The family Opilioacaridae (Parasitiformes: Opilioacarida) in Mexico, description of two new species, new records, and geographical distribution.

Two new species of Neocarus (Opilioacarida: Opilioacaridae), N. haicolous n. sp. and N. queretanus n. sp., are described from mesophyll and pine-oak forests in the state of Querétaro, central Mexico. One species was described from adults and tritonymphs. Distribution and habitat preferences of all known collections of Opilioacarida are reviewed. In Mexico, they have been collected in all habitats, from semideserts areas to tropical forest and from to sea level in dunes to high temperate and cloud forest.

The family Opilioacaridae (Parasitiformes: Opilioacarida) in Mexico, description of two new species and notes on biology and geographical distribution.

Two new species of Opilioacaridae from Mexico are described, Neocarus chactemalensis sp. nov. and N. comalensis sp. nov., and new records for N. texanus Chamberlin & Mulaik and N. veracruzensis Vazquez & Klompen are presented. Relative positions of internal structures of the ovipositor, a highly variable character, are described based on comparisons of invaginated and evaginated ovipositors. A study of records of Opilioacaridae in Mexico shows that the group is distributed across a wide range of ecosystems and elevations, from dry, semi-desert to wet tropical forest, and coastal plains to the altiplano (>2,000 m).

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

In order to study homology among the major lineages of the mite (super)order Parasitiformes, developmental patterns in Opilioacarida are documented, emphasizing morphology of the earliest, post-embryonic instars. Developmental patterns are summarized for all external body structures, based on examination of material in four different genera. Development includes an egg, a 6-legged prelarva and larva, three 8-legged nymphal instars, and the adults, for the most complete ontogenetic sequence in Parasitiformes. The prelarva and larva appear to be non-feeding. Examination of cuticular structures over ontogeny allows development of an updated model for body segmentation and sensillar distribution patterns in Opilioacarida. This model includes a body made up of a well-developed ocular segment plus at most 17 additional segments. In the larvae and protonymphs each segment may carry up to six pairs of sensilla (setae or lyrifissures) arranged is distinct series (J, Z, S, Sv, Zv, Jv). The post-protonymphal instars add two more series (R and Rv) but no extra segments. This basic model is compatible with sensillar patterns in other Parasitiformes, leading to the hypothesis that all taxa in that (super)order may have the same segmental ground plan. The substantial segmental distortion implied in the model can be explained using a single process involving differential growth in the coxal regions of all appendage-bearing segments.

Brasilacarus cocaris (Acari: Opilioacaridae), a new genus and species from Amazonia, Brazil.

A new genus and species of Opilioacaridae, Brasilacarus cocaris n. gen., n. sp., is described from adult females and males from Manaus, Brazil. Brief descriptions of damaged tritonymphs and deutonymphs are also provided. The new genus appears to be related to Caribeacarus but possess a unique group of additional strongly modified setae on the tibiotarsus. 

A new genus and two new species of Opilioacaridae (Acari: Parasitiformes) from Amazonia, Brazil with a key to world genera.

Collections of Opilioacaridae made close to 50 years ago in Manaus in the Amazonian Region have allowed the description of a new genus and two new species from Brazil, Amazonacarus setosus n.gen, n.sp. and A. paraensis n.gen, n.sp. These species show a unique combination of characters in the Opilioacaridae: a high number of foliate setae (10) on the palp tarsus with each seta bearing many lobes (6-7), a group of large, serrate setae (26-31) on the palp tibia (this group of setae is much smaller in other species), and 5-7 dorsal setae on idiosomal segment XVIII. Indiacarus and some Opilioacarus show 3-5 setae on segment XVIII, but these genera (and Caribeacarus) have fewer foliate setae on the palp (3-4). Females of Amazonacarus have an ovipositor of the "complex" type, with spiny projections and 2-4 genital setae, while males have two pairs of rounded, large glands.