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This paper is the first of a series in which more information will be added to the existing on biogeographical distribution of oribatid mites. Here we describe a new species of a phthiracarid mite collected from forest floor litter in southwestern Nigeria. Differences between this species, Atropacarus (Hoplophorella) nigeriensis, and other Hoplophorella species are the foveoli on the aspis and notogaster, the shape of notogastric setae, as well as shapes and chaetotaxy of the genital and anal plates. More differences in taxonomically important features such as the morphological features of the infracapitulum and epimeron as well as leg chaetotaxy between this species and others could not be determined, not only because of lack of information on the latter in literature, but also because many type specimens are not available for dissection which must be done in order to reveal fine morphological details. Atropacarus (Hoplophorella) nigeriensis belongs to the "cucullata" group of Hoplophorella which possess one enlarged adanal seta. It differs from other members of this group in respect of adanoanal and tarsal chaetotaxy. Hoplophorella is considered as a subgenus of Atropacarus in this paper, because there is no evidence in literature that Hoplophorella as a group is a separate phylogenetic entity.
In this paper, we describe a new species of Mesoplophora collected from forest floor litter in southwestern Nigeria. Mesoplophora is a cosmopolitan genus of pytchoid mites that has been recorded from the Palaearctic region as well as Morocco
and Tchad in the Ethiopian region. M. ife an a is the first Mesoplophora species to be fully identified and described from Nigeria. Differences between this species, M. ifeana, and other Mesoplophora species recorded from Africa are observed in
respect of the number of spines on the sensillus, presence of two pairs of exobothridial setae and leg chaetotaxy. The lack of information on fine taxonomic details of adults and deutonymphs of M. africana from Tchad as well as the discrepancies in the description of certain morphological features such as organisation and chaetotaxy of the ventral plates as well as the nomenclature of setae on the aspis were noted. Attention was drawn to the unique combination of traits of both lower
and higher Oribatida in Mesoplophora, a trait which may be responsible for its ubiquitous distribution.
Whip spiders belong to a small arachnid order (Amblypygi) that is not well known. Their most conspicuous feature are
the elongated, extremely thin front legs (“whips“, or antenniform legs). These are no longer used for walking but are modified extremities carrying various sense organs - very much like the antennae of insects. Whereas hundreds of olfactory
hairs are concentrated near the tip of each antenniform leg, large bristles (contact chemoreceptors) are evenly distributed over the entire antenniform leg. The sensory hairs of each antenniform leg contribute about 30,000 small sensory
axons which proceed toward the central nervous system (CNS). The sensory fibers originating from the mechanoreceptive bristles make chemical synapses with a few giant interneurons in the periphery. The giant axons (10-20 pm in diameter) of these large interneurons transmit nerve impulses with a high velocity (6 m/s) to the CNS. The purpose of this fast pathway still needs to be determined. Originally it was thought that the fast giant axons would trigger quick escape reactions, but this was not confirmed in physiological experiments. However, other possible behaviors that may be aided by the giant interneurons are prey capture, fighting, and orientation. What makes whip spiders unique is that both synapses and giant neurons are located far out in the peripheral nervous system. In all other arthropods - except for some arachnids - synapses and giant fiber systems are always found inside the CNS, never in the periphery.
An insect inclusion in Upper Cretaceous Burmese amber contained a well preserved flat bug, Archearadus burmensis gen.
n., sp. n., which is described and figured. It is distinguished from all known genera of Aradidae by various characters that
are discussed. A catalogue is given for Aradidae from Amber deposts described to date.