Notoglanidium macrostoma (Pellegrin 1909)

Geerinckx, Tom, Vreven, Emmanuel, Dierick, Manuel, Hoorebeke, Luc Van & Adriaens, Dominique, 2013, Revision of Notoglanidium and related genera (Siluriformes: Claroteidae) based on morphology and osteology, Zootaxa 3691 (1), pp. 165-191 : 178-180

Notoglanidium macrostoma (Pellegrin 1909)

( Figs. 3 C, 3D & 10D)

Auchenoglanis macrostoma Pellegrin 1909 Parauchenoglanis ansorgii Boulenger 1912

Holotype. MNHN 1909.17: Ngomo (Batanga), Lower Ogowe river, Gabon; 0° 49’ S, 9° 58’ E; 194 mm SL.

Other specimens examined. BMNH 1912.4.1:447 (holotype of Parauchenoglanis ansorgii , examined on pictures): Loango River downstream of N’Kutu (Necuto), Shiloango basin, Angola, ca. 4° 57' S, 12° 37' E; 144 mm SL. MRAC 73-29-P- 1465–1466: Ebogo, Nyong river, Cameroon; approx. 4° 9’ N, 11° 52’ E; 2 spec., 207–233 mm SL. MRAC 73-2-P-1811: same locality; 281 mm SL. MRAC 73-29-P-1468: same locality; 172 mm SL. MRAC 73-29-P-1472: same locality; 125 mm SL. MRAC P.173142–143: between Ebam and Macora, basin of Ntem River, Equatorial Guinea; 2 spec., 43–46 mm SL. MRAC 95-19-P-779–780: first left tributary downstream of the bridge east of Nko’elon, Bitandé River, Cameroon; 2° 23' N, 10° 03' E; 2 spec., 81–105 mm SL. MRAC P.22532: Sankuru Lomela, Busira-Congo basin, Democratic Republic of the Congo ( Congo-Kinshasa); 92 mm SL. MRAC P.20423: Sangha, Republic of the Congo ( Congo-Brazzaville); 58 mm SL. MRAC 75-56-P-896–897: Djaposten, Dja River, Cameroon; approx. 3° 25’ N, 13° 32’ E; 2 spec., 179–193 mm SL. MRAC 95-42-P-239–241: Mpep River, 34.15 km south of Djolimpoum, Dja basin, Cameroon; approx. 3° 02’ N, 12° 52’ E; 3 spec., 137–185 mm SL. MRAC 99-90-P-1812: creek crossing the Bongolo-Mbélénatembe road, Ngounié-Ogowe basin, Gabon; 90 mm SL.

Diagnosis. Notoglanidium macrostoma differs from other species in the genus in having: a very broad combined premaxillary tooth plate (33.5–41.7% HL) [vs. 30.1–35.3% HL in N. boutchangai , and less than 30% HL in the other species (Table 4)]; large eye diameter (9.1–13.3% HL) [vs. smaller in N. maculatum (3.3–5.3% HL), N. pallidum (3.8–7.0% HL) and N. depierrei (6.8–8.8% HL), but overlapping with the eye size range of the other species]; a rather large interorbital distance (28.0–36.6% HL) [vs. 24.0% HL or less in N. akiri , N. depierrei , N. pallidum and N. pembetadi ]; only seven soft dorsal-fin rays [vs. more than eight in N. depierrei (9 or 10), N. maculatum (16–22), N. pallidum (10–13), N. pembetadi (10–13), N. thomasi (12–16) and N. walkeri (11–15)]; a rather long dorsal fin spine (6.9–14.7% SL) [vs. shorter in N. depierrei (2.5–3.7% SL), N. maculatum (2.5–3.7% SL), N. pembetadi (3.9–5.6% SL) and N. thomasi (4.6–6.2% SL)].

Description. Body and head rather depressed (pre-dorsal body depth 16.1–18.0% SL, minimal caudal peduncle depth 13.2–15.9% SL, head depth 45.9–60.0 HL). Branchiostegal membranes, each supported by 12 rays, almost not fused, with a deep medial slit separating them (they may overlap). Dorsal fin relatively high and rounded (spine 6.9–14.7% SL), 7 branched dorsal-fin rays. Adipose fin moderately deep (4.0–6.2% SL). Total number of 38 vertebrae. See also Table 4.

Colouration in life. Dark brownish gray to pale yellow with numerous black or brown spots and blotches on the head, body and fins, often aligned in transverse bands along the flanks. Juvenile colouration more variable, with larger, often confluent blotches (only yellow and light and dark brown alternating bands visible).

Maximum size recorded. 281 mm SL.

Etymology. From Greek, makros (big) and stoma (mouth), referring to the large mouth of the species (in other Notoglanidium species, the mouth is of comparable size). The species name macrostomus, found in Ferraris (2007), is an unjustified emendation, as it is a compound noun and therefore must not agree in gender with the genus name (International Code of Zoological Nomenclature art. 31.2.1; ICZN 1999).

Distribution. Lower Guinea river basins from Sanaga to Shiloango, and also found in the northern half of the Congo basin ( Fig. 13 ).

Notoglanidium maculatum (Boulenger 1916) ( Figs. 4A –B, 10E)

Liauchenoglanis maculatus Boulenger 1916

Syntypes. BMNH 1915.5.19.9–12: Sierra Leone, North Sherbo (Sherbro) District; 3 spec., 35–49 mm SL. The fourth syntype is badly damaged.

Other specimen examined. BMNH 1968.9.17.42: Kasewe Forest, Sierra Leone; 55 mm SL.

Diagnosis. Notoglanidium maculatum differs from other species in the genus in having: very small eyes (eye diameter 3.3–5.3% HL) [vs. 6.0–13.3% HL in all other species (Table 4) except N. pallidum (3.8–7.0% HL)]; a rather large interorbital distance (35.3–36.8% HL) [vs. larger in N. thomasi (41.0–46.7% HL), and <34% HL in all other species except N. macrostoma (Table 4)]; a small combined premaxillary tooth plate width (10.5–13.6% HL) [vs.>13.6% HL in all other species except N. pallidum and N. thomasi (Table 4)]; a greater number of soft dorsalfin rays (16–22) [vs. <16 in other species except N. thomasi (12–16 rays)].

Description. Body slender, but not elongate; head broad and prominent in ventral or dorsal view. Head not depressed, with a broad snout. Branchiostegal membranes completely fused, supported by 9 or 10 branchiostegal rays. Adipose fin very low (1.0–1.8% SL). See also Table 4.

Colouration in life. Pale brown with many somewhat darker and irregular spots covering head, body and most fins. On average, spots smaller than in N. thomasi .

Maximum size recorded. 54 mm SL.

Etymology. Maculatum (Latin for spotted) refers to the colouration of the species.

Distribution. Only known from two collections from the Kasewe Forest Reserve and North Sherbo (Sherbro) district in Sierra Leone ( Fig. 13 ).

Figures

FIGURE 13. Distribution of all * documented specimens of Notoglanidium species known by the authors (* not exhaustive for N. macrostoma).

FIGURE 3. A, Dorsal and B, lateral view of the skull region of Notoglanidium depierrei (holotype, MNHN 1978 - 759, 153 mm SL). C, Dorsal and D, lateral view of the skull region of N. macrostoma (MRAC 99 - 90 - P- 1912, 90 mm SL). CT scan reconstructions. Only selected structures indicated (see text for details). Scale bars = 5 mm.

FIGURE 4. A, Dorsal and B, lateral view of the skull region of Notoglanidium maculatum (syntype, BMNH 1915.5. 19.9, 49 mm SL, lower jaw damaged). C, Dorsal and D, lateral view of the skull region of N. pallidum (paratype, MRAC 76 - 17 - P- 5 – 6, 76 mm SL). CT scan reconstructions. Only selected structures indicated (see text for details). Scale bars = 5 mm.