Latitudinal diversity patterns in marine species are commonly estimated from literature records, which at times are incomplete and/or biased. Advances in molecular phylogenetics have contributed to avoid this bias, clarifying the identity of the species, improving our knowledge of species diversity and distribution. With the aim to identify biogeographic biases, we compiled and compared range distribution data of polyplacophorans along the South-eastern Pacific (SEP) coast (0°–56° S) generated from: (i) literature review (LIT dataset) and (ii) Operational Taxonomic Units (OTUs dataset), based on the analysis of 8949 individuals obtained from field sampling and biological collections. Cytochrome oxidase I (COI) and 16S rRNA of 104 specimens were used for genetic identification of conflictive morphospecies. Multivariate analysis (nMDS, PERMANOVA) were applied to test differences between datasets (LIT, OTUs) and also between biogeographic ecoregions. Just like prior studies based on literature reviews, the richness of LIT species showed an increase with latitude. Contrastingly, OTUs’ richness peaked at intermediate latitudes showing a bell-shaped distribution, indicating that the LIT dataset was flawed by inaccuracies in the identification and location of polyplacophoran species on the South-eastern Pacific, causing an overestimation of their geographic ranges. Our results contrast with the previous richness patterns described for the SEP polyplacophorans, where species richness was reported to increase with latitude. Both an overestimation of geographic ranges and inaccuracies in the identification of species cause these differences. Biogeographical studies should be conducted on the basis of a comprehensive review of specimens with verifiable occurrences, and incorporate as far as possible genetic analysis to define the identity of conflicting morphospecies, in order to improve the estimation of species richness and the understanding of marine biodiversity.

中文翻译：

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东南太平洋沿岸多斑的横向分布：揭示地理多样性格局中的偏见

海洋物种的纬度多样性模式通常是根据文献记录估算的，有时这些记录是不完整和/或有偏见的。分子系统学的进展有助于避免这种偏差，澄清了物种的身份，提高了我们对物种多样性和分布的认识。为了识别生物地理学偏见，我们收集并比较了东南太平洋（SEP）海岸（0°-56°S）沿岸的多斜足动物的范围分布数据，这些数据来自：（i）文献综述（LIT数据集）和（ii ）操作分类单位（OTUs数据集），基于对从野外采样和生物采集中获得的8949个人的分析。104个标本的细胞色素氧化酶I（COI）和16S rRNA被用于遗传鉴定冲突形态学。多元分析（nMDS，PERMANOVA）用于测试数据集（LIT，OTU）之间以及生物地理生态区域之间的差异。就像先前基于文献综述的研究一样，LIT物种的丰富度随着纬度的增加而增加。相反，OTUs的丰富度在中纬度达到峰值，呈钟形分布，这表明LIT数据集因东南太平洋多生斑菌种的识别和定位不准确而存在缺陷，从而导致对其地理范围的高估。我们的研究结果与先前描述的SEP多色性物种的丰富度模式形成对比，后者据报道物种丰富度随纬度增加。地理范围的高估和物种识别的不准确都造成了这些差异。