若干种枝角类卵鞍表面亚显微结构的比较研究

COMPARATIVE STUDIES ON THE ULTRA STRUCTURES OF EPHIPPIA OF THREE SPECIES AND A SUBSPECIES OF CLADOCERA (CRUSTACEA)

以扫描电镜对发头裸腹溞、蚤状溞、隆线溞指名亚种以及隆线溞东湖一亚种的卵鞍分别进行了比较研究,发现卵鞍表面的亚显微结构有明显的差异,但亚种之间差异较小。隆线溞指名亚种与隆线溞东湖一亚种二者的卵鞍在光学显微镜下看不出有什么差异,然而亚显微结构却互不相同。这就为东湖一新亚种的确定提供了一项可靠的依据,同时也进一步证实卵鞍的超微结构确可作为枝角类分类的表征。

The ulrastructure of the ephippia of Moina irrasa, Daphnia pulex, Daphnia (Ctenodaphnia) carinata carinata (King), and Daphnia(Ctenodaphnia) carinata ssp. were studied by scanning electron microscopy. The outer surfaces of the ephippia of M. irrasa, D. pulex, D. carinata carinata and D. carinata ssp. are distinctly different from one another. The ephippium of M. irrasa has an outer surface composed of closely spherical lobes ca. 21.6u. In D. pulex and D. carinata carinata, the ephippial surfaces are covered by recesses; the latter species has scaly structure on its surface near the dorsum. The outer surface of the ephippium of D. carinata ssp. in 'ake Dong Hu of Wuhan is only covered by polygonal scaly structure and has no recesses. The ephippia in the four species and subspecies differ greatly in shape and uhrastructure of the dorsal margin. In M. irrasa, the dorsal margin of the ephippium is void of any surface ornamenation. In D. pulex, it has a lot of leptospines and thorns. The dorsal margin of the ephippium of D. carinata ssp., has many seta, besides two rows of small spines observed in D. carinata carinata. It is clear that the surface characteristics of the ephippia are species-specific and subspecies-specific. The uniquely structured outer surface of the ephippium of D. carinata ssp. provides a morphological proof for the validity of this taxon as a true subspecies.