RHIPICEPHALUS SULCATUS Neumann, 1908.

(Figures 309 to 312)

THE GROOVED BROWN TICK

Bahr El Ghazal:

DISTRIBUTION IN THE SUDAN

200 from an oribi, Ourebia ourebi subsp., near Tonj, 18 March 1953, N. A. Hancock legit. loo, 300 from chest of leopard, Panthera pardus subsp. and lo crawling on leg of man, Alel, 36 miles south of Yirol, 18 March 1953, E. T. M. Reid legit. These specimens are in the HH collection.

These are the only definite records of R. sulcatus from the Sudan. Those reported by King (1926) have proven, upon examination of his specimens by Dr. Theiler, to be R. s. san guineus. A single male was R. supertritus.

DISTRIBUTION

(Known Correct References)

As now known, the range of R. sulcatus extends from the Congo and southwestern Sudan to Nyasaland. Whether this dis tributional picture is more restricted than this tick's range in nature remains to be seen.

CENTRAL AFRICA: "CONGO" Type locality as stated by Neumann (1908). According to Bequaert (1931) this probably refers to French Equatorial Africa (French Congo) but Theiler and Robinson (1953B) refer it to the Belgian Congo.7

EAST AFRICA: SUDAN

tified by Dr. G. Theiler.

Hoogstraal (1954B). Material iden

TANGANYIKA A few actual oo R. sulcatus among R. s. sangui neus collection reported as R. sulcatus by Zumpt (194287; see Theiler and Robinson (1953B)

SOUTHERN AFRICA: NORTHERN RHODESIA (Theiler and Robinson

1953B. NYASALAND (g from Chitala, Theiler and Robinson

Known Incorrect References

FRENCH WEST AFRICA: Rousselot (1951) reported specimens of "R. sanguineus sulcatus", which, as illustrated (1953, figure 37), represent a typical o and g of R. s. sanguineus.

BELGIAN CONGO: Bequaert's (1931) "R. sulcatus" is R. longus according to Zumpt (1942B) and confirmed by Theiler and Robinson (1953B).

SUDAN: The material reported by King (1926) as R. sulcatus has been identified by Dr. Theiler as R. s. sanguineus (Sudan Government collections). The specimen from a dog at Bor is R. supertritus.

TANGANYIKA: Zumpt (1942B) in part. See Known Correct

References above.

Questionable References

FRENCH WEST AFRICA: Adults provisionally identified, from goats at Dakar (Theiler and Robinson 1953B). CAMEROONS: Rageau (1953A,B). UGANDA: Two doubtful og mentioned by Theiler and Robinson (1953B). Mettam (1932) recorded a puff adder as host. BELGIAN CONGO: Schwetz (1927); specimens need checking. NORTHERN RHODESIA: Adults from hares, civet, and genet (Matthysse 1954). SOUTHERN RHODESIA: Jack (1921,1928,1942); specimens need checking. MOZAMBIQUE: As R. sanguineus punctatissimus: (Santos Dias 1952H). SOUTHWEST AFRICA: Questionable mentioned by Theiler and Robinson (1953B). UNION OF SOUTH AFRICA: Cooley (1934); specimens need checking.

HOSTS

(From Known Correct References Only)

Hare (Lepus saxatilis) and two leopards (Theiler and Robinson 1953B). Leopard (Zumpt 1942B). An oribi and a leopard, also one crawling on leg of man (Sudan records above).

BIOLOGY

Life Cycle

The developmental periods under summer laboratory conditions have been reported by Theiler and Robinson (1953B) to be:

Adults did not attach. The laboratory hosts were guinea pigs (Theiler, correspondence).

Unstudied.

Ecology

DISEASE RELATIONS

Unstudied.

REMARKS

Zumpt (1942B) included R. sulcatus in the R. capensis group, which is represented in the Sudan also by R. longus (see page 665) and R. supertritus.

The original specimens of R. sulcatus are in collection num ber 1439 of the Veterinary School of Toulouse.

Santos Dias (1952H) considers R. sulcatus Neumann, 1908, to be a synonym of R. sanguineus punctatissimus Gerstacker, 1873, which Zumpt (1950A) considers to be a synonym of R. s. sanguineus. Inasmuch as the original description of R. sanguineus punctatis simus is not sufficiently detailed satisfactorily to settle this question, and the type specimens have not been examined by Santos

Dias, the more conservative approach of Zumpt for this difficult problem is utilized here.

Theiler and Robinson (1953B) stress the difference between this species and R. capensis Koch, 1844, and R. serranoi Santos Dias, 1950, two ticks not known to occur in the Sudan. In our territory, R. sulcatus is easily differentiated from all species but R. s. sanguineus in its coarser forms. In northern Sudan and usually in Central Sudan, R. s. sanguineus is usually not coarse enough to be confused with R. sulcatus, but in southern areas both species may superficially resemble each other. AL though Neumann's original description of R. sulcatus, together with its illustration, was excellent, the perplexing variation in R. s. sanguineus and the previously unrecognized fact that the latter species has a pattern of large punctations, no matter how densely punctate it may be, has long confused the real iden tity of R. sulcatus. We have spent dozens of hours trying to differentiate among hundreds of collections of R. s. sanguineus before the arrival of R. sulcatus specimens from Dr. Theiler's reared series. Afterwards, no question concerning their specific differences remained.

If one turns a questionable male obliquely to the light, punctations of coarse R. s. sanguineus will be observed to be relatively shallow, mostly nondiscrete and sloping. Most im portant, a few more or less clearly defined rows of widelyspaced, large, deeper, punctations will be noted among the shal lower interstitial punctations. In R. sulcatus no row formation of large punctations is present, large punctations are numerous and deep, and medium size punctations are also deep. Specimens, if well preserved, should be briskly rubbed with damp tissue paper until their surface shines in order best to distinguish these characters.

In females, the relative isolation of large punctations among small or medium size ones usually differentiates R. s. sanguineus from R. sulcatus in which large and medium size punctations are indiscriminately scattered. scattered. The actual relatively greater length of the sulcatus scutum, which gives a first impression of being even longer than it is, easily distinguishes most specimens. Some variable R. s. sanguineus females may so closely approximate this elongate scutal appearance that care must be used when applying this character.

Material referred to as R. sulcatus by Enigk and Grittner (1953), in their remarks on the breeding and biology of ticks, should be re-examined for identity.

IDENTIFICATION

The diagnosis presented below is modified from Theiler and Robinson (1953B).

Male: Size small, averaging 2.5 mm. long and about 1.5 mm. wide (Neumann's specimens from 2.9 mm. to 3.4 mm. long and from 1.5 mm. to 1.8 mm. wide). Scutum narrow anteriorly, widening posterior of level of eyes, surface slightly convex, shiny. Lateral grooves discrete and pronounced, may contain large punc tations; in some specimens extended to include penultimate fes toon. Posteromedian and paramedian grooves widely elongate, wrinkled. Punctations deep, medium to large size, dense, some confluent; fewer laterally but some on festoons, scapulae, and lateral folds. Eyes flat, may be bounded by a few large puncta tions. Coxa I may have a dorsal, unpointed hump. Basis capituli one and a half to two times as wide as long, with pronounced lateral angles at anterior third of length (Neumann's original, frequently reproduced illustration of this species shows the basis capituli extremely wide and pointed, most probably the artist's impression, drawn foreshortened, gained from a downward pointing capitulum). Adanal shields typically like those of large R. s. sanguineus but in some specimens they may be more elongately rounded and the inner margin emarginate (as is common in smaller R. s. sanguineus); an approach to the sickleshape is seen in a Small Sudan male.

Female: Medium size, unengorged about 3.00 mm. long and 1.75 mm. wide (Neumann: 3.0 mm. x 1.5 mm.). Scutum flat, shiny, rich brown, emargination wide; as broad as long or slightly longer than broad, but appearing long due to the pronounced lateral grooves and the somewhat tapering, sinuous posterior margin (Neumann: 1.5 mm. x 1.25 mm.). Cervical pits short, deep; cervical grooves short and inconspicuous. Lateral grooves pronounced, with external ridge, and picked out with irregular punctations which may be confluent. Eyes large, flat, flush with surface, may be bounded dorsally by a few large confluent