 |
| Enteromius walshae
Mamonekene, Zamba & Stiassny, 2018
|
ABSTRACT
A new species of smiliogastrin cyprinid is described from the Louesse, Lekoumou (upper Niari basin), and Djoulou (upper Ogowe basin) rivers in the Republic of Congo, west-central Africa. The new species is readily distinguished from congeners by the presence of a flexible, weakly ossified and smooth bordered last unbranched dorsal-fin ray, well-developed barbels, and a straight and complete lateral line in combination with a characteristic pigmentation patterning consisting of a distinctive, rounded black spot at the base of and extending over the first rays of the anal fin and a prominent, darkly pigmented blotch over the base of the anterior dorsal-fin rays. A combination of morphological features and pigmentation patterning that appears to be unique among Enteromius. The new species is widespread throughout the Louesse-Djoulou region, and the fact that such a seemingly common species has gone undetected until now serves to underscore how poorly known this region of the Republic of Congo remains.
 |
| FIGURE 2. Enteromius walshae, new species: A, AMNH 266856, holotype (female) in preservation; B, individual from the same population in life. C, AMNH 266858, paratype (male) in preservation; D, individual from same population in life; E, digestive tract, after removal of liver and adherent tissues (approximately to scale). |
Enteromius walshae, new species
Differential diagnosis: While no unambiguous morphological autapomorphies have been located to diagnose Enteromius walshae the species is nonetheless readily distinguished from all congeners by the presence of a flexible, weakly ossified, and smooth-bordered last unbranched dorsal-fin ray, well-developed barbels, and a straight and complete lateral line in combination with a characteristic pigmentation patterning consisting of a distinctive, rounded black spot at the base of and extending over the first rays of the anal fin and a prominent, darkly pigmented blotch over the base of the anterior dorsal-fin rays.
....
 |
| FIGURE 4. A, Known distributional range of Enteromius walshae; yellow stars indicate collection sites and red star indicates collection locality of holotype (AMNH 266856). B, Type locality of holotype, in a small tributary of the Mandoro River (upper Louesse River basin). |
Distribution: Found in forested streams and rivers throughout the surveyed region (fig. 4A). Commonly encountered in tributaries and subtributaries of the Louesse River in the Niari basin, and in the Djoulou River, a tributary of the upper Ogowe. The species is not found in tributaries of the lower Kouilou-Niari or in coastal basin systems in the Republic of Congo (Walsh et al., 2014). Although no data are currently available, we anticipate that further collecting in the upper Ogowe basin will extend the species’ distributional range into adjacent forested regions of that basin in Gabon.
Etymology: We name this new smiliogastrin cyprinid for our colleague Gina Walsh (University of Witwatersrand, South Africa), whose ongoing research continues to enhance conservation efforts throughout the region.
Victor Mamonekene, Armel Ibala Zamba and Melanie L. J. Stiassny. 2018. A New Small Barb (Cyprininae: Smiliogastrini) from the Louesse, Lekoumou (upper Niari basin), and Djoulou (upper Ogowe basin) rivers in the Republic of Congo, west-central Africa. American Museum Novitates. 3917. DigitalLibrary.AMNH.org/handle/2246/6921
