1. Morphology, keys and DNA diagnostics
IDENTIFYING SNAKES
Morphology, keys and DNA diagnostics

2. MORPHOLOGY: Head shape

3. MORPHOLOGY: Head shape
Colubrid-Elapid type
Viperid type

4. VENOMOUS or NON-VENOMOUS?
Front-fanged or non-front fanged: all snakes are potentially venomous
Magenetic resonance imaging, lizard is Varanus exanthematicus
As are some lizards……

5. MORPHOLOGY: Body Pattern
UNIFORM
SPECKLED
STRIPED
SPOTTED
BLOTCHED
DIAMONDS
BANDED
RINGED

6. MORPHOLOGY: Head Pattern

7. MORPHOLOGY: Scale counts
The dorsal scales cover the snake's back. These are the scales you can see when the snake is 'sitting' on the ground. You count these scales at the widest part of the snake's body. This is the mid-body region, about halfway down the snake's length. The diagram shows you how to count these scales. In this particular example, our snake has 17 rows of dorsal scales at mid-body. This is often just abbreviated as '17 midbodies'.
1. Number of dorsal scales at mid-body

8. MORPHOLOGY: SCALE STRUCTURE
SMOOTH
KEELED
The dorsal scales cover the snake's back. These are the scales you can see when the snake is 'sitting' on the ground. You count these scales at the widest part of the snake's body. This is the mid-body region, about halfway down the snake's length. The diagram shows you how to count these scales. In this particular example, our snake has 17 rows of dorsal scales at mid-body. This is often just abbreviated as '17 midbodies'.

9. MORPHOLOGY: Scale counts
Ventral scales These are the 'belly scales' of the snake. They run from the neck down to the bum. Pythons have ventral scales that are about half the width of the body. Both colubrid and elapid snakes have ventral scales that are about the same width as the body. Anal scale This is the scale just in front of the cloaca (the snake's 'bum'). The anal scale may be single or divided. Subcaudal scales These are the scales underneath the snake's tail. Scales are either single or divided, but snakes may have a combination of both single and divided subcaudal scales.
2. Number of ventral, anal and subcaudal scales

10. MORPHOLOGY: Head scales
Snakes of Western and Central Africa

11. Scale row reductions
Ovophis spp.

12. KEYS 1. Traditional dichotomous keys How to Use this Key:
Start with the first question. Decide whether 1a or 1b best describes the characteristics of the snake you are trying to identify. (There are links to examples of these traits if you need help.)
If the snake is striped, click on 6; if it is not striped, click on 2. Your choice will lead you to the next appropriate pair of questions.
Work through the questions, each time choosing the characteristic that best matches your snake from the two choices. This will lead you to the final choice which identifies the snake.
1. Traditional dichotomous keys

13. Quinn Snake Identification Chart
2. Flowchart

14. 3. Interactive On-line

15. 3. Interactive On-line

16. 3. Interactive On-line

17.
3. Interactive On-line

18. Species File Software 3. Interactive On-line
3. Interactive On-line

19. (DEscription Language for TAxonomy)
3. Interactive On-line

20. PROBLEMS TO BE SOLVED
A key is only as good as the data that it is based on
Most venomous snakes have not yet been sampled within India well
Outstanding issues needing further work in many spp.
Naja spp (N. naja and N. kaouthia)
Echis spp (E. carinatus and E. sochureki)
Daboia russelii
Pitvipers (many spp)

21. Asian cobras Naja (11 spp. since 2000) oxiana mandalayensis atra
Asian cobras Naja
(11 spp. since 2000)
oxiana
mandalayensis
atra
naja
kaouthia
phillipinensis
siamensis
This puzzling situation was at least partly resolved by the realization that there are in fact multiple full spp of naja present in Asia an that in many parts, including india, moe than one spp may be present, with different venom effects.
samarensis
sagittifera
sumatrana
sputatrix

22. Cryptic diversity of cobras in India?
Morphology
Mitochondrial DNA
Naja naja
Naja kaouthia
Naja oxiana
Wüster & Thorpe 1992
N. kaouthia
N. kaouthia
N. kaouthia
N. kaouthia
N. kaouthia
N. sagittifera
N. sagittifera
N. kaouthia
N. oxiana
N. oxiana
N. naja Sri Lanka
N. naja Sri Lanka
But there are sill unanwwered questions which need more sampling to resolve: eg in India.
N. naja Nepal
N. naja Nepal
N. naja Pakistan
0.01
Cryptic species associated with N. kaouthia?
Deep divergences in N. naja

23. ? Morphology vs. molecules in Naja naja and the importance of sampling
Morphological cline vs.
deep molecular splits:
one species or two?
Morphology ?
N. naja Nepal
N. naja Nepal
N. naja Pakistan
N. naja Sri Lanka
N. naja Sri Lanka

24. ? Bungarus niger Cryptelytrops erythrurus Ovophis monticola Naja spp.
Echis sochureki/
E. carinatus ?
Orissa placed with north-east simply because of record of monocellate cobra from this state. But clearly will be very diff to ne/hilly regions. Eastern region actually extends quite far west along the himalayan region: recent account of a greater black krait bite from Uttarakhand. Pitvipers are also present in this region, but from different lineages to those present in S India: Of these, erythrurus found to be the commonest cause of sakebite in the Chittagong Hills in Bangladesh, with quite severe effects, Ovophis monticola common in Nepal, with severe local sequelae though low fatality rate.
MP and Chattisgarh? Unaware of any work on species in this region.
Peltopleor macrolepis
Trimeresurus malabaricus
Hypnale hypnale
Cryptelytrops spp.
Naja sagittifera
Mohapatra et al. (2011) PLoS Negl Trop Dis 5(4): e1018. doi: /journal.pntd

25. DNA IDENTIFICATION: THE WAY FORWARD?
Pook and McEwing (2005) Toxicon 46:
- mtDNA PCR amplified from dried venom samples
mg dried venom used
Kuch (unpublished): bite site swabs successfully used to identify biting species in Bangladesh
Relies on presence of species sequences in “barcoding” databases against which query sequence is matched
More useful for research than diagnostics

26. DNA IDENTIFICATION: THE WAY FORWARD?
With enough information, specific diagnostic tests can be designed to identify important species by length differences in amplified product alone (time c. 30 mins, cost c. $10-20)