Zoology Department, College of Science, King Saud University, Saudi Arabia, Riyadh, Saudi Arabia.
Laboratory of Biodiversity, Parasitology and Ecology of Aquatic Systems, Department of Biology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia.
Folia Parasitol (Praha). 2021 Jun 28;68:2021.017. doi: 10.14411/fp.2021.017.
Myxobolus allami sp. n. is described from the intestinal wall of the silvery black porgy, Sparidentex hasta (Valenciennes), off Saudi Arabian coast of Arabian Gulf. Two of 20 examined fish were found to be infected with irregular-shaped plasmodia 3-8 mm long × 2-3 mm wide. Mature myxospores are subspherical to elliptical in the valvular view and oval in the sutural view, and are 11-13 (12) µm long, 7-8 (7.5) µm wide and 10-12 (10.8) µm thick. Spores have relatively thin valves and mostly (~ 72%) end with short caudal appendages of ~3 µm long. The spores also have two polar capsules, which are oval to elliptical and measure 5-7 (5.7) µm in length and 2-3 (2.7) µm in width. Polar filaments are coiled, with three turns. Transmission electron microscopy revealed that caudal appendages originated from the sutural edge at the posterior pole of the myxospore with density similar to that of its valves. The SSU rRNAgene sequence of the present species does not match any available sequences in GenBank. Phylogenetically, this species is sister to Myxobolus khaliji Zhang, Al-Qurausihy et Abdel-Baki, 2014 within a well-supported clade of Myxobolus-Henneguya with species infecting marine fishes. The combination of molecular data and morphological differences between this and other species of Myxobolus Bütschli, 1882 lead us to propose that the present form be established as a new species, M. allami. The present study also provides more evidence for the idea that caudal appendages cannot be reliably used to distinguish the species of the genera Myxobolus and Henneguya Thélohan, 1892.
从沙特阿拉伯阿拉伯湾海岸的 Sparidentex hasta（Valenciennes）的银黑色鲷的肠壁中描述了一种新的 Myxobolus allami sp. n。在检查的 20 条鱼中，有两条鱼发现感染了不规则形状的原生动物，长 3-8 毫米，宽 2-3 毫米。成熟的孢子在瓣状视图中呈亚球形到椭圆形，在缝合视图中呈椭圆形，长 11-13（12）µm，宽 7-8（7.5）µm，厚 10-12（10.8）µm。孢子的瓣较薄，大部分（约 72%）末端带有长约 3 µm 的短尾附属物。孢子还具有两个极囊，呈椭圆形到椭圆形，长 5-7（5.7）µm，宽 2-3（2.7）µm。极丝卷曲，有三圈。透射电子显微镜显示，尾附属物起源于孢子后极的缝合缘，密度与瓣相似。本种的 SSU rRNA 基因序列与 GenBank 中任何现有序列均不匹配。系统发育上，该种与 Myxobolus khaliji Zhang，Al-Qurausihy 等人在一个由感染海洋鱼类的 Myxobolus-Henneguya 组成的支持度很高的分支中为姐妹种。分子数据与该种与其他 Myxobolus Bütschli，1882 种之间的形态差异相结合，使我们提出将该种确立为一个新种，即 M. allami。本研究还为尾附属物不能可靠用于区分 Myxobolus 和 Henneguya Thélohan，1892 属的种的观点提供了更多证据。
