Key to the monadal Micrurus from the Western Amazon

1a. Bicolored pattern (black and white or black and red).......................................................... 2

1b. Tricolor pattern....................................................................................... 6

2ª1 Internasals and supraoculars with white dots, 67 to 81 black rings on body, 6 to 13 on tail.... Micrurus albicinctus (Fig. 4 A)

2b. Internasals and supraoculars whitout white dots.............................................................. 3

3a. Black rings on body 7–14, black rings on tail 2–3.................................. Micrurus putumayensis (Fig. 4 E)

3b. Black rings on body 17–83, black rings on tail 3–13.......................................................... 4

4a. Nuchal collar absent, venter tricolored (black, brown, and white)..................... Micrurus margaritiferus (Fig. 4 C)

4b. Nuchal collar present, venter bicolored..................................................................... 5

5a. Color pattern black and white, post-ocular white or yellow on parietals........... Micrurus annellatus annellatus (Fig. 4 B)

5b. Color pattern black and red, post-parietal narrow band separating black cephalic-cap from nuchal collar................................................................................................. Micrurus medemi (Fig. 4 D)

6a. Snout with white scales or white spotted scales.............................................................. 7

6b. Snout uniformly black................................................................................. 11

7a. Nuchal collar absent.................................................................. Micrurus tikuna (Fig. 1)

7b. Nuchal collar present................................................................................... 8

8a. Tail tricolor................................................................. Micrurus pacaraimae (Fig. 7 D)

8b. Tail bicolor.......................................................................................... 9

9a. Venter with black rings replaced by yellow.......................................... Micrurus langsdorffi (Fig. 7 B)

9b. Venter with black rings fully developed................................................................... 10

10a. Body with 38 to 67 black rings.................................................. Micrurus ornatissimus (Fig. 7 C)

10b. Body with 20 to 21 black rings....................................................... Micrurus petersi (Fig. 6 B)

11a. Nuchal collar absent................................................................ Micrurus averyi (Fig. 6 F)

11b. Nuchal collar present.................................................................................. 12

12a. Body with white rings limited by black accessory rings, dorsally isolated from red rings... Micrurus catamayensis (Fig. 7 A)

12b. Body with white rings contacting red rings dorsally.......................................................... 13

13a. Black cephalic-cap short, post-ocular white band on parietals separating black cephalic-cap from nuchal collar................................................................................ Micrurus annellatus bolivianus (Fig. 6 E)

13b. Black cephalic-cap long, covering parietals, narrow post-parietal white band...................................... 14

14a. Black cephalic-cap on parietals bordered by red scales....................................................... 15

14b. Black cephalic cap on parietals bordered by white scales..................................................... 16

15a. Ventral scales 200–210 in males, 227–231 in females.................... Micrurus steindachneri steindachneri (Fig. 6 A)

15b. Ventral scales 214–215 in males, 224–231 in females.......................... Micrurus steindachneri orcesi (Fig. 4 F)

16a. Black cephalic-cap contacting nuchal collar................................................................ 17 16b. Black cephalic-cap not contacting nuchal collar............................................................. 18 17ª1 Red rings 4–8 scales long with red-spotted scale; nuchal collar present and connected to cephalic-cap through a black line on