青石爬鮡头骨形态的观察

MORPHOLOGICAL OBSERVATIONS ON THE SKULL OF Euchiloglanis davidi (Sisoridae)

对青石爬鮡的头骨形态作了描述.结果表明,其头骨不仅具有鲶形目鱼类的共有特征,而且具有一些高度特化的特征,如头骨极为平扁,腭骨、颌骨特化并高度发达,鳃弓的基-下鳃区骨化程度很低,大部分为结缔组织.这些特化是与其山溪激流生活相适应的.

This paper presents a morphological description of the skull of Chinese sisond catfish, Euchiloglams davidi. It was found that the organization of its skull is typical of Siluriformes, such as the absence of parietals and suboperculars, the specialized palatines and maxillaries, the cartilaginous sympletics, and the nerve foramina for the rami trigemiaal spinalis on the supraocipital. The well-developed palatines and maxillaries which strongly support the mandibular barbels, the parethmoids which do not form the lateral processes of the skull, the imcompletely ossified circumorbitals which are large in numbers (10 pairs) and small in size, the toothless vomer and the absence of interhyals, all were noted and were belived to be the characteristics of Sisoridae.The specialization of the skull of E. davidi, which derived from the adaptation to bottom-living in brook, was noted as well. Its skull is very depressed due to the highly lateral-expanded hyomandibulars, metapterygoids, quadrates and opercular series. The specialized palatines and maxillaries support the paired mandibular barbels which are large in size and function as adhesive apparatus. In addition, the branchial arches are poorly ossified. Except for two pairs of hypobranchials and one basibranchial, the remaining portion of the basi-hypo-branchial is composd of connective tissue which, in our opinion, is closely related to its adhesive apparatus on the thorax.