Robertsicus, Barker & Burger, 2018

Barker, Stephen C. & Burger, Thomas D., 2018, Two new genera of hard ticks, Robertsicus n. gen. and Archaeocroton n. gen., and the solution to the mystery of Hoogstraal’s and Kaufman’s “ primitive ” tick from the Carpathian Mountains, Zootaxa 4500 (4), pp. 543-552 : 544-547

Robertsicus n. gen.

Type species: Robertsicus elaphensis n. comb. ( Price, 1959)

Type depositories: The record of Guglielmone et al. 2014 (p. 415) about the types is apparently correct: USNTC (holotype, paratype), BMNH, OVI, UM (paratypes) ( Keirans & Hillyard 2001, under A. albopictum ) as Aponomma elaphensis . BMNH, The Natural History Museum, London, England; OVI, Onderstepoort Veterinary Research Institute, Onderstepoort, South Africa; UM, University of Maryland, College Park, USA.

Diagnosis. With characteristics of its sole constituent species Robertsicus elaphensis n. comb. ( Price, 1959). Keirans and Degenhardt (1985) has detailed diagnoses of the larvae, nymphs, males and females; these will not be repeated here. Keirans and Degenhardt (1985) also has fine scanning electron photon micrographs of the larvae, nymphs, males and females. R. elaphensis n. comb. is the only reptile-tick that is known to be native to the USA; this information together with the detailed diagnoses of Keirans and Degenhardt (1985) make R. elaphensis n. comb. readily distinguishable from all other ticks.

Etymology. The name of this new genus honours Dr F. H. S. Roberts the “father” of Australian tick taxomomy. The English family name “Roberts” means son of “Robert”; both “Roberts” and “Robert” are masculine names. Thus, the name Robertsicus is masculine; this should be taken into consideration should any other species be added to the genus Robertsicus n. gen.

New combination. Robertsicus elaphensis ( Price, 1959) for Amblyomma elaphense ( Price, 1959) .

Remarks. The name elaphense is neuter and thus, is here changed to the masculine form, elaphensis , so that the gender of the genus and the species names are compatible. We propose the vernacular name, "tail-eating tick" for the sole member of this genus, R. elaphensis n. comb., since this species “may very well be a common cause for tail loss” in Bogertophis subocularis ( Degenhardt & Degenhardt 1965 p. 169; Fig. 3 of the present paper).

Robertsicus elaphensis n. comb. is of considerable interest since it is the only species of reptile-tick that is native to the USA. We propose that R. elaphensis n. comb. is a relic of a once more speciose lineage; perhaps other relic-species in this lineage, and indeed also in the lineage of Ar. sphenodonti n. comb., await discovery. The only known host of R. elaphensis n. comb., the Trans-Pecos rat-snake, B. subocularis (Brown, 1901) , is a medium to large, nonvenomous snake of the family Colubridae . B. subocularis is endemic to the Chihuahuan Desert of Mexico and southeastern US (parts of Arizona, West Texas and New Mexico).

One thesis ( Kaufman, 1972) and five main papers provide information and insight into R. elaphensis n. comb.: Price (1959); Degenhardt & Degenhardt, (1965); Keirans & Degenhardt, (1985); and Burger et al. (2012, 2013).

We note that Keirans and Degenhardt (1985) amended the date of the authority of this species from Price 1958 to Price 1959, without comment: obviously Keirans and Degenhardt (1985) concurred with Kaufman (1972, p. 226) who wrote that “The date for the species should be 1959, since the December 1958 issue of the Journal of Parasitology containing the original description actually appeared in January 1959 ”. Authors after Keirans and Degenhardt (1985), including us, have accepted 1959 as the amended date for this species of tick. Our opinion is that the date should have stayed as 1958, but there is no need to amend this date, again, now. We simply record this for the benefit of readers and authors of the future who may also wonder, like us, if the date in the authority of the species should have been 1958 not 1959.

Figures

FIGURE 3. Robertsicus elaphensis n. comb. (8 engorged ticks) on the tail-tip of a Trans-Pecos rat-snake, Bogertophis subocularis. Image by Jake Scott.