identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
03812165E429D017FC9324C9048AFEC8.text	03812165E429D017FC9324C9048AFEC8.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Anura	<html xmlns:mods="http://www.loc.gov/mods/v3">
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            <p> Anura</p>
            <p>The long bones of all anuran taxa have a typical tubular architecture, with solid walls void of the wide erosion bays observed in the urodeles (small erosion cavities can be nonetheless present in the perimedullary region). In cross-section, the cortices of anuran long bones are more markedly monorefringent than those of the urodeles (Fig. 3A). Likewise, in longitudinal sections, the birefringence of the bone matrix is particularly strong, with alternation of bright and dark phases when rotating the microscope stage (Fig. 3C). These observations indicate that the fibres of the collagenous matrix have a more strictly longitudinal orientation in anurans. In longitudinal sections, osteocyte lacunae appear flat and parallel to the sagittal axis of the bones (Fig. 3D); an aspect confirming that long bone cortices in anurans are made of well-characterized parallel-fibred bone tissue. Sharp cyclical growth marks, in the form of LAGs or birefringent annuli, occur in most anuran bones (Fig. 3A), as also do bundles of radial or oblique Sharpey’s fibres (Fig. 3B, C). The main differences between anuran taxa consist of some variability in the regularity of the spatial orientation of the collagenous meshwork, as well as in the morphology of osteocyte lacunae, which can be circular (Fig. 3G), multipolar or ellipsoid (Fig. 3H) in cross-section.</p>
            <p>Although the canaliculi appear short in longitudinal section (Fig. 3D), the cross-sections of most limb bones reveal the presence of complex canalicular networks in the vicinity of the osteocyte bodies (Fig. 3E–H). The aspect of these networks is somewhat reminiscent of the so-called aspidinocytes, which are thin and elongated unmineralized spaces observed in aspidin, a type of acellular bone. The origin and function of these structures have been subject of debates. (Hancox, 1972; see also the critical discussion of this concept in Francillon-Vieillot et al., 1990b). The canaliculi have a primarily radial orientation, but tend to converge towards the lumen of vascular canals, when present (Fig. 3E). It is rare to observe a direct contact between these canalicular extensions and the peri-somatic part of osteocyte lacunae. Their presence in the layer of lamellar endosteal bone (centripetally deposited) surrounding the medullary cavity (Fig. 3F), testifies that these structures are not anchoring fibres (e.g. Sharpey’s fibres), with which they could have a superficial resemblance. There is little doubt that they indeed represent a complex network of canaliculi, but with ramifications mainly developing at some distance from osteocyte bodies. This situation could indeed explain why it is difficult to clearly show that they originate from the osteocyte lacunae.</p>
            <p> Vascular canals are mostly represented by primary osteons, whose lumen varies from 10 to 40 µm in diameter, depending on the level of the section, and the individual or species considered (Figs 3H, 4–6). Simple vascular canals are also observable, although they are less frequent and always associated, when present, to primary osteons. In many individuals of diverse taxa, the cortical layers (of periosteal origin) show a pronounced deflection under the vascular canals (Fig. 4B). This feature is evidence of the primarily periosteal origin of intra-cortical vascularization. Besides the primary osteons, some secondary osteons occur in the peri-medullary region of  Nanorana vicina and  Pipa pipa (Fig. 4A). Vascular canals have a preferential longitudinal orientation; however, oblique or even radial canals can be observed in association with longitudinal ones (Figs 3H, 4A, B, 5, 6). The distribution of the vascular canals, regardless of their nature, can be random (Fig. 4C), but this condition is rare; they rather tend to be organized either in radial rows (Figs 4D, 5B, 6A–D), or in circumferential layers (Fig. 4F), or in a combination of both. In  Rhinella marina , the primary osteons are arranged in concentric layers and tend to have a circumferential orientation (Fig. 4F); this locally gives the bone an apparent laminar organization (but the latter does not correspond, of course, to a fibro-lamellar complex). </p>
            <p>STATISTICAL ANALYSES</p>
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	https://treatment.plazi.org/id/03812165E429D017FC9324C9048AFEC8	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Canoville, Aurore;Laurin, Michel;De Buffrénil, Vivian	Canoville, Aurore, Laurin, Michel, De Buffrénil, Vivian (2018): Quantitative data on bone vascular supply in lissamphibians: comparative and phylogenetic aspects. Zoological Journal of the Linnean Society 182 (1): 107-128, DOI: 10.1093/zoolinnean/zlx016, URL: http://academic.oup.com/zoolinnean/article/182/1/107/3873883
