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KEY TO SUDAN SPECIES OF RHIPICEPHALUS

MALES

1. Eyes convex or hemispherical, distinctly furrowed laterally or protruding from a depression ("orbited"). Coxa I with distinct dorsal projection......

...2

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*R. simpsoni (R. simus group), a small parasite of canerats only, typically bears this projection but this projection is so small and frequently so reduced that it is not considered distinct enough to include in this section.

- 586

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4. Lateral grooves faint, absent, or indicated only by a row of puncta tions. (Rare species)*.....

Lateral grooves distinct as such..

5. Scutal punctations in more or less
definite rows of R. simus type,
interstitials variable but always
insignificant in comparison with
primary punctations.

Scutal punctations scattered, not
in rows, fairly numerous....

6. Posteromedian and paramedian grooves
absent. Adanal shields with inner
margin in a straight line centrally
and with a peculiar protrusion at
juncture of inner and posterior
margins..

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..5 ..8

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..R. LONGICOXATUS Figures 273 and 274

.R. BEQUAERTI Figures 249 and 250

.R. ARNOLDI

Figure 245

..R. MUHLENSI Figures 281 and 282

*R. distinctus atypically may have apparently shallow lateral grooves due to the size and depth of the row of large punctations in its bed.

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11. Scutal punctations either excessively
rare or in a pattern of four more or
less linear rows (sometimes with one
or two partial additional rows); among
these interstitial or secondary puncta-
tions are present or absent, if present
they are smaller and more superficial*,

12.

Scutal punctations not in these patterns,
rather dense, not separated into primary
and interstitial punctations but uniform
or mixed. (Uncommon southern species)...

Scutum impunctate or with excessively
few, shallow punctations. Adanal
shields typically tending towards
sickleshape but quite variable in
series from single hosts. Postero-
median and paramedian grooves pres-
ent or absent. Lateral grooves
distinct or indicated only by a row
of punctations. Coxa I with a small
dorsal projection which may be much
reduced. (Small, rare, pear shaped,
variable species, confined to cane
rats).....

Scutum with more, larger, and deeper
punctations. Other combinations of
characters differing.

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..R. SIMPSONI

Figures 297 and 298

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*The linear punctation pattern of heavily punctate specimens of R. s. sanguineus in southern Sudan may be somewhat obscured by dense, moderately large interstitial punctations, but can be discerned by turning the specimen obliquely to the source of the light.

13. Posteromedian and paramedian grooves pronounced, deep, and wide*. Interstitial punctations varying from faint to large and numerous enough to some.. what obscure basic pattern of four rows of larger punctations. (Common, widely distributed in Sudan)....

Posteromedian and paramedian grooves
indistinct, shallow, or absent.......

14. Adanal shields elongately triangular
with rounded marginal junctures. Only
middle festoon protrudes. Posterior
grooves absent, rarely very faintly
indicated (but never distinct). Scutum
arched; interstitial punctations usual
ly absent or insignificant, rarely more
definite but never confusing basic
pattern. (Common, widely distributed
in Sudan)....

Adanal shields either distinctly sickle
shaped or with peculiar inner or outer
posterior protrusion. (More localized
in southern Sudan and less common)..

....R. S. SANGUINEUS Figures 289 and 290, 293 and 294.

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...R. S. SIMUS Figures 301 and 302

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*This character is constant in this variable species in all but a very few individuals obviously misformed in several characters.

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