New collections from the Yangambi Biosphere Reserve (YBR) and Okapi Wildlife Reserve (OWR) revealed the presence of two groups of specimens similar to, but different from Marcusenius moorii. To study both these groups, an integrated morphological and genetic (mtDNA, cytb) approach was used. This study revealed that one of the two groups is conspecific with Marcusenius lambouri, a junior synonym of M. moorii, which is herein revalidated, with M. moorii longulus as its junior synonym. Marcusenius lambouri differs from M. moorii by a higher number of lateral line scales (44-46 v. 40-43), a shorter pectoral-fin length (14.6-19.9 v. 20.3-25.2% standard length; LS ) and a more elongated body due to a usually shallower middle body depth (19.8-26.5 v. 26.3-35.9% LS ). The other group revealed to be a new species for science, Marcusenius verheyeni, which can be distinguished from its congeners with eight circumpeduncular scales by the following unique combination of characters: a rounded head with a terminal mouth; a short and deep caudal peduncle (caudal peduncle depth, 44.9-54.6% caudal peduncle length; LCP ), a deep body (body depth, 27.7-34.2% LS ), 38-43 scales on the lateral line, 40-41 vertebrae, 20-21 dorsal-fin rays and 26 anal-fin rays. Some specimens previously attributed to M. moorii were examined and reassigned to M. lambouri or M. verheyeni. As a result, M. moorii and M. lambouri occur in sympatry in the middle Congo Basin, with the distribution area of M. moorii still further extending into the lower Congo Basin. Instead, the distribution of M. verheyeni is limited to some right bank tributaries of the upstream part of the middle Congo Basin. Two museum records from the Lilanda River (YBR), collected in the 1950s and previously identified as M. moorii, were re-identified as belonging to the new species, M. verheyeni. However, the species now seems locally extinct in that region, which reflects the significant anthropogenic effects even within this reserve. This article is protected by copyright. All rights reserved.

中文翻译：

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来自刚果盆地的 Marcusenius moorii (Teleostei: Mormyridae) 的隐藏物种多样性

来自 Yangambi 生物圈保护区 (YBR) 和 Okapi 野生动物保护区 (OWR) 的新收藏揭示了两组与 Marcusenius moorii 相似但不同的标本。为了研究这两个群体，使用了综合的形态学和遗传学（mtDNA、cytb）方法。这项研究表明，这两组中的一个与 Marcusenius Lambouri 同种，后者是 M. moorii 的初级同义词，此处重新验证，M. moorii longulus 作为其初级同义词。Marcusenius lambouri 与 M. moorii 的不同之处在于更多的侧线鳞片 (44-46 v. 40-43)、较短的胸鳍长度 (14.6-19.9 v. 20.3-25.2% 标准长度; LS ) 和更多由于通常较浅的中间体深度（19.8-26.5 v. 26.3-35.9% LS ）而延长体。另一组被揭示为科学新物种，Marcusenius verheyeni，可以通过以下独特的字符组合与具有八个环柄鳞片的同类区分开来：圆形的头部和末端的嘴；一个短而深的尾柄（尾柄深度，44.9-54.6%尾柄长度；LCP），一个深体（体深，27.7-34.2% LS），侧线上有38-43个鳞片，40-41个椎骨，背鳍鳍条 20-21 条，臀鳍鳍条 26 条。一些先前归属于 M. moorii 的标本被检查并重新分配给 M.lambouri 或 M. verheyeni。因此，M. moorii 和 M.lambouri 共生于刚果盆地中部，M. moorii 的分布区域还进一步延伸到刚果盆地下游。相反，M. verheyeni 的分布仅限于中刚果盆地上游部分的一些右岸支流。来自利兰达河 (YBR) 的两份博物馆记录于 1950 年代收集，之前被鉴定为 M. moorii，被重新鉴定为属于新物种 M. verheyeni。然而，该物种现在似乎在该地区局部灭绝，这反映了即使在该保护区内也存在显着的人为影响。本文受版权保护。版权所有。