Biogeography of East African montane forest millipedes - Biogeography and Ecology of the Rain Forests of Eastern Africa - page 108

fewer than 20 genera, and Tanzania alone con-
tains 18 genera (half of them, however, sill
undescribed). Several genera, such as Eviulisoma
Silvestri, 1910, Aklerobunus Attems, 1931, Xan-
thodesmus and Eaodesmus Cook, 1898, are
polyypic and fairly widespread; some of them
have local species apparently endemic to some of
the montane forest isolates. A few genera are
endemic to Tanzania, their species being mon-
tane obligates.
Suohelisoma Hoffman, 196 7, with the single
species ulugurense Hoffman, seems to be a local
derivaive of the widespread related taxon
Eviulisoma known so far only from the Uluguru
Mountains (without precise locality but probably
near Morogoro). Nasmoesosoma Hoffman &
Howell is so specialised in gonopod sructure that
its afiniies have not yet been perceived.
Eosviulisoma Brolemann, 1920, is known from
one species on Mount Kilimanjaro (E. julinum
Attems) and an apparent congener E. abnome
Attems in the Rwenzori. It is interesing that so
far (and taking undescribed taxa into account)
these several genera do not seem to have indulged
in much local speciaion as described, e.g. for
many spirosrepid and oxydesmid genera.

monotypic, the ype species G. castaneus Cook
resricted to the East Usambaras. A closely
related genus Us ambaranus (Hoffman & Howell,
1983) is likewise monoypic, . stuati Hofman &
Howell being known only from the West Usam-
baras. Presumably difereniaion of these genera
has been effected or enhanced by the Lwengera
Valley; if so, an accelerated evoluionary rate
would seem indicated for the taxa involved.
luu ia inepeaata (Hofman, 1964) is so far
known only from the Uluguru Mountains (exact
localiy unknown), and both the species and genus
are doubtless restricted to those mountains.
Related genera occur to the north around Kili-
manjaro and easten Kenya; none so far are
known south of the Ulugurus.
My choesmus miramma (Cook, 1898) was des-
cribed only from 'Mpwapwa'. However, recently
collected material suggests that this species (and
genus) is endemic in the Rubehos, with the ype
specimen carrying only the name of the original
territory (or the nearest large settlement at the
ime).
Pending compleion of a amily revision no
inferences can be drawn concening the geo-
graphic ainiies of the genera menioned above.
It does seem, however, that gomphodesmids fol-
low the general patten of local speciaion associ-
ated with climaic fragmentaion of former rain
orest.

Family Gomphodesmidae. This family is
resricted to subsaharan Africa, from Sierra
Leone and The Gambia to Cape Peninsula, a
disribuion paralleling that of the Odontopy-
gidae. The two groups have further in common a
tendency or maimal generic diversity in
equatorial Africa with the few southward-ranging
genera speciaing profusely south of the Zambezi.
Again, gomphodesmids represent a great biogeo-
graphic potenial presently unavailable because of
the lack of moden revisions. Only a few genera
have so far been monographed, out of the 23
currently recognised. Thirteen genera occur in
Tanzania (the largest number for any single
counry) but unpublished informaion to hand
indicates that an equal number remain to be
defined and published, some of them endemics in
the easten mountain arc. What little is known
about the local distribuion of the named taxa may
be briefly summarised.
The nominate genus Gomphoesmus is so ar

Family Oydesmidae. This endemic African
family is the subject of a recently completed
monograph (Hoffman, 1990) and details about its
representaives in Tanzania can be presented with
some confidence. Two of the recognised sub-
families (Oydesminae and Plagiodesminae)
occur in cenral and westen Africa and enter the
eastern countries only marginally in Uganda.
However, the third, Orodesminae, is widespread
from Ethiopia and Sudan south as far as Mozam-
bique and Malawi, represented in this area by
three ribes and 19 genera. Excluding those which
are extralimital to the area covered in this topic,
we have the following taxa: Tribe Orodesmini,
Oroesmus Cook, 1895; Tribe Mimodesmini,
Morogoesmus Hoffman, 1967, Gonpara Hoff-
man, 1986, Allotocoproaus Hoffman, 1986; Tribe