A new coccidian species, Isospora lugensae n. sp., was described from a single Kerguelen petrel (Lugensa brevirostris). Sporulated oocysts (n = 25) were characterized as subspheroidal to ellipsoidal measuring 24–25 μm × 21–23 μm (24.8 × 22.2 μm) in length/width (L/W), respectively, with a ratio of 1.07–1.14 μm (1.12). They contained a bi-layered wall with a thickness of 0.8–1.2 μm (1.0) and the outer layer smooth, with c.2/3 of total thickness. The oocyst contained two polar granules with both micropyle and oocyst residuum absent. Ovoidal sporocysts (n = 25) measured 15–16 μm × 10–11 μm (15.7 × 10.8 μm) in L/W, with a ratio of 1.41–1.49 μm (1.46). A flattened to knob-like Stieda body was present (c.0.5 μm deep × 2.5 μm wide) as well as a rounded to trapezoidal sub-Stieda (c.1.5 μm deep × 3.0 μm wide); however, no para-Stieda body was detected. The sporocyst residuum was composed of scattered spherules of different sizes, while vermiform sporozoites contained a refractile body, nucleus and visible striations. Analysis of the full-length mitochrondrial (mtDNA) genome revealed 3 protein-coding genes, (CytB, COI and COIII), 18 LSU and 14 small subunit (SSU) rDNA fragments, without transfer RNA genes with a total length of 6257 bp. Phylogenetic analysis of genomic SSU ribosomal sequences indicated that Isospora lugensae n. sp. is genetically similar to Eimeria reichenowi, isolated from a red-crowned crane (Grus japonensis) from Japan, with a 96.6% homology. The mtDNA sequence is most similar to Isospora serinuse with a 95.8% genetic similarity. Based on morphological and molecular data, this isolate is a new species of coccidian parasite that to date has only been found in a Kerguelen petrel.

一种新的球虫种，Isospora lugensae n。从一个单一的Kerguelen海燕（Lugensa brevirostris）描述。孢子状卵囊（n  = 25）的特征是长/宽（L / W）为24–25μm×21–23μm（24.8×22.2μm），呈球下体到椭圆体，比率为1.07–1.14μm（ 1.12）。它们包含双层壁，厚度为0.8-1.2μm（1.0），外层光滑，总厚度约为c / 2/3。卵囊含有两个极性颗粒，且都没有胶束和残留的卵囊。卵圆形孢子囊（n  = 25）的长宽比为15–16μm × 10–11μm （15.7× 10.8μm ），比率为1.41–1.49μm（1.46）。存在一个扁平到球形的Stieda身体（c。为0.5μm深×2.5微米宽），以及圆形到梯形子Stieda（角为1.5μm深×3.0微米宽）; 但是，没有检测到对斯蒂安达尸体。孢子囊残体由大小不一的散在小球组成，而蠕虫状的子孢子包含一个可折射的体，核和可见的条纹。全长线粒体（mtDNA）基因组的分析揭示了3个蛋白质编码基因（CytB，COI和COIII），18个LSU和14个小亚基（SSU）rDNA片段，而没有转移RNA基因，全长6257 bp。对SSU基因组核糖体序列的系统发育分析表明，Isospora lugensae n。sp。在遗传上类似于艾美叶菊（Eimeria reichenowi），是从丹顶鹤（Grus japonensis）中分离出来的），其同源性为96.6％。mtDNA序列与丝孢菌最相似，具有95.8％的遗传相似性。根据形态和分子数据，该分离物是一种新的球虫寄生虫，迄今为止仅在克格伦海燕中发现。