Distribution and morphology of the ampullary organs of the salmontail catfish,Arius graeffei

Whole body staining of Arius graeffei revealed that ampullary pores cover the body with their highest densities occurring on the head and lowest densities on the mid‐ventral surface. Each ampullary organ consists of a long canal (0.2–1.75 mm) passing perpendicular to the basement membrane, through the epidermis into underlying dermal connective tissues, curving thereafter to run roughly parallel to the epidermis. Histochemical staining techniques (Alcian blue and Lillie′s allochrome) indicate that the canals contain a neutral to acidic glycoprotein‐based mucopolysaccharide gel that varies in composition along the length of the canal. Collagen fibers, arranged in a sheath, surround a layer of squamous epithelium that lines each ampullary canal. At the proximal end of the canal, squamous cells are replaced by cuboidal epithelial cells that protrude into the lumen, thus constricting the lumen to form a small pore into the ampulla. The ampulla is lined with receptor and supportive cells. The numerous (60–120) pear‐shaped receptor cells bear microvilli on their luminal surface. Two forms of receptor cells exist in each ampullary organ: basal and equatorial receptor cells. Each receptor cell is connected to an unmyelinated nerve. Each receptor cell is surrounded by supportive cells on all but the apex. Tight junctions and underlying desmosomes occur between adjacent receptor and supportive cells. This form of ampullary organ has not previously been described for teleosts. J. Morphol. 239:97–105, 1999. © 1999 Wiley‐Liss, Inc.     

中国海鲇属丝鳍海鲇(原"中华海鲇")的分类学厘定及其性别差异

海鲇属Arius鱼类是世界上重要的海洋捕捞对象之一。长期以来,国内有关研究者将分布于我国海域的腭骨齿单侧一群的海鲇属个体定名为中华海鲇A·sinensis。据查证,原TachysurussinensisLac啨p埁de,1803的命名仅依据一幅中国画,不具科学上的有效性。而Valenciennes在1840年记录的新种A·sinensis背鳍无棘,臀鳍鳍条数13,与我国被定名为“中华海鲇”的标本(背鳍有棘,臀鳍鳍条数16-19)的特征不符。基于中国科学院动物研究所标本馆馆藏标本的研究认为,A·sinensis的科学名无效,我国原被定名为“中华海鲇A·sinensis”的标本实际应为丝鳍海鲇A·arius(Hamilton,1822)。进一步分析显示,丝鳍海鲇雌雄个体间存在显著的形态差异:雌性个体与雄性个体相比腭骨齿群面积较大,两侧齿群间距较小(0·2%vs0·4%,体长),腹鳍较长(17·7%vs14·4%,体长),眼后头长较小(12·3%vs14·7%,体长)[动物学报51(3):431-439,2005]。     

中国海鲇属海鲇的分类学厘定及一新记录种--双线海鲇(鲇形目:海鲇科)

长期以来,国内绝大多数有关研究者将海鲇属Arius中腭骨齿单侧3群的个体鉴定为海鲇A．thalassinus。基于中国科学院动物研究所标本馆馆藏海鲇标本的研究发现,标本中存在两种腭骨齿的分化类型;经文献查证,其中一种应为双线海鲇A．bilineatus,该种在我国尚未见有研究报道,为一新记录种。双线海鲇与海鲇外形相似,但前者吻较钝,唇薄,腭骨齿于前部相连,游离脊椎骨数目较多(46—51 vs 38—43),臀鳍鳍条数较多(15—18 vs 1316),无囟门沟,从而可与后者相区别[动物学报51(3)：423—430,2005]。