. Bonner zoologische Monographien. Zoology. 11 TERMINOLOGY The differentiation of a cartilaginous plate into separate, articulating elements (Arratia 1990a, Arratia & Schultze 1990) is characterized by structural changes that produce changes in the density of the cartilage in the area where an articulation will form. The articular region itself is characterized by a change in the position of the cartilage cells, so that it appears more or less dense and fibers develop. The appearance of the future articular region under a compound microscope or stereomicroscope shows differences among spec
. Bonner zoologische Monographien. Zoology. 11 TERMINOLOGY The differentiation of a cartilaginous plate into separate, articulating elements (Arratia 1990a, Arratia & Schultze 1990) is characterized by structural changes that produce changes in the density of the cartilage in the area where an articulation will form. The articular region itself is characterized by a change in the position of the cartilage cells, so that it appears more or less dense and fibers develop. The appearance of the future articular region under a compound microscope or stereomicroscope shows differences among species. For instance, a clear, less dense region appears where an articulation will form in trichomycterids (Fig. 1), or a more dense region than the surrounding areas will t. : Pterygoquadrate portion of the hyo-symplectic-pterygoquadrate plate of Trichomycterus areolatus (22 mm specimen; PC 221081) illustrating the changes of the density of the cartilage where an articulation will form (in- dicated by an arrow) (after Arratia 1990a). mtg: metapterygoid; q: quadrate. form in ictalurids. Changes in density are due to different positions and distributions of the cartilaginous cells and fibers. Secondary cartilage and chondroid bone is usually found in the articular facets of synchondral articulations of large specimens, as already established by Beresford (1981) and Smith & Hall (1991). The types of articulation between bones of the Suspensorium differ among teleost groups. Sutures are described as serrate, dentate, harmonic, following the ter- minology of human anatomy (Gray 1982), in the absence of a specific terminology for fishes. In the early ontogeny of teleosts, the surfaces producing a sutural joint are smooth (harmonic suture) and from this stage the suture may be modified into a den- tate or serrate one, or stay as a harmonic suture (see below). Combinations of articula- tions are explained in the Please note that these images are extracted from sca
Size: 2273px × 1099px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectzoology
