Chiloglanis kerioensis, 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 : 47-51

Chiloglanis kerioensis sp. nov.

Figs. 1 , 3 ; Table 1

Chiloglanis spec. “Kerio”— Seegers et al. 2003: 38.

Chiloglanis sp. “Kerio River”— Schmidt et al. 2014: 416, 419.

Holotype. NMK FW/3959/1, male ALC, 40.3 mm SL; Kenya, Rift Valley Province, Barwessa River (Barwessa Village) near Lake Kamnarok, Georeferenced: 00.63505° N, 35.618126° E; L. De Vos, 4 January 1999.

Paratypes. NMK FW/599/1-13, 9 ALC, 32.1–37.6 mm SL; same collection data as holotype.— NMK FW/ 2794/1-6, 6 ALC, 27.4–38.4 mm SL; same collection data as holotype.—TU 204096, 3 ALC, 32.6–35.9 mm SL; same collection data as holotype.— NMK FW/2243/1-24, 21 ALC, 27.6–32.9 mm SL; tissue vouchers: IRES 1514— IRES 1517; Kenya, Rift Valley Province, Kerio Rift near Chebloch Gorge, off Kabernet—Tambach Rd. (C51), 00.45017° N, 35.64670° E, 2011 IRES team, 23 June 2011.—TU 204094, 3 ALC, 29.7–31.1 mm SL; same collection data as NMK FW/2243/1-24.

Diagnosis. Chiloglanis kerioensis is distinguished from C. somereni and C. devosi in having fewer mandibular teeth (eight or fewer versus eight or more) and a larger orbit (>4% SL versus <4% SL). Chiloglanis kerioensis is distinguished from C. brevibarbis by longer barbels (maxillary barbels usually>30% HL versus <30% HL, medial mandibular barbels>10% HL versus <9% HL, and lateral mandibular barbels>17% HL versus <15% HL) and in the arrangement of the mandibular teeth (exposed length of teeth not equal to row width versus exposed portion equal or greater than row width in C. brevibarbis populations). Chiloglanis kerioensis differs from C. deckenii in having a longer premaxillary tooth pad (>3% SL versus <3% SL) and longer lower lip (>60% HL versus <55% HL). The species is distinguished from Chiloglanis sp. aff deckenii by the following combination of characters: C. kerioensis has a longer postcleithral process (>9% SL versus <9% SL) and longer lateral mandibular barbels (>15% HL versus>15% HL).

Description. Morphometric measurements and meristics for holotype and paratypes of C. kerioensis are summarized in Table 1. Dorsal, lateral, and ventral views ( Fig. 3 ) illustrate body shape, fin shape and placement, oral disc shape and size, and barbel length.

A small, relatively deep-bodied Chiloglanis , maximum standard length observed 40.3 mm. Body dorsally depressed anteriorly and laterally compressed posteriorly. Predorsal angled towards snout. Pre-orbital convex. Postdorsal body angled ventrally towards caudal fin. Preanal profile horizontal; postanal sloping dorsally towards caudal fin. Skin with numerous small unculiferous (horny unicellular projections) tubercles, body uniformly covered with higher concentrations of more pronounced tubercles in the head region. Lateral line complete, arising slightly above 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 broadly 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 and medial flaps. Mouth inferior, upper and lower lips united to form sucking disc. Oral disc moderate in size, wider than long and covered in papillae. Barbels in three pairs; maxillary barbel originating from posterolateral region of the disc, unbranched, long, reaching 45% of head length. Lateral and medial mandibular barbels moderate, lateral barbels twice the length of medial barbels, incorporated into lower lip and positioned on both sides of prominent midline cleft on the posterior margin of disc.

Primary maxillary teeth numerous (36–80), “S” shaped with exposed tips light brown in color, arranged in three rows on oval shaped tooth. 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, grouped near midline. The anterior row (functional row) supporting 6–8 brown tipped sharp teeth.

Dorsal fin originates in anterior third of body. Dorsal fin with small spinelet, spine and 6 rays. Dorsal spine short, anterior margins of spine marked with 2 small notches distally, posterior margins smooth. Adipose fin moderate in length, length into SL four to five times; margin convex with a small incision posteriorly. Caudal fin forked with gently pointed lobes, lower lobe slightly longer than upper lobe, count i, 7, 8, i. Anal fin extending beyond adipose fin terminus, 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, five to six times into standard length, count i, 8–9. Post cleithral process going into standard length nine to ten times, buried under the skin. No apparent sexual dimorphism in shape or size of fins. Dimorphism of body size apparent with females being the largest specimens collected.

Coloration. Live coloration: Body with yellowish-brown ground color with overlying melanophores and gold iridescent flecks alongside of body. Fins yellow to orange. Typical coloration of preserved specimens is shown in Figure 3 . In dorsal view, specimens appear medium brown with three light bands. The first lies anterior to the dorsal fin; second and third bands are anterior and posterior to the adipose fin. Lighter spots visible along sides above lateral line. Head uniformly medium brown.

In lateral view, specimens have cream-buff ground color with overlying medium brown above lateral line and cream to yellow from lateral line to belly. Three light bands observed from above extend beyond midline. Light spots on sides above and below lateral line, light areas on lateral line extending dorsally. Numerous small black melanophores scattered across sides, more concentrated below lateral line.

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

Etymology. The specific epithet refers to the Kerio River, Lake Turkana basin, where the species is believed to be endemic.

Distribution. This species is known from two localities in the upper Kerio River system (the type locality on Barwessa River (asterisk, Fig. 1 ) and in the Kerio River at Chebloch Gorge (cross, Fig. 1 )) and is likely endemic to the system. This species was abundant in the medium rapids upstream from the road crossing (Chebloch Gorge) and were aggregated near the larger boulders. It is likely that further sampling efforts within the upper Kerio River system will reveal addition populations.

MORPHOMETRICS Holotype Range Mean±%SD Standard length (mm) 40.3 27.4–40.3

Head length 29.5 27.6–33.1 30.6±1.3 Head depth (maximum) 18.4 13.8–19.6 16.3±1.5 Body depth at anus 15.4 12.1–19.1 14.4±1.6 Occipital shield width (minimum) 3.6 3.6–4.7 4.2±1.3 Prepectoral length 29.6 28.5–34.1 31.2±1.3 Predorsal length 42.0 40.2–44.5 42.0±1.1 Prepelvic length 56.5 53.3–57.3 55.7±1.4 Preanal length 70.8 67.2–74.9 71.1±1.6 Eye diameter (horizontal) 4.3 3.9–5.3 4.5±0.3 Orbital interspace 7.6 6.9–8.8 7.7±0.5 Snout length 18.9 15.8–20.1 18.4±0.9 Premaxillary tooth-patch width 13.2 12.4–16.0 14.0±0.9 Premaxillary tooth-patch length 3.5 3.0–4.3 3.6±0.3 Mandibular tooth row width 2.1 1.3–2.7 2.4±0.3 Anterior nares interspace 4.5 3.8–5.3 4.7±0.3 Posterior nares interspace 4.4 3.8–5.4 4.7±0.4 Maxillary barbel length 9.8 8.5–13.4 11.7±1.1 Medial mandibular barbel length 3.2 2.5–4.2 3.3±0.4 Lateral mandibular barbel length 6.0 4.5–7.1 5.9±0.5 Mouth width 9.1 8.3–10.3 9.2±0.5 Oral disc width 19.0 18.1–23.0 20.3±1.1 Oral disc length 18.2 17.4–21.4 19.4±1.0 Upper lip length 4.1 3.1–5.2 4.0±0.4 Lower lip length 7.6 6.1–8.7 7.7±0.6 Pectoral-spine length 16.6 16.4–21.4 18.7±1.2 Pectoral-fin length 22.0 19.3–24.7 21.9±1.5 Width at pectoral-fin insertion 24.0 23.0–28.2 25.0±1.0 Length of postcleithral process 11.9 9.3–13.3 10.9±0.9 Pelvic-fin length 14.9 12.4–16.8 14.5±1.0 Depth at dorsal-fin insertion 20.9 14.6–25.0 18.9±2.3 Dorsal-spine length 12.7 12.2–16.1 14.5±1.1 Dorsal-fin length (longest ray) 17.7 16.3–20.4 18.1±1.0 Dorsal-fin base length 10.1 9.9–13.9 11.9±1.0

......continued on the next page Meristics

Mandibular tooth rows 1,2

Mandibular tooth count (total) 6–16; 8* Mandibular tooth count (functional anterior row) 6–8; 8* Mandibular tooth count (posterior replacement row) 1–8; Primary premaxillary teeth (total) 36–80; 56* Pectoral-fin count I, 8*(37); I, 9(6) Pelvic-fin count i, 6*(43) Dorsal-fin count II, 6 (43) Anal-fin count iii, 7(1); iii, 8*(10) Caudal-fin count i, 7, 8, i* (43)

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 3. Dorsal, lateral and ventral views of Chiloglanis kerioensis holotype, NMK FW / 3959 / 1, male, 40.3 mm SL; Kenya, Rift Valley Province, Barwessa River (Barwessa Village) near Lake Kamnarok Scale bar equals 1 cm. Photographs by R. C. Schmidt.