Synodontis kogonensis, Musschoot & Lalèyè, 2008

Musschoot, Tobias & Lalèyè, Philippe, 2008, Designation of a neotype for Synodontis schall (Bloch and Schneider, 1801) and description of two new species of Synodontis (Siluriformes: Mochokidae), Journal of Natural History 42 (17 - 18), pp. 1303-1331 : 1317-1322

Synodontis kogonensis sp. nov.

( Table 5, Figure 8 )

Holotype

MRAC 92-059 -P-1933: Ndyarendi ( Guinea), Kogon River (11 ° 219–14 ° 309W), Coll. G. Teugels et al., collected 09/04/ 1992, 108 mm SL.

Paratypes

MRAC 92-059 -P-1934-1936: Ndyarendi ( Guinea), Kogon River (11 ° 219– 14 ° 309W), Coll. G. Teugels et al., collected 09/04/1992, 90– 95 mm SL ; MRAC 92-059 -P-1940: Kogon ( Guinea), Kogon River (11 ° 229N–13 ° 559W), Coll. G. Teugels, 50 mm SL .

Differential diagnosis

Gill opening not extending ventrally beyond the level of the insertion of the pectoral fin spine (vs. gill opening extending ventrally beyond the level of the insertion of the pectoral fin spine: S. dekimpei , S. batensoda and S. membranaceus ); maxillary barbel without ramifications or tubercles (vs. ramifications or tubercles present: S. resupinata , S. clarias and S. annectens ); dorsal spine not serrated or very finely serrated anteriorly, except for some larger distal serrations (vs. spine entirely and clearly serrated anteriorly: S. serrata , S. batesii and S. albolineata ); humeral process without posteriorly directed spines (vs. spines present: S. omias and S. budgetti ); maxillary barbels longer than head (vs. shorter than head: S. sorex , S. vermiculata , S. haugi , S. gobroni , S. violacea , S. thysi , S. guttata , S. xiphias , S. courteti and S. voltae ); skin more or less villose, especially in front of the flanks (vs. skin non-villose: S. caudovittata , S. ocellifer , S. arnoulti , S. marmorata , S. punctifer , S. victoriae , S. euptera , S. ansorgii , S. koensis , S. velifer , S. filamentosa , S. bastiani , S. eburneensis , S. obesus , S. robbianus , S. waterloti , S. tourei , S. macrophthalma , S. tessmanni , S. frontosa , S. khartoumensis , S. gambiensis , S. melanoptera and S. comoensis ); maxillary barbel with a very small and indistinct membrane, or membrane absent (vs. very clear or even large membrane present: S. steindachneri , S. nigrita and S. rebeli ); 18–36 mandibulary teeth (vs. 40–90 mandibulary teeth: S. afrofischeri and S. polyodon ); adipose fin base length at least 2.4 times the distance between dorsal and adipose fin (vs. maximum 1.5 times this distance: S. ruandae ). Pectoral girdle width 68.3–87.5% HL; specimens between 95 and 125mm SL have OD 17.6–25.9% HL and IOD 28.4–36.2% HL; East African specimens with PGW.85.0% HL have OD 22.1–26.0% HL and IOD 37.6–38.5% HL or 88.8– 91.5% SNL (vs. PGW minimum 85% HL, OD 22.3–26.2% HL, IOD 33.3–39.2% HL or 77.1–89.1% SNL: S. macrops ; only known from type specimens between 95 and 125 mm SL); premaxillary toothplate width 6.3–9.9% SL or 21.6–32.7% HL; predorsal length 35.7–42.7% SL, snout length 42.0–48.6% HL or 49.0–65.0% PGW and orbit diameter 42.9–63.9% SNL (vs. premaxillary toothplate width 3.9–8.0% SL or 12.9–24.3% HL for specimens from 31 to 319 mm SL, and 4.0–8.0% SL or 12.9–24.3% HL for specimens between 39 and 213 mm SL: S. schall ; or predorsal length 35.4–36.6% SL and snout length 47.3–50.5% HL or 60.9–67.2% PGW and orbit diameter 39.0–44.7% SNL: S. levequei ); orbit diameter 5.5–6.8% SL (19.4– 21.0% HL), caudal peduncle height 10.4–11.1% SL (32.4–41.5% HL), prepectoral length 21.6–23.3% SL (69.6–82.8% HL), pectoral girdle width 22.0–25.1% SL (68.3– 83.0% HL), distance between humeral process and occipito-nuchal shield 11.8– 14.6% SL (41.6–46.1% HL) (vs. orbit diameter 6.6–8.2% SL (20.5–26.8% HL), caudal peduncle height 8.9–10.9% SL (26.5–38.0% HL), prepectoral length 23.4– 28.2% SL (76.1–89.0% HL), pectoral girdle width 23.2–28.2% SL (78.0–87.5% HL), distance between humeral process and occipito-nuchal shield 9.7–13.1% SL (30.3– 45.5% HL): S. ouemeensis ).

Description (based on five types and one additional specimen)

Predorsal profile straight, slightly convex in small specimens; head subconical when viewed dorsally; snout rounded or slightly pointed when viewed dorsally; maxillary barbels with a small membrane, indistinct; gill opening from level of ventral margin of eye down to level of pectoral spine base; occipito-nuchal shield terminating posteriorly with two more or less pointed processes on each side of the dorsal fin; maxillary barbels almost reaching posterior tip of humeral process in smaller specimens, reaching posterior tip in larger specimens, unbranched; external mandibular barbels with filaments, reaching base of pectoral fin or beyond, except in the smallest paratype; internal mandibular barbels with short filaments, reaching a vertical from anterior margin of eye; anterior nostrils tubular with small lateral flap, posterior nostrils with flap along anterior margin; eye superolateral; orbit with free margin; mouth inferior; teeth unicuspid; 24–34 mandibular teeth; humeral process with a small ridge along the ventral margin, upper margin straight or a little concave, lower margin straight or weakly convex; proximal part of lateral line positioned above mid-lateral line; dorsal spine smooth anteriorly with one to two serrations distally, and weakly serrated posteriorly; dorsal fin spine slightly curved backwards; adipose fin well developed with a convex margin; caudal fin forked; anterior side of pectoral spine with fine serrations proximally, becoming a little larger distally, directed outwards, posteriorly with less but marked serrations along its entire side, which are directed towards the body; pelvic fins inserted approximately at the level of the adipose fin origin (except for the smallest paratype, where the pelvic fins are inserted between dorsal and adipose fin), posterior margin rounded, not reaching anal fin base; anal fin reaching beyond a vertical through the posterior margin of adipose fin (except in the smallest paratype where it does not reach a vertical through the posterior margin of the adipose fin); urogenital pore and vent positioned a little beyond the level of the adipose fin origin.

Dorsal fin I7; anal fin 11–12; pectoral fin I8–9; pelvic fin 7.

Colouration (preserved specimens)

No bars or spots, except for a supra-humeral spot; body dark brownish-grey dorsally and on the flanks, with pale brownish-grey venter; maxillary barbels light browngrey as venter; mandibular barbels light brown-grey as venter with pale brownyellowish filaments, or entirely pale brown-yellowish; pectoral, pelvic, dorsal and anal fins dark grey; paired fins sometimes with a pale (pinkish) base ventrally; adipose fin same colour as dorsal body surface; caudal fin grey, a little lighter than the other fins; caudal fin of holotype, smallest paratype and larger specimen from the Fatala River with a slightly darker band in upper and lower lobe. No large differences were observed between specimens of different sizes, but note that the smallest size class, which in S. schall often shows a typical colour pattern, is represented only by a single specimen of 50 mm SL.

Distribution

Known from the rivers Kogon and Fatala ( Guinea).

Etymology

Named for the type locality, the Kogon River ( Guinea) .

Additional specimens

MRAC 92-059-P-1937-1939: Ndyarendi ( Guinea), Kogon River (11 ° 219–14 ° 309W), Coll. G. Teugels et al; MNHN 2000-1179: Yetofan ( Guinea), Coll. Bigorne, 212 mm SL.

Synodontis schall ( Bloch and Schneider, 1801) ( Table 5, Figure 9 )

Neotype

MNHN 1898-0131 : Assouan ( Egypt), Nile River , Coll. Chantre, 239 mm SL.

Differential diagnosis

Gill opening not extending ventrally beyond the level of the insertion of the pectoral fin spine (vs. gill opening extending ventrally beyond the level of the insertion of the pectoral fin spine: S. dekimpei , S. batensoda and S. membranaceus ); maxillary barbel without ramifications or tubercles (vs. ramifications or tubercles present: S. resupinata , S. clarias and S. annectens ); dorsal spine not serrated or very finely serrated anteriorly, except for some larger distal serrations (vs. spine entirely and clearly serrated anteriorly: S. serrata , S. batesii and S. albolineata ); humeral process without posteriorly directed spines (vs. spines present: S. omias and S. budgetti ); maxillary barbels longer than head (vs. shorter than head: S. sorex , S. vermiculata , S. haugi , S. gobroni , S. violacea , S. thysi , S. guttata , S. xiphias , S. courteti and S. voltae ); skin more or less villose, especially in front of the flanks (vs. skin non-villose: S. caudovittata , S. ocellifer , S. arnoulti , S. marmorata , S. punctifer , S. victoriae , S. euptera , S. ansorgii , S. koensis , S. velifer , S. filamentosa , S. bastiani , S. eburneensis , S. obesus , S. robbianus , S. waterloti , S. tourei , S. macrophthalma , S. tessmanni , S. frontosa , S. khartoumensis , S. gambiensis , S. melanoptera and S. comoensis ); maxillary barbel with a very small and indistinct membrane, or membrane absent (vs. very clear or even large membrane present: S. steindachneri , S. nigrita and S. rebeli ); 18–36 mandibulary teeth (vs. 40–90 mandibulary teeth: S. afrofischeri and S. polyodon ); adipose fin base length at least 2.4 times the distance between dorsal and adipose fin (vs. maximum 1.5 times this distance: S. ruandae ). Pectoral girdle width 68.3–87.5% HL; specimens between 95 and 125mm SL have OD 17.6–25.9% HL and IOD 28.4–36.2% HL; East African specimens with PGW.85.0% HL have OD 22.1–26.0% HL and IOD 37.6–38.5% HL or 88.8–91.5% SNL (vs. PGW minimum 85% HL, OD 22.3–26.2% HL, IOD 33.3– 39.2% HL or 77.1–89.1% SNL: S. macrops ; only known from type specimens between 95 and 125mm SL); premaxillary toothplate width 3.9–8.0% SL or 12.9–24.3% HL for specimens from 31 to 319 mm SL, and 4.0–8.0% SL or 12.9–24.3% HL for specimens between 39 and 213 mm SL; predorsal length 36.2–47.5% SL, snout length 37.2–46.0% HL or 47.3–64.2% PGW and orbit diameter 35.5–67.0% SNL (vs. premaxillary toothplate width 6.3–9.9% SL or 21.6–32.7% HL: S. ouemeensis , S. kogonensis ; or predorsal length 35.4–36.6% SL, snout length 47.3–50.5% HL or 60.9–67.2% PGW and orbit diameter 39.0–44.7% SNL: S. levequei ).

Description

Predorsal profile more or less straight; head subconical when viewed dorsally; snout rounded, sometimes slightly pointed when viewed dorsally; maxillary barbels without membrane, or with a hardly visible membrane; gill opening from level of eye (variably between upper and lower margin), down to level of pectoral spine base; occipito-nuchal shield terminating posteriorly with two usually rounded, rarely more pointed, processes on each side of the dorsal fin; maxillary barbels almost reaching posterior tip of humeral process, rarely beyond, unbranched; external mandibular barbels with filaments, reaching base of pectoral fin; internal mandibular barbels with short filaments, reaching a vertical from anterior, sometimes posterior, margin of eye; anterior nostrils tubular with small lateral flap, posterior nostrils with flap along anterior margin; eye superolateral; orbit with free margin; mouth inferior; teeth unicuspid; 18–32 mandibular teeth; humeral process usually without ridge along the ventral margin, upper margin straight or a little concave, lower margin straight or a little convex; proximal part of lateral line positioned above mid-lateral line; anterior side of dorsal spine smooth or with some very fine serrations proximally and with some larger serrations distally, posterior side clearly serrated, mainly distally; dorsal fin spine slightly curved backwards; adipose fin height very variable; adipose fin well developed with a convex, sometimes rather straight, margin with a variable slope; caudal fin deeply forked, upper lobe a little longer than lower; anterior side of pectoral spine with fine serrations proximally, becoming a little larger distally, but often none at the tip, directed outwards, posterior side with less but marked serrations along its entire side, which are directed towards the body; pelvic fins inserted at the level of the adipose fin origin or a little before, posterior margin usually straight, not or barely reaching anal fin base; anal fin reaching beyond a vertical through the posterior margin of adipose fin; urogenital pore and vent positioned at the level of the adipose fin origin or a little beyond.

Colouration (preserved specimens)

Variable; generally body brown or grey dorsally, becoming lighter on the flanks, belly light brown or grey or whitish (specimens from Agneby River dark grey, those from Benue River dark brown, with lighter belly); humeral spot present; barbels either whitish or brown, including filaments; adipose, dorsal and caudal fin more or less the same colour as dorsal body surface; pectoral, pelvic and anal fins whitish or grey or brown, usually depending on body color, sometimes relatively dark (specimens from Agneby River). Smallest specimens (around 50 mm SL): small dark spots (, 1 mm) all over body, except ventrally but including all fins (except sometimes the pelvic fins); sometimes marbly or mottled on body or with some larger irregular pale spots; sometimes with larger dark spots (. 1 mm) on adipose, dorsal and caudal fins. Larger specimens (below about 100 mm SL): variably with or without small dark spots (, 1 mm), mainly on dorsal body surface and flanks above lateral line, including the adipose fin; usually disappear in specimens larger than about 100 mm SL, but still present on some specimens from Senegal (Rivers Gorom and Lampsar), Uganda (Lake Albert) and Black Volta (in the latter they also occur below the lateral line).

Distribution

Widely distributed in West African basins, except for the coastal basins of Sierra Leone and Liberia; absent from the Ogun, Oueme and Mono basins; known from the basins of the Nile and Uebi Giuba (5Uebi Shebeli), and in lakes Abaia, Stephanie, Turkana and Tchad ( Poll 1971).

Etymology

Named in reference to the vernacular name for the species in Egypt, schall ( Bloch and Schneider, 1801) .

Specimens examined

Senegal: MRAC 168229-247: Boundoum ( Senegal), Gorom River, Coll. D. Thys v.d. Audenaerde, 66–91 mm SL; MRAC 79-02-P-278-283: Camp Djoudj ( Senegal), Gorom River, Coll. K.U.L. Expedition, 91–170 mm SL; MRAC 78-14-P-90: Mbane ( Senegal), lac de Guiers, Coll. K.U.L. Expedition, 185 mm SL. Gambia: MRAC 79-02-P-284: Ba Foula Be´, Gambia River ( Gambia), Coll. K.U.L. Expedition, 135 mm SL; BMNH 2005.9.9.1: Gambia, 230 mm SL (holotype S. gambiensis ). Mali: MRAC 168449: Mopti ( Mali), Niger River, Coll. H. Matthes, 147 mm SL; MRAC 168471: Mopti ( Mali), Coll. H. Matthes, 40 mm SL; MRAC 168470: Mopti ( Mali), Niger River, Coll. H. Matthes, 37 mm SL. Guinea: MNHN 1981-1019: Bantala ( Guinea), Coll. Leveque and Paugy, 165–177 mm SL; MNHN 1982-1195: Gaoual ( Guinea), Coll. Leveque and Paugy, 110 mm SL. Ivory Coast: MRAC 95-014-P-0577-0580: Bianouan ( Ivory Coast), Bia River (6 ° 019N –3 ° 129W), Coll. G. Gourène, 94–117 mm SL; MRAC 95-014-0599: Armébé ( Ivory Coast), Agnéby River (5 ° 219N–4 ° 209W), Coll. G. Gourène, 118–139 mm SL. Burkina Faso: MRAC 144291-298: Massili River ( Burkina Faso), affluent of the White Volta, Coll. B. Roman, 59–63 mm SL; MRAC 141755-756: Bougouriba River ( Burkina Faso), affluent of the Black Volta, Coll. B. Roman, 103–113 mm SL. Benin: MRAC A1-064-P-0026-0028: Porga ( Benin), Pendjari River, Coll. P. Vandewalle, 118–131 mm SL; BMNH 2005.7.26.312-314: Pendjari ( Benin), Coll. Timo Moritz, 31–46 mm SL. Niger: MRAC 86-16-P-191: 20 km from Niamey ( Niger), Niger River, Coll. W. Van Neer and R. Lauwers, 115 mm SL. Nigeria: MRAC 119407-408: Birmin Kebbi ( Nigeria), Sokoto River, Coll. J. Holden, 115– 126 mm SL; MRAC 9018P95: Polaku ( Nigeria), Nun River, Coll. A.J.T. Otobo, 40 mm SL; MRAC 91-055-P-0560-0561: Okoso creek ( Nigeria), Nun River (5 ° 07N – 6 ° 21E), Coll. C.B. Powell, 111–124 mm SL; MRAC 87-36-P-68-69: Niamey area ( Nigeria), Niger River, Coll. E. Coenen, 36–41 mm SL. Cameroon: MRAC 73-15-P-1296-297: Garoua ( Cameroon), Benue River, Coll. W. Verheyen and T. De Vice, 137–140 mm SL; MRAC 80-30-P-70-71: Lake Douloumi ( Cameroon), Coll. P. De Kimpe, 105–116 mm SL. Tchad: MRAC 153925-932: Bahr Sara mouth ( Tchad), Mandoul River, Coll. A. Suiter, 82–191 mm SL; MRAC 154176: Lake Iro, Chari System, Salamat Province ( Tchad), Coll. Cl. Cornet d’Elzius, 118 mm SL. Central African Republic: MRAC 82-21-P-777: Gounda River (Centr. Afr. Rep.), Coll. J. Marquet, 210 mm SL. Egypt: MNHN 0000-4203: Nile ( Egypt), 237 mm SL (syntype S. arabi ); MNHN 0000-4205: Nile ( Egypt), 125 mm SL (syntype S. arabi ); MNHN 0000-4207: Egypt, Coll. Joannis, 319 mm SL; MNHN 1898-0131: Assouan ( Egypt), Coll. Chantre, 239 mm SL; BMNH 1850.7.29.15: Cairo, Nile ( Egypt), 56–132 mm SL (paralectotypes S. maculosus ); SMF 5417-5421: Cairo, Nile ( Egypt), 33–54 mm SL (paralectotypes S. maculosus ). Uganda: MRAC 89-59-P-276-278: Nyawiega ( Uganda), Lake Albert, Coll. W. Van Neer, 185–200 mm SL. Sudan: MRAC 154739: Khartoum ( Sudan), Coll. Bishai and A. Gudeiri, 171 mm SL. Ethiopia: BMNH 1895.12.31.68: Lake Stephanie ( Ethiopia), 177 mm SL (holotype S. smithii ).

Figures

Figure 8. Holotype of Synodontis kogonensis MRAC 92-059-P-1933: Ndyarendi (Guinea), Kogon River (11°219–14°309W), Coll. G. Teugels et al., 108 mm SL.

Figure 9. Neotype of Synodontis schall MNHN 1898-0131: Assouan (Egypt), Nile River, Coll. Chantre, 239 mm SL.