Laimosemion leticia, Valdesalici, 2016

Valdesalici, Stefano, 2016, Laimosemion leticia (Teleostei: Cyprinodontiformes: Rivulidae), a new species from the upper Rio Amazonas, Southern Colombia, Zootaxa 4085 (2) : 280-282

Laimosemion leticia , new species

( Figs. 1–2 )

Holotype. IAvH-P 12943 , male, 21.1 mm SL, Colombia, Department of Amazonas, swamp area near Leticia at km 13–14, Rio Tacana drainage, Rio Amazonas basin (4° 07" 02' S 69° 57" 64' W), 85 mt asl. Tim Addis, Deborah Gale Bull & Pedro. Preserved after four months in captivity; December 2013 .

Paratypes. MSNG 58039, 1 male, 21.0 mm SL C&S, 2 females, 16.0& 23.1 mm SL, same data as holotype.

Diagnosis. Males of Laimosemion leticia are distinguished from all the other species of the genus by uniquely possessing orange unpaired fins with marginal blue stripe (vs. never this coloration). Males also differ from other congeners except L. jauaperi , L. uatuman and L. ubim by possessing an irregular arrangement of light blue dots on the flank (vs. never this coloration), but differs from L. jauaperi and L. ubim by having more pelvic fin rays (6 vs. 5) and branchiostegal rays (5 vs. 4), and from males of L. uatuman by having 30 vertebrae (vs. 31–32).

Description. Morphometric data given in Table 1 . Female larger than male, largest female 23.1 mm SL. Dorsal profile almost straight to slightly convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile convex on head, slightly convex from anterior portion of venter to end of anal-fin base, nearly straight on caudal peduncle.

Body slender, subcylindrical anteriorly to compressed posteriorly. Greatest body depth at level of pelvic-fin base. Tip of dorsal and anal fin rounded. Caudal fin rounded. Pectoral fin rounded. Pelvic fin short, rounded. Tip of pelvic fin reaching urogenital papilla in males, between anus and urogenital papilla in females. Dorsal-fin origin slightly posterior to anal-fin base. Dorsal-fin rays 6; anal-fin rays 9; caudal-fin rays 25; pectoral-fin rays 12; pelvicfin rays 6. Scales large, cycloid. Body and head entirely scaled except anterior ventral surface of head. Few scales on caudal-fin base; no scales on dorsal and anal fins. Frontal squamation S-patterned; E-scales not overlapping medially; scales arranged in transverse pattern, all scales with exposed posterior margin. Longitudinal series of scales 31–32; transverse series of scales 9; circumpeduncular scale rows 14–16. Supraorbital neuromasts 3 + 3. Premaxillary and dentary teeth canine, teeth of outer series longer, inner teeth irregularly arranged; anterior teeth of outer row of premaxilla and dentary hypertrophied in males. Five branchiostegal rays. Second pharyngobranchial teeth absent. Gill-rakers on first branchial arch 7. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal absent. Total vertebrae 30.

Coloration. Male: Side of body orange, four to five irregular longitudinal rows of blue dots on flank. Dorsum brown-orange, venter light yellow orange. Side of head orange; sometimes a wide dark gray stripe between posterior edge of orbit and flank above pelvic-fin base; Lower jaw black, upper jaw orange. Iris yellowish with light blue reflection. Dorsal fin orange, distal margin light blue, black submarginal stripe and blue dots near base; anal and pelvic fin orange, broad light blue distal margin with some yellowish reflection. Caudal fin orange, distal margin light blue. Pectoral fin hyaline. Female: Side of body and dorsum light brownish grey, with narrow brown stripes between scale rows and faint oblique pink marks on flank; oblique rows of light blue dots irregularly arranged on centre of flank, sometimes extending to caudal peduncle; dark brown spots and bars on dorso-lateral portion of flank. Venter white, urogenital papilla grey. Opercular and infra-orbital regions brownish grey; dark brown stripe from chin to anterior orbital area, and from posterior orbital area to opercle end. Jaws light brownish grey. Iris silver. Dorsal fin hyaline, basal portion light grey. Anal fin hyaline, basal portion light grey. Caudal fin hyaline with dark grey dots. Pectoral fin hyaline. Pelvic fin hyaline, anterior portion light grey.

Distribution. ( Fig.3 ) Upper Rio Amazonas basin, thus far limited to a small area north of Leticia, southern Colombia.

Habitat notes. ( Fig.4) All specimens were collected in a swampy area with a very slight flow within the Amazonian forest. Water depth was only a few centimetres.

Etymology. The name leticia is a reference to the occurrence of the new species near the town of Leticia, southern Colombia.

Figures

FIGURE 1. Laimosemion leticia, IAvH-P 12943, holotype, male, 21.1 mm SL; Colombia: Amazonas: Leticia (Photo S. Valdesalici).

FIGURE 2. Laimosemion leticia, MSNG 58039, paratype, female, 23.1 mm SL; Colombia: Amazonas: Leticia (Photo S. Valdesalici).

FIGURE 3. Distribution of subgenus Owiyeye black dot, miniature species white dot. Symbol may represent more than one locality.

Tables

TABLE 1. Morphometric data for holotype and paratypes of Laimosemion leticia.

	Holotype	Male C&S	Female	Female
Standard length (mm)	21.1	21.0	23.1	16.0
Percents of standard length
Body depth	16.5	15.2	19.0	19.3
Caudal peduncle depth	16.1	12.8	14.2	15.6
Pre-dorsal length	79.1	57.1	74.4	72.5
Pre-anal lenght	66.8	63.3	67.5	66.8
Pre-pelvic length	57.8	55.2	56.2	58.1
Length of dorsal-fin base	7.1	4.7	9.0	9.3
Length of anal-fin base	12.7	10.9	12.1	12.5
Caudal-fin length	29.3	28.5	25.5	36.8
Pectoral-fin length	12.7	12.8	14.7	20.0
Pelvic-fin lenght	7.1	6.6	6.9	6.2
Head length	24.6	24.2	22.0	24.3
Percents of head length
Head depth	65.3	62.7	60.7	66.6
Eye diameter	38.4	31.3	37.2	41.0
Interobital width	50	49.0	39.2	46.1