Costapycnodus costae (HECKEL, 1856), from the Lower Cretaceous of the Capo d’Orlando (Castellammare di Stabia, Campania, southern Italy), was firstly identified as Stemmatodus rhombus and, after that, described as Coelodus costae. More recently, the species was ranged with some doubt in the genus Ocloedus but remained in need of revision. The skeleton of Costapycnodus costae is here studied in details. The dermic bones of the skull are strongly ornamented. There is a brush-like process on the parietal, attesting that C. costae belongs to the family Pycnodontidae. The prefrontal is well developed. The dermosphenotic is not a free bone but is included in the lateral wall of the skull roof. A temporal fenestra is present. The exoccipital is visible behind the dermopterotic and is fused to a synarcual. Both the premaxilla and the dentary bear two incisiform teeth. The maxilla is reniform, with a notch in its posterior margin. The preopercle is wider than the exposed part of the hyomandibula. The opercle is strongly reduced. Comparisons are done with Stemmatodus rhombus, Ocloedus subdiscus and Coelodus saturnus. The osteological data show that C. costae represents a new genus of pycnondontid fish. The systematic position of C. costae within the family Pycnodontidae is discussed.

The pycnodont fishes from the Lower Cretaceous of the Capo d’Orlando, near Castellammare di Stabia (Naples, Campania, southern Italy), with the description of the new genus Costapycnodus

Capasso L.;
2019

Abstract

Costapycnodus costae (HECKEL, 1856), from the Lower Cretaceous of the Capo d’Orlando (Castellammare di Stabia, Campania, southern Italy), was firstly identified as Stemmatodus rhombus and, after that, described as Coelodus costae. More recently, the species was ranged with some doubt in the genus Ocloedus but remained in need of revision. The skeleton of Costapycnodus costae is here studied in details. The dermic bones of the skull are strongly ornamented. There is a brush-like process on the parietal, attesting that C. costae belongs to the family Pycnodontidae. The prefrontal is well developed. The dermosphenotic is not a free bone but is included in the lateral wall of the skull roof. A temporal fenestra is present. The exoccipital is visible behind the dermopterotic and is fused to a synarcual. Both the premaxilla and the dentary bear two incisiform teeth. The maxilla is reniform, with a notch in its posterior margin. The preopercle is wider than the exposed part of the hyomandibula. The opercle is strongly reduced. Comparisons are done with Stemmatodus rhombus, Ocloedus subdiscus and Coelodus saturnus. The osteological data show that C. costae represents a new genus of pycnondontid fish. The systematic position of C. costae within the family Pycnodontidae is discussed.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11564/705534
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