿非测量性状是准连续变量，大多源于遗传。因此，这类性状集可用于估计样本间的生物学距离。下颌磨牙窝结节（MMPT）是Weets（2009年）在爱尔兰样本中定义的一种颊侧性状。本研究旨在分析葡萄牙样本中MMPT的（a）性状频率、（b）等级定义、（c）观察者内误差、（d）两性异形、（e）不对称性以及（f）性状关联。对来自科英布拉藏品的600名已鉴定个体的第一（LM1）、第二（LM2）和第三（LM3）下颌磨牙在三个评分阶段进行MMPT评分。使用肯德尔τ-b检验观察者内误差、双侧不对称性和性状相关性，而使用皮尔逊χ检验两性异形。频率（LM1：2.1%；LM2：3.5%；LM3：30.3%）与先前报告相似。然而，检测到一种新的游离尖牙形态（3+级）。考虑三个评分阶段，观察者内精度高于85%，观察之间的相关系数为正且中等至非常强（0.291＜τ-b＜0.835）。样本内变异较低，因为只有LM3显示出两性异形（女性：30.2%；男性：16.2%；χ=15.512；p＜0.001；自由度=1；n=556）和较大的不对称性（27.1%）。不存在涉及MMPT的强（τ-b＞0.3）性状间关联。MMPT在稳定牙齿（LM1和LM2）中显示出低性状出现率、两性异形和不对称性。观察者内精度较高，因此评分应该可靠，尽管需要一个菌斑和更好的阈值等级定义。在对非欧洲样本进行进一步研究后，MMPT可用于生物距离研究。
