Monday, November 28, 2022

[Ichthyology • 2022] Clarias monsembulai • A New Species of Air-Breathing Catfish (Siluriformes: Clariidae: Clarias) from Salonga National Park, Democratic Republic of the Congo

  B, Clarias monsembulai Bernt & Stiassny, 2022
A, Clarias buthupogon Sauvage, 1879
 DOI: 10.1206/3990.1 

A new species of air-breathing catfish, Clarias monsembulai, is described from Congo River tributaries within and bordering the Salonga National Park (Democratic Republic of the Congo). The new taxon is recognized by its exceptionally long, white barbels, which lend a superficial resemblance to Clarias buthupogon, from which it differs in characters of the cleithrum and pigmentation patterning. We suggest placement of this species into the subgenus Clarioides but note the current dearth of morphological data to unite members of this group. We additionally discuss the validity of the subspecies Clarias angolensis macronema.

Lateral view of Clarias monsembulai new species, holotype AMNH 244176, 226 mm SL. Luilaka River at Ilenge, Salonga National Park. Scale bar = 1 cm.

Exposed cleithrum (demarcated by dashed line) of A, Clarias buthupogon, AMNH 227571, 162 mm SL and B, Clarias monsembulai, AMNH 244162, 183 mm SL. Scale bar = 1 cm

Clarias monsembulai, new species
Diagnosis: Clarias monsembulai can be distinguished from all congeners, with the exception of C. buthupogon, by its exceptionally long maxillary barbels (60% of standard length or greater) vs. maxillary barbels less than 60% SL (usually considerably less). It differs from C. buthupogon in the absence of fine, pale spots over the surface of the body and by an exposed bony surface of the cleithrum reaching 14%–20% of head length (vs. cleithrum deeply imbedded in soft tissue with only a narrow bony ridge visible externally). Clarias monsembulai can be further differentiated from C. angolensis, the species with which it shares closest phenotypic similarity, by longer nasal barbels (37%–51% SL vs. 22%–34% SL), longer internal mandibular barbels (29–37% SL vs. 16–27% SL), longer external mandibular barbels (45%–57% SL vs. 24%–40% SL); and by the coloration of maxillary barbels which are white or cream-colored distally over more than half of their length (vs. brown or gray over more than half their length).

Distribution: The species is currently known only from the Momboyo, Luilaka, Salonga, and Yenge river systems within the Cuvette Centrale of the middle Congo River Basin (fig. 6). However additional collecting throughout the region will likely extend this range (E. Decru, personal commun.).

Etymology: Named in honor of Raoul Monsembula Iyaba (professor of biology, University of Kinshasa) for collecting the type series of this species, and in recognition of his substantial contributions to central African ichthyology.  

 Maxwell J. Bernt and Melanie L.J. Stiassny. 2022. A New Species of Air-Breathing Catfish (Clariidae: Clarias) from Salonga National Park, Democratic Republic of the Congo. American Museum Novitates, (3990); 1-20. DOI: 10.1206/3990.1