Astyanax embera, Ruiz-C & Román-Valencia & Taphorn & Buckup & Ortega, 2018

Ruiz-C, Raquel I., Román-Valencia, César, Taphorn, Donald C., Buckup, Paulo A. & Ortega, Hernán, 2018, Revision of the Astyanax orthodus species-group (Teleostei: Characidae) with descriptions of three new species, European Journal of Taxonomy 402, pp. 1-45 : 6-10

Astyanax embera sp. nov.

urn:lsid:zoobank.org:act:9B1792A8-70D6-4167-9136-0DD74844B040

Figs 2 , 3B , 4 , Table 1

Diagnosis

Astyanax embera sp. nov. is a member of the orthodus species-group of Astyanax , differing from other members of the group as follows: from A. villwocki, A. superbus , A. gandhiae sp. nov., A. bopiensis nom. nov., A. boliviensis sp. nov. and A. yariguies comb. nov. by the absence of a dark stripe on the sides of the body (vs dark lateral stripe present or anterior prolongation of the caudal peduncle spot extending anteriorly over the silvery lateral stripe). It differs from A. orthodus in having the caudal peduncle spot extending onto the ventral and dorsal margins of the caudal peduncle, covering 4–6 horizontal scale rows (vs covering 2–4 horizontal scale rows on the caudal peduncle, Fig. 3 ). It also differs from A. orthodus in having an unpigmented band across the anal-fin rays in both sexes (vs pigmentation uniform on analfin rays). It differs from A. moorii comb. nov. in the body depth> 39% SL (vs <39% SL), the dorsalpectoral fin distance> 40.5% SL (vs <40.5% SL), maxilla length <33.5% HL (vs> 33.5% SH), upper jaw length <32% HL (vs> 47% SH) and by the number of lateral-line scales 36–41 (vs 44–50).

Etymology

The specific epithet embera is a noun in apposition and refers to the native Americans known as the Embera, who occupy the type locality of this new taxon.

Material examined

Holotype

COLOMBIA: 83.0 mm SL, Nariño Department, Barbacoas Municipality, Patía River Basin (Pacific Coast), Telembí River drainage, in Telembí River at mouth of Yamunde River, 1 km below Barbacoas , 01°39′56″ N, 78°09′12″ W, 61 m a.s.l. ( IUQ 3614 ).

Paratypes

COLOMBIA: all from Nariño Department, Barbacoas Municipality, Patía River Basin, Telembi River Drainage : 9 ♂♂, 40.3–52.3 mm SL, La Tundera Brook, Barbacoas, Nariño , 01°39′03″S 78°10′33″W, 41 m a.s.l. ( IUQ 2264 ) ; 4 ♂♂, 5 ♀♀, 45.6–89.8 mm SL, 4C&S (sex unknown), 52.8–63.0 mm SL, same locality as for holotype ( IUQ 701 ) ; 36 ♂♂, 11♀♀, 43.2–62.7 mm SL, 4C&S (sex unknown), 39.2– 68.0 mm SL, brook on La Hacienda Ranch ( IUQ 2252 ); 11 ♂♂, 8 ♀♀, 38.61–50.63 mm SL, Barbacoas, Yamunde River , 01°39′39″ N, 78°09′04″ W, 43 m a.s.l. ( IUQ 2259 ) ; 3 ♂♂, 52.6–85.5 mm SL, collected with holotype ( IUQ 989 ) ; 1 specimen (sex unknown) C&S, 53.8 mm SL, collected with holotype ( IUQ1165 ) .

Description

Body compressed, greatest body depth at or anterior to dorsal-fin origin. Mouth terminal. Dorsal profile of head straight between snout tip to posterior margin of supraoccipital spine, convex between head and dorsal fin, convex between last dorsal-fin ray and adipose-fin origin. Caudal peduncle arched, with dorsal profile concave and ventral profile convex. Ventral profile convex between snout tip and posterior end of anal-fin base in males; in females convex to pelvic-fin insertions, concave beyond the insertion of pelvic fin to anal-fin origin.

Premaxillary teeth in two series; outer series with four tricuspid teeth covering three most medial teeth of internal series; inner row with five pentacuspid teeth. Maxilla long, of same width along entire length, with two tricuspid teeth set in anterior-most part of ventral margin. Dentary with anterior four teeth pentacuspid, following ten teeth smaller, progressively inclined posteromedially, varying from tri- to unicuspid; proportion of tri- vs unicuspid teeth quite variable.

Pored lateral-line scales 36(1), 37(11), 38(11), 39(13), 40(1), 41(1) (n = 38); transverse scales from lateral line to dorsal-fin origin 7(13), 8(25) (n = 38); scales from lateral line to anal-fin origin 7(1), 8(29), 9(8) (n = 38); scales from lateral line to pelvic-fin insertion 6(22), 7(15), 8(1) (n = 38). Predorsal midline covered with bilobed medial scales for more than three quarters of its length, naked anteriorly. Dorsalfin rays iii 9 (n = 38); first simple ray reduced in size, easily visible only in C&S specimens, detectable with dissecting needle in non-C&S specimens; second simple ray about half length of third simple ray. Distal margin of dorsal fin slightly convex. Adipose-fin origin anterior to vertical through insertion of last anal-fin ray. Pectoral-fin rays i 10 i (2), i 11 i (23), i 12 i (12), i 13 (1) (n = 38). Anal-fin rays iii 25 (7), iii 26 (9), iii 27 (12), iii 28 (9), iii 29 (1) (n = 38); first simple rays only visible in C&S material. Anal-fin origin posterior to vertical through insertion of last dorsal-fin ray ( Table 1 ). Principal caudal-fin rays 10(8) associated with four dorsal hypurals, 9(8) associated with three ventral hypurals; dorsal procurrent rays 10–11(8); ventral procurrent rays 9–10(8).

Total vertebrae 34(8), including those of the Weberian apparatus: precaudal centra 16(2)–17(6), last two without true ribs; caudal centra 17(2)–18(6). Epipleurals 21(2)–22(6). Epineurals 30(2)–31(6); posterior-most epineural may reach anterior surface of urostyle. Hypurals 7(8); first dorsal hypural with anterior margin dotted, without projections without extensions that articulate the urostyle; second and third hypural with anterior margin swollen that contacting urostyle.

Pigmentation in alcohol

Sides of body yellowish, with reticulated pattern predominant over dorsal region of coelomic cavity. Silvery stripe present from humeral region to caudal-peduncle base, overlain by series of chevronshaped marks formed by dark lines along myosepta between myotomes extending from dorsal region of coelomic cavity to caudal peduncle; pigmented muscle septae forming chevrons not coinciding with scale rows. Chevrons without distal extensions both in juvenile and adult specimens.

Dorsal region of head and body chestnut brown. Sides of cranium and ventral surface of body light brown, not silvery. The pigments of the humeral region form an anterior and posterior humeral spot. The anterior spot is formed by two layers of pigment: brown melanophores distributed in thin superficial layer of the epithelium (Layer 1, Fig.1 ); deeper layer with dark melanophores (Layer 2, Fig. 1 ). Layer 2 forming polygon-shaped spot, with two parts, forming vertices on margins, usually with four sides, located from third to sixth or seventh scale of lateral series. Posterior humeral spot situated two or three scales posterior to anterior humeral spot, arc- or sigmoid-shaped, inconspicuous, covering two to three scales above lateral-line. Scales on sides of body with spots or dots. Caudal peduncle spot pentagonal, its posterior tip or margin centered on middle caudal-fin rays, usually not further prolonged on middle caudal-fin rays. Pectoral and pelvic fins mostly hyaline; pelvic fins with melanophores at tips of rays. Dorsal, caudal and anal fins with melanophores on interradial membranes.

Sexual dimorphism

Sexual dimorphism was observed in the ventral profile, which is convex from snout tip to posterior end of anal-fin base in males, but in females is convex from snout tip to the pelvic-fin insertions, then concave to the origin of the anal fin. No hooks were detected on fins of examined adult individuals.

Distribution

Middle portion of the Telembí River drainage, which is a tributary of the Patía River, Nariño Department, Pacific coast of Colombia ( Fig. 4 ).

Comments

The stream where the type locality of this species is located is subject to mining activity for gold, silver and platinum.

Figures

Fig. 2. Astyanax embera sp. nov., holotype, 83.0 mm SL, Telembí River at mouth of Yamunde River, 1 km below Barbacoas, Municipality of Barbacoas, Nariño, Pacific coast of Colombia (IUQ 3614). Scale bar = 1 cm.

Fig. 3. Shape of caudal-peduncle spot in species of the Astyanax orthodus species-group. A. Astyanax orthodus Eigenmann, 1907. B. Astyanax embera sp. nov. Scale bar = 1 cm.

Fig. 4.Distribution of speciesof the Astyanaxorthodus species-group(symbol includestypelocalities).

Fig.1.A.DistributionofpigmentinthehumeralregionofAstyanaxspecies.B.A.bimaculatus(Linnaeus, 1758).C.A.caucanus(Steindachner,1879).D.A.mexicanus(DeFilippi,1853).E.A.courensisBertaco, Carvalho & Jerep, 2010 (modified from Bertaco et al. 2010). The anterior humeral spot consists of two overlapping layers of pigment identified by numbers 1 and 2 (see Román-Valencia et al. 2015: fig. 1): 1. Diffuse vertical bar. 2. Horizontal spot with concentrated pigments.