Chiloglanis devosi, Schmidt, Ray C., Bart Jr, Henry L. & Nyingi, Wanja Dorothy, 2015

Schmidt, Ray C., Bart Jr, Henry L. & Nyingi, Wanja Dorothy, 2015, Two new species of African suckermouth catfishes, genus Chiloglanis (Siluriformes: Mochokidae), from Kenya with remarks on other taxa from the area, Zootaxa 4044 (1), pp. 45-64 : 51-55

Chiloglanis devosi sp. nov.

Figs. 1 , 4 , 5 ; Table 2

Chiloglanis spec. “Northern Ewaso Nyiro”— Seegers et al. 2003: 38.

Chiloglanis sp. “Northern Ewaso Nyiro”— Schmidt et al. 2014: 416, 419.

Holotype. NMK FW/3958/1, male ALC, 36.0 mm SL; Kenya, Eastern Province, Northern Ewaso Nyiro (Ewaso Ng’iro) below Chanler’s Falls, Isiolo—Merti Road, 00.78056° N, 38.08021° E; 2012 IRES team, 12 June 2012.

Paratypes. NMK FW/2777/1-11, 8 ALC, 34.0– 49.2 mm SL; tissue vouchers: IRES 10051— IRES 10053; same collection data as holotype.—TU 204093, 2 ALC, 35.1–52.5 mm SL; same collection data as holotype.

Diagnosis. Chiloglanis devosi is distinguished from C. somereni by having shorter dorsal spines (12.3–17.2% SL versus 17.9–23.0% SL) and having the anterior and posterior nares the same distance apart (versus posterior nares further apart in C. somereni ). Chiloglanis devosi is easily distinguished from the other Kenyan congeners in having a wider occipital shield width (>5% SL versus <5% SL), more mandibular teeth (eight or more versus 8 or fewer), and a smaller orbit (<4% SL versus>4% SL).

Description. Morphometric measurements and meristics for holotype and paratypes of C. devosi are summarized in Table 2. Dorsal, lateral, and ventral views ( Figs. 4 & 5 ) illustrate body shape, fin shape and placement, oral disc shape and size, and barbel length.

Moderate to small sized Chiloglanis , maximum standard length observed 49.2 mm. Body dorsally depressed anteriorly and laterally compressed posteriorly. Predorsal convex, post-orbital slightly so, pre-orbital sharply convex. Postdorsal body sloping ventrally towards caudal fin. Preanal profile horizontal; postanal sloping dorsally towards caudal fin. Skin with numerous small unculiferous tubercles, body uniformly covered with higher concentrations in the head region. Lateral line complete, arising horizontal to orbit and sloping ventrally to midlateral alongside of body. Urogenital papillae elongate in males; reduced and separated from anus by shallow invagination in females.

Head depressed. Gill openings restricted, from level of pectoral fin attachment to middle of eye. Gill membranes broadly united. Occipital-nuchal shield covered and visible through skin. Eyes small, horizontal axis longest, orbit without free margin. Anterior and posterior nares positioned mid-snout length and equidistant. Nares with raised rim, posterior nares with elongated anterior flaps.

Mouth inferior, upper and lower lips united to form sucking disc. Oral disc moderate in size, slightly wider than long and covered in papillae. Barbels in three pairs; maxillary barbel originating from posterolateral region of the disc, unbranched, moderate in length, reaching 25% of head length. Lateral and medial mandibular barbels short, one-third length of maxillary barbel, and incorporated into lower lip. Mandibular barbels positioned on both sides of prominent midline cleft on the posterior margin of disc; medial mandibular barbel adjacent to cleft and lateral mandibular barbel just lateral to medial barbel.

Primary maxillary teeth numerous (51–81), “S” shaped with exposed tips brown in color, arranged in three scattered rows on kidney-shaped patched on ventral surface. Secondary premaxillary teeth fewer in number and scattered on posterior surface of premaxillae. Tertiary teeth small and needle-like, inserted near midline on dorsal edge of toothplate. Mandibular teeth arranged in one to two rows, “S” shaped and crowded at midline. The anterior row (functional row) supporting 7–12 brown tipped sharp teeth.

Dorsal fin origin in anterior third of body. Dorsal fin with small spinelet, spine and 4–6 rays. Dorsal spine long, nearly half as long as head length. Anterior margins of spine marked with three small notches distally, posterior margins smooth. Adipose fin moderate in length, length into SL four times; margin convex and slightly incised posteriorly. Caudal fin forked with rounded lobes, lower lobe slightly longer than upper lobe, count i, 7, 8, i. Anal fin sexually dimorphic; males displaying elongated rays that extend well beyond terminus of adipose fin, margin convex, count iii, 8. Pelvic fin origin at vertical between dorsal and adipose fin, margins convex, count i, 6. Pectoral fin with slightly curved smooth spine, moderate in length, count i, 8–9. Post cleithral process elongate, going into standard length ten times, buried under the skin. Body dimorphism present with females attaining larger sizes than males.

Coloration. Live coloration of this species shown in Figure 4 . Body with pinkish brown ground color with overlying melanophores that produces the pattern observed in preserved specimens. Iridescent gold markings along sides of body, large iridescent gold area dorsal and posterior to pectoral fin origin with smaller gold markings on side of body, dorsal of lateral line. Fins yellows with brown markings. Typical coloration of preserved specimens is shown in Figure 5 . In dorsal view, specimens appear medium brown with three distinct areas of light brown to cream coloration. The first lies anterior to the dorsal fin; second and third bands are anterior and posterior, respectively, to the adipose fin. Lighter spots visible along sides of dorsal fin above lateral line. Head medium brown with areas of mottled lighter brown.

In lateral view, specimens with cream-buff ground color with medium brown present along sides and above lateral line. Cream-buff ground color anterior to dorsal fin extends to lateral line, dark area anterior to adipose fin extends onto side below lateral line, and the light area posterior to adipose fin extends through caudal peduncle, giving the peduncle a depigmented appearance. Light spots on sides above and along lateral line. Numerous small black melanophores scattered across sides, more concentrated posteriorly and below lateral line.

Ventral surface cream colored. Few melanophores near origin of pelvic fins and around anal fin. Oral disc and barbels yellow to cream colored.

Etymology. We take pleasure in naming this species in honor of Dr. Luc DeVos, the late ichthyologist and director of the Ichthyology Section at the National Museums of Kenya. Dr. DeVos was instrumental in establishing the collection at NMK and building it into a regional and internationally invaluable collection. DeVos and others ( Seegers et al. 2003) were also responsible for discovering and recognizing both new species described herein as distinct.

Distribution. This species is only known from the type locality (below Chanler’s Falls on the Northern Ewaso Nyiro River ( Fig. 1 )). Specimens were collected around rocks and small boulders in flowing water. Additional populations on this species may occur in favorable habitats downstream from Chanler’s Falls and within tributaries that join the Northern Ewaso Nyiro until the river flows into the largely endorheic Lorian Swamp ( Fig. 1 ).

MORPHOMETRICS Holotype Range Mean±%SD Standard length (mm) 36.0 34.0–49.2

Head length 30.1 30.1–34.7 32.2±1.4 Head depth (maximum) 14.5 14.5–17.4 15.5±1.0 Body depth at anus 13.5 13.1–16.8 14.4±1.3 Occipital shield width (minimum) 5.7 5.5–7.1 5.9±0.5 Prepectoral length 30.6 28.2–32.7 30.4±1.2 Predorsal length 39.0 36.7–42.0 39.8±1.6 Prepelvic length 55.5 52.1–59.4 56.3±1.9 Preanal length 70.2 68.1–72.0 69.7±1.3 Eye diameter (horizontal) 3.3 3.0–3.9 3.5±0.3 Orbital interspace 7.3 7.3–8.6 8.0±0.4 Snout length 18.1 17.2–19.7 18.8±0.7 Premaxillary tooth-patch width 13.0 13.0–15.3 14.5±0.7 Premaxillary tooth-patch length 3.7 3.3–4.3 3.8±0.3 Mandibular tooth row width 2.9 2.4–3.9 3.0±0.5 Anterior nares interspace 4.6 3.9–5.6 4.5±0.4 Posterior nares interspace 4.4 3.4–4.8 4.2±0.4 Maxillary barbel length 8.7 3.0–9.8 7.5±1.8 Medial mandibular barbel length 2.4 1.8–3.0 2.2±0.4 Lateral mandibular barbel length 3.7 3.0–4.9 3.8±0.6 Mouth width 10.7 10.1–12.6 11.2±0.8 Oral disc width 20.5 19.7–23.7 21.8±1.1 Oral disc length 19.7 18.7–21.8 20.2±1.1 Upper lip length 4.4 3.9–5.4 4.5±0.4 Lower lip length 8.9 5.2–10.3 8.8±1.4 Pectoral-spine length 17.7 15.6–21.4 18.8±1.8 Pectoral-fin length 21.3 19.3–22.2 20.6±1.0 Width at pectoral-fin insertion 23.3 23.0–25.3 23.6±0.7 Length of postcleithral process 8.9 8.9–12.3 10.5±0.9 Pelvic-fin length 22.0 11.3–22.0 13.6±3.0 Depth at dorsal-fin insertion 15.5 15.3–18.5 16.6±1.0

......continued on the next page MERISTICS

Mandibular tooth rows 2

Mandibular tooth count (total) 10–16; 11* Mandibular tooth count (functional anterior row) 7–15; 9* Mandibular tooth count (posterior replacement row) 2–6; 2* Primary premaxillary teeth (total) 51–81; 63* Pectoral-fin count I, 8*(10); I, 9(1) Pelvic-fin count i, 6*(11) Dorsal-fin count II, 4(1); II, 5(4); II, 6*(6) Anal-fin count iii, 7(1); iii, 8*(10) Caudal-fin count i, 7, 8, i*(11)

Figures

FIGURE 1. Collection localities of Chiloglanis specimens included in this study and type localities of new species described herein: Chiloglanis deckenii (triangle), C. brevibarbis (circle), C. somereni (square), C. kerioensis (type locality—asterisk, paratypes—cross), and C. devosi (type locality—star). Drainage boundaries denoted by white lines.

FIGURE 4. Lateral views of Chiloglanis devosi showing life coloration: (A), NMK FW / 2777 / 1 - 11 male, 36.0 mm SL, (B) NMK FW / 2777 / 1 - 11, female, 49.0 mm SL. Scale bar equals 1 cm. Photographs by H. L. Bart Jr.

FIGURE 5. Dorsal, lateral and ventral views of Chiloglanis devosi holotype, NMK FW / 3958 / 1, male, 36.0 mm SL; Kenya, Eastern Province, Northern Ewaso Nyiro (Ewaso Ng’iro) below Chanler’s Falls, Isiolo—Merti Road, 00.78056 ° N, 38.08021 ° E. Scale bar equals 1 cm. Photographs by R. C. Schmidt.