RHIPICEPHALUS ?DISTINCTUS Bedford, 1932 (B)*

No other specimens of this species have been found in the
See HOSTS and REMARKS below.

Sudan.

DISTRIBUTION

The hyrax glossy tick ranges from southern Sudan to Southwest Africa. Its distribution is probably more continuous than present records indicate. Possibly two species are represented in the material quoted below.

EAST AFRICA: SUDAN (Not previously reported).

UGANDA (A. J. Haddow, correspondence; common at Kaabong, Kara moja). TANGANYIKA (Theiler 1947).

SOUTHERN AFRICA: SOUTHERN RHODESIA (Bulawayo specimens; Theiler, unpublished). MOZAMBIQUE (Santos Dias 1953C).

SOUTHWEST AFRICA (Bedford 1929A,1932B. Zumpt 1943A. Theiler 1947. BMNH collections contain numerous specimens from Bellrode, Naukluft, and Otjosongombe; K. Jordan legit, H. H. det.). UNION OF SOUTH AFRICA (Cooley 1934. Theiler 1947. Note: Occurs in Cape Province, Orange Free State, and Transvaal. Earlier records appear to be based on misidentification; see HOSTS below).

*The possibility that the single specimen available from the Sudan represents an undescribed species should be considered. See REMARKS and IDENTIFICATION (pages 638 and 639).

HOST S

Hyraxes, or dassies, both rock and arboreal kinds, are the chief host of this tick. Procavia coombsi (Bedford 1929,1932B). P. capensis meneliki (Uganda material noted above). P. habessinica Slatini (Sudan record above). P. johnstoni matschiei and Hetero hyrax welwitschi volkmanni (Theiler 1947). Procavia waterbergensis (Southwest Africa; Theiler, unpublished). Dendrohyrax a. arboreus (Santos Dias 1953ć). Procavia sp. and Heterohyrax sp. All other

records.

Although other animals have been reported as hosts, Theiler (correspondence) now believes these records to be based on in correct identification. Bedford (1934) and Theiler (1947) referred to domestic sheep in Cape Province of South Africa; and A. J. Haddow (correspondence) to the long-snouted dikdik in Karamoja, Uganda.

It is of some interest that we found only a single specimen of this tick on the numerous rock hyraxes taken in Torit and Juba Districts in Equatoria Province. Few of these mammals were taken at Rejaf, where the tick was found, but good series were obtained and carefully examined in a number of other localities.

It is of equal interest to note that while 21 rhipicephalid larvae and nymphs were found on two hyraxes (Heterohyrax brucei hoogstraali) in Torit District, these represent, according to Theiler (correspondence), an unidentifiable species, not R. distinctus. Inasmuch as hyrax parasites are most distinctive and host specific, it is probable that these larvae and nymphs represent the same species as the single Sudanese male, which differs from Southwest African specimens of R. distinctus, and that these represent an undescribed species.

BIOLOGY

Nymphs and adults are found on rock hyraxes. Nothing else is known about the biology of this species.

Unstudied.

DISEASE RELATIONS

REMARKS

This species is a member of the R. simus group (Zumpt 1942A). On superficial examination, males might be confused with either R. S. sanguineus or R. s. simus, or, as noted below, they may easily be miskeyed. Once the basic characters are learned, the worker recognizes this as a most distinct species, the female of which is even more unique than the male. This note applies to material from both southwestern and eastern Africa.

The single Sudanese male agrees with numerous specimens from Southwest Africa in all respects except the width and shape of the exteroposterior juncture of the adanal shields (see below). Should further Sudanese specimens be consistent in this respect, it is likely that they represent a subspecies or species differing from R. distinctus of Southwest Africa. In this respect, the Mozam bique specimen illustrated by Santos Dias (1953C, figure 3) is like the Sudanese specimen. The female accompanying Santos Dias' male has a much longer scutum than those from Southwest Africa and a much more narrowly pointed posterior margin. This fact may support the premise that populations from Mozambique to the Sudan represent an undescribed species. Note that the female herein illustrated (Figures 263 and 264) is from Southwest Africa and possibly not representative of Sudanese populations. Presumably, also, the immature specimens referred to as Rhipicephalus sp. (page 778), which differ from R. distinctus, may be associated with the single available Sudanese male.

It is unfortunate that more time could not have been devoted to determining the actual status of the Sudanese male during the course of the present study. Although we collected this specimen in 1948, it had been separated from the rest of the collection by another member of the party and eventually sent to the Museum of Comparative Zoology. Just as the present work was being completed, Dr. J. Bequaert noted this specimen and kindly returned it to our collection.

IDENTIFICATION

This is a member of the R. simus group (page 751).

Males: Males are characterized by a combination of characters including few, large scutal punctations arranged in four irregular longitudinal rows that form an especially distinctive pattern posteriorly (as in R. simus senegalensis); lateral grooves varying from deep to shallow (narrow and shallow in Sudanese specimen) but containing a row of large, deep, almost adjacent puncta tions extending from the first or second festoon to the eyes (this row of punctations also extending from the eyes to the scapulae but more widely spaced and not in a groove; coxa I with a dorsal projection that is small but definitely pointed; posteromedian groove and paramedian grooves more or less marked, indicated by narrow, shallow depressions (uncommonly all but ob solete; distinct in Sudanese specimen). The adanal shields of material from southern Africa are narrowly elongate, subovate, with rounded external margin, pointed anterior and posterior junctures, and slightly recurved inner margin posteriorly; those of the single available Sudanese specimen (Figure 262) are broader posteriorly and the externo posterior juncture forms almost a right angle (see REMARKS above). Accessory shields are indicated only by posterior points. In addition to the already mentioned scutal punctations, there is a cluster of several punctations on the scapulae and two to six others may be scattered on the scutum; interstitial punctations are faintly indicated.

Females: The scutum of specimens from Southwest Africa is subcircular and either as wide as long or slightly wider than long; lateral grooves are entirely absent but are replaced by a convex line of three to seven large punctations; in the median field four or five other large punctations are scattered and a few others are clustered on the scapulae; interstitial puncta tions are fine and cover most of the scutal surface. Lateral margins are slightly elevated, devoid of punctations posterior of the scapulae, and bear flat eyes. Cervical grooves are short, deep, and either convex or narrowly ovate and converging. Porose areas are small, circular, and not widely separated. Color is as in males; size is slightly greater than that of males but increases greatly when feeding; upon engorgement the body out line is subcircular.

As stated in REMARKS above, it is possible that when females of this species are found in the Sudan they will be similar to those described and illustrated herein except that the scutum will be considerably more elongate and narrowly pointed posteriorly.

Note: Zumpt (1950A) attributes the name R. distinctus to "Bedford, Fmg. S. Afr., no.11, 1935, p.6," an error repeated by Santos Dias (1953C). The name R. distinctus was proposed on page 523 of Bedford's (1932B) checklist.