海阳和烟台近岸口虾蛄群体的形态比较

于2017年4月,分3次采集山东海阳和烟台近岸的口虾蛄(Oratosquilla oratoria)样本,采用传统形态学直线测量的方法获取样本的11项形态学指标,运用独立样本t检验、CD检验、主成分分析和判别分析等统计方法,比较其15项比例性状指标。独立样本t检验和CD检验显示,海阳群体比烟台群体体型更细长,烟台群体的头胸甲、尾部和第2颚足在整体体型中占比较大,而海阳群体的腹部占比较大。2个群体在头胸甲部、胸节、尾部和第2颚足的掌节4个部位上形态差异显著(P<0.01),但尚未达到亚种水平(CD<1.28),为种内不同地理群体间的形态差异。主成分分析发现,雌性群体和雄性群体均分别构建了3个主成分,累计贡献率分别为87.571%和83.156%。而海阳和烟台群体在横向体型因子方面差异明显。通过判别分析,建立口虾蛄群体的判别函数式,综合判别准确率为74.0%。研究表明,口虾蛄具有雌雄二态性,烟台和海阳群体成体形态差异明显,雄性个体差异更为显著。

Morphological comparison of Oratosquilla oratoria stocks along the coast of Haiyang and Yantai

In spring (April) of 2017, Oratosquilla oratoria samples were collected three times near the coast of Haiyang and Yantai. Twelve morphological parameters were measured by traditional morphological method of linear measurement. Fifteen proportional trait indexes were calculated and compared by multiple statistical methods such as Independent-Sample t-test, CD test, principal component analysis, and discriminant analysis. The t-test and CD test results showed that the samples from Haiyang (Haiyang stock) had a longer and thinner body shape than those from Yantai (Yantai stock). The carapace, tail, and raptorial claw of the Yantai stock, whereas the abdomen of the Haiyang stock constituted larger proportion of the total length of the organism. Although there were significant differences in the length of the carapace, thoracic somite, tail, and the propodus between the two stocks (P<0.01), they did not reach the level of subspecies (CD<1.28), characterized by morphological differences between different geographic groups within the same species. According to the principal component analysis, the female stock constructed three principal components with a cumulative contribution rate of 87.571%. The male stock also constructed three principal components with a cumulative contribution rate of 83.156%. The difference in the transverse body shape factor between Haiyang and Yantai stocks was clear. The discriminant function of stocks was established by discriminant analysis and the comprehensive discriminant accuracy was 74%. These results showed that O. oratoria shrimps were species with sexual dimorphism. The difference in adult morphology is more evident, particularly in males between Yantai and Haiyang stocks.