Costa Natália Alves, Gentile Rosana, Alvarez Martin R, Maldonado Junior Arnaldo
Programa de Pós-graduação em Biologia Parasitária, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz- FIOCRUZ, Rio de Janeiro, RJ, Brasil.
Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, Instituto Oswaldo Cruz- FIOCRUZ, Av. Brasil, 4365, Rio de Janeiro, RJ, 21040-900, Brasil.
Acta Parasitol. 2024 Dec;69(4):1911-1918. doi: 10.1007/s11686-024-00928-6. Epub 2024 Oct 16.
The genus Stilestrongylus (Freitas, Lent, and Almeida, 1937) is defined by having 24 or more subequal cuticular ridges, an asymmetrical caudal bursa, and a hypertrophied genital cone. It comprises 25 recognized species, mainly parasitizing cricetids, and shows significant diversification linked to the evolution of its hosts. Stilestrongylus magnumspiculum n. sp. is a newly described nematode species identified in the small intestine of the rodent Euryoryzomys russatus (Cricetidae, Sigmodontinae) from the Atlantic Forest of Northeast Brazil. This study aims to characterize the new species and its prevalence in host populations.
A total of 43 Euryoryzomys russatus individuals were collected and analyzed for parasitic infections. Morphological features of Stilestrongylus magnumspiculum n. sp. were examined, focusing on the number of ridges, synlophe characteristics, caudal bursa type, lobe hypertrophy, and the spicule length to body length ratio.
The new species exhibited a prevalence of 21% among the sampled hosts. Distinctive morphological features were observed, including:the synlophe structure exhibited specific ridge patterns that differentiate it from other species within the genus; the caudal bursa was identified as a type 2-2-1; hypertrophy of the right lobe was observed, indicating notable morphological adaptation; rays 4 and 5 were found to be equivalent in size and diverged at the distal end; the spicule length to body length ratio (SpL/BL) was measured at 30-36%, representing the largest ratio recorded for the genus. In comparison, other Stilestrongylus species displayed the following ratios: S. rolandoi (21-33%), S. lanfrediae (25-29%), S. kaaguyporai (20-24%), S. inexpectatus (20-23%), and S. stilesi (26-28%).
This report presents Stilestrongylus magnumspiculum n. sp. as a new species of nematode, contributing to the diversity of the genus Stilestrongylus. The findings underscore the importance of studying host-parasite interactions within the Atlantic Forest ecosystem and provide a basis for future ecological and parasitological research.
斯氏线虫属（Freitas、Lent和Almeida，1937年）的定义特征为具有24条或更多近乎相等的角质嵴、不对称的尾翼膜和肥大的生殖锥。该属包括25个已确认的物种，主要寄生于仓鼠科动物，并且显示出与其宿主进化相关的显著多样化。大刺斯氏线虫（Stilestrongylus magnumspiculum）是一种新描述的线虫物种，在巴西东北部大西洋森林的啮齿动物红广肩鼠（Euryoryzomys russatus，仓鼠科，棉鼠亚科）的小肠中被鉴定出来。本研究旨在对该新物种及其在宿主种群中的流行情况进行特征描述。
总共收集了43只红广肩鼠个体，并对其进行寄生虫感染分析。检查了大刺斯氏线虫的形态特征，重点关注嵴的数量、交合伞特征、尾翼膜类型、叶的肥大情况以及交合刺长度与体长的比例。
在抽样宿主中，新物种的流行率为21%。观察到了独特的形态特征，包括：交合伞结构呈现出特定的嵴模式，使其与该属内的其他物种区分开来；尾翼膜被鉴定为2-2-1型；观察到右叶肥大，表明有显著的形态适应；发现第4和第5条辐肋大小相等且在远端分开；交合刺长度与体长的比例（SpL/BL）测量值为30%-36%，是该属记录到的最大比例。相比之下，其他斯氏线虫物种的该比例如下：罗兰多伊斯氏线虫（S. rolandoi，21%-33%）、兰弗雷迪氏线虫（S. lanfrediae，25%-29%）、卡古伊波赖斯氏线虫（S. kaaguyporai，20%-24%）、意外斯氏线虫（S. inexpectatus，20%-23%）和斯氏斯氏线虫（S. stilesi，26%-28%）。
本报告将大刺斯氏线虫作为一种新的线虫物种呈现出来，为斯氏线虫属的多样性增添了内容。这些发现强调了研究大西洋森林生态系统内宿主-寄生虫相互作用的重要性，并为未来的生态学和寄生虫学研究提供了基础。
