Estudo do escápulo-coracóide e da cartilagem sinarcual cérvico-torácica de Rhinoptera brasiliensis Müller & Henle e Rhinoptera bonasus (Mitchill) Elasmobranchii, Rhinopteridae)

Abstract

ABSTRACT. Study of lhe scapu locoracoid and cervico-thoracic synarcual carti lage 01' Rflilloplero brasiliellsis Miillcr & Hcnlc anel Rflilloplera bOIlOSlIS (Milchill) (Elasmobranchii, Rhinopterielae). A cOlllparalive analysis 01' lhe seapulocoracoid and cervieo-thoracie sy narcual cartilage ofjuvenile speeilllens ofRhilloplera brosili elJsis Müller & Henle, 1841 and R. bOIlOSIIS (Mitehi ll, 1815) was accomplished. in order to idenlify specilic, individual and onlogenelic differences. ln lhe scapulocora coid, lhe scapular foramen and the posterodorsal feneslra is larger in R. brosiliellsis. The anterior fenestra bridge is lhicker and lhe l11etacondyle is lhinner and longer in R. bOIlOSIIS. This species also possesses a larger re-entrance between lhe l11esocondyle and lhe metacondyle, as well as in the litling region ofthe synarcual cartilage, placed close to the scapular processo Thc individual differcnces are: posteroventral tenestra with variable diallleter independenl ofthe size of the specimens; scapuloeoracoids, in some spccimens, are more fi'agile even ifthey have been kept in the same conservation conditions. ln the cervico-thoracic synarcual cartilage, the lateral stay in R. brasiliellsis encloscs complelely the superior portion 01' lhe anteroscapular bridge. Therc are lhree more prominent condyles beside the suprascapula in R. brasiliellsis. R. bOIlOSIl.\', however, shows a protuberance close to the suprascapula, ineonspicuous and more distant li'om lhe seapular lamina. Several specimens 01' dirterenl size 01' R. bonoslIs show a sy narcual carlilage wider in ventral view and higher in lateral view. ln the majori ty ofspeeimens, the number ofvenlral spinal f0r3min3 i s higher than lhe dorsal ones in both speeies. R. bOIlOSlIS has only one pair 01' asymmetric basal foralllina, whereas R. brasiliensis possesses three or four foramina. Regarding individual dilTe rences, at least one speci1l1en of R. bOllaslls exhibits a single basal fora1l1en. KEY WORDS. Chondrichthyes, Myliobaliformes, RiJil1oplera, scapulocoracoid, cer vieo-thoracic synarcual carti lage, Brazil A cintura peitoral em Chondrichthyes, também denominada escápulo-cora cóide, consiste de vários elementos anatômicos fusionados, supot1ando a nadadeira peitoral (LOVEJOY 1996). Ela está posicionada atrás da cabeça, como em outros Gnathostomata, localizando-se mais posteriormente em clasmobrânquios, não sen do ligada ao condroneurocrânio por elementos esqueléticos.

The first three-dimensional fossils of Cretaceous sclerorhynchid sawfish:Asflapristis cristadentisgen. et sp. nov., and implications for the phylogenetic relations of the Sclerorhynchoidei (Chondrichthyes)

“…Aschliman's observations were reviewed using extant material from different collections (see Material examined). In cases were extant material was not available, published images (e.g Nishida 1990;Alfonso & Gallo 2001;. Domínguez & González-Isaís 2007; Claeson 2010; Da Silva & De Carvalho 2015) and electronic material (https://sharksrays.org, to access this image bank contact Gavin Naylor) were used.…”