Trilepida

Pinto, Roberta R. & Fernandes, Ronaldo, 2017, Morphological variation of Trilepida macrolepis (Peters 1857), with reappraisal of the taxonomic status of Rena affinis (Boulenger 1884) (Serpentes: Leptotyphlopidae: Epictinae), Zootaxa 4244 (2), pp. 246-260 : 254

Key for the currently recognized species of the genus Trilepida

1. Infralabials three............................................................................... T. nicefori

- Infralabials four or more............................................................................... 2

2. Scale rows in the middle of the tail 10.....................................................................3

- Scale rows in the middle of the tail 12................................................................... 13

3. Supraocular present...................................................................................4

- Supraocular absent.......................................................................... T. brasiliensis

4. Two supralabials (1+1)................................................................................. 5

- Three supralabials (2+1)............................................................................... 7

5. Frontal smaller than supraocular and coloration of the dorsum of head similar to body color pattern....................6

- Frontal longer than supraocular and coloration of dorsum of head lighter than dorsal body color pattern........... T. affinis

6. Snout truncate in dorsal and ventral views, slender body, and frontal with same size as supraocular................ T. jani

- Snout rounded in dorsal and ventral views, robust body, and frontal smaller than supraocular................ T. dimidiata

7. Ventral coloration similar to the dorsal pattern..................................................... T. anthracina

- Ventral coloration lighter than the dorsal color pattern or with center of scales darker than their edges.................. 8

8. Rostral semicircular........................................................................... T. dugandi

- Rostral subtriangular................................................................................. 9

9. Supraocular shorter than frontal.........................................................................10

- Supraocular longer than frontal......................................................................... 11

10. Rostral reaching the imaginary transverse line between anterior border of ocular and ventral scales with the center darker than their edges.................................................................................... T. koppesi

- Rostral not reaching the imaginary transverse line between anterior border of ocular and ventral color pattern uniformly cream........................................................................................... T. fuliginosa

11. Frontal longer than other middorsal cephalic scales................................................. T. macrolepis

- Frontal similar in size to the other middorsal cephalic scales...................................................12

12. Middorsal scales lower than 200 (141–172)....................................................... T. brevissima

- Middorsal scales higher than 200 (200–233)...................................................... T. salgueiroi

13. Fused caudals present................................................................................ 14

- Fused caudals absent.................................................................... T. guayaquilensis

14. Middorsal scales lower than 200 (174–199), uniform dark brown dorsally and pale brown ventrally and head dorsally paler than dorsal scales of body, with some brown pigmentation concentrated on the center of cephalic scales......... T. joshuai

- Middorsal scales higher than 200 (203–214), uniformly gray dorsally and reticulate gray ventrally, and head with the same color pattern as the body......................................................................... T. pastusa