Tilapia pra Dunz & Schliewen, 2010, new species
Creators: name: Dunz, Andreas R.
name: Schliewen, Ulrich K.
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Cichlidae
Tilapia
Tilapia pra

description: Tilapia pra, new species
(Fig. 3; Tab. 3)
Holotype: ZSM 36123 (1, 83.5 mm SL), Ghana, Ashanti Region, Anum River, tributary to Pra, at Anumso village (6° 25' 44''N, 1° 17' 59'' W), D. Neumann & G. Baffur E, 29 Oct. 2002.
TABLE 1. Factor Loadings of PC I–III for Figure 1. Highest loadings for PC II and PC III indicated in boldface. Paratypes: ZSM 36116 (1, 84.2 mm SL), ZSM 36117 (1, 110.1 mm SL), ZSM 36118 (1, 73.1 mm SL), ZSM 36119 (1, 76.6 mm SL), ZSM 36120 (1, 77.7 mm SL), ZSM 36121 (1, 73.7 mm SL), ZSM 36122 (1, 76.1 mm SL), ZSM 36124 (1, 81.1 mm SL), ZSM 36125 (1, 79.1 mm SL); all collected with holotype. ZSM 36149 (2 now 1, 62.6 mm SL), Ghana, Ashanti Region, Oda River, tributary to Pra, floodplain and small affluent left to road entrance at bridge on road Bekwai-Awiankwata (6° 27' N, 1° 37' W), D. Neumann & K. Mensa, 2 Nov. 2002. AMNH 250601 (1 ex ZSM 36149, 57.7 mm SL), Ghana, Ashanti Region, Oda River, tributary to Pra, floodplain and small affluent left to road entrance at bridge on road Bekwai-Awiankwata (6° 27' N, 1° 37' W), D. Neumann & K. Mensa, 2 Nov. 2002. ZSM 39005 (3 now 2, 40.3–58.8 mm SL), Ghana, Nyelei, tributary to Ankobra, near Akropong at the new bridge (5° 5' 6'' N, 2° 17' 13'' W), U. Schliewen, 10 Mar.–30 Apr. 1998. AMNH 250602 (1 ex ZSM 39005, 54.7 mm SL), Ghana, Nyelei, tributary to Ankobra, near Akropong at the new bridge (5° 5' 6'' N, 2° 17' 13'' W), U. Schliewen, 10 Mar. – 30 Apr. 1998. ZSM 39000 (3, 48.7–58.4 mm SL), Ghana, Draw River at new bridge (5° 10' 04'' N, 2° 15' 20'' W), U. Schliewen, 10 Mar. – 30 Apr. 1998. ZSM 39001 (1, 108.2 mm SL), Ghana, Tano at Mempansem (5° 22' 12'' N, 2° 39' 36'' W), U. Schliewen, 10 Mar. – 30 Apr. 1998. MRAC 87-18- P- 5204-240 (3, 95.7–103.4 mm SL), Ghana, Birim River at Anyinam (6° 22' 48'' N, 0° 33' 0'' W), G. Teugels, 14 Feb. 1987. MRAC 87-18- P- 5189-203 (1, 91.0 mm SL), Ghana, Pra River at Prasu (5° 55' 48'' N, 1° 22' 12'' W), G. Teugels, 13 Feb. 1987. MRAC 87-18- P- 5248-314 (1, 66.7 mm SL) Ghana, Pra River near Nkawkaw (6° 36' 0'' N, 0° 54' 0'' W), G. Teugels, 14 Feb. 1987. MRAC 79-36- P- 70-84 (5, 73.9–126.9 mm), Cote d'Ivoire, Ayamé I, dam, River Bia (5° 36' 0'' N, 3° 10' 48'' W), T. v. d. Audenaerde, 15 Oct. 1979. MRAC 86-18- P- 1948-951 (1, 57.6 mm SL), Cote d'Ivoire, Ayamé, River Bia (5° 37' 12' 'N, 3° 10' 48'' W), K. Traore, 19 Apr. 1986.
Differential diagnosis. Tilapia pra sp. nov. is distinguished from all other Tilapia sensu lato except T. sparrmanii, T. ruweti, T. guinasana, T. baloni, “ T. ” brevimanus, “ T.” mariae, “T. ” cabrae and “ T. ” busumana in having bicuspid pharyngeal teeth in the posterior two rows of lower pharyngeal jaw. It differs from T. baloni and T. ruweti in having more gill rakers on first ceratobranchial (lower) gill-arch (10–12 vs. 6–9), from T. guinasana in having a higher number of upper lateral line scales (18–22 vs. 14–17) and from T. sparrmanii in a combination of a higher number of upper lateral line scales (18–22 vs. 14–19), a shorter anal fin base (15.0–18.6% vs. 18.0–23.8% of SL) and a lower number of vertical stripes (6–7 vs. 8–9). It further differs from “ T. ” mariae and “ T. ” cabrae in having fewer scales on the lower lateral line (8–11 vs. 10–14) and not having spatulate shaped teeth in the outer row of both jaws, from “ T. ” brevimanus in having fewer gill rakers on the ceratobranchial gill-arch (10–12 vs. 12–16) and not having spatulate shaped teeth in the outer row of both jaws. It differs from “ T. ” busumana in possessing a longer last dorsal-fin spine (16.2–21.3% vs. 11.6– 14.9% of SL), a shorter lower lip length (8.0–10.7% vs. 9.6–13.9% of SL) and a shorter lower jaw length (9.9–13.6% vs. 10.5–15.2% of SL). In addition, T. pra sp. nov. differs from “ T. ” busumana in ground coloration. T. pra sp. nov. possesses a light brown to greyish dorsum and a beige to yellow ventral area vs. a bluish-purple to blackish dorsum and darker on underside of head and body of “ T. ” busumana.
Description. Morphometric and meristic data for the holotype and 29 paratypes are presented in Table 3 (for comparison with “ T. ” busumana see Table 4). See Figure 3 for general appearance. Tilapia pra sp. nov. is a medium-sized “ Tilapia ” (maximum observed size 126.9 mm SL). Body laterally compressed. Head dorsal and ventral profile straight, head length 33.5–39.5% of SL. Head pointed. Snout outline obtuse, jaws equal anteriorly. Eye moderately large, 7.6–11.8% of SL. Interorbital width greater than eye diameter. Greatest body depth at level of first dorsal spine. Dorsal line slightly posteroventrally curved. Caudal peduncle always deeper than long; on average being 1.4 times deeper than long.
Squamation. Body covered with cycloid scales. Upper lateral line extending from posterior margin of gill cover to approximately last dorsal ray. Two scale rows with or without a small scale at the basis of dorsal fin separate the upper lateral line from the last dorsal spine. Lower lateral line originating at level of first dorsal branched rays and terminates midlaterally on caudal peduncle. One or two scales of lower lateral line extending onto caudal fin. Two scale rows between upper and lower lateral lines.
Gill rakers. First lower gill-arch with 10–12 gill rakers and first upper gill-arch with 3–5 gill rakers.
Fins. Origin of dorsal fin at level of origin of pelvic fin. Dorsal-fin base 59.2% of SL in holotype and 54.2–63.7% of SL in paratypes. Dorsal spines 16 in holotype, 14–16 in paratypes. Dorsal rays 12 in holotype and 11 or 12 in paratypes. First dorsal spine always shortest, last dorsal spine always longest. Spines always shorter than rays. Last dorsal ray most deeply branched. Caudal fin outline emarginate. Anal-fin base 17.6% of SL in holotype and 15.0–18.6% of SL in paratypes. Anal spines in holotype and paratypes three. Anal rays 9 in holotype and 8–10 in paratypes. Third anal spine always longest. Last dorsal ray most deeply branched. Pelvic fin length 35.0% of SL in holotype and 29.1–37.6% of SL in paratypes. Tip of longest pelvic-fin ray mostly crossing anus, rarely reaching first anal spine Pectoral-fin length 36.9% of SL in holotype and 32.2– 40.7% of SL in paratypes. Pectoral-fin rays 14 in holotype and 13–15 in paratypes.
Jaws and dentition. Upper and lower outer row in both jaws bicuspid, but some teeth appear unicuspid due to wear. Neck of anterior jaw teeth slender (i.e. about half the height of the tooth), crown expanded and cusps truncated (Fig. 4). Three to four incomplete inner rows of smaller tricuspid teeth in both jaws. Lower pharyngeal jaw as long as broad, anterior keel shorter than toothed area (Fig. 5a). Posterior pharyngeal teeth bicuspid (Fig. 5 b), stout, slightly hooked and regularly arranged, especially over the posterior third of the toothed area. Most of the teeth in the anterior two thirds of the toothed area approach the “kukri” tooth shape (sensu Greenwood, 1987).
Coloration in alcohol. Ground coloration light brownish with dark spots at base of each flank scale. Chest whitish, upper side of head dark brown. Markings on body: Six to seven dark vertical bars on dorsum and sides (the first bar at level of first dorsal spine, the last two on caudal peduncle) and a nape band. Vertical bars never bifurcate. In some specimens a longitudinal mid-lateral band is visible. Dark preorbital band extending from lachrymal to jaw angle; dark opercular spot. Fins: Pectoral fins transparent. Pelvic fins transparent, anterior margins dark. Anal fin greyish, darker basally. Caudal fin greyish. Dorsal fin greyish, darker basally, “tilapia-spot” well visible at level of fourth vertical bar. Some light colored spots around the “ tilapia spot”.
Coloration in life. (Fig. 6) Description based on a photograph of T. pra sp. nov. from the Draw River drainage, i.e. the same location as the paratypes ZSM 39000. Ground coloration on dorsum light brown to greyish and on ventral area beige-yellow to golden, chest and belly pale. Lips bluish and upper part of opercular blotch yellowish. Light yellow colored spots around “ tilapia spot”. Tips of dorsal, caudal and pelvic fin white. Body with seven indistinct dark vertical stripes and a nape band. All stripes approximately as wide as the area between stripes.
Distribution. (Fig. 7) This species is known from the Pra, Ankobra, Tano and Bia Rivers in southwestern Ghana and southeastern Cote d’Ivoire.
Etymology. The species name pra refers both to the Akan word “ pra ” (river) of the Kwa language family spoken in Ghana and to the River Pra, from which drainage the holotype was collected. It refers to the riverine distribution as compared to the lacustrine distribution of its apparent sister taxon “ T.” busumana. A noun in apposition.
Ecological notes. The holotype and most paratypes were collected over sandy/muddy substrate in the Anum River near Anumso village. At the collection site the Anum is 5–20 m broad and about 1–2 m deep. Specimens from the Ankobra (Draw) drainage were collected in moderately turbid water in deeper places (approx. 1–2 m depth) of medium sized rivers. No further ecological data are available.
description: Published as part of Dunz, Andreas R. & Schliewen, Ulrich K., 2010, Description of a new species of Tilapia Smith, 1840 (Teleostei: Cichlidae) from Ghana, pp. 1-21 in Zootaxa 2548 on pages 5-15, DOI: 10.5281/zenodo.196768