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In South Africa (Theiler 1947), R. tricuspis occurs in the warmer areas with thorn trees, from the semiarid bushveld of the Kalahari to the moister bushveld of the lowveld of northern and eastern Transvaal and of Natal. It is absent in the Karroo scrubveld, the open grassveld of Orange Free State, and the middleveld and highveld of Transvaal.

Dr. Theiler's present study indicates that R. tricuspis appears to be resistant to a wide range of humidity and aridity. It may be found in heavy rainfall areas with 42 inches annually and in areas where there is as much as seven months of drought. Santos Dias' (1950D,1952C) records of R. tricuspis and "R. lunulatus" are from areas with the same kinds of vegetation and drought periods and the same average rainfall. Dönitz's (1910B) specimen from Little Namaqualand probably fell from its host when the Trekboers were migrating with their sheep from Bushmanland and the southern Kalahari into Namaqualand in search of rains and pasturage.

In Northern Rhodesia, Matthysse (1954) found adults of the tricuspid brown tick mainly in the tail brush of cattle but also on the feet, amus, and ears. Most specimens that I have seen have been from the tail brush. They appear to be present chiefly during the rains but also in the dry season.

DISEASE RELATIONS

MAN: Specimens from Portugese Guinea have been reported to be free of Q fever (Coxiella burnetii).

PIGS: This tick is "possibly a vector of porcine piroplasmosis (Babesia trautmanni)". REMARKS R. tricuspis was described by Dönitz (1906) from the Kalahari of Bechuanaland. The following year, Neumann (1907B) des

cribed R. lunulatus from the Congo, and in 1919(A) Dönitz described R. glyphis from Togo and Tanganyika. Dönitz's papers

were long overlooked by earlier workers, and obvious specimens of R. tricuspis were identified as R. lunulatus.

Zumpt (1943A,1950A) accepted the differing descriptions of R. tricuspis and R. lunulatus as referring to separate species. He synonymized R. glyphis under R. lunulatus but did not see specimens of R. tricuspis. Theiler (1927) reared R. tricuspis and observed tha e range of variation in the Fl generation from a single female included characters ascribed to R. tricuspis as well as to R. lunulatus. For the purposes of the present WOFX, Theiler has restudied her material and confirmed her earlier observations. Santos Dias (1950D,1952C) described differences, which Theiler has found to be intraspecific, for R. tricuspis and R. lunulatus. •

It might be indicated that in Theiler and Robinson (1954) the term R. lunulatus is used only for literature references of that name, but does not infer that these authors consider R. lunulatus to be a valid species. •

In the following description, the range of variation in Theiler's material is noted. Only typical specimens were described in her 1947 paper, in which R. tricuspis was compared with R. simus simus

IDENTIFICATION

Male: The somewhat linear arrangement of the few large, deep scutal punctations identifies R. tricuspis in the R. simus group within which it stands out easily by # curiously sinuous posterior margin of the adanal shields that are projected more or less as a spur at the inner or outer juncture, or at both junctures. In typical specimens, these two pointed spurs and the pointed, heavily sclerotized accessory anal shields give this area of the tick a tricuspid appearance. The spurlike outer juncture is pronounced but the inner point is frequently more rounded and shorter. Lateral grooves, usually well indicated, rarely may be much reduced or indicated by only a line of adjacent punctations. The posterior grooves are typically distinct but in some specimens tend to disappear. A Note that in specimens of R. simpsoni from a single host the same variation in scutal grooves

occurs. Small rhipicephalid species that crowd into a small area of the host frequently show these modifications.7 Small or fine interstitial punctations are present, though they may be faint. Coxa I bears a pointed dorsal projection that typically is prominent but in some specimens is smaller, though still pointed. This reddish to black tick usually has a pearshaped body and measures up to 3.5 mm. or even 4.3 mm. long.

Female: Usually small size (up to 4.5 mm. long and 2.3 mm. wide) and association with the male distinguishes this sex from that of R. s. simus. Clearcut characters to distinguish these two females are difficult to define in view of the frequent reduction of the lateral grooves in R. s. simus. In most specimens of R. tricuspis the shieldshaped scutum contrasts with the subcircular scutum of R. s. simus. The lateral grooves are characteristically short (shorter than in R. s. simus) and contain four to six closely adjacent punctations."

Larvae and nymphs have been described by Theiler (1947) and compared with those of R. s. simus.

RHIPICEPHALUS 2SP.

(not illustrated)

L N Q. C. EQUATORIA PROVINCE RECORDS 2 17 Imatong Heterohyrax brucei hoogstraali Feb l l

Imurok Heterohyrax brucei hoogstraali Feb

REMARKS

,, . These nymphs were originally identified as those of R: mühlensi (Hoogstraal 1954B). Subsequent study of the difficult problem of immature rhipicephalid identification indicates that they are of a different species and most closely resemble R. maculatus Neumann, 1901, (Theiler, correspondence) an ornamented

species from southeastern Africa that is not known from the Sudan.

Note (page 637) that it is quite possible that these spec

imens are the immature stages of the species referred to herein as E. 2distinctus.

AN |MALS AND OTHER SOURCES FROM WHICH

TICKS HAVE BEEN COLLECTED

The following lists are a résumé of Sudanese tick host records in the present collection. The fauna of Torit District in Equatoria Province has been most thoroughly studied, that of Eastern and Juba Districts, to the east and west of Torit District respectively, has also received considerable attention though not to the extent of that in Torit District. These three Districts comprise that part of Equatoria Province lying east of the Nile. The west bank of Equatoria Province remains poorly known and will undoubtedly provide a rich source of new data to future workers.

In Bahr El Ghazal Province, the area from Yirol to Wau and northwards has been fairly well studied; the remainder of this Province has been surveyed but should receive more attention. Upper Nile Province is the least studied of this group of three Provinces with tropical African savannah landscape and big game animals. Some East African tick species presently unknown in the Sudan may occur on animals in this area. Hosts from which ticks have been collected in the remaining Provinces, comprising desert scrub, semidesert, and desert zones of the Sudan, are mostly domestic animals. Kassala and Northern Provinces are less well represented in these collections than Darfur and Kordofan Provinces.

Equatoria Province data are more representative of the overall picture of host parasite relationships than those of other Provinces and are, therefore, reviewed in greater detail than data for other Provinces. Certain significant negative data are also included.

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