Aegyria foissneri Qu, Ma, Al-Farraj, Lin & Hu, 2017 from the benthic sand of the brackish channel between Fresh Pond and Napeague Bay
I returned to the brackish channel which connects Fresh Pond with the marine estuarine bay Napeague Harbor. I took a sample of the first 6 cm of sand from the channel. I found this rapidly swimming ciliate measuring 112 um in length which eventually calmed down and began rotating in one spot on the coverglass where I could see it was pivoting on a podite. The podite, taken with a dark anterior pigment spot made me think of Hartmannula but I couldn't visualize that genus' prominent cyrtos of nematodesmal rods surrounding the cytostome. Also, the angular beak-like anterior protrusion didn't fit with Hartmannula. In addition, there was a cleft in the posterior end and a raised ridge anteriorly (also similar to Hartmannula) which made me think of dysteriids.
I sent some videos and screen caps to my friend Bill Bourland and Ivan Cepicka- Bill kindly did some digging and provided me with an excerpt from a publication of the great German protistologist Alfred Kahl illustrating various dysteriids, one of which, Dysteria (Aegyria) oliva (Entz, 1884 ) was a very close apparent match. Noting the nomenclatural relationship between this and Aegyria, I Googgled around a bit and literally stumbled on a 2017 paper by Qua et al (see below) describing Aegyria foissneri sp. n. which was a perfect match for my observed protist! This made perfect sense after reading the paper by Qua et al who delineated the historically changing classifications of Aegyria:
"Aegyria was established by Claparède and Lachmann (1859) but no type was specified. For a long time Aegyria was thought to be a synonym of Dysteria Huxley,1857 (Deroux 1974; Kahl 1931). Deroux (1974) established Aegyriana and assigned Aegyriana oliva (basionym Aegyria oliva Claparède and Lachmann, 1859) as the type. Chen et al. (2012) re-activated the genus Aegyria and fixed Aegyria oliva Claparède and Lachmann, 1859 as the type based on the fact that Aegyria was actually not a synonym of Dysteria" (1).
Genetically, Qua et al's analysis of the SSU rDNA showed that "Aegyria foissneri sp. n. (KX364493) differs from A. oliva (FJ998029) by 58 bp, demonstrating the distinctness of A.foissneri as a new species" (1). Aegyria foissneri sp. n. clusters with A. oliva with full support, forming a clade to Trichopodiella faurei within the family Hartmannulidae Poche, 1913" (1).
The brief description from Qua et al: "Order Dysteriida Deroux, 1976. Family Hartmannulidae Poche, 1913. Aegyria Claparède and Lachmann, 1859. Species: Aegyria foissneri. Diagnosis. Cell size 85–170 × 45–80 m in vivo; body inverted oval with a protrusion and a dark pigment spot on anterior left part; 42–77 somatic kineties; one preoral and three to six circumoral kineties; five to eight transpodial segments; 31–44 nematodesmal rods; 12–16 contractile vacuoles; single oval macronucleus"(1).
It is interesting that modern day descriptions of Aegyria oliva state that there is no rostriforn protrusion but Kahl's depiction of Dysteria (Aegyria) oliva (Entz, 1884 ) clearly shows this feature.
I cannot seem to visualize the anterior cystostome surrounded by non-toothed nematodesmal rods no matter how I adjust my Nomarski but as you can see, it is not at all obvious in the photomicrographs of Qua et al either. I'll keep trying and post an update.
Zhishuai Qua,Honggang Ma, Saleh A. Al-Farraj, Xiaofeng Lin, Xiaozhong Hu. Morphology and molecular phylogeny of Aegyria foissneri sp. n. and
Lynchella minuta sp. n. (Ciliophora, Cyrtophoria) from brackish waters of southern China. European Journal of Protistology 57 (2017) 50–60
You can access the paper here:
https://faculty.ksu.edu.sa/sites/default/files/morphologyandmolecularphylogenyofaegyriafoissneri.pdf
