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The Boma Plains specimens constitute the first and only defi. nite record of A. cohaerens from the Sudan. If the tentative im. mature stage identifications are correct, we may expect that A. cohaerens occurs in other parts of Equatoria Province, especially where buffalos roam. The East African buffalo tick has not been found in Bahr El Ghazal or in Upper Nile Provinces, although buffalos are present in these Provinces and frequently have been examined for ticks by H. H. King, Sudan Veterinary Service personnel, and the writer.
A. cohaerens is an East and Central African buffalo parasite that reaches the northern limit of its range in Equatoria Province and extends southwards into Tanganyika.
*Tentative identification by Dr. G. Theiler.
CENTRAL AFRICA: [ ?CAMEROONS: Noted by Schulze (1941) with out data. Recorded on (?imported) cattle at Yaounde by Rousselot (1951) but not repeated by him_(1953B). Rageau (1951, 1953A,B), apparently quoting Rousselot.) FRENCH EQUATORIAL AFRICA (Rousse_ lot 1951, 1953B).
BELGIAN CONGO and RUANDA_URUNDI (Nuttall and Warburton 1916. Robinson 1926. Schwetz 1927B,C,1932. Bequaert 1930A,B,1931. Rousselot 1951,1953B. As A. cohaerens and also as A. hebraeum: Schoenaers 1951A,B; see REMARKS below. Theiler and Robinson 1954. Van Vaerenbergh 1954).
EAST AFRICA: HEAST AFRICA" (Dönitz 1909).
SUDAN (Hoogstraal 1954B).
FRENCH SOMALILAND (Hoogstraal 1953D).
KENYA (Robinson 1926. Lewis 1934. Weber 1948). UGANDA (Neave 1912. Robinson 1926. Tonelli Rondelli 1930A. Richardson 1930. Mettam 1932. Mettam and Carmichael 1936. Wilson 1948A, 1950C. Hoogstraal 1954C). TANGANYIKA (As A. anceps: Dönitz 1909. Hoogstraal 19540).
NOTE: The ANGOLA record by Sousa Dias (1950) is actually A. astrion, not A. cohaerens (Theiler, correspondence). See REMARKS below. I
All authors list the African buffalo, Syncerus caffer, as the chief host of A. cohaerens.
The East African buffalo tick is frequently reported to attack domestic cattle in areas where buffaloes are common or after large numbers of these animals have been shot out for disease control. Domestic cattle have been listed as hosts by Robinson (1926), Schwetz (1932), Schoenaers (1951B), and Rousselot (1951,1953B). Cattle are frequently parasitized when near game, especially buffalo (Wilson 1948A ,19500). In
certain Uganda areas, A. cohaerens, together with A. variegatum, is the predominant cattle tick on old buffalo grazing grounds (Richardson 1930). It would be interesting to know how long the buffalo tick remains in an area as a cattle parasite after its chief host has been exterminated.
Other animals are rare hosts of adults. Elephants (Robinson 1926). Tortoise, and domestic sheep and goats (Mettam 1932). Eland (Lewis 1934, Weber 1948). Warthog (Theiler, unpublished). Black rhinoceros (Hoogstraal 19540. Also 200 removed from a Tanganyika rhinoceros skin by a taxidermist - CNHM collections).
Hosts of nymphs (tentatively identified as this species) are ground birds and a tree rat (Equatoria Province records above). Dozens of Thammomys tree rats have been examined by me in the Sudan and Kenya without finding other ticks on them. Several nymphs have been taken from a warthog near Lake Edward, Uganda, by It. Col. Don Davis, U.S.A. (HH collection).
Unstudied. In Ruanda-Urundi, A. cohaerens occurs as high as 2200 meters altitude (Schoenaers 1951B, as A. hebraeum).
Sections of the mouthparts of A. cohaerens have been illus trated by Schulze (1936A), who also illustrated the form of haller's organ (1941), and (1950A) discussed the dentition of this species, Schulze also (19320) utilized this tick to illustrate his concept of the relation of ornamental design to location of muscle attache ments. A number of other remarks and illustrations concerning the exoskeleton of this species are presented in the same study.
The middle festoon of a few males may be largely pale and other festoons may be equally so; such specimens would key to A. hebraeum. There are no excessively pale festooned individuals In our own collection or in that of British Museum (Natural His tory), but some material in the Onderstepoort collections shows this variation (Theiler, correspondence). Such a specimen, seen in the Rocky Mountain Laboratory collection, was the cause of mis identification of A. cohaerens as A. hebraeum in Schoenaers' (1951B) list. A. Tebraeum, though colorful, never shows as much iridescence as most other ticks of this genus (Theiler, corres. pondence).
Should specimens resembling A. cohaerens be found on the west bank in Equatoria Province, they should be checked against A. splendidum Giebel, 1877, of the Congo and West Africa (cf. Robin son 1926, pp. 123_125). A. splendidum males are somewhat larger, have a vermillion-red spot in the center of the scutum, and never have a falciform stripe. Females are indistinguishable from those of A. cohaerens although they are often a little larger.
A. cohaerens also closely resembles A. astrion of West Africa. Sousa Dias (1950) confused A. astrion with A. cohaerens. Recent studies by Theiler indicate the distinctness of the two species. Since A. astrion is unlikely to be found in the Sudan tick fauna, it is unnecessary to mention further detail. However, students who may compare our nomenclature with that of Sousa Dias should be aware that this discrepancy exists.
A. cohaerens is easily recognized within the known Sudan tick fauna. closely related species, some of which may occur in the Sudan, are mentioned above.
Males fall into a group in which the eye is not in a de. pression, although it may be very slightly convex; festoons are mixed dark and pale, scutal punctations are only fine, scutal ornamentation is as illustrated (Figure 64) but either with or without a falciform stripe; lateral grooves reach nearly to the eyes. This is a medium size tick, from 5.0 mm. to 6.0 mm. long and from 4.0 mm. to 4.7 mm, wide.
Females have a triangular scutum with only fine punctations and with an extensive pale central area; the lateral scutal areas are dark except for one or two very small light marginal spots. The eyes are not in a depression though they may be very slightly convex. Leg segments are ringed by broad bands. Females are of medium size, approximately 5.0 mm. long and 4.0 mm, wide. The scutum is approximately 2.8 mm. long and 2.9 mm. wide.