Nothobranchius lucius Wildekamp, Shidlovskiy & Watters, 2009

Costa, Wilson J. E. M., 2017, Redescription of Nothobranchiuslucius and description of a new species from Mafia Island, eastern Tanzania (Cyprinodontiformes, Aplocheilidae), Zoosystematics and Evolution 93 (1), pp. 35-44 : 35-37

Nothobranchius lucius Wildekamp, Shidlovskiy & Watters, 2009 Fig. 1, Table 1

Nothobranchius lucius Wildekamp, Shidlovskiy & Watters, 2009: 247 (holotype: MRAC A7-02-P-9, 49.6 mm SL; type locality: large pool on west side of road between Ifakara and the Kilombero River ferry, 2 km south of Ifakara, 1 km north of the Kilombero River, Tanzania, 8°10.30' S 36°41.54' E).

Material examined.

MRAC A7-02-P-9, holotype; MRAC A7-02-P-10-25, 16 paratypes (1 C&S); Tanzania: pool on west side of the road between Ifakara and the Kilombero River ferry, 2 km south of Ifakara, 1 km north of the Kilombero River, 8°10.30'S 36°41.54'E, about 250 m asl; B. Watters et al., 10 Jun. 2000. - MRAC 98-008-P-0007-0012, 6 paratypes; Tanzania: 2 km south of Ifakara, on east side of the road to Kilombero River ferry, northernmost pool between village and ferry; 8°10.04'S 36° 41.61'E, about 250 m asl; B. Watters et al., 7 Jun. 1995. - MRAC A7-02-P-26-27, 2; Tanzania: 1 km south of Minepa village, large circular pool on west side of Ifakara-Lupiro road, 17 km south of Ifakara; 8°16.34'S 36°40.83'E, about 270 m asl; B. Watters et al., 11 Jun. 2000. - MRAC A7-02-P-28-32, 5; Tanzania: 2 km southwest of Lupiro on road to Malinyi, 27 km south of Kilombero River ferry, ditch on southeast side of road; 8°23.45'S 36°39.45'E, about 300 m asl; B. Watters et al., 11-12 Jun. 2000. - MRAC A7-02-P-37, 1; Tanzania: small pool at culvert on southeast side of Ifakara-Ruipa road, 37 km west of Ifakara, 0.5 km northeast of the junction to Narubungo village, on northern flanks of Kibasira Swamp; 8°08.88'S 36°24.91'E, about 280 m asl; B. Watters et al., 9 Jun. 2002.

Diagnosis.

Nothobranchius lucius differs from all other species of the Nothobranchius melanospilus group, except Nothobranchius insularis , by having snout pointed in lateral view, jaws moderately long (vs. snout blunt to weakly pointed, jaws short); caudal fin, in males, with broad dark grey to black band on the posterior margin (vs. narrow); presence, in females, of dark dots over the whole flank (dark dots when present restricted to the posterior portion of the flank). It is distinguished from Nothobranchius insularis by having inner premaxillary teeth larger than teeth of the outer premaxillary tooth row (vs. smaller); caudal fin rounded in males (vs. subtruncate); in females, flank dark dots are rounded and arranged in horizontal rows (vs. dots vertically elongated, often arranged in oblique rows); unpaired fins, in females, with dark grey dots extending over most fin (dots restricted to the basal portion of unpaired fins); caudal, pectoral and pelvic fins longer (caudal fin length in males 31.3-34.9% SL and 30.3-32.9% SL in females of Nothobranchius lucius , vs. 26.9-29.6% SL in males and 22.8-27.4% SL in females of Nothobranchius insularis ; pectoral-fin length 22.2-24.5% SL in males and 20.2-24.6% SL in females, vs. 17.1-21.8% SL and 14.2-19.3% SL, respectively; pelvic-fin length 11.6-13.1% SL in males and 11.5-13.0% SL in females, vs. 8.6-11.0% SL and 9.6-11.0% SL, respectively); and two neuromasts in the posterior section of the anterior supraorbital series (vs. three).

Description.

Morphometric data appear in Table 1. Dorsal profile slightly concave to nearly straight on head, convex from nape to posterior end of dorsal-fin base, about straight on caudal peduncle; ventral profile convex from lower jaw to anal-fin base, about straight on caudal peduncle. Body deep, compressed. Greatest body depth at vertical between bases of pectoral and pelvic fins. Jaws short, snout blunt in lateral view. Jaw teeth canine, numerous, irregularly arranged, outer teeth greater than internal teeth. Gill-rakers of first branchial arch 4 + 14-15. Six branchiostegal rays.

Dorsal and anal fins moderate in males, extremity rounded, with short filamentous rays along distal margin, dorsal fin longer than anal fin; in females, dorsal fin rounded, anal fin sub-triangular and slightly longer than dorsal fin. Caudal fin subtruncate. Pectoral fin rounded, posterior extremity between pelvic-fin base and anus. Pelvic fin small, tip reaching urogenital papilla; pelvic-fin bases medially in contact. Dorsal-fin origin on vertical between base of first and second anal-fin rays. Dorsal-fin rays 14-16; anal-fin rays 16-18; caudal-fin rays 29-31; pectoral-fin rays 19-20; pelvic-fin rays 6. Minute contact organs on first and second pectoral-fin rays and distal portion of dorsal fin in males; rows of papillate contact organs along two distal thirds of most rays of anal fin in males.

Scales small, cycloid; body and head entirely scaled, except ventral surface of head. Minute filamentous contact organs along posterior margin of scales on middle portion of flank and latero-ventral portion of head in males. Body squamation extending over anterior 30% of caudal-fin base; no scales on dorsal and anal-fin bases. Frontal squamation irregularly arranged in two longitudinal rows. Longitudinal series of scales 29-30; transverse series of scales 9-11; scale rows around caudal peduncle 16.

Anterior supraorbital series of neuromasts arranged in single section placed in shallow depression, with five neuromasts; in specimens above 45 mm SL, anterior series partially divided in two sections, with two larger neuromasts in each section and smaller one between them. Posterior supraorbital series with four neuromasts placed in shallow depression. Infraorbital series with 16-17 neuromasts, pre-opercular series 12-13, mandibular 10-13. One neuromast per scale of lateral line.

Colouration in alcohol

(Fig. 1). Males. Flank, dorsum and head light brown, darker on posterior portion of scales of dorsal portion of flank, dorsum and opercle; venter pinkish grey; pale grey spots on suborbital region; branchiostegal membrane dark grey. Dorsal and anal fins hyaline with transverse series of grey spots, almost inconspicuous in anal fin. Caudal fin pale yellow with broad dark grey to black stripe along whole fin margin, broader on posterior margin; posterior sub-marginal area lighter. Pectoral fin hyaline, pelvic fin greyish hyaline with black tip.

Females. Flank and dorsum pale brown, side of head and venter pale yellow; rounded dark brown to black dots highly concentrated on whole trunk and head except venter, irregularly arranged in horizontal rows on flank. Whole unpaired fins hyaline with dark grey dots. Paired fins hyaline; few dark grey dots on basal portion of pectoral fin.

Distribution.

Nothobranchius lucius occurs in localities along the Kilombero Valley, which is limited to west by the Udzungwa Mountains and to east by the Mbarika Mountains, forming the Kibasira Swamp that is part of the Rufiji River basin (Fig. 2). This region is about 300 km from the coastline and collecting localities are situated at between 250 and 300 m asl. Two specimens collected in the Luhule River floodplains, in coastal Tanzania (MRAC A7-02-P-35-36, one male and one female, 7°19.95'S 39°17.38'E, at about 20 m asl) are here tentatively identified as Nothobranchius lucius . This species has been also recorded from the Mbezi and Ruhoi river basins, eastern Tanzanian ( Wildekamp et al. 2009), but no specimen was deposited in museum collections, making identity of these records still uncertain.