The montane butterflies of the eastern Afrotropics - Biogeography and Ecology of the Rain Forests of Eastern Africa - page 143

Table 8.2. Distribution of montane rassland buttelies (sp ecies and subspecies) over combined mountain
areas or eplanation, see Ta ble 8. 1)

N % N(end) %(endN) %(end)

1 Ethiopia 8 15.38 8 100.00 15.38

2 E Tanzania 11 21.15 7 63.64 13.46

3 Malawi

4 7.69 1 25.00 1.92

4 W Tanzania

5.77 11 21.15 3 27.27

5 W Range 15

28.85 10 66.67 19.23

6 Kenya-N Tanzania 19 12

36.54 63.16 23.08

Summay
It can be concluded that the 58 taxa of montane
grassland butterflies do not show much of a geo-
graphic patten. A cautious subdivision of the
montane grasslands could be (see also Table 8.2):
(i) Ethiopia, (ii) Kenya-north Tanzania, (iii) east
Tanzania, (iv) Westen Border Range, with con-
nections between the four. The number of taxa
supporing such a subdivision is prety low, but
these ranges show more intenal and inter-range
coherence than the mountains further south in
Tanzania and Malawi. Also note the absence of
widespread endemics. Widespread taxa like Colias
electo, Actizera stellata and the three lssoria species
together are not endemic to EAT. Even if a pro-
porion of the species listed in Appendix 8.1
tuned out to form monophyletic groups within
EAT (possible in all genera with at least two spe-
cies represented), the coherence would hardly be
stronger.

Table 8.3. Geographical connections in montane
grassland buttelies epressed as the number of
shared sp ecies or sister sp ecies

Area 2 3 4 5

Inside area 3 12 9 10 4

Northen 5 4 4 3 1

Westen 1 1 1 2 1

Southern 2 2 4 2

Total 9 14

17 15 5

Note: 1, Ethiopia; 2, Kenya-N Tanzania; 3, Eastern Arc
mountains-Malawi; 4, E Zaire to NW Tanzania; 5,
Rwenzori.

outside Africa (see Methods, p. 134). The case of
lssoria is more difficult to interpret: there are two
opposing views. Either the African species have a
Palaearcic ancesty (de Jong, 1976), or their
occurrence in Africa is a relict distribuion of
Gondwana origin (Bernardi, 1980). It seems
fashionable to interpret the occurrence of
present-day taxa in areas that over 80 Myr BP
formed part of Gondwana as an indicaion of
Gondwana origin. However, at least in this case
there are good arguments against it. First, there
are no indications that the genus lssoria eisted 80
Myr BP. The oldest butterfly fossils known are
about 40 Myr old and belong to exinct genera of
the Papilionidae. Secondly, it would be vey
srange for a Gondwana element to be mainly
restricted to mountains that are at most 2 Myr old.
Thirdly, there is a rich development (11 genera)
of the Argynnina, the subtribe lssoia belongs to,
in the Holarcic; there is no evidence that the

Extenal geographic connetions

Geographic connections are in all directions, to
the north, west and south. They have been sum-
marised in Table 8.3. The connecions are,
however, of a different kind.

No then connections
Five of the 15 genera are represented outside
Africa: Colias, Pieis, Aryreus, lsson · a and Lycaena.
Except for lssoria the African species are either
the same as outside Africa (Colias erate, Aryreus
hyperbius, Lycaena phlaeas) or they are very closely
related to non-African species. These species or
their ancestors are supposed to have originated