Walters Jacklynn, Marais Sumine, Johnson Olga, Bennett Nigel C, Alagaili Abdulaziz N, Mohammed Osama B, Kotzé Sanet H
Division of Anatomy and Histology, Department of Biomedical Sciences, Stellenbosch University, Tygerberg 7505, South Africa.
J Morphol. 2014 Sep;275(9):980-90. doi: 10.1002/jmor.20270. Epub 2014 Mar 24.
Meriones rex (King jird), Meriones libycus (Libyan jird), Acomys dimidiatus (Eastern spiny mouse), Acomys cahirinus (Egyptian spiny mouse), and Dipodillus dasyurus (Wagner's dipodil) are five species of small rodents of the superfamily Muroidea with distributions in Eastern Africa, Egypt, and the desert regions of the Arabian Peninsula. Water is scarce in these regions and may result in relatively low-digestible food. The aim of the present study is to describe and compare the gastrointestinal tract morphology and morphometry of these five species in order to elucidate whether morphology is influenced by phylogeny or dietary preference. Each segment of the gastrointestinal tract of each species was macroscopically examined and the length and basal surface area of each segment was measured. Standard histologic procedures were performed to determine a surface enlargement factor to determine the mucosal luminal surface area. A unilocular-hemiglandular stomach was observed in all the species examined. The caeca of all the species were long and arranged into a loose spiral toward the caecal tip with the ileocaecal and caeco-colic openings positioned close together. Two rows of oblique folds could be observed in the proximal colon of all species except in D. dasyurus which had longitudinal folds. Morphometric analysis showed the largest stomach in A. cahirinus and the largest caecum and colon in M. libycus. All the species can be grouped in the family Muridae in two subfamilies and similarities were observed including the hemiglandular stomach and relatively large caecum. It could be concluded that phylogeny plays an important role in determining gastrointestinal morphology while diet plays a subordinate role in the desert rodents in the present study.
大沙鼠（Meriones rex）、利比亚沙鼠（Meriones libycus）、中东刺鼠（Acomys dimidiatus）、埃及刺鼠（Acomys cahirinus）和瓦氏沙鼠（Dipodillus dasyurus）是鼠总科的五种小型啮齿动物，分布于东非、埃及和阿拉伯半岛的沙漠地区。这些地区水资源稀缺，可能导致食物的消化率相对较低。本研究的目的是描述和比较这五个物种的胃肠道形态和形态测量学特征，以阐明形态是否受系统发育或饮食偏好的影响。对每个物种的胃肠道各段进行宏观检查，并测量各段的长度和基底表面积。采用标准组织学程序确定表面放大因子，以确定粘膜腔表面积。在所检查的所有物种中均观察到单室半腺胃。所有物种的盲肠都很长，朝着盲肠尖端呈松散的螺旋状排列，回盲口和盲结肠口位置靠近。除瓦氏沙鼠有纵向褶皱外，在所有物种的近端结肠中均可观察到两排斜褶。形态测量分析显示，埃及刺鼠的胃最大，利比亚沙鼠的盲肠和结肠最大。所有物种可分为鼠科的两个亚科，观察到的相似之处包括半腺胃和相对较大的盲肠。可以得出结论，在本研究中，系统发育在决定胃肠道形态方面起重要作用，而饮食在沙漠啮齿动物中起次要作用。
