Bryconops

Barry Chernoff & Antonio Machado-Allison, 2005, Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Gunther)., Zootaxa 1094, pp. 1-23: 20-22

publication ID

z01094p001

publication LSID

lsid:zoobank.org:pub:2847B8DC-ED42-4562-9EF6-A4E8DC5F59A0

persistent identifier

http://treatment.plazi.org/id/0B827A5C-B7A3-3838-8C95-927B6F17DA19

treatment provided by

Thomas

scientific name

Bryconops
status

 

Artificial key to the species of Bryconops  

1 Posterior extension of maxilla not reaching junction of second and third infraorbital bones. Border between second and third infraorbital bones leaving a small naked triangle between them. Maxilla without teeth, rarely a single small conical tooth, usually on just one side (subgenus Bryconops   )........................................................................ 2

- Posterior extension of maxilla reaching junction of second and third infraorbital bones. Ventro-posterior margin of second infraorbital squared-off, forming a complete border with third infraorbital, without naked area between them. Maxilla with one to three teeth on both sides (subgenus Creatochanes   ) ..............................................................7

2 Snout pointed slightly. Lower jaw included in upper jaw when closed. Premaxillary teeth generally in three rows. Caudal fin with yellow in life on both dorsal and ventral portions, lacking any ocellus; posterior margin dusky to dark. Anal fin long with 32- 37 branched rays. Pored lateral line scales 57-61. Scales above lateral line 9-10. Scales below lateral line 5-6.................................................................... B. alburnoides  

- Snout blunt and rounded. Lower jaw terminal or only slightly included in upper jaw. Premaxillary teeth generally in two rows. Caudal fin with well formed ocellus on dorsal lobe, intense red in life (clear in preserved material); remainder of fin dark to dusky. Anal fin with 22-30 branched rays. Pored lateral line scales 9-43. Scales above lateral line 7-8. Scales below lateral line 4-5................................................... 3

3 Pored lateral line scales>36, extending beyond base of last anal fin ray.................... 4

- Pored lateral line scales <31, not extending to base of last anal fin ray.......................6

4 Pored lateral scales reaching end of hypural plate. Ocellus on dorsal lobe of caudal fin well-formed, completely filled with red color. Clear area at base of ventral lobe of caudal fin with red color.................................................................. B. caudomaculatus  

- Pored lateral scales extending 2-3, rarely 1, scales beyond hypural plate onto caudal fin rays. Ocellus on dorsal lobe of caudal fin irregular or diffuse, only upper half filled with red color. Without red color in ventral lobe of caudal fin................................... 5

5 Snout length 5.8-8.0% SL (mean 6.8%). Length of anal fin base 24.8-27.9% SL (mean 26.6%). Lateral scales 41-44, modally 42. Pored lateral scales 43-47, modally 44-45. Total vertebrae 40-42, modally 41-42. Gill rakers on lower arch, 8-10, modally9 ....................................................................................................... B. magoi   ZBK   , n. sp.

- Snout length 4.2-5.4% SL (mean 4.7%). Length of anal fin base 27.3-29.8% SL (mean 28.8%). Lateral scales 42 - 45, modally 44. Pored lateral scales 44- 48, modally47. Total vertebrae 42-44, modally 43. Gill rakers on lower arch, 8-11, modally 11 ............................................................................................................. B. collettei   ZBK   , n. sp.

6 Pored lateral line scales not extending beyond second or third branched anal fin rays, 9-23 pored scales. Branched anal fin rays 26-28 ..................................... B. disruptus  

- Pored lateral line scales extending beyond third branched anal fin ray, 30 pored scales. Branched anal fin rays 25 ............................................................................... B. durbini  

7 Humeral mark(s) present .............................................................................................. 8

- Humeral mark(s) absent ............................................................................................. 10

8 Two humeral marks. Dark to dusky pigment obscuring the caudal peduncle from over the middle of the anal-fin base onto the central part of the caudal fin. Caudal fin dusky without ocelli on either lobe. Body metallic blue in life ................................. B. inpai  

- Single humeral mark. Caudal peduncle not obscured by pigment. Caudal fin with ocellus on dorsal lobe. Body silver to olivaceous in life ............................................ 9

9 Scales below lateral line 4-5. Gill rakers on the lower limb of first arch 10-11. Caudal peduncle least depth 6.6-10.2 % SL (mean 8.0 % SL). Upper jaw length 11.8-16.9 % SL (mean 14.5 % SL) ................................................................................. B. humeralis  

- Scales below lateral line 6. Gill rakers on lower limb of first arch 9-10. Caudal peduncle least depth 9.2-11.1 % SL (mean 10.0 % SL). Upper jaw length 15.2-20.6 % SL (mean 16.9 % SL) .................................................................................. B. vibex  

10 Caudal fin with well developed ocellus on dorsal lobe .............................................. 11

- Caudal fin pigmented but lacking a well formed ocellus ............................................ 12

11 Caudal fin with almost symmetrical well-formed ocelli on both lobes .......... B. affinis  

- Caudal fin with only a single, well-formed ocellus on the dorsal lobe .... B. giacopinii  

12 Caudal fin with prominent black stripe, width almost equal to the pupil, asymmetrically from the central fin rays onto the dorsal lobe; remainder of fin clear to lightly pigmented and with dusky margin. Outer teeth on premaxilla 3-6, modally 4. Precaudal vertebrae 17-18. Anal fin originates under 17th -18th centrum ........ B. melanurus  

- Darkened central caudal rays not principal pigment pattern on fin; wide stripe absent. In life, caudal fin either completely blackened or carmine red with dusky posterior margin. In preservation, caudal fin with black striations along all fin rays. Outer teeth on premaxilla 4-6, modally 5. Precaudal vertebrae 18-20. Anal fin originates under 19th -20th centrum, rarely 18th centrum ..................................................................... 13

13 Caudal fin principally black with some red suffused among outer 3-4 principal rays of both lobes. Anal fin with broad prominent black stripe along entire base of fin. Cheek with conspicuous blotch of pigment. Lower lobe of caudal fin longer than upper lobe .................................................................................................................... B. colanegra  

- Caudal fin completely carmine red. Anal fin with pigment along fin rays, not in membranes, not forming prominent wide stripe along entire length of fin. Cheek lacking conspicuous blotch of pigment. Upper lobe of caudal fin longer than lower lobe ... 14

14 Circumdorsal scales 14-16, modally 15. Maxilla reaching articulation of second and third infraorbitals. Third infraorbital contacting preopercle at angle.......... B. colaroja  

- Circumdorsal scales 17-19, modally 17. Maxilla not reaching articulation of second and third infraorbitals. Third infraorbital not contacting preopercle at angle ............... ........................................................................................................................ B. imitator