Chiloglanis kazumbei, Friel, John P. & Vigliotta, Thomas R., 2011

Friel, John P. & Vigliotta, Thomas R., 2011, Three new species of African suckermouth catfishes, genus Chiloglanis (Siluriformes: Mochokidae), from the lower Malagarasi and Luiche rivers of western Tanzania, Zootaxa 3063, pp. 1-21 : 9-13

Chiloglanis kazumbei sp. nov.

( Figs. 1 B & 4; Table 2 )

Chiloglanis aff. lukugae — De Vos et al. 2001: 131. Chiloglanis sp. “burundi” — Vigliotta 2008: 125.

Holotype. CU 95230, male ALC, 49.1 mm SL; Tanzania, Kigoma Region, Malagarasi River at rapids ~ 6.4 km upriver from Ilagala barge crossing, 5.2013400° S, 29.9001400° E; J.P. Friel, P.B. McIntyre & R.C. Schelly, 14 August 2009.

Paratypes. AMNH 251410, 20 ALC, 26.0– 54.1 mm SL; same collection data as holotype. — CU 95231, 19 ALC, 1 C&S, 25.5-54.5 mm SL; same collection data as holotype. — MRAC 2010-006- P- 6-10, 5 ALC., 27.1–56.8 mm SL, same collection data as holotype. — SAIAB 87164, 5 ALC, 30.6–51.9 mm SL, same collection data as holotype.

Non-type specimens. AMNH 251409, 8 ALC, 26.3–35.0 mm SL; Tanzania, Kigoma Region, Malagarasi River down river 4 km W from Uvinza, near village of Nkwasa, 5.0979300° S, 30.3544900° E; J.P. Friel, P.B. McIntyre & R.C. Schelly, 11 August 2009. — CU 90387, 10 ALC, 1 C&S, 38–63 mm SL; Burundi, Ruyigi, River Rugoma at point south of route from Kinyinya to Rumpungwe; L. De Vos, L. & L. Taverne, 2 June 1992. — CU 90402, 1 ALC, 56.0 mm SL; Tanzania, Kigoma Region, Malagarasi River, 5.2010000° S, 29.9020000° E; J.P. Friel & G. Kazumbe, 9 September 2004. — CU 90405, 1 ALC, 35 mm SL; Tanzania, Kigoma Region, Luiche River near Ujiji, 4.9328000° S, 29.7057000° E; J.P. Friel, G. Kazumbe & S. Loader, 14 September 2004. — CU 90420, 1 ALC, 47 mm SL; Tanzania, Kigoma Region, Malagarasi River, upriver from bridge at Malagarasi City, 5.0885000° S, 30.8473000° E; J.P. Friel, G. Kazumbe & E. Michel, 24 September 2004. — CU 90565, 4 ALC, 34.6–38.7 mm SL; Tanzania, Tabora, Igombe River Forest Preserve, 4.5190000° S, 31.9068000° E; J.P. Friel & S. Loader, 29 September 2004. — CU 90566, 4 ALC, 38.2–44.6 mm SL; Tanzania, Kigoma Region, Luiche River at bridge, 4.8682000° S, 29.7403000° E; J.P. Friel, G. Kazumbe & S. Loader, 14 September 2004. — CU 90570, 5 ALC, 44.6-50.3; Tanzania, Kigoma Region, Ruchugi River at bridge in Uvinza, 5.0963000° S, 30.3863000° E; J.P. Friel, G. Kazumbe & S. Loader, 19 September 2004. — CU 90571, 1 ALC, 41.4 mm SL; same collection data as CU 90420. — CU 90573, 9 ALC, 26.7–43.9 mm SL; same collection data as CU 90405. — CU 90574, 7 ALC, 28.6– 61.3 mm SL; same collection data as CU 90420. — CU 90754, 1 ALC, 40.9 mm SL; Tanzania, Kigoma Region, Malagarasi River at Uvinza, small side channel, 5.1110000° S, 30.3932000° E; J.P. Friel, G. Kazumbe & S. Loader, 18 September 2004. — CU 95228, 1 ALC, 45.1 mm SL; Tanzania, Kigoma Region, Malagarasi River at rapids ~ 8 km down river of Igamba Falls, 5.1799300° S, 29.9803500° E; J.P. Friel, P.B. McIntyre & R.C. Schelly, 7 August 2009. — CU 95229, 7 ALC, 23.9–38.4 mm SL; same collection data as AMNH 251409. — MRAC 91-03- P- 0464- 0 502, 36 ALC, 32.2–62.9 mm SL, Burundi, Ntanga River, Malagarasi affluent, at bridge on General Interest Route 4 at 7 km from Kinyinya, De Vos and Taverne, 0 5 April 1991. — MRAC 93-152- P- 0260-0299, 39 ALC, 34.2–65.9 mm SL, Tanzania, Kigoma Region, Mungonya River, affluent of Luiche, route from Kigoma Region to Kasulu, ~ 10 km, 4.883333° S, 29.716667° E, L. De Vos, 19 August 1993. — MRAC 93-152- P- 0361-0366, 6 ALC, 35.9– 71.1 mm SL, Tanzania, Kigoma Region, Kaseke River, Luiche affluent, km 17 on route from Kigoma Region to Kasulu, 4.883333° S, 29.8° E, L. De Vos, 19 August 1993.

Diagnosis. Chiloglanis kazumbei can be distinguished from all species in the Malagarasi and Luiche basins by the following combination of features: relatively long dorsal spine length (16.1–21.3 % SL vs. 7.5–13.6 % SL in C. asymetricaudalis ; 8.2–12.7 % SL in C. igamba ; 4.1–7.8 % SL in C. orthodontus ); relatively long pectoral spine length (19.1–23.6 % SL vs. 12.1–16.5 % SL in C. asymetricaudalis ; 9.9–15.1 % SL in C. igamba ; 10.9–17.2 % SL in C. orthodontus ); relatively wide occipital shield width (6.1–8.3 % SL vs. 3.7–4.7 % SL in C. asymetricaudalis ; 2.8–4.9 % SL in C. igamba ; 2.4–3.8 % SL in C. orthodontus ); and moderately long adipose fin length (17.1–22.8 % SL vs. 13.3-19.8 % SL in C. asymetricaudalis ; 10.3–16.3 % SL in C. igamba ; 25.0-31.3 % SL in C. orthodontus ). Additional features that distinguish C. kazumbei from congeners within its range include a distinctive pigmentation pattern with dark patches on the dorsal and pectoral fins, a dark band on the anal fin, and a caudal fin that is deeply forked with a slightly longer lower lobe vs. not deeply forked ( C. lufirae , C. igamba ( Fig. 3 ) & C. orthodontus ( Fig. 5 ), or forked with greatly elongated upper lobe in males ( C. asymetricaudalis ( Fig. 6 )).

Description. Dorsal, lateral and ventral views in Figure 4 illustrate body shape, form and position of fins and barbels. Morphometric and meristic data for holotype and 19 paratypes are summarized in Table 2 .

MORPHOMETRICS Holotype Range Mean±%SD Lower caudal-fin lobe length 23.8 22.3–28.4 24.9±1.93 Upper caudal-fin lobe length 22.2 20.1–25.2 22.5±1.62 Caudal-peduncle depth (maximum) 11.2 9.2–11.4 10.7±0.57 Caudal-peduncle length 17.9 15.9–21.6 17.5±1.21

MERISTICS

Mandibular tooth rows 1 or 2* Mandibular tooth count (total) 12–24; 17* Mandibular tooth count (functional anterior row) 7–14; 9* Mandibular tooth count (posterior replacement row) 3–12; 8* Primary premaxillary teeth (total) 47–85; 68* Secondary premaxillary teeth (total) 30–40

Tertiary premaxillary teeth (total) 16

Pectoral–fin count I, 7(1); I, 8*(19) Pelvic–fin count i, 6*(20) Dorsal–fin count II, 5(3); II, 6*(17) Anal–fin count iii, 7(13); iii, 8*(7) Caudal–fin count i, 7, 8, i*(20) Pleural rib count (pairs) 7(2); 8*(18) Total vertebral count 34(4); 35*(16)

Moderately sized Chiloglanis species, maximum standard length <70 mm. Body roughly cylindrical, depressed anteriorly and compressed posteriorly. Predorsal profile gently convex; postdorsal body sloping gently ventrally. Preanal profile horizontal. Anus and urogenital opening located slightly behind vertical though origin of adipose fin. Skin covered with rounded unculiferous tubercles. Lateral line complete and midlateral along side of body.

Head depressed and broad, snout margin rounded when viewed dorsally. Gill opening restricted to lateral aspect of head from level of base of pectoral spine to level of middle of eye. Gill membranes broadly united to, and attached across isthmus, supported by 6 or 7 branchiostegal rays. Skin covering skull roof with numerous small, round unculiferous tubercles. Occipital-nuchal shield large, slightly visible through skin dorsally. Mouth inferior, lips form ventrally-directed oral disc. Oral disc moderate in size, wider than long and covered by numerous papillae. Posterior margin of oral disc with well-developed cleft present at midline. Barbels in three pairs and well developed. Maxillary barbel slender and unbranched, originating just anterior to widest point of oral disc and extending to middle of eye. Short basal membrane present on maxillary barbel. Mandibular barbels incorporated into lower lip and visible as trifurcate structures in cleared and stained specimens. Medial mandibular barbels on each side of midline; primary barbel elongate and bordered by short auxiliary barbel on each side. Lateral mandibular barbels just lateral to medial mandibular barbels, somewhat more pronounced than medial mandibular barbels; primary barbel elongate and bordered medially by single short auxiliary barbel.

Premaxillae formed as block-like plates supporting 47–85 “S”-shaped (in lateral view), pointed primary teeth on ventral surface; 30-40 small secondary teeth on posterior surface of premaxillae; 16 needle-like tertiary teeth inserting above and behind secondary teeth towards roof of mouth and gathered at midline. Dentary with wellformed tooth cup along anterior margin supporting one or two rows of 3–14 robust, “S”-shaped (in lateral view) teeth per row with pointed tips; when present, posterior row represents replacement teeth. Mandibular teeth bunched at midline ( Fig. 1 B).

Eyes small and ovoid, horizontal axis slightly longer than vertical axis; approximately one half of orbital interspace. Orbit without free margin. Anterior nares slightly further apart than posterior nares. Anterior nares tubular with short, raised rim. Posterior nares with elevated flaps along anterior margin.

Dorsal fin located at anterior third of body. Dorsal fin with spinelet, spine and 5 or 6 rays; fin membrane not adnate with body. Dorsal-fin spine long and straight; relatively smooth along anterior margin, but posterior margin with weakly developed serrations only visible in cleared and stained specimens. Adipose fin moderate in size, base less than one quarter of SL; margin gently convex and incised posteriorly. Caudal fin forked; count i, 7, 8, i. Procurrent caudal-fin rays symmetrical and extending only slightly anterior to fin base. Anal-fin base located ventral to adipose-fin base; margin convex. Anal-fin count iii, 7 or 8. Pelvic-fin origin at vertical between bases of adipose and dorsal fins. Pelvic-fin margins convex, tip of appressed fin just short of anal-fin origin. Pelvic-fin count i, 6. Pectoral fin with slightly curved, stout spine; anterior margin smooth, but posterior margin with weakly developed serrations only visible in cleared and stained specimens. Pectoral fin count I, 7 or 8. Cleithral processes moderate in length and pointed, but largely buried in skin. Axillary pore present along ventral margin of cleithral process; often depigmented relative to surrounding skin surface.

No obvious sexual dimorphism in body ornamentation or skin tuberculation. The head and body of males and females of all sizes are covered with numerous unculiferous tubercles ( Fig. 4 ). Adult males with slightly larger anal fins (up to 19.8% SL vs. up to 15.5% SL in females).

Coloration. In 70% ethanol: The general pigmentation of this species is shown in Figure 4 . In dorsal view, specimens appear dark brown, with two lighter bands on posterior half of body. First band lies midway between dorsal and adipose fins. Second band lies at posterior end of adipose fin. Head is uniformly dark brown. In lateral view, specimens appear dark brown with varying numbers of small irregular light patches. Ventral surface cream colored and peppered with dark melanophores from oral disc to caudal fin. Oral disc, all barbels, anus and urogenital opening cream colored. Some specimens with midline cluster of melanophores just anterior to premaxillae.

Dorsal and pectoral spines and rays light brown; base of dorsal and pectoral-fin rays generally darker; fin membranes translucent with dark patch, broadest at spine and tapering towards inner rays. Pelvic and anal fins translucent. Anal fin bisected by dark band running across fin rays. Adipose fin translucent with dark base. Each lobe of caudal fin with dark crescent-shaped patch ventral patch continuous with very dark pigment at base of fin rays.

Etymology. This species is eponymously named for Mr. George Kazumbe, an expert fisherman and friend from Kigoma, Tanzania. He has assisted the authors and several of our colleagues doing fieldwork in Tanzania, and we wish to honor him for his service.

Distribution. This species is known from both the lower Malagarasi River and adjacent Luiche River ( Fig. 2 ), and is typically found in small to moderate sized rapids.

Figures

FIGURE 1. Dorsal view of the lower jaw and dentary dentition of three new Chiloglanis species. A. Chiloglanis igamba sp. nov., CU 94005; B. Chiloglanis kazumbei sp. nov., CU 90387; C. Chiloglanis orthodontus sp. nov., CU 90755.

FIGURE 2. Map of the general area surrounding Lake Tanganyika showing the type localities of three new Chiloglanis species (white square & star) along with those of 16 additional Chiloglanis species previously described from the region (black circles). For those species displaying secondary sexual dimorphism of the caudal fin in adult males, a silhouette of the fin is illustrated.

FIGURE 3. Dorsal, lateral and ventral views of Chiloglanis igamba sp. nov., holotype, CU 90576, Tanzania, Kigoma Region, Malagarasi River at Lower Igamba Falls. Photo by T. R. Vigliotta. Scale bar equals 1 cm.

FIGURE 4. Dorsal, lateral and ventral views of Chiloglanis kazumbei sp. nov., holotype, CU 95230, Tanzania, Kigoma Region, Malagarasi River at rapids ~ 6.4 km upriver from Ilagala barge crossing. Photo by T. R. Vigliotta. Scale bar equals 1 cm.

FIGURE 5. Dorsal, lateral and ventral views of Chiloglanis orthodontus sp. nov., holotype, CU 90567, Tanzania, Kigoma Region, side channel of Malagarasi River around island. Photo by T. R. Vigliotta. Scale bar equals 1 cm.

FIGURE 6. Dorsal, lateral and ventral views of Chiloglanis asymetricaudalis, CU 90575, Tanzania, Kigoma Region, Luiche River. Photo by T. R. Vigliotta. Scale bar equals 1 cm.

Tables

TABLE 2. Summary of morphometric measurements and meristic counts for Chiloglanis kazumbei sp. nov. (N = 20; holotype and 19 paratypes). Standard length expressed in mm. All other measurements expressed as % SL. Meristic data for holotype is identified by an asterisk, and the number of specimens with a particular value for fin rays, ribs and vertebrae is shown in parentheses.

MORPHOMETRICS Standard length (mm) Head length Head depth (maximum) Body depth at anus Occipital shield width (minimum)	Holotype 49.1 33.4 18.1 17.1 7.1	Range 25.2–54.2 30.4–35.5 15.7–18.1 14.0–17.1 6.1–8.3	Mean±%SD 33.3±1.36 16.9±0.71 15.1±0.68 7.2±0.61
Prepectoral length Predorsal length	29.7 41.8	27.3–31.1 38.4–42.0	29.4±1.18 40.6±1.14
Prepelvic length Preanal length Eye diameter (horizontal) Orbital interspace	58.5 72.5 4.9 9.6	55.2–59.6 68.5–72.5 4.2–5.5 8.1–10.5	57.2±1.04 70.0±1.23 4.9±0.43 9.3±0.65
Snout length Premaxillary tooth-patch width	20.4 14.9	17.8–21.0 12.9–16.3	19.9±0.79 14.6±0.80
Premaxillary tooth-patch length Mandibular tooth row width Anterior nares interspace Posterior nares interspace Maxillary barbel length Medial mandibular barbel length	3.7 3.1 5.3 4.7 8.4 3.1	2.5–4.0 2.1–3.6 4.0–5.7 3.3–4.8 5.5–10.2 1.9–3.5	3.4±0.40 2.7±0.36 5.0±0.41 4.2±0.41 8.0±1.03 2.7±0.48
Lateral mandibular barbel length Mouth width Oral disc width Oral disc length	4.5 12.2 22.6 20.0	2.7–5.8 9.6–12.7 19.5–22.8 16.8–20.6	4.1±0.78 11.0±0.76 21.2±0.94 19.0±1.09
Upper lip length Lower lip length	4.7 9.4	3.6–5.7 7.8–10.1	4.6±0.52 8.9±0.76
Pectoral-spine length Pectoral-fin length Width at pectoral-fin insertion Length of postcleithral process Pelvic-fin length Depth at dorsal-fin insertion	20.6 22.0 26.5 11.2 13.0 22.0	19.1–23.6 20.1–23.9 23.9–27.0 9.1–13.1 12.0–16.0 17.0–22.0	21.3±1.06 22.0±1.08 25.5±0.85 11.0±0.90 13.6±1.03 18.8±1.25
Dorsal-spine length Dorsal-fin length (longest ray) Dorsal-fin base length Dorsal fin to adipose-fin length Adipose-fin base length Adipose fin to caudal-peduncle length	18.3 17.7 10.8 21.0 19.8 16.3	16.1–21.3 16.4–20.8 10.4–14.4 15.2–22.0 17.1–22.8 14.7–17.5	18.2±1.61 18.4±1.03 12.4±1.30 19.7±1.91 20.2±1.62 16.0±0.71
Adipose-fin height Anal-fin length (longest ray) Anal-fin base length	4.7 15.5 11.2	3.0–5.2 11.8–19.9 10.9–15.1	4.1±0.57 15.4±2.21 12.2±1.05 continued next page