This genus is the third largest in the family Ixodidae, afterIxodes andHaemaphysalis, with its species primarily occupying thetorrid zones of all the continents. The centre of species diversity is on the American continent, where half of all the species occur. On this continent,Amblyomma species reach far beyond the torrid zone, up to the 40th parallel in theNorthern Hemisphere, to the 50th parallel in theSouthern Hemisphere, and even reaches thealpine zone of theAndes. They also occur in Eurasia, Africa and Australia.[1]
Amblyomma is the largest genus in the Amblyocephalus lineage, and the only member of the Amblyomminae subfamily. Modelling suggests the most recent common ancestor (MRCA) of the Amblyocephalus originated approximately 48 million years ago, and the genus began to diversify approximately 37ma.[2] TheAmblyommaMRCA likely evolved in a region betweenSouth America andAntarctica, lending credence to an out-of-Antarctica hypothesis for the genus' origin. A genetic divide in modern lineages betweenAustralianAmblyomma andAmblyomma from the rest of the world supports the idea that the genus diverged in two directions out of Antarctica, with one lineage dispersing intoAustralianGondwana, and another intoSouth AmericanGondwana, at the end of theEocene.[2]
The genus has historically been large, and highly varied, morphologically, making circumscription criteria in accordance with genetic phylogenies difficult to define. Following the 2020 and 2024 excision ofAfricaniella andCryptocroton species, respectively,Amblyomma is nowmonophyletic. Manyspecies complexes remain unresolved, however. Additionally, mostAmblyomma subgenera remainpolyphyletic (Cernyomma,Anastosiella,Haemalastor,Xiphiastor,Adenopleura,Aponomma, andDermiomma), with onlyAmblyomma (Amblyomma) andAmblyomma (Walkeriana) being monophyletic.[4][2]
Amblyomma are medium to large, often ornamented ticks. They are subcircular to elliptical, with subpentagonal basis capituli and elongate mouthparts. Most species have eyes, except for those of the subgenusAmblyomma (Aponomma). Lateral grooves and festoons are usually distinct.Amblyomma ticks parasitise a wide range of vertebrates, except foramphibians.[5][6]
^Nava, S., Guglielmone, A.A., Mangold, A.J. An overview of systematics and evolution of ticks. Front Biosci. 2009;14:2857–77.
^Barker, Stephen; Barker, Dayana (2023).Ticks of Australasia: 125 species of ticks in and around Australia. Auckland, New Zealand: Zootaxa, Magnolia Press. p. 12.ISBN978-1-77688-700-2.
^Apanaskevich, Dmitry A.; Apanaskevich, Maria A. (2018). "Description of a new species ofAmblyomma Koch, 1844 (Acari: Ixodidae), parasite of deer (Artiodactyla: Cervidae) and wild pigs (Artiodactyla: Suidae) in the Philippines".Systematic Parasitology.95 (5):415–425.doi:10.1007/s11230-018-9797-x.PMID29721661.S2CID13748257.
.jpg)
_-_Mites_-_Collection_Anthonie_Cornelis_Oudemans.jpeg)
.jpg)
