Redescription of Moenkhausia melogramma (Characiformes: Characidae), a poorly known tetra from the western Amazon basin

ABSTRACT Moenkhausia melogramma is herein redescribed, based on the examination of the holotype plus additional specimens from the western Amazon basin in Brazil, Colombia, Peru, and Ecuador. Moenkhausia melogramma shares with M. collettii, M. conspicua, M. copei, M. venerei, and M. flava a broad dark longitudinal stripe across the eye, and a well-defined dark stripe on the anal-fin base. It can be promptly distinguished from these species by having two humeral blotches. Additionally, we provide comments on the putative relationships of Moenkhausia melogramma with the aforementioned congeners and the Hemigrammus lunatus species-group.

摘要：本研究基于正模标本以及采自巴西、哥伦比亚、秘鲁与厄瓜多尔境内亚马孙河流域西部的额外标本，对黑线蒙克脂鲤（Moenkhausia melogramma）进行重新描述。黑线蒙克脂鲤与科氏蒙克脂鲤（Moenkhausia collettii）、醒目蒙克脂鲤（Moenkhausia conspicua）、科普蒙克脂鲤（Moenkhausia copei）、维氏蒙克脂鲤（Moenkhausia venerei）以及黄色蒙克脂鲤（Moenkhausia flava）具有共同特征：眼部具宽阔的深色纵纹，臀鳍基部带有轮廓清晰的深色条纹。该物种可通过具有两处肱骨斑这一特征，与上述物种快速区分。此外，本研究还就黑线蒙克脂鲤与前述同属物种以及月形半线脂鲤类群（Hemigrammus lunatus species-group）的推测系统发育关系进行了探讨。