Notoglanidium boutchangai

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 : 176-178

Notoglanidium boutchangai (Thys van den Audenaerde 1965)

( Figs. 2 C, 2D & 10B)

Parauchenoglanis boutchangai Thys van den Audenaerde 1965

Holotype. MRAC P.153160: rapids of the Ngounié or the Louetsi river (Ogowe basin), Gabon; approx. 2° 12’ S, 11° 30’ E; 198 mm SL.

Paratypes. MRAC P.153161–162: same locality; 2 spec., 110–182 mm SL.

Other specimens examined. MRAC 80-51-P-10–11: Louetsi or Ngounié rivers near Lebamba, Gabon; 2 spec., 65–76 mm SL.

Diagnosis. Notoglanidium boutchangai differs from other species in the genus in having: a rather large combined premaxillary tooth plate width (30.1–35.3% HL) [vs. larger in N. macrostoma (33.5–41.7% HL), and smaller in N. akiri (22.0–26.1%), N. pembetadi (21.0–26.4% HL), and much smaller in the other species except N. depierrei (Table 4)]; a small interorbital distance (17.2–23.4% HL) [vs. larger in N. akiri (24.1–32.8% HL), and over 27.7% HL in N. macrostoma , N. maculatum , N. thomasi and N. walkeri (Table 4)]; a relatively large eye diameter (7.5–10.4% HL) (negatively allometric with body size) [vs. smaller in N. pallidum (3.8–7.0% HL) and N. maculatum (3.3–5.3% HL)]; only seven soft dorsal-fin rays [vs. more than eight in N. depierrei (9–10), N. maculatum (16–22), N. pallidum (10–13), N. pembetadi (10–13), N. thomasi (12–16) and N. walkeri (11–15)].

Description. Both head and body extremely dorsoventrally flattened, with depth almost constant from head to body (predorsal body depth 10.9–12.9% SL, minimal caudal peduncle depth 10.0–11.0% SL, head depth 36.6– 38.9% HL, or 7.38–9.7% SL). Branchiostegal membranes almost not fused, with a deep medial slit separating them (they may overlap). Dorsal-fin spine short (3.4–7.4% SL). See also Table 4.

Colouration in life. Uniform brownish red, paler ventrally; in young specimens 5–7 pale vertical dotted bars may be visible on the flanks; most fins somewhat transparent.

Maximum size recorded. 198 mm SL.

Etymology. Named in honour of H. Boutchanga, collector of the type specimens (Thys van den Audenaerde 1965).

Distribution. Only known (and unclear) locality is the Louetsi or the Ngounié river near Lebamba in southern Gabon ( Fig. 13 ).

Figures

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

FIGURE 2. A, Dorsal and B, lateral view of the skull region of Notoglanidium akiri (paratype, MRAC 84 - 15 - P- 3 – 4, 92 mm SL, lower jaw damaged). C, Dorsal and D, lateral view of the skull region of N. boutchangai (MRAC 80 - 51 - P- 10 – 11, 76 mm SL). CT scan reconstructions. Only selected structures indicated (see text for details). Scale bars = 5 mm.