A New Species of Air-breathing Catfish (Clariidae: Clarias) from Salonga National Park, Democratic Republic of the Congo Bernt, Maxwell J. Stiassny, Melanie L. J. American Museum Novitates 2022 2022-08-30 2022 3990 1 20 Bernt & Stiassny, 2022 Bernt & Stiassny 2022 [453,713,1289,1316] Actinopterygii Clariidae Clarias Animalia Siluriformes 3 4 Chordata species monsembulai sp. nov.    Figures 2–5, table 1   Clarias buthupogon(in part): Monsembula Iyaba and Stiassny (2013).    HOLOTYPE: AMNH 244176, 1, 226 mmSL, Democratic Republic of the Congo, Equateur, Salonga National Park, Luilaka Riverat Ilenge, 2°35′ 47″S, 21°34′ 36″E. R. J.C. Monsembula Iyaba,  11 November 2007.   PARATYPES: AMNH 244163, 1, 244 mmSL; Yenge Riverca. Boyenga, 1°03′50″S, 20°44′44″E;  AMNH 252236, 3, 164–193 mmSL; small stream at Katanyongo, near Salonga National Park, 2°08′10.7″S, 21°07′9.5″E;  AMNH 244162, 1, 183 mmSL; Salonga Riverat Watsikengo;  AMNH 252219, 2, 187–231 mmSL; Salonga National Parkat Bekongo, 1°54′42.74″S, 20°51′11.35″E;  AMNH 244164, 1, 127 mmSL, Luilaka River, beach at Monkoto;  AMNH 252267, 1, 179 mmSL, Mpongo, large stream ca. 2 kilometers from Luilaka River, near Salonga National Park, 1°55′19.9″ S, 20°51′49.8″E;  AMNH 252222, 1, 167 mmSL; Luilaka Riverat Lokaka in Salonga National Park, 2°0′24.9″S, 20°58′6.2″E;  RMCA 2022-019-P-0001-0002, 2, 143–172 mmSL, Salonga Riverat Watsikengo.   NONTYPE SPECIMENS: AMNH 242721, 14, 54–81 mmSL, small tributary of Luilaka Rivernear Monkoto in Salonga National Park, 1°45′0″S, 20°40′49.9″E.  DIAGNOSIS:  Clarias monsembulaican 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. buthupogonin 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 monsembulaican 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).  DESCRIPTION: Morphometrics summarized in table 1. Maximum observed total length 270 mm(standard length 244 mm). Head broad, depressed with slightly convex dorsal profile, snout rounded. Anterior nares tubular, medial to posterior nares and nasal barbels. Mouth subterminal, lips and bases of barbels papillose. Four pairs of barbels, all extending beyond dorsal fin origin. Barbels rounded at base, becoming flat, ellipsoid in cross section. Body cylindrical between head and anal fin origin, becoming laterally compressed posteriorly. Dorsal fin with 80–86 rays, originating a short distance (less than 10% SL) behind supraoccipital process. Anal fin with 57–61 rays, origin nearly equidistant from snout tip and caudal fin base. Dorsal and anal fins not confluent with caudal fin. Pectoral fin with robust spine and 10–12 rays. Spine sharply pointed with slight posterior curve. Strong serration present on both anterior and posterior margins. Serrae angled proximally, larger on posterior margin, increasing in number with body size. Pelvic fins present on all specimens examined, with six rays. Caudal fin rounded, with 18–22 rays.  FIGURE 3. Computed tomography scan reconstruction of the skull and pectoral girdle of  Clarias monsembulai( at left and above), AMNH 252267, 179 mm SL in A,dorsal; B,ventral; and C, lateral views. Abbreviations: ang,anguloarticular; apal,autopalatine; br,branchiostegal rays; ch-a,anterior ceratohyal; ch-p,posterior ceratohyal; cl,cleithrum; cor,coracoid; den,dentary; fr,frontal; hhv,ventral hypohyal; hm,hyomandibula; io-ii,infraorbital ii; io-iii,infraorbital iii; io-iv,infraorbital iv; iop,interopercle; lac,lacrimal; leth,lateral ethmoid; meth,mesethmoid; mx,maxilla; na,nasal; ns,neural spines; op,opercle; o-susp,os suspensorium; pmx,premaxilla; pop,preopercle; pp-v4,parapophysis of 4th vertebra; pp-v5,parapophysis of 5th vertebra; ps,pectoral spine; pt,pterotic; pt-scl,posttemporo-supracleithrum; q,quadrate; rad,radials; soc,supraoccipital; sph,sphenotic; spop,suprapreopercle; trsc,transcapular process; uh,urohyal; vo,vomer. Scale bars = 1 cm. Elements of skull and pectoral girdle shown in figure 3. Neurocranium robustly ossified. Fourth infraorbital contacting suprapreopercle in all specimens examined ( 80–244 mmSL). Frontal fontanel long and narrow (knife shaped). Supraoccipital fontanel narrowly oblong, supraoccipital process sharply pointed in both juveniles and adults. Premaxillary and vomerine tooth plates similar in width, about 30% of head length. Premaxillary teeth villiform. Vomerine toothplate with short posterior median process, teeth subgranular. Dentary teeth villiform, extending over half of dorsal surface, nearly reaching coronoid process. First branchial arch with 16–18 slender gill rakers. Second and fourth arches diverticulate, forming arborescent suprabranchial organ (fig. 4). Rosette on second arch with few branches, not overlapping larger, more extensively, branched rosette on fourth arch. Respiratory organ occupies approximately one fourth of suprabranchial chamber volume. Seven or eight branchiostegal rays. Urohyal trifurcate, lateral processes longer than posteromedial process. Cleithrum superficial, visible externally as striated bony band at isthmus (fig. 5). Coracoid with single circular foramen at margin with cleithrum near articulation with pectoral spine.  FIGURE 4. Suprabranchial organ of  Clarias monsembulai, AMNH244162, 165 mm SL (suprapreopercle removed). Scale bar = 1 cm. Parapophyses of fourth and fifth vertebrae expanded, forming hourglass-shaped Weberian apparatus encapsulating bilobed gas bladder. Posterolateral processes of os suspensorium forming ventral floor of Weberian capsule. Fifty-eight to 61 (mode = 60) vertebrae posterior to first four vertebrae comprising Weberian apparatus. Two free neural spines between skull and first dorsal-fin pterygiophore. First rib articulated with seventh vertebra, 12 ribs present. No fusion of caudal fin hypurals. COLORATION: Preserved specimens are dark brown dorsally, fading to light brown, gray, or cream colored ventrally. Some lighter colored specimens exhibit a faint mottling of irregular dark brown markings over a slightly lighter background. Fins uniformly dark brown. Barbels brown at base, becoming creamy white over most of their length. Underside of head pale, but with band of dark pigment above fleshy furrow between mandibular barbels and isthmus. Lateral line visible as a series of small regularly spaced white pores extending from the base of the head to the base of the caudal peduncle. Pores of the secondary canals of the lateral line system form a regular pattern over the flanks, but these pores are not readily visible against the darkly pigmented skin.  DISTRIBUTION: The species is currently known only from the Momboyo, Luilaka, Salonga, and Yenge river systems within the Cuvette Centrale of the middle CongoRiver 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 typeseries of this species, and in recognition of his substantial contributions to central Africanichthyology. 3922431314 2007-11-11 R J. C. Monsembula Iyaba Democratic Republic of the Congo Ilenge -2.5963888 Salonga National Park 21 21.576668 Luilaka River 3 4 AMNH 244176 1 holotype 3922431301 [156,1208,1569,1596] AMNH -1.0638888 Yenge River 21 20.745556 Boyenga 3 4 AMNH 244163 1 paratype 3922431307 AMNH -2.1363056 Katanyongo 1 21.119307 Salonga National Park 3 4 AMNH 252236, 3 1 paratype 3922431303 [407,1110,1644,1671] AMNH Salonga River Watsikengo 3 4 AMNH 244162 1 paratype 3922431320 AMNH -1.9118721 Salonga National Park 1 20.853153 Bekongo 3 4 AMNH 252219, 2 1 paratype 3922431318 [108,874,1719,1745] AMNH Luilaka River Monkoto 3 4 AMNH 244164 1 paratype 3922431323 AMNH Salonga National Park 4 5 -1.9221945 Mpongo 1 20.863834 Luilaka River 3 4 AMNH 252267 1 paratype 3922431304 AMNH -2.0069168 Luilaka River 1 20.96839 Lokaka in Salonga National Park 4 5 AMNH 252222 1 paratype 3922431319 RMCA Salonga River Watsikengo 4 5 RMCA 2022-019 1 paratype 3922431312 AMNH -1.75 Luilaka River 15 20.680527 Monkoto in Salonga National Park 4 5 AMNH 242721, 14 1 3922431316 central African 8 9 1 Kinshasa