Erioscelis emarginata is a species of pollinator scarab beetle whose adults are predominantly associated with night-blooming aroid inflorescences (Araceae) of the Neotropical genus Thaumatophyllum, towards which they are attracted by volatile organic compounds (VOCs). It is assumed that olfactory preferences towards species-specific floral VOCs emitted by different plant hosts, as well as geographical segregation of natural populations of E. emarginata, might reinforce their reproductive isolation and differentiation, but external morphological dissimilarities between them are not evident. In the present work, body shapes of geographically isolated populations of E. emarginata associated with different species of Thaumatophyllum were compared using landmark-based geometric morphometrics. A total of 86 adult specimens of E. emarginata were analyzed, collected in inflorescences of Thaumatophyllum spp. at four locations in Brazil distant 333–912 km from one another. Eighteen landmarks and semi-landmarks were digitized to capture the shapes of the elytra and pronotum separately, and landmarks configurations were compared through Canonical Variates and pairwise Discriminant Function Analyses. There were significant shape differences between specimens from the four different populations of E. emarginata (p < 0.05) in all paired comparisons, for both the shape of the elytra and pronotum and correct classification levels were high for most pairwise comparisons. Further investigations on the morphological variation across these populations and assessments of the specificity of their olfactory-oriented relationship with host plants are important next steps in understanding the full scenario of the segregation and diversification of E. emarginata. In addition, a lectotype male of Apogonia emarginata (ZIN) was designated to fix the identity of E. emarginata.

Erioscelis emarginata是一种授粉的金龟子甲虫，其成年主要与新热带属Thaumat ophyllum的繁花似锦的花序（Araceae）有关，它们被挥发性有机化合物（VOC）吸引。据推测，朝不同的寄主植物，以及自然种群的地理隔离发出的种属特异性花挥发性有机化合物的嗅觉喜好E. emarginata，可能会加强他们的生殖隔离和分化，但它们之间的外部形态相异不明显。在当前的工作中，与不同种类的Thaumat有关的E. emarginata地理上分离的种群的体型使用基于地标的几何形态计量学对卵泡进行比较。总共分析了86个成年的E. emarginata的标本，收集在Thaumat ophyllum spp的花序中。在巴西的四个地点之间相距333-912公里。将18个地标和半地标数字化以分别捕获鞘翅和前胸背板的形状，并通过规范变量和成对判别函数分析比较地标配置。四个不同种群的E. emarginata的标本之间存在明显的形状差异在所有成对的比较中（p <0.05），对于鞘翅和前胸背板的形状，大多数成对比较的正确分类水平都很高。进一步研究这些种群的形态变异，并评估其与寄主植物的嗅觉导向关系的特异性，是理解E. emarginata分离和多样化的完整场景的重要下一步。另外，指定了Apogonia emarginata（ZIN）的选型雄性来固定E. emarginata的身份。