Dermacentor rhinocerinus

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Dermacentor rhinocerinus
Dermacentor rhinocerinus (Denny, 1843), male, from the first description

Dermacentor rhinocerinus ( Denny , 1843), male, from the first description

Systematics
Subclass : Mites (acari)
Superordinate : Parasitiformes
Order : Ticks (ixodida)
Family : Shield ticks (ixodidae)
Genre : Colored ticks ( Dermacentor )
Type : Dermacentor rhinocerinus
Scientific name
Dermacentor rhinocerinus
( Denny , 1843)
Dermacentor rhinocerinus on a blade of grass

Dermacentor rhinocerinus is a blood-sucking ectoparasite of the two African rhinos, white rhinoceros ( Ceratotherium simum ) and black rhinoceros ( Diceros bicornis ). It is a very large tick and one of about 35 species of the genus Buntzecken ( Dermacentor ) in the family Schildzecken (Ixodidae).

features

The following information is based on a new description by the parasitologist James E. Keirans from 1993, in which the larvae of Dermacentor rhinocerinus were also described for the first time .

Adult male ticks

The scutum of the exceptionally large male ticks is broadly oval, the capitulum has a rectangular base with a concave rear edge. The scutum has a chocolate-brown basic color and an ivory-colored pattern, which consists of spots symmetrically along the body axis and mostly in pairs. At the rear edge of the body there are eleven partially drawn festoons . The scutum has only a few large pores. The two eyes are flat and sit on the edges of the scutum. The coxes of the first pair of legs each have two short, strong and triangular spines.

Adult female ticks

The scutum of the very large female ticks is oval, the capitulum has a rectangular base with a straight rear edge. The alloscutum has a dark brown to black base color and isolated areas with dense reddish brown setae . At the back of the body there are eleven festoons in the color of the alloscutum. The scutum is large, almost heart-shaped and drawn ivory over almost the entire surface, only around the pores and the two flat eyes at the edges of the scutum are small dark brown areas.

Nymphs

The nymphs are large, about 1.15 millimeters long and 0.75 millimeters wide, the rear area of ​​the alloscutum is densely covered with setae. The base of the capitulum is dorsally straight in the middle and slightly concave at the edges. Ventrally, at the base, there are two strong, rearward-facing spinous processes. The coxes of the first pair of legs carry two triangular spikes of different lengths.

Larvae

The body is oval, with a length of 0.612 to 0.644 millimeters. The width at the widest point behind the coxes of the rear pair of legs is 0.427 to 0.554 millimeters. The length of the scutum, which extends over the entire width of the body, is 0.241 to 0.265 millimeters. The relatively large, flat eyes are located at the rear corners of the scutum. The capitulum is about as wide as it is long, with a length of up to 0.179 millimeters and a width of up to 0.191 millimeters. The coxes of the first pair of legs only carry an inner, moderately long and triangular spine. The coxes of the second and third pair of legs lack inner spines, but all have a short outer spine.

Way of life and distribution

The main hosts of adult Dermacentor rhinocerinus are the white rhinoceros and the black rhinoceros . Occasional hosts include domestic cattle , domestic sheep , house donkeys , black-backed and striped jackals , African elephants , Cape buffalo and eland . The ticks primarily attack the genital area of ​​their hosts. There are only isolated finds of a monitor lizard , a roan antelope and a black heel antelope . All of these occasional hosts are unlikely to play a role in the natural life cycle of Dermacentor rhinocerinus . Nymphs and larvae were found in a reserve, live in the white rhino on multiple species of rodents: the white-bellied nude sole gerbil ( Gerbilliscus leucogaster , larvae and nymphs) of the bush rat Aethomys chrysophilus with a larvae Fund, and the Natal frequent teat mouse ( Mastomys natalensis ) with a nymph. It is believed that in southern Africa elephant shrews ( Elephantulus ), particularly the Eastern cliff elephant shrew ( Elephantulus myurus ), are important hosts of the subadult stages of Dermacentor rhinocerinus .

The South African acarologist Jane B. Walker reported in 1974 in a monograph on the tick fauna of Kenya that in two cases Dermacentor rhinocerinus had been found on humans. She did not provide any further details. The distribution area of Dermacentor rhinocerinus largely coincides with that of the two African rhinoceros species and includes large parts of southern and eastern Africa.

Carrier of piroplasms

Two piroplasms transmitted as a vector by ticks , Babesia bicornis and Theileria bicornis , can cause parasitosis in black rhinos with fatal outcome. The tick host has not yet been identified, but Dermacentor rhinocerinus and Amblyomma rhinocerotis have been suggested in the literature. It is considered likely that the two piroplasms would also die out with these ticks. A recent study from South Africa showed that more than 36 percent of the white rhinos examined were infected with Theileria bicornis and more than nine percent with Theileria equi . In white rhinos, however, the infections were asymptomatic. Babesiosis is of particular importance for rhinos that have been released into the wild, who were not confronted with the pathogens in their youth and can experience infections with severe disease processes in the wild.

Danger

The US Parasitologen Lance A. Durden and James E. Keiran lead Dermacentor rhinocerinus next Amblyomma Personatum , Amblyomma rhinocerotis and Cosmiomma hippopotamensis as one of those types of ticks, which exclusively or almost exclusively white rhino parasitize and black rhino. The tick populations decreased with those of their hosts. The existence of host-specific parasites is also endangered by the fact that trapped rhinos are routinely cleared of their parasites and treated with antiparasitics before they are released. Amblyomma rhinocerotis is less endangered than species-specific parasites of the black rhinoceros, such as Amblyomma personatum . The investigation of the tick fauna of both rhinoceros in southern Africa produced evidence of Amblyomma rhinocerotis , with prevalence between 3.8 and 66.7 percent. In contrast, the prevalence of Amblyomma hebraicum infestation in both rhino species was up to 100 percent.

Systematics

External system

Dermacentor rhinocerinus ( Denny , 1843), with more than 700 species in 14 genera, belongs to the family of ticks (Ixodidae) that is widespread worldwide . The genus Buntzecken comprises around 35 species that parasitize on mammals, reptiles and amphibians.

The German zoologist Paul Schulze established the genus Amblyocentor for the species in 1932 , which was occasionally accepted as a subgenus of the colored ticks by subsequent authors. Today, Amblyocentor is considered a synonym of Dermacentor .

Internal system

In 1910, the French acarologist Louis Georges Neumann described the subspecies Dermacentor rhinocerotis permaculatus after two male ticks with a different color and pattern that were collected on Kilimanjaro in 1905 . In fact, Neumann did not mean Dermacentor rhinocerotis as a synonym of Amblyomma rhinocerotis ( De Geer , 1778), but the species Dermacentor rhinocerinus ( Denny , 1843). Don R. Arthur corrected this mistake in 1960 and confirmed the existence of distinguishable shapes that differed not only in drawing but also in size. The subspecies was synonymous with the nominate form by Agustin Estrada-Peña in 1992 , as there are numerous transitional forms between the two alleged subspecies and a demarcation according to morphological criteria is not possible.

The acarologist E. Aneurin Lewis described another subspecies, Dermacentor rhinocerinus arangis , after a single specimen in 1934 . Lewis himself refuted the validity of the subspecies in a footnote to this publication, stating that the examined specimen was only an atypical specimen of Dermacentor rhinocerotis (sic!).

First description and history of taxonomy

The first description of Dermacentor rhinocerinus was in 1843 by Henry Denny in the journal Annals and Magazine of Natural History after a single male specimen. The tick was made available to Denny by the 13th Earl of Derby and collected by Joseph Burke in South Africa around 1840 . Denny described the species as Ixodes rhinocerinus and named the black rhinoceros as the type host. It is possible, however, that Denny's specimen actually came from a white rhinoceros, since the distinction between two species of African rhinos had not yet become established in linguistic usage. The nymphs were first described in 1964 by Carleton M. Clifford and George Anastos . In 1993, James E. Keirans described the species again and for the first time including the larval stage.

Synonymy

For Dermacentor rhinocerinus , several synonyms have been published over the years, and confusion with the species Amblyomma rhinocerotis ( De Geer , 1778) occurred again and again :

  • Ixodes rhinocerinus Denny , 1843
  • Ixodes rhinocerotis Gervais , 1844
  • Amblyomma rhinocerinus Koch , 1844
  • Amblyomma rhinocerotis Koch , 1844
  • Dermacentor rhinocerotis permaculatus Neumann , 1910
  • Dermacentor rhinocerinus permaculatus Neumann , 1910
  • Amblyocentor rhinocerinus Schulze , 1932
  • Dermacentor rhinocerinus arangis Lewis , 1934
  • Dermacentor (Amblyocentor) rhinocerinus Lewis , 1934

Web links

Commons : Dermacentor rhinocerinus  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e f g h i j k James E. Keirans : Dermacentor rhinocerinus (Denny 1843) (Acari: lxodida: Ixodidae): redescription of the male, female and nymph and first description of the larva . In: Onderstepoort Journal of Veterinary Research . tape 60 , 1993, pp. 59-68 ( up.ac.za [PDF; 599 kB ]).
  2. ↑ a b c Andrei Daniel Mihalca, Călin Mircea Gherman, Vasile Cozma: Coendangered hard-ticks: threatened or threatening? In: Parasites & Vectors . tape 4 , 2011, 71, doi : 10.1186 / 1756-3305-4-71 .
  3. ↑ Barend L. Penzhorn, Rosina Claudia Krecek, Ivan G. Horak, Anna JM Verster, Jane B. Walker, Joop DF Boomker, SE Knapp, Sybille KF Quandt: Parasites of African rhinos: a documentation . In: Barend L. Penzhorn, NPJ Kriek (Ed.): Proceedings of a symposium on rhinos as game ranch animals, Onderstepoort, Republic of South Africa, September 9-10, 1994 . SAVA Wildlife Group, Onderstepoort 1994, ISBN 1-875088-11-3 , p. 168–175 ( rhinoresourcecenter.com [PDF; 411 kB ]).
  4. ↑ a b c Don R. Arthur : Ticks. A Monograph of the Ixodoidea . Part V. On the genera Dermacentor, Anocentor, Cosmiomma, Boophilus & Margaropus. Cambridge University Press, London 1960, pp. 171-178 ( digitized versionhttp: //vorlage_digitalisat.test/1%3D~GB%3D~IA%3Dticksmonographof00arthuoft~MDZ%3D%0A~SZ%3Dn197~ double-sided%3Dja~LT%3D~PUR%3D ).
  5. ↑ Jane B. Walker : A review of the ixodid ticks (Acari, Ixodidae) occurring in Southern Africa . In: Onderstepoort Journal of Veterinary Research . tape 58 , 1991, pp. 81-105 ( up.ac.za [PDF; 2.9 MB ]).
  6. ↑ Ivan G. Horak , Marlene Cohen: Hosts of the immature stages of the rhinoceros tick, Dermacentor rhinocerinus (Acari, Ixodidae) . In: Onderstepoort Journal of Veterinary Research . tape 68 , 2001, p. 75-77 ( up.ac.za [PDF; 267 kB ]).
  7. ↑ Alberto A. Guglielmone , Richard G. Robbins: Hard Ticks (Acari: Ixodida: Ixodidae) Parasitizing Humans. A Global Overview . Springer International Publishing, Cham 2018, ISBN 978-3-319-95551-3 , pp. 112 .
  8. Jump up ↑ Ard M. Nijhof, Banie L. Penzhorn, Godelieve Lynen, Johnson O. Mollel, Pete Morkel, Cornelis PJ Bekker, Frans Jongejan: Babesia bicornis sp. nov. and Theileria bicornis sp. nov .: Tick-Borne Parasites Associated with Mortality in the Black Rhinoceros (Diceros bicornis) . In: Journal of Clinical Microbiology . tape 41 , no. 5 , 2003, p. 2249-2254 , doi : 10.1128 / JCM.41.5.2249-2254.2003 .
  9. ^ Banie L. Penzhorn: Babesiosis of wild carnivores and ungulates . In: Veterinary Parasitology . tape 138 , no. 1-2 , 2006, pp. 11–21 , doi : 10.1016 / j.vetpar.2006.01.036 .
  10. ↑ Lance A. Durden , James E. Keirans : Host – Parasite Coextinction and the Plight of Tick Conservation . In: American Entomologist . tape 42 , no. 2 , 1996, p. 87-91 , doi : 10.1093 / ae / 42.2.87 .
  11. ↑ Ivan G. Horak et al .: Parasites of domestic and wild animals in South Africa. XLIX. Ticks (Acari: Ixodidae) infesting white and black rhinoceroses in southern Africa . In: Onderstepoort Journal of Veterinary Research . tape 84 , no. 1 , 2017, 1301, doi : 10.4102 / ojvr.v84i1.1301 .
  12. ^ A b Paul Schulze : New and little known species of the tick genera Amblyomma and Aponomma . In: Journal of Parasitic Studies . tape 4 , 1932, pp. 459-476 , doi : 10.1007 / BF02119995 .
  13. ^ A b Louis Georges Neumann : 2. Ixodidae . In: Yngve Sjöstedt (Hrsg.): Scientific results of the Swedish zoological expedition to Kilimandjaro, Meru and the surrounding Massai steppes of German East Africa 1905-1906, under the direction of Prof. Dr. Yngve Sjöstedt . 3rd volume. P. Palmquists AB, Stockholm 1910, 20. Arachnoidea, p. 17–30 , 23 ( digitizedhttp: //vorlage_digitalisat.test/1%3D~GB%3D~IA%3Dwissenschaftlich03sj~MDZ%3D%0A~SZ%3Dn461~doppelseiten%3D~LT%3D~PUR%3D version - this publication was used as a source by Estrada-Peña 1992 and Keirans 1993, but each cited with different and completely incorrect bibliographical information).
  14. ↑ a b Agustin Estrada-Peña : Notes on Dermacentor ticks (V): taxonomic identity of D. (Amblyocentor) rhinocerinus permaculatus Neumann (Acari: Ixodidae) . tape 33 , no. 3 , 1992, p. 261-263 ( inra.fr ).
  15. ^ A b Henry Denny : Description of Six supposed new species of Parasites . In: Annals and Magazine of Natural History . tape XII , no. LXXVIII , 1843, pp. 312-316, Plate XVII ( digitizedhttp: //vorlage_digitalisat.test/1%3D~GB%3D~IA%3Dannalsmagazineof11lond~MDZ%3D%0A~SZ%3Dn338~ double-sided%3D~LT%3D~PUR%3D ).
  16. ^ A b Carl Ludwig Koch : Systematic overview of the order of ticks . In: Archives for Natural History . tape 10 , 1844, pp. 217-239 ( digitized versionhttp: //vorlage_digitalisat.test/1%3D~GB%3D~IA%3Darchivfrnaturg101berl~MDZ%3D%0A~SZ%3D231~ double-sided%3D~LT%3D~PUR%3D ).