Compound odontomas are the commonest benign odontogenic tumours of jaws affecting mostly children and adolescents. These developmental malformations display many tooth-like structures or denticles that consist well-defined dental tissues with diverse morphologies. Majority these lesions occur as intraosseous masses in maxillary anterior region incidental radiographic findings. primarily associa...

The order Pristiformes (sawfishes) (Compagno, 1973), contains seven species in two genera (Compagno, 1999). These cartilaginous, benthic fishes present a worldwide distribution in tropical and subtropical coastal waters of Atlantic and Indo-Pacific areas, including estuaries and rivers mouths, and many studies have been conducted on their morphology and ecology (Garman, 1913; Bigelow & Schroede...

Potamotrygon limai, sp. nov., is described from the Jamari River, upper Madeira River system (Amazon basin), state of Rondônia, Brazil. This new species differs from congeners by presenting unique polygonal or concentric patterns formed by small whitish spots better defined over the posterior disc and tail-base regions. Potamotrygon limai, sp. nov., can be further distinguished from congeners i...

How long-extinct jawless fishes fed is poorly understood, yet interpretations of feeding are an important component of many hypotheses concerning the origin and early evolution of vertebrates. Heterostracans were the most diverse clade of armoured jawless vertebrates (stem gnathostomes), and the structure of the mouth and its use in feeding are the subjects of long-standing and heated controver...

The specification of the body plan in vertebrates and invertebrates is controlled by a variety of cell signaling pathways, but how signaling output is translated into morphogenesis is an ongoing question. Here, we describe genetic interactions between the Wingless (Wg) signaling pathway and a nonmuscle myosin heavy chain, encoded by the crinkled (ck) locus in Drosophila. In a screen for mutatio...

The Wingless (Wg)/Wnt signal transduction pathway directs a variety of cell fate decisions in developing animal embryos. Despite the identification of many Wg pathway components to date, it is still not clear how these elements work together to generate cellular identities. In the ventral epidermis of Drosophila embryos, Wg specifies cells to secrete a characteristic pattern of denticles and na...

The insect integument displays uniform posterior orientation of cuticular denticles or bristles formed by the epidermal cells. We want to understand how cell polarities become uniformly oriented in the plane of the epidermal sheet. Here we test whether directed cell migration disturbs the orientation of denticles. Burning a circular area of epidermal cells beneath the cuticle causes cells to mi...