Mormotomyia hirsuta Austen, 1936 is one of the most extraordinary and unusual looking Diptera and was placed by E.E. Austen into a family of its own, the Mormotomyiidae, upon its discovery in 1933. Adults superficially resemble small solifugids (sun spiders), having extremely long legs that are clothed, especially in males, in very long, closely-packed brown hair-like setae. The wings are reduced to dysfunctional straps, the halteres to small nodular processes, and the eyes are greatly reduced. M. hirsuta is cavernicolous in all life stages and guanobious at least in the larval stages. The phylogenetic position of the family has long been a subject of much speculation and disagreement. Until recently M. hirsuta had only been collected on two occasions: in May 1933 and December 1948, although there have been numerous unsuccessful rediscovery attempts. The species is apparently confined to the type locality and is, therefore, widely regarded as the "rarest fly in the world". Here we report the rediscovery of adults, larvae and puparia at the type locality, a cave-like rock fissure at Ukasi Hill, Eastern Province, Kenya, in December 2010. This rediscovery has facilitated a more thorough examination and study of the immature stages using scanning electron microscopy (SEM). This has revealed numerous microstructures not previously described by van Emden in 1950, and the larva and puparium are therefore re-described. An SEM study was conducted of the leg features of adults, specifically the form and structure of the tarsal claw and pulvillus, and these were compared to the same structures in examples of the true bat fly ectoparasitic families Nycteribiidae and Streblidae, and to the phoretic Mystacinobiidae. The basal sclerites of the wing are interpreted for the first time using SEM, the functional morphology of the larva, puparium and adult is discussed and notes are provided on the biology, development and cavernicolous habits of the species. The cuticular parts of the internal female reproductive tract are further described. They comprise a tubular vagina, two sclerotized spermathecae, paired accessory glands, and a small one-chambered sclerotized ventral receptacle. These are compared to species in the Mystacinobiidae, Sphaeroceroidea and Ephydroidea, and it is concluded that the structure of the female reproductive tract lends support to the inclusion of the Mormotomyiidae in the Ephydroidea.

Recent mousebirds are the smallest of the living neognathous bird orders – just two genera comprising six species. Understanding the evolutionary dynamics of this avian lineage is important because these birds occupy a critical position within Neoaves and can be used as a model for patterns of morphological diversification in other taxa. We present a review of all known fossil mousebirds (Aves: Coliiformes), which formed a diverse assemblage in the Paleogene (65–23.8 ma). We also present a new phylogenetic analysis including the living and fossil representatives of the order, on the basis of a larger character/taxon matrix. This analysis suggests that the Lower Eocene Eocolius is the most basal member of clade Coliiformes, while the Lower–Middle Eocene Sandcoleidae form a basal clade with respect to all other known coliiforms. We show that the Eocene taxon Chascacocolius is the sister group of the crown Coliidae, and that the Middle Eocene taxon Selmes is basal to a clade comprising Chascacocolius and Coliidae. On the basis of this phylogenetic analysis, we propose a new classification for the order Coliiformes including two new families, Chascacocoliidae and Selmeidae. For all families (clades) of mousebirds we provide descriptive osteological diagnoses and discuss a number of functional considerations related to the evolution of their hindlimbs; these considerations can be extended across all extant and fossil perching birds because we show that the hindlimb morphology of Coliiformes is strongly related to their lifestyle, as reflected in their evolutionary history.
Palaeontology. 2008. V. 51(6): 1403-1418.