Research on the mosquitoes of Angola - Systematic Catalog of ...

RIBEIR0, H. & RAMOS, 1-. Cunha -- <strong>Research</strong> o the mosquitoes of Agola -- X
TAXONOMIC NOTES. Adults of C. simpsoni show little variation and
agree quite well with Edwards description, including the terminalic characters
of male. It is perhaps worth to note, however, that the scutal
pattern described by Edwards is by no means obvious and the decumbent
scales of head are mostly pale even toward sides.
In that concerns larvae, on the contrary. much variation of
apparently different kinds has been reported by Hopkins (24),
Mattingly (in Hopkins, op. cit.), Mattingly & Lips (42), Mattingly
& Brown (75), Hamon et al. (76), Mouchet et al. (77)
and others. Most of the described variation in larval C. ,simpsoni
was also found by the present writers in Angola. Besides, after
careful examination of thirty full-grown larvae from eight different
Angolan localities, it was possible to distinguish two main larval forms
(A and B), almost always separable on the basis of the characters used
in the key (see under 6). Besides these ones, the following characters
may also be useful for distinguishing between the two larval forms: head
seta C is bifid in about 80 per cent (and single in about 20 p.c.) of
form A larvae, while these percentages are inverted in larval form B;
the mean number of pecten teeth in form A larvae is 10.1 (range 8-12),
while in larval form B we found 11.8 and 10-15 teeth, respectively; lastly,
the saddle hair has 2-5 branches (mean 3.5) in form A larvae and is
single, bifid or, at most, trifid (mean 2.4 branches) in larval form B.
Even if no differences have been found in external and terminalic
characters between adults associated with each one of the larval forms A
and B, it is quite apparent that we are dealing with an incipient process
of speciation within C. simpsoni (s. l.), an hypothesis that seems to be
confirmed by distributional data in Angola (see below).
DISTRIBUTION. C. simpsoni is an Ethiopian species known to occur
in the African mainland, Madagascar, Mauricius, Seychelles (75), and
S. W. Arabia (38). As it was pointed out by Mattingly & Brown (op. cit.),
this species seems to be more common and more widely distributed
throughout East and South African biomes than in West African ones,
at least according to the available data. In Angola, as it is shown on
Map 11, C. simpsoni is a quite common and widespread mosquito in the
South-west Arid Zone and also occurs in the West African Savanna Zone
(Map 3). A most interesting finding is the apparent association of each
of the two larval forms described above with each one of these biotic
104 Estud., Ets. e Doc.- 134