Pyxicola Pusilla (Wrześniowski, 1866) Kent, 1882
The common solitary loricate and operculate sessile peritrich Pyxicola attached to plants from the brackish channel between Fresh Pond and Napeague Bay. Hoffman modulation contrast 200x plus variable phone cropping.
From: https://www.nies.go.jp/.../morpho/ciliopho/pyxicola.htm
Pyxicola
Pyxicola Kent, 1881 (ref. ID; 1248) or 1882 (ref. ID; 2014)
Class Oligohymenophora: Subclass Peritricha: Order Peritrichida: Suborder Sessilina (ref. ID; 2014)
Family Vaginicolidae Kent, 1881 (ref. ID; 1248)
Synonym; Caulicola Stokes, 1894 (ref. ID; 2014); Pachytrocha Kent, 1882 (ref. ID; 2014)
[ref. ID; 2014]
Elongate, trumpet-shaped body contained within an erect pseudochitinous lorica and mounted upon a stalk. While the lorica itself is without valves etc., the body bears a discoid operculum beneath the peristome border which seals the aperture when the animal contracts. Strong contraction results in the animal retreating deep into the lorica and the operculum then only covers the peristome region. The lorica and operculum as well as the basal plate which attaches to the substrate become orange to brown in older individuals due to absorption of iron or other minerals. I show you several individuals of different ages all from the same sample.
I base my speciation on the description of the stalk and lorica for P. pusilla (1) which conforms perfectly to this observation.
The lorica is urceolate, about 60–70 × 30–35 μm in size and with a colour the same as the operculum (Fig.3A–G). The anterior portion of the lorica is constricted and bent, forming a short neck (Figs 2G–J, 3A–G), which is about one-eighth of the lorica in length. The aperture is circular and oblique, about 19–22 μm across (Figs 2G–J, 3A–G, J). There are three distinct annular ridges at the main part of the lorica (Figs 2A–J, 3A–G) that reaches its greatest width at the lowest ridge. The bottom of the lorica is double-layered and holds the mesostyle and endostyle within a tube extension (Figs 2G–J, M, 3H, I, M, N).
The endostyle, mesostyle and stalk are contiguously connected with longitudinal striae. This combination penetrates the lorica wall via a tube-like structure (Figs 2A–D, M, 3M, N). The zooid sits on top of the endostyle and the tube. The endostyle is 1.0–1.5 μm long and the mesostyle is 2.0–2.6 μm long, knot-like and flared at the equator (Figs 2M, 3M, N). The lorica attaches to the substrate via a non-contractile stalk that is continuous with the mesostyle, attaching to the substrate via a basal disc (Figs 2A–E, 3N). The stalk itself varies significantly in length (between 2 and19 μm), but this variance is not correlated with age. Like the lorica, the basal disc becomes more coloured with age (Fig. 3A–G).
- (ref: https://www.researchgate.net/publication/345494459_Novel_contributions_to_the_peritrich_family_Vaginicolidae_Protista_Ciliophora_with_morphological_and_phylogenetic_analyses_of_poorly_known_species_of_Pyxicola_Cothurnia_and_Vaginicola/figures)
Novel contributions to the peritrich family Vaginicolidae (Protista: Ciliophora), with morphological and phylogenetic analyses of poorly known species of Pyxicola, Cothurnia and Vaginicola. BORONG LU, , LIFANG LI, XIAOZHONG HU, DAODE JI, KHALED A. S. AL-RASHEID,and WEIBO SONG. Zoological Journal of the Linnean Society, 2019, 187, 1–30.
