江豚胎儿形态发生及生殖规律的研究

STUDY ON THE MOKPHOGENESIS OF FOETUS AND REPRODUCTIVE REGULARITY OF THE FINLESS POKPOISE, NEOPHOCAENA PHOCAENOIDES

  • 摘要: 在胚胎发育早期,江豚上颌生有短须;左侧1-3根,右侧2-3根.具有半月形外耳廓.雄性胎儿阴茎露于体外.脐带较短.胎儿运动器官(胸鳍、尾鳍和尾柄)发育较快.随着胚胎的发育,外耳廓消失,阴茎藏于体腔.江豚胚胎发育过程中的这些形态学变化,再现了鲸类祖先在陆上生活的历史,同时也反映了鲸类在二次入水过程中所形成的对水环境的适应.此外.通过对收集的17头江豚胎儿资料进行统计,结果表明长江江豚胎儿的生长速度约为9.08cm/月(O.303cm/d),妊娠期为9.4个月,交配季节为6-8月份,分娩为3-5月份.

     

    Abstract: At the early development of the embryo, short bristles were observed on eachside of upper jaw in Neophocaena phocacnoides.The number of the bristles variedfrom 1-3 on the left and 2-3 on the right.Semicircle ear outline was visible. The penis of male foetus was exposed out of body.The swimming organs(flipper,fluke and midway anus to luke notch)developed prominently. As embryo develo-ped,external ear outline of foetus disappeared and the penis of male foetus concea-led in the penial pouch. These morphological changes in the course of the embryo-development indicated that cetacean ancestor might have lived on land and that ce-tacean adapted to water environment whcn coming into water secondly.In addition,statistical analysis on 17 foetuses and juveniles showed that: the growth rate offoetus was 9.08cm/month(0.303cm/day)in Neophocaena phocacnoides, the gesta-tion period may be about 9.4 months in Neophocaena phocaenoides in the YangtzeRiver,and mating may take place from June to August,parturition time fromMarch to Mav each Vear.

     

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