Doumea sanaga Skelton, 2007, sp. nov.
Creators: name: Paul H. Skelton
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Siluriformes
Amphiliidae
Doumea
Doumea sanaga

description: Doumea sanaga sp. nov.
(Fig. 11)
Type material. Holotype, MRAC 95-054-P-130, SL 79.6 mm, male, Mbal river, at Mbal, Sanaga River system, 05°37'N, 14°03'E, Cameroon, col. E. van den Bergh and Forbin, 4 March 1994; 31 paratypes, 1, MRAC 95-054-P-131, SL 50 mm, same data as holotype; 2, MRAC 95-054-P-132-133, SL 36-39 mm, Kinkina River, tributary of the Lom River, below the Garoua Boulai bridge, Sanaga River system, 06°04'N, 14°22'E, Cameroon, col. E. van den Bergh and Forbin, 6 March 1994; 3, MRAC 95-054-P-134-136, SL 31-35 mm, Sessé River, at the entrance to Massa and Manboya, Sanaga River system, 05°04'N, 13°30'E, col. E. van den Bergh and Forbin, 3 March 1994; 1, MRAC 95-054-P-137, SL 42 mm, Lom river, at Wakaso, Sanaga River system, 06°19'N, 14°30'E, Cameroon, col. E. van den Bergh and Forbin, 8 March 1994; 8, MRAC 95-054-P-138-145, SL 36-44 mm, Lom river, at bridge entrance to Betare Oya and Garoua Boulai, Sanaga River system, 06°05'N, 14°23'E, Cameroon, col. E. van den Bergh and Forbin; 16, MRAC 95-054-P-146-151, SL 35-53.6 mm, Mi river, at Tigoum, Sanaga River system, 06°14'N, 14°23'E, Cameroon, col. E.van den Bergh and Forbin, 6 March 1994; 5, AMNH 240491 (ex MRAC 95-054-P-158-162), 38.7-47.1 mm SL, same data as MRAC 95-054-P-146-151; 6, SAIAB 79511 (ex MRAC 95-054-P-152-157), 39-46.1 mm SL, same data as MRAC 95-054-P-146-151.
Diagnosis. D. sanaga is a relatively small species of Doumea (maximum size recorded is SL 79.6 mm) with a relatively long, (3.4-3.6 times in SL), slender (depth into length 9-11.5 times) caudal peduncle. The species is most similar to D. typica and D. gracila but differs from both these species in several features including: the shape of the head, which has a broad round snout and anterior profile vs. a triangular and pointed profile in D. typica and D. gracila; the edge of the branchiostegal membrane forms a distinct shallow ‘V across the ventral surface vs.a straight or nearly straight edge in D. typica and D. gracila; the leading dorsal (nuchal) pterygiophore intercepting at least the second or third post Weberian vertebra vs.in D. typica and D. gracila the dorsal leading pterygiophore intercepts the first post-Weberian vertebra; in the relative position of the pelvic fins, the origin of the pelvic fins is beneath the base of the dorsal fin vs.behind the base of the dorsal in D. typica and D. gracila. It differs from D. gracila sp. nov. in the length of the caudal peduncle (D. gracila caudal peduncle in SL 2.9-3.2 vs. 3.4-3.6 D. sanaga). It differs from D. thysi in the length and depth of the caudal peduncle (28-30% SL vs.in D. thysi the caudal peduncle is short 20% SL, and stout, 9-11 times long as deep vs.2.5-4.0 times long as deep in D. thysi),as well as in color pattern (D. sanaga has a series of light saddles that are not characteristic of D. thysi, and the latter has a distinctly demarcated white band along the lateral line that is not characteristic of D. sanaga).
Description. Measurements and fin ray counts given in Table 8. Body firm, slender, moderately depressed, strongly tapered to caudal base, with a mid dorsal ridge from dorsal to adipose, and thin bi-lateral ridges along caudal peduncle. Skin is smooth or in larger individuals the head and upper body is covered with short vermiculate white unculi. Head short 4.8-5.5 times in SL, obtusely pointed, flat below, rounded above; snout longer than postorbit, 1.5-1.9 times in head length; nares separated, on anterior half of snout; mouth ovoid, ventral, upper lips fleshy and papillose, lower lip divided by medial triangular pad; barbels short, tapered, papillose, maxillaries longest less than 2/3 head length, extend from lateral edge of upper lip not reaching edge of branchiostegal membrane; outer mandibular barbels from lateral corner of mouth to about 2/ 3 distance to edge of branchiostegal membrane; inner mandibular barbels from medial position on ventral side of mandible separated by medial mandibular pad, reaching less than halfway to edge of branchiostegal membrane; eyes small, orbits bony, widely separated by distance 1.9-2.4 times orbit diameter; supraoccipital process slender, half length of snout, separated from nuchal shield by gap; obscure short humeral process above gill openings; branchiostegal membrane united ventrally, margin with shallow medial notch. Caudal peduncle long, 3.4-3.6 times in SL, slender, length 8.7-11.1 times depth, and bony. Fins large and pointed; origin of dorsal less than one head length behind head, dorsal entirely in advance of pelvic fins, dorsal fin pointed with concave hind margin; pectoral fins falcate, not reaching bases of pelvic fins, leading ray curved, pectinate and padded, outer rays lie horizontal, inner rays vertical against body; origin of pelvic fins beneath posterior edge of dorsal base, pelvic fins falcate, reaching base of anal fin, leading ray curved, pectinate and padded; anal fin large, trailing edge straight; caudal fin with compact base, forked with ventral lobe slightly longer than dorsal; adipose fin triangulate, positioned over posterior base of anal. Ano-genital pores placed midway between bases of pelvic fins and origin of anal fin, males with conical genital papillae. Skin smooth or rugose with small white unculi on predorsal and dorsal surface of head in larger specimens. Lateral line complete, with short dorsal and ventral branches to pores along its length, visible as a thin white line in preserved specimens. Reaches 80 mm SL.
Coloration. Dark brown above, light cream below, flanks light brown, lateral line highlighted in cream, head with dark pre-orbital stripes and light patches above, a series of 5-6 lighter saddles along back, dark brown patches above pelvic fin bases, fins with brown rays and dark mid-distal band, outer rays of caudal brown. Lateral line visible as thin white line along mid-flanks.
Distribution. Upper reaches of the Sanaga River, in Cameroon (Fig. 10).
Etymology. From ‘Sanaga’ the name of the river system where the species occurs. Used as a noun in apposition.
description: Published as part of Paul H. Skelton, 2007, New species of the amphiliid catfish genera Amphilius, Doumea and Phractura and the taxonomy of Paramphilius from West Central Africa (Siluriformes, Amphiliidae)., pp. 41-68 in Zootaxa 1578 on pages 63-65