Ok, my head hurts. And I am most likely too dense to understand all this, so help me out. These are the emails from a conversation. I will try to post all the links that match.


Dear Jeff,
You are correct - identification and species boundaries in Pyxicephalus are confused and are currently subject to research by several groups (although in general the biology of this group is well studied). There is no question that P. adspersus and P. edulis are different species, however, immatures and smaller individuals can be very difficult to identify. Also, it is likely that multiple species are hiding under each of these names, occurring in different parts of Africa, contributing geographic variation to the difficulties of identification. In general, in southern Africa, P. edulis occurs in the lower lying coastal and river valley savanna, with P. adspersus in the high-lying (>1000m asl) grasslands, inland savanna and semi-arid areas.

I suggest that you find a copy of:

DuPreez L & Carruthers V (2009) A complete guide to the frogs of Southern Africa. Struik-random House, Cape Town ISBN: 978-1-77007-446

for the latest overview (P. edulis & P. adspersus).

Also another great site for the sort of information you might need is AmphibiaWeb
http://www.amphibiaweb.org/index.html

for the link to Pyxicephalus see...


http://www.amphibiaweb.org/cgi-bin/a...re-submittedby

this extracts information from authoritative books.

regards,
michael

Dr Michael Cunningham
University of the Free State, Qwaqwa
Private Bag X13, Phuthaditjhaba 9866, SOUTH AFRICA
phone: +27-(0)58 718 5327, fax: +27-(0)58 718 5444

My comments back:

 Michael,

Thanks for the heads up. Yes, the variation of the species populations across Africa could be a real problem in identification. And babies and juveniles are a nightmare to look for specific traits. Traits which may not be there yet or may be there but will fade to adulthood. Tough call.

Great info on the geographic location. I will make note of that. Any thoughts on P. obbianus?

Your last link leading to CalPhotos even shows some of the problems occurring with identification. In the first link, this photo is neither adspersus or edulis?
http://calphotos.berkeley.edu/cgi/im...1111+1111+1200

And in this second link, the photo on the left is very different from the photo on the right. What I am finding is the photo on the left is what is called edulis in the states, and the photo on the right is what is called edulis in Africa. What a mess.
http://calphotos.berkeley.edu/cgi/im...el-lifeform=ne

Thank you for your time.

Sincerely,

Jeff

Comments back: That I guess I don't see that they can be the same.

Hi Jeff,
At least in Southern Africa it isn't so hard to separate the two species - including the juveniles.

DuPreez & Carruthers give the following characters...
edulis usually has a white mark on the tympanum which is absent in adspersus
edulis has a pale interorbital bar (with pale transverse marks on the dorsal eyelid) which is absent in adspersus
edulis has the tympanum about 1 eye-width from the eye, in adspersus it is closer to twice this distance
edulis has irregular pale vertical bars on the upper lip which are absent from adspersus

in addition adspersus tend to have the orange axillary marks and mouth and elongate white marks along the dorsal skin folds

On all these characters the photos from CalAcad check out pretty well - I don't see that the edulis photos are necessarily from different species...it looks more like different individuals being photographed under different conditions and all correctly IDed.

P. adspersus is the type species of the genus (which is type genus of the family).

The type locality for P. adspersus is Cape Town (Cape of Good Hope) - which is actually ~400km SW of their distributional limit - meaning that this is where they were shipped or where the collectors were based (as were all collectors in Southern Africa of that period). At the time of description (1838) a few collectors had just reached as far as the Tropic of Capricorn but it is likely that this particular collection was made around Port Elizabeth on the South Coast.

The type locality for P. edulis is Tete on the Zambezi R in NW Mozambique.

These are the populations that must define the names and they are consistent with the above differences. The captive populations could be from anywhere and so their IDs may be dubious. I notice that one of the photos is referenced to Central South America - which is in error.

P. obbianus is an obscure taxon from Somalia - I've never read the literature on it and don't really know how it would compare.

The real problem is to discover whether P. anchietae from Mozambique near the Zambezi mouth is a valid species different from P. edulis and whether the species from Southern Africa are the same as those from North and West African savannas that are assigned to the same names.



End: Please let me know if there are any clarifying question you all would like me to send back.