Holothyrids and ticks: new insights from larval morphology and DNA sequencing, with the description of a new species of Diplothyrus (Parasitiformes: Neothyridae)

Post-embryonic development in the mite suborder Opilioacarida, with notes on segmental homology in Parasitiformes (Arachnida)

“…Most of these observations could be confirmed for specimens of Neocarus, Salfacarus Van der Hammen, Caribeacarus Vázquez & Klompen, and a new genus from Australia available to us, with one exception: we have not been able to consistently recognize two forms of tritonymph (male and female) in most of the species we studied (Vázquez and Klompen 2002, 2009, 2010, at least not using the characters identified by Van der Hammen (1969) or Coineau and Van der Hammen (1979). Specifically we have not noted a consistent difference in setation of the pregenital and genital region among putative male versus female tritonymphs in either of the four genera we studied for this phenomenon, suggesting that the phenomenon described for N. platensis and Phalangiacarus brossetti Coineau & Van der Hammen may be genus, or even species, specific.…”

“…We believe that there is sufficient evidence to support such a view, at least for the hysterosoma/opisthosoma (Lindquist 1984). Moreover, although developed for Mesostigmata, we have successfully applied this system to other parasitiform suborders, including larval Ixodidae (Klompen et al 1996), Opilioacarida (Klompen 2000), and Holothyrida (Klompen 2010). The distribution pattern of cuticular structures (setae, lyrifissures, glands) in larval Opilioacarida is particularly striking in this context, as it appears to fit the model better than any of the mesostigmatid species for which it was designed.…”

“…Unlike larval Allothyridae (Holothyrida) (Klompen 1992), but similar to larval Neothyridae (Holothyrida) (Klompen 2010), Ixodida and all instars of Mesostigmata, opilioacarid larvae, protonymphs and deutonymphs show whorls of at most six setae (the condition for tarsus I is not considered). This condition is maintained for the telotarsi and (most) basitarsi, but starting with the tritonymph, the tibiae, genua, and femora consistently show whorls of eight setae (Fig.…”

“…On occasion Opilioacarida have been assigned to a rank (Opilioacariformes) equivalent to that of Parasitiformes and Acariformes (e.g. Grandjean 1969;Johnston 1982;Walter and Proctor 1999), but recent molecular studies clearly support the hypothesis that the group is part of Parasitiformes (Klompen 2010;Klompen et al 2007;Murrell et al 2005;Pepato et al 2010).…”

Ancestral reconstruction of tick lineages

“…Relationships between these groups have indicated a relative consensus of morphological and molecular data, with Opilioacarida being the most basal lineage, Holothyrida sharing a sister group relationship with the Ixodida and the Mesostigmata as their sister group (Klompen, 2010;Klompen et al 2015Klompen et al , 2007Lehtinen, 1991). Even so, a study has indicated a closer relationship between Ixodida and Mesostigmata (Burger et al 2014a).…”