J. Bequaert.
The Giant Ticks of the Malayan Rhinoceroses; with a Note on Ixodes walckenaerii Gervais.
Psyche 40:137-143, 1933.

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19331 Giant Ticks of Malayan Rhinoceroses 137 THE GIANT TICKS OF THE MALAYAN
RHINOCEROSES; WITH A NOTE ON
IXODES WALCKENAERII Gervais
Department of Tropical Medicine and
Museum of Comparative Zoology, Harvard University In January, 1932, Major Arthur S. Vernay obtained, in Lower Perak, for the British Museum, one of the few re- maining specimens of the Sunda Rhinoceros, Rhinoceros sondaicus Desmarest. At the suggestion of my friend and colleague, Harold J. Coolidge, Jr., he undertook to col- lect the ecto- and endoparasites of this animal. The helminths have been reported upon by my colleague, Dr. Jack H. Sandground (1933, Jl. of Parasitology, XIX, pp. 192-204). Of ectoparasites, only numerous ticks were found; but shortly after the animal was shot, a number of horse-flies (Tabanzis brzmnezis Macquart) were observed biting through the thick hide.
More recently (June, 1933) Major Vernay commissioned Major Rawley to secure, if possible, another R. sondaicus. An animal believed to be of that species was located in Selangor ; but, after being shot, it proved to be a Sumatran Rhinoceros, Rhinoceros sumatrensis Cuvier. Again the only ectoparasites met with were ticks; these were very few in number, eight in all being collected.
Since the ticks obtained from these two Rhinoceroses belong to two different species, one of which is as yet im- perfectly known, some notes on these parasites may be of interest. I am much indebted to Major Vernay, Major Rawley, and Mr. Coolidge for the efforts they made in order to secure the specimens; and to Dr. P. H. Hodgkin, Ento- mologist, Institute for Medical Research, Kuala Lumpur, for preserving and mailing them.




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138 Psyche
[December
Amblyomma crenatum Neumann
Amblyomma, crenatum Neumann, 1899, M6m. Soc. Zool. France, XII, p. 214, fig. 52 ( Q ; off a Rhinoceros sup- posedly from the Cape of Good Hope) ; 1901, Loc. cit., XIV, p. 297 ( 9 8 ; Sumatra; no host) ; 1911, Das Tierreich, Lief 26, Acarina, Ixodidse, p. 77, fig. 34 ( s 8 ). Robinson, 1926, Ticks, IV, Amblyomma, pp. 12, 21 and 75, figs. 32-33 ( 9 8 ) . Amblyomma subluteum Neumann, 1899, M6m. Soc. Zool. France, XII, p. 263 (8 ; two without locality, one of them supposedly off an African Rhinoceros). ? Acarus elephantinus Linnaeus, 1758, Syst. Nat., 10th Ed., I, p. 615 ("Habitat in India", no host) ; 1767, Loc. cit., 12th Ed., I, pt. 2, p. 1022. Gervais, 1844, in Walck- enaer, Hist. Nat. Ins. Apteres, 11, p. 250. Neumann, 1911, Das Tierreich, Lief. 26, Acarina, Ixodidae, p. 126. A. C. Oudemans, 1926, Tijdschr. v. Entom., LXIX, Suppl., p. 95 ; 1929, LOG. cit., LXXII, Suppl., p. 207 (with references to the older literature). Not of Schrank, 1776.
? Ixodes elephantinus Fabricius, 1805, Syst. Antl., p. 351. ? Amblyomma elephantinam C. L. Koch, 1844, Arch. f. Naturgesch., X, pt. 1, p. 230; 1847, Uebersicht des Arachnidensystems, IV, p. 19. Neumann, 1899, M6m. Soc. Zool. France, XII, p. 282.
Specimens Examined.-Twenty-four males and twelve females (two fully engorged), off Rhinoceros sondaicus Desmarest, shot four miles north of Teluk Anson and south of the Sungei Lampan, Lower Perak, Federated Malay States (Major Arthur S. Vernay and Dr. P. H. Hodgkin) . The true country of origin and correct host of A. crena- turn are now definitely established with this material. The information available thus far was summarized by Robin- son as follows: "Amblyomma crenatzim is an African spe- cies and the only known host is the Rhinoceros. Neumann's earlier description of the female was based on a single spec- imen off Rhinoceros, Cape of Good Hope (Paris Mus.) ; his description of Amb. sublutezim was based on two males, one



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19331 Giant Ticks of Malayan Rhinoceroses 139 of unknown origin, the other off Rhinoceros, Africa. The Berlin Museum collection contains 2 males and 2 females labelled as having been collected by Mosch, in Sumatra. It would seem improbable that this tick is to be found in two parts of the world so remote as Africa and Sumatra without its occurrence being recorded in intermediate parts, and the indication of origin of the Berlin specimens is prob- ably erroneous." The present collection from Perak shows, on the contrary, that the locality "Sumatra" was correct, while there is no reliable evidence of this tick occurring in Africa. Neumann's specimens were most likely obtained from animals kept in captivity in Europe. Ticks have fre- quently been collected in large numbers in Africa from both the White and the Black Rhinoceros; but, so far as I know, A. crenatum was never found among them.l A. crenatum is one of the largest ticks in existence. In our series of 24 males, the scutum of the largest measures 9 mm. in length (not including the capitulum) and 7.8 mm. in greatest width, and that of the smallest 5 mm. and 4.8 mm. respectively. It is noteworthy that the smaller the specimen, the more the scutum approaches the perfect orbicular shape. The 10 unengorged females are 8 to 9 mm. long (without the capitulum) and 7 to 8 mm. wide, the scutum proper being about the same size in the largest and smallest specimens. Two engorged females are enormous, reaching 21 and 22 mm. in length (without the capitulum), 20 mm. in greatest width, and 16 and 17 mm. in thickness. Capitulum and legs also are unusually long. The coloration is remarkably uniform in the series seen and agrees well with Robinson's account. The most remarkable feature is the absence of metallic spots in the male, while the fe- male has three distinct coppery areas, one in each corner of the scutum, that of the apical corner the largest. The holotypes of A. crenatum ( and of A. subluteum ( d> ) are at the Paris Museum.
I strongly suspect that Linnaeus based the following '1 am unable to account for Neumann's including "Liberia" in the range of A. cren-atum (1911, Das Tierreich, Lief. 26, p. 78), since there is no Rhinoceros in that country and he does not mention it in his ear- lier papers.




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140 Psyche [December
description of his Acarus elephantinus upon A. crenatum: "A. orbicularis depressus: macula baseos ovata. Habitat in India. Magnitude seminis Lupini albi, depressus, lividus, margine crasso, subtus utrinque 3 sulcis. Macula baseos nigra, ovata, trifida." No host is mentioned and the name refers, not to the supposed host, as Houttuyn surmised, but to the unusual size ("elephantine"), this being one of the largest ticks known to Linnaeus. In answer to an in- quiry concerning this tick, Professor Ivar Arwidsson writes me that the type is not in Linnaeus' collection at the Zoological Museum of the University of Uppsala. Perhaps it is kept at the Linnaean Society of London, a point which I have not yet been able to investigate. Amblyomma infestum infestum C. L. Koch
Amblyonzrna infestum C. L. Koch, 1844, Arch. f. Natur- gesch., X, pt. 1, p. 226 ( Q 8 ; no host; Bintang Island near Singapore) ; 1847, Uebersicht des Arachnidensys- terns, IV, p. 68, PI. XII, figs. 41-42 ( 9 $ ). Amblyomma infestum inf estum Schulze, 1932, Zeitschr. f. Parasitenk., IV, pt. 3, p. 468 ( $ 6 ; after Koch's types). Amblyomrna testudimg-izim Robinson, 1926, Ticks, IV, Am- blyomma, pp. 17, 23 and 253 (in part; not the description and figures).
Specimens Examined.-One male and three females (two partly engorged), off Rhinoceros sumatremis Cuvier, shot on the Bernam River, Selangor, Federated Malay States (Major Rawley ) .
A. infestum is a much smaller tick than A. crenatum, with the capitulum and legs of normal length. P. Schulze has recently claimed (1932, Zeitschr. f. Par- asitenk., IV, pt. 3, p. 468) that the tick described and fig- ured by Robinson (1926) as A. testzidinarium, was not Koch's species of that name, but a new tick, which he calls A. fallax P. Schulze. Robinson's specimens came from Mouse-Deer (Tragulus sp.) at Biserat, Jalor, Federated Malay States. P. Schulze also attempts to separate infes- turn Koch and testudinarium Koch as distinct races of a



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19331 Giant Ticks of Malayan Rhinoceroses 141 species for which he uses the name A. infesturn (because it comes before testudinariurn on the same page of Koch's pa- per). Although I have seen no ticks agreeing with Robin- son's descriptions and figures, I am inclined to believe that Schulze was correct in introducing A. fallax as a new spe- cies. At any rate, the male off Sumatran Rhinoceros ven- trally lacks the small muscular scutes shown in Robinson's figure, while the peltae run parallel with the festoons (in Robinson's figure they are oblique, slightly salient at the postero-internal angles. In the three females, the inner margin of the scapulas is yellowish (not brown, as in Robin- son's figure) ; and the median anterior area of the scutum is almost wholly yellowish (not dark, as in Robinson's fig- ure), although I am not able to see that the yellow color forms two longitudinal stripes.
I am, however, by no means convinced that infesturn, proper, and testudinarium are racially distinct. Obviously, Schulze's material was insufficient to show that they are geographically segregated. Of infesturn, proper, he saw only Koch's types from Bintang Island near Singapore, one of the Rhio Archipelago, not 75 miles off the Northeast coast of Sumatra. Of testudinarium, he saw, in addition to Koch's type from "Java," 4 males and 4 females from Soekaranda, Sumatra.
The male of infesturn, proper, is said to be smaller (length, including palpi, 6 mm. ; width, 5 mm.), with much white enamel among the coarse punctures of the alloscu- turn. That of testudimriurn would be larger (8 by 6 mm.) , with reduced enamel among the coarse punctures. The sin-
gle male from Selangor measures 7 mm. (with the palps) by 4.8 mm., and the enamel is quite extensive. According
to Schulze, in the female of infesturn, proper, the scutum measures 3 by 5 mm. and has the scapular stripe well-de- fined, dark brown.
In that of testudinarium the scutum is
larger (4 by 5 mm.), with the scapular stripe obsolete, pale brown. In all three females from Selangor the scutum measures 3 by 4.5 mm.; but the scapular stripes (on the anterior margin, between the scapulae and the eyes) are dark brown and sharp in two specimens, very faint and pale in the third.
While the Selangor specimens are un-




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142 Psyche [December
doubtedly typical infestum, the value of testudinarium as a distinct race remains a question.
In the foregoing bibliography, I have not included Neu- mann's references to A. testudimrium (1899 ; 1901 ; Igll), nor those of Krijgsman and Ponto (1931 ; 1932), since these authors may have confused more than one species under that name. Neumann (1901) synonymized with his testu- dinarium, Ixodes auriscutellatus Koningsberger (1900, Teysmannia, XI, pt. 1, p. 6) and later (1911) also Ambly- omma compactum Neumann (1901, Mem. Soc. Zool. France, XIV, p. 296 ; 9 ; Sumatra ; no host). The standing of these two names remains open to discussion. Robinson's many locality and host records of testudinarium probably cover more than one species. In view of this fact the true distribution and range of hosts of A. infestum cannot be given.
Hyalomma ( ?) walckenaerii Gervais
Ixodes zualckenaerii Gervais, 1842, Ann. Soc. Ent. France, XI, Bull. Seances, p. xlvii (off Rhinoceros; without de- scription) ; 1844, in Walckenaer, Hist. Nat. Ins., Ap- teres, 111, p. 246, PI. XXXIV, fig. 11 (no sex; no local- ity, off a rhinoceros of unknown species). Neumann, 1911, Das Tierreich, Lief. 26, Acarina, Ixodidae, p. 133. Amblyomma (?) zualckenaerii Neumann, 1899, Mem. Soc. France, XII, p. 279.
Gervais' species is as yet unrecognized. Neumann merely suggested that it might have been an Amblyomma. The
original description reads: "Corps roux-grenat, un pen plus pale en dessous, passant au roux-cannelle ainsi que les pattes qui sont allongees et fauves k leurs articulations; abdomen rid6 en dessous ; point de taches sur le dos ; denti- cules des machoires mbdiocres; palpes un peu velus mon- trant un pore terminal k leur dernier article; ouverture genitale au niveau de la deuxieme paire de pattes; hanches de la premiere paire bispinulees ii leur bord posterieur; celles des autres simplement echancrbes ; stigmates dans une impression en fossette subreniforme ii l'aisselle de chaque patte posterieure. Longueur du corps, 0.005 [m] ;



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19331 Giant Ticks of Malayan Rhinoceroses 143 de la patte posterieure, 0.006 % [m]. Cette espece, dont les hanches anterieures ressemblent a celles de 191xode de Savigny, a ete prise sur un Rhinoceros dont nous ignorons Ie nom specifique; nous l'avons dbdiee a M. de Walckenaer, 9 .
de qui nous tenons 1 UUQLE ex-me-
observe." The rather crude figure represents the ventral side of what appears to be an unengorged female. Surmising that Gervais9 type might be preserved at the Paris Museum, I wrote to Mr. Marc Andre, who kindly in- formed me that none of Gervais' ticks are in their col- lections. Neumann evidently never saw them and I have been unable to trace whether or not they are lost. I believe, however, that a study of the description and figure might help to recognize the species. Turning first to the Amblyomma known to occur on Rhinoceroses, A. crenatum is ruled out at once by the size, the hind legs of that species measuring 11 to 12 mm. in length. On the other hand, none of the smaller Rhinoceros ticks could be described as having the body "roux-grenat9', all being dis- tinctly spotted dorsally. The statement about the color, and even more so the comparison of the cox2 I with those of Ixodes savignyi Gervais, induce me to regard Ixodes walckenaerii as based in all probability upon a female Hyal~rnma.~ Ticks of that genus have been found repeat- edly on the African Black Rhinoceros; and P. Schulze bases his Hyalomma planum (1919, Sitzungsber. Ges. Naturf. Fr. Berlin, pp. 195 and 196; 8 ; Tanganyika Territory) on ticks taken from this host. Might not H. planum and H. zualckenaerii be one and the same species? ^Ix& savignyi was based upon the common cattle Hyalomma of Egypt.
According to P. Schulze (1930, Zeitschr. f. Parasitenk., Ill, pt. 1, p. 28).
Hyalomma savigwyi (Gervais) is the correct name of the cattle tick which thus far has been called HyaZomma a.egyptium (Lin- naeus.




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