CT-scan reveals new cranial features in Devonian chondrichthyan“Cladodus” wildungensis

Braincase of the Upper Devonian Shark Cladodoides Wildungensis (Chondrichthyes, Elasmobranchii), With Observations on the Braincase in Early Chondrichthyans

“…OCCIPITAL ARCH: Scanning reveals that the occipital region in the Cladodoides braincase is far more complete than was previously supposed (Maisey, 2001c). In dorsal view, the occipital arch intrudes only slightly between the otic capsules (although it also extends behind them) and there is a persistent otico-occipital fissure similar to that described in Orthacanthus, Tamiobatis vetustus, ''Tamiobatis sp.…”

“…Interpretathions of the basicranial circuit in Cobelodus aculeatus by Zangerl and Case (1976) and Schaeffer (1981) are probably erroneous in depicting the aorta as paired and external to the basicranium. While Coates and Sequeira (1998) may be correct that a median groove or canal for the dorsal aorta is primitive for gnathostomes, paired aortic canals are present in Pucapampella and many other Paleozoic chondrichthyans (Maisey, 2001c). In fact, the only chondrichthyans in which a median aortic canal is known are symmoriids and stethacanthids (although the paired lateral aortae are combined within a common sheath in some modern hexanchiforms; Jarvik, 1980).…”

“…(AMNH 2140), Akmonistion (Coates and Sequeira, 1998), and ''Cobelodus'' (in prep.). However, in Orthacanthus and Pucapampella, a tectum is absent and the fontanelle is confluent with the otico-occipital fissure posteriorly (Schaeffer, 1981;Maisey, 2001c;Maisey and Anderson, 2001). In adult neoselachians and hybodonts, the otico-occipital fissure is closed, but in many neoselachian embryos a posterior tectum separates the parietal fossa from the embryonic otico-occipital fissure.…”

“…braincase described by Schaeffer (1981: figs. 14, 22, 23), and in chimaeroids and Puca- pampella (Maisey, 2001c). By contrast, in many neoselachians the postorbital process is lateral to the anterior ampulla, and in some carcharhiniforms the ampulla is positioned even farther anteriorly.…”

A classic Late Frasnian chondrichthyan assemblage from southern Belgium

“…Order Ctenacanthiformes Glikman, 1964Family Ctenacanthidae Dean, 1909 Genus Cladodoides Maisey, 2001 John Maisey, the author of the name of this genus, noted as follows: "It is important to note that the braincase described by Gross (1937) is not the ho- (Jaekel 1921), and while Gross (1937) presented a circumstantial case for including the braincase in this species, no diagnostic characters can actually be compared. Thus, the precise identity of the braincase is problematic, despite its importance as a source of data concerning early elasmobranch cranial morphology."…”