PURPOSE Despite recent advances in the study of amphimerosis, aspects related to the taxonomy of the opisthorchiid species involved in human infection in Ecuador are not completely known. In the present study, previous morphological descriptions of Amphimerus sp. found in human beings and animals from Ecuador were re-studied, aiming to the identification of the parasite. METHODS The morphological traits and measures of isolates of Amphimerus from Ecuadorian foci of transmission previously reported by different authors were critically analyzed and used to achieve the specific identification of the parasite. Morphological and morphometric data, including measures of structures, ratio between suckers, and disposition of vitellaria, were used for taxonomic identification based on taxonomic keys, reviews, and descriptive works. RESULTS The morphological study based on literature data reveals that Amphimerus lancea (Diesing, 1850) is a species potentially involved in human amphimerosis in Ecuador. The main characteristics here used for differential diagnoses of this species is the larger size of the ventral sucker, which results in an oral sucker/ventral sucker ratio in isolates here considered as A. lancea (1.8-2.7) higher than those verified in other seven species of the genus Amphimerus reported in South America (0.5-1.3). The relative space that the ventral sucker occupies in relation to body width (at the level of ventral sucker) is also greater in A. lancea (49-64% vs 15-38%). CONCLUSION Amphimerus lancea is at least one of the species involved in human amphimerosis in Ecuador. The parasite distribution and animal reservoirs are updated and the possibility of new areas of occurrence of human diseases in South America is highlighted. Future integrative taxonomic studies using material properly fixed is encouraged, which can corroborate the morphological identification here achieved and result in progress in the complex taxonomy of Amphimerus spp.

中文翻译：

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Amphimerus lancea 作为南美洲人类 Amphimerosis 的潜在病原体：基于文献数据的形态学分析。

目的尽管最近在两栖动物研究方面取得了进展，但与厄瓜多尔人类感染中涉及的 opisthorchiid 物种的分类学相关的方面尚不完全清楚。在本研究中，以前对 Amphimerus sp. 的形态学描述。对在厄瓜多尔人和动物中发现的寄生虫进行了重新研究，旨在鉴定这种寄生虫。方法对不同作者先前报道的厄瓜多尔传播疫源地安非鱼分离株的形态特征和检测方法进行批判性分析，并用于实现对寄生虫的特异性鉴定。形态学和形态学数据，包括结构的测量、吸盘之间的比率和黄斑的处置，被用于基于分类学关键字、评论和描述性作品的分类学识别。结果 基于文献数据的形态学研究表明，Amphimerus lancea (Diesing, 1850) 是一种可能参与厄瓜多尔人类两栖动物病的物种。此处用于鉴别诊断该物种的主要特征是腹侧吸盘的较大尺寸，这导致此处被视为 A. lancea (1.8-2.7) 的分离株的口腔吸盘/腹侧吸盘比率高于其他七种分离株南美洲报道的 Amphimerus 属的物种 (0.5-1.3)。A. lancea 中腹侧吸盘相对于体宽（在腹侧吸盘的水平）所占的相对空间也更大（49-64% vs 15-38%）。结论 在厄瓜多尔，Amphimerus lancea 至少是与人类两栖动物相关的物种之一。寄生虫分布和动物宿主得到更新，并突出了南美洲人类疾病发生新区域的可能性。鼓励使用正确固定的材料进行未来的综合分类学研究，这可以证实这里实现的形态学鉴定并导致 Amphimerus spp 复杂分类学的进展。