López-Jiménez A, Pérez-Ponce de León G, García-Varela M
Departamento de Zoología,Instituto de Biología, Universidad Nacional Autónoma de México,Avenida Universidad 3000,Ciudad Universitaria,C. P. 04510, Distrito Federal,Mexico.
J Helminthol. 2018 Nov;92(6):725-739. doi: 10.1017/S0022149X17000888. Epub 2017 Oct 11.
Members of the genus Uvulifer are distributed worldwide and infect aquatic snails and freshwater fishes as first and second intermediate hosts, respectively, and fish-eating birds (kingfishers) as definitive hosts. Metacercariae of Uvulifer spp. were collected from the fins and skin of 20 species of freshwater fishes in Mexico, Guatemala, Honduras, Nicaragua and Costa Rica, and the adults were recovered from the intestine of kingfishers in four localities of Mexico. The genetic divergence among 76 samples (64 metacercariae and 12 adults) was estimated by sequencing the 28S and 5.8S nuclear genes, as well as the internal transcribed spacers ITS1 and ITS2, and one mitochondrial gene (cox1). Maximum likelihood and Bayesian inference analyses inferred with each dataset showed a high genetic diversity within the genus Uvulifer across Middle America, revealing the existence of four genetic lineages that exhibit some level of host specificity to their second intermediate hosts. The metacercariae of lineage 1 were associated with characids and cyprinids in central and northern Mexico. Metacercariae of lineages 2 and 3 were associated with cichlids distributed widely across Middle America. The lack of adults of these lineages in kingfishers, in lineages 2 and 3, or the fact that just a few adult specimens were recovered, as in lineage 1, prevented a formal description of these species. The metacercariae of lineage 4 were found in poeciliids, across a distribution range comprising Mexico, Guatemala, Honduras and Nicaragua, and the adult was found in the green kingfisher in Mexico. The number of specimens sampled for lineage 4, for both gravid adults and metacercariae, allowed us to describe a new species, Uvulifer spinatus n. sp. We describe the new species herein and we discuss briefly the genetic diversity in Uvulifer spp. and the importance of using DNA sequences to properly characterize parasite diversity.
悬宫吸虫属的成员分布于世界各地，分别以水生蜗牛和淡水鱼作为第一和第二中间宿主，并以食鱼鸟类（翠鸟）作为终末宿主。在墨西哥、危地马拉、洪都拉斯、尼加拉瓜和哥斯达黎加，从20种淡水鱼的鳍和皮肤中采集到了悬宫吸虫属的囊蚴，并在墨西哥的四个地点从翠鸟的肠道中获得了成虫。通过对28S和5.8S核基因以及内部转录间隔区ITS1和ITS2，还有一个线粒体基因（cox1）进行测序，估计了76个样本（64个囊蚴和12个成虫）之间的遗传差异。用每个数据集进行的最大似然法和贝叶斯推断分析表明，中美洲的悬宫吸虫属内存在高度的遗传多样性，揭示了四个遗传谱系的存在，这些谱系对其第二中间宿主表现出一定程度的宿主特异性。谱系1的囊蚴与墨西哥中部和北部的脂鲤科和鲤科鱼类有关。谱系2和3的囊蚴与广泛分布于中美洲的丽鱼科鱼类有关。在谱系2和3的翠鸟中缺乏这些谱系的成虫，或者像谱系1那样只采集到少数成虫标本，这使得无法对这些物种进行正式描述。在墨西哥、危地马拉、洪都拉斯和尼加拉瓜分布范围内的食蚊鱼中发现了谱系4的囊蚴，在墨西哥的绿翠鸟中发现了成虫。对于谱系4，无论是成熟成虫还是囊蚴，所采集的标本数量都使我们能够描述一个新物种，即旋形悬宫吸虫。我们在此描述这个新物种，并简要讨论悬宫吸虫属的遗传多样性以及使用DNA序列正确表征寄生虫多样性的重要性。
