Aphyosemion aurantiacum Chirio, Legros & Agnèse, 2018

Agnèse, Jean-François, Chirio, Laurent, Legros, Olivier, Oslisly, Richard & Bhé, Hervé Mvé, 2018, Unexpected discovery of six new species of Aphyosemion (Cyprinodontiformes, Aplocheilidae) in the Wonga-Wongué Presidential Reserve in Gabon, European Journal of Taxonomy 471, pp. 1-28 : 20-21

Aphyosemion aurantiacum Chirio, Legros & Agnèse sp. nov.

urn:lsid:zoobank.org:act:93840539-567F-4817-B774-3568D388E094

Fig. 6 A–D, Table 7

Etymology

The specific epithet refers to the main colour of this species (dark orange).

Material examined

Holotype

GABON: adult ♁, 33 mm SL (39.7 mm TL), Wézé spring, 0.58186 S, 9.46718 E, 89 m a.s.l., field reference code CHRSP5 -sources Wézé, 3 Jul. 2014, Laurent Chirio leg. ( MRAC 2016-019 -P-64).

Paratypes

GABON: 4 ♁♁, 5 ♀♀, 23.4–29.9 mm SL, same collection data as for holotype ( MRAC 2016-019-P- 65-73); 18 ♁♁, 22.2 –32.1 mm SL, northern tributary of Wézé River, 0.56336 S, 9.33732 E, 45 m a.s.l., field reference code CHRSP 5-Wézé2, 1 Mar. 2016, Laurent Chirio leg. ( MRAC 2016-019-P-74-91); 1 ♀, 23 mm SL, southern tributary of Wézé River, 0.66401 S, 9.42652 E, 87 m a.s.l., field reference code CHRSP 5-Wézé3, 5 Mar. 2016, Laurent Chirio leg. ( MRAC 2016-019-P-92).

Differential diagnosis

Differs from all other species in A. alpha group through combination of following features: head orange, flanks beige, ventral region orange (vs never the same colour pattern), orange anal fin with no punctuation (vs blue-orange, purplish-blue or orange with punctuation). Distinguished from all other species of Chromaphyosemion by an alpha-shaped drawing in pre- and post-opercular region (vs no alpha-shaped drawing, only some red macules).

Colouration of live males ( Fig. 6A )

FLANKS AND VENTER. Flanks beige with two grey, rarely visible lateral stripes, four lines of red dots from opercle to caudal peduncle. Ventral region orange and region between end of anal fin and caudal peduncle intense orange, two rows of blue iridescent scales between end of anal fin and caudal peduncle. Dorsal region brown, with two rows of paradorsal copper scales from operculum to caudal peduncle with two lines of carmine red dots.

HEAD. Orange with premaxilla brown, mandible orange with black lower lips, brown supraorbital region, orange infraorbital region with black macule, postorbital region orange with two black macules, orange pre-opercle with one black macule, orange opercle with two black macules; black macules on pre- and post-opercular region reveal an alpha-shaped drawing.

FINS. Dorsal fin blue, large orange zone on rays, rows of carmine red dots between rays, and carmine red streaks on distal and posterobasal portions of fin. Orange acumen on apex. Anal fin orange, blue zone near submarginal band, regular, red submarginal band, blue marginal band, orange acumen. No punctuation. Caudal fin blue with orange caudal peduncle, 5–6 red dots in median region, very long red streaks in median region and in upper and lower lobes, regular, red submarginal band, blue marginal band, and orange acumens. Pelvic fins orange with no punctuation, submarginal red band and blue marginal band. Pectoral fins with orange reflections.

Colouration of live females ( Fig. 6B )

FLANKS AND VENTER. Flanks pale yellow, with four lines of red dots from opercle to caudal peduncle, two greyish lateral stripes, yellow venter, white on basal portion. Two rows of paradorsal golden scales

in dorsal region from operculum to start of anal fin with red dots, copper scales from start of anal fin to caudal peduncle with red dots.

HEAD. Premaxilla brown, mandible pale yellow with black lower lips, brown supraorbital region, white infraorbital region with black macule, white postorbital region with two red macules, yellow pre-opercle with red dot, yellow opercle with two red dots.

FINS. Dorsal fin yellow-green, with rows of carmine red dots between rays, red streaks on distal portion. Anal fin blue on basal portion with row of red dots between rays, some red streaks between rays on median portion, pale orange on distal portion. Caudal fin yellow-green near caudal peduncle, with some red dots on basal portion, red streaks between rays from median to distal portion. Pelvic fins translucent with blue reflection on the edge. Pectoral fins translucent.

Colouration of ethanol-preserved males and females ( Fig. 6 C–D)

FLANKS AND VENTER. Flanks of males grey-yellow with no red dots, venter grey-yellow. Two rows of paradorsal black scales in grey-yellow dorsal region from operculum to caudal peduncle, visible greyish upper lateral stripe. Flanks of females beige with two grey lateral stripes and two lines of two to three red dots behind opercle. Venter beige, with two grey lateral stripes. Two rows of paradorsal red scales in grey dorsal region from operculum to caudal peduncle.

HEAD. Head of male grey-yellow mandible with black lower lips, grey-yellow infraorbital region with small black macule, grey-yellow pre-opercular region, opercle with two black macules; dark macules in post-opercular region. Head of female with black lower lips, infraorbital region with black macule, dark opercle.

FINS. Dorsal fin of male orange with two to three black dots on basal portion, streaks between rays on distal portion. Anal fin orange with dark rays. Caudal fin orange with many red streaks on distal portion, red submarginal band. Dorsal fin of female light orange, rows of red dots between rays. Anal fin greyish with no red dots. Caudal fin light orange, with some red dots on upper portion, red streaks on edge.

Distribution and habitat

This species has been found at three localities in the Wézé Basin ( Table 1 , Fig. 1 ) and never elsewhere. The species seems to be endemic to this hydrographic basin. It lives only in very small forest streams and water holes, often with a bottom consisting of roots and dead leaves, where it can be very abundant. In the southern-most locality, it was found hidden under dead leaves along the river banks in a 2 metre wide river with a sandy bottom. This species was found in syntopy with three undescribed species of Aphyosemion , Epiplatys and Plataplochilus .

Figures

Fig. 6. A–D. Aphyosemion aurantiacum Chirio, Legros & Agnèse sp. nov. A. Adult, ♁, from locality 12, not preserved. Photo O. Buisson. B. Adult, ♀, from locality 12, not preserved. Photo O. Buisson. C. Holotype, adult, ♁, from Wézé Spring (MRAC 2016-019-P-64). D. Paratype, adult, ♀, from Wézé Spring (MRAC 2016-019-P-65-73). E–H. A. rubrogaster Chirio, Legros & Agnèse sp. nov. E. Adult, ♁, from locality 16, not preserved. Photo O. Buisson. F. Adult, ♀, from locality 16, not preserved. Photo O. Buisson. G. Holotype, adult, ♁, from the Niengé River (MRAC 2016-019-P-93). H. Paratype, adult, ♀, from the Niengé River (MRAC 2016-019-P-94-108).

Fig. 1. Collecting sites of the different populations. Black circles: Aphyosemion alpha Huber, 1998; Black triangles: A. flavocyaneum Chirio, Legros & Agnèse sp. nov.; red triangle: A. flammulatum Chirio, Legros & Agnèse sp. nov.; yellow triangles: A. barakoniense Chirio, Legros & Agnèse sp. nov.; red circles: A. pusillum Chirio, Legros & Agnèse sp. nov.; yellow circles: A. rubrogaster Chirio, Legros & Agnèse sp. nov.; red squares: A. aurantiacum Chirio, Legros & Agnèse sp. nov.