Morpho-molecular Delineation of Odonaticola nonapetalis n. sp. (Apicomplexa: Eugregarinida: Actinocephalidae) Parasitising Brachythemis contaminata (Fabricius, 1793) from West Bengal, India, Including Taxonomic Revision of the Genus Odonaticola

IF 1.5 3区农林科学 Q4 PARASITOLOGY

Acta Parasitologica Pub Date : 2026-05-02 DOI:10.1007/s11686-025-01192-y

Susobhan Mondal, Biplob Kr. Modak

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引用次数: 0

Abstract

Purpose

Septate gregarines are widespread in insects but remain largely unexplored in odonates, with only ~ 1% of odonate species investigated and minimal molecular or ultrastructural data available. The present study characterises a septate gregarine parasitising Brachythemis contaminata using modern microscopy and phylogenetic analysis to clarify its taxonomic placement and improve understanding of the genus Odonaticola.

Methods

Fixation was performed using Schaudinn’s solution, followed by staining with Heidenhain’s haematoxylin; SEM involved glutaraldehyde and osmium tetroxide fixation. SSU rDNA was amplified, sequenced, and analysed using the neighbour-joining method.

Results

Trophozoites are elongated (321.12 ± 50.63 μm). Epimerite complex (111.58 ± 18.24 μm) comprising an umbrella-shaped epimerite proper bearing nine petaloid spines and a cylindrical diamerite. Gamonts are solitary and elongated (362.13 ± 65.91 μm), with a broadly obpanduriform protomerite featuring an elevated apical zone and a narrowly ovoid deutomerite. Nucleus broadly orbicular to elliptoid (45.48 ± 5.38 μm × 35.06 ± 5.51 μm), containing multiple karyosomes. Both stages exhibit longitudinal epicytic folds (~ 5–6 folds/µm), except the epimerite proper, which has undulating ridges and grooves. Gametocysts are orbicular (360.78 ± 31.32 μm), surrounded by a thick ectocyst, and dehisce by simple rupture. Oocysts are tetrahedral (7.13–8.82 μm), with projections bearing terminal sucker-like structure. Phylogenetic analysis places Odonaticola nonapetalis n. sp. as an independently branching lineage within Actinocephalidae (bootstrap = 88%), with a long terminal branch (0.050), indicating strong divergence.

Conclusion

Combined morphological and molecular data support the recognition of Odonaticola nonapetalis n. sp. as a novel species and justify an emended diagnosis of the genus Odonaticola.

Graphical Abstract

The alternative text for this image may have been generated using AI.

Abstract Image

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印度西孟加拉邦寄生Brachythemis （Fabricius, 1793）的Odonaticola nonapaptalis n. sp.（顶复体目：Eugregarinida：放线头蝇科）的形态-分子描述及Odonaticola属的分类修订

目的：分离碱在昆虫中广泛存在，但在齿形动物中仍未被开发，仅研究了约1%的齿形动物物种，并且获得的分子或超微结构数据很少。本研究利用现代显微镜和系统发育分析鉴定了一种独立的寄生于短毛线虫的绿虫，以澄清其分类位置并提高对短毛线虫属的认识。方法Schaudinn溶液固定，Heidenhain氏血红素染色；扫描电镜涉及戊二醛和四氧化二锇固定。对SSU rDNA进行扩增、测序，并采用邻联法进行分析。结果复殖体呈细长状（321.12±50.63 μm）。煌铜矿复合体（111.58±18.24 μm），由一个伞状煌铜矿组成，含9个花瓣状棘和一个圆柱形辉长岩。单体呈单生细长状（362.13±65.91 μm），原长毛石呈宽斜菱形，尖区隆起，细卵圆形。细胞核宽圆形至椭圆形（45.48±5.38 μm × 35.06±5.51 μm），含有多个核小体。这两个阶段均表现为纵向上胞褶皱（~ 5 ~ 6次/µm），但表浅铜矿本身具有起伏的脊和凹槽。配子囊呈圆形（360.78±31.32 μm），外包囊较厚，单纯性破裂。卵囊呈四面体（7.13 ~ 8.82 μm），卵囊突起端部呈吸盘状结构。系统发育分析表明，Odonaticola nonapetalis n. sp在Actinocephalidae （bootstrap = 88%）中是一个独立的分支谱系，其末端分支较长（0.050），表明分化程度较强。结论形态学和分子生物学的综合资料支持了Odonaticola nonapetalis n. sp.的新种鉴定，并对Odonaticola属的诊断进行了修正。此图像的替代文本可能是使用AI生成的。

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来源期刊

Acta Parasitologica 医学-寄生虫学

CiteScore

3.10

自引率

6.70%

发文量

149

审稿时长

6-12 weeks

期刊介绍： Acta Parasitologica is an international journal covering the latest advances in the subject. Acta Parasitologica publishes original papers on all aspects of parasitology and host-parasite relationships, including the latest discoveries in biochemical and molecular biology of parasites, their physiology, morphology, taxonomy and ecology, as well as original research papers on immunology, pathology, and epidemiology of parasitic diseases in the context of medical, veterinary and biological sciences. The journal also publishes short research notes, invited review articles, book reviews. The journal was founded in 1953 as "Acta Parasitologica Polonica" by the Polish Parasitological Society and since 1954 has been published by W. Stefanski Institute of Parasitology of the Polish Academy of Sciences in Warsaw. Since 1992 in has appeared as Acta Parasitologica in four issues per year.