Tracheloraphis prenanti

Ma, Mingzhen, Xu, Yuan, Yan, Ying, Li, Yuqing, Warren, Alan & Song, Weibo, 2021, Taxonomy and molecular phylogeny of four karyorelictid species belonging to the genera Apotrachelocerca and Tracheloraphis (Protozoa: Ciliophora), with descriptions of two new species, Zoological Journal of the Linnean Society 192 : -

TRACHELORAPHIS PRENANTI Dragesco, 1960

( Figs 5–6; Table 3)

Since Tracheloraphis prenanti was originally described by Dragesco (1960), several isolates/populations have been reported ( Raikov & Kovaleva, 1968; Agamaliev,

Significant differences (P <0.05) between the best maximum likelihood tree and constrained topologies are in bold.

1983; Wright, 1983; Dragesco & Dragesco-Kernéis, 1986). Due to the similarity in living morphology between T. prenanti and T. phoenicopterus ( Cohn, 1866) Dragesco, 1960 , it was thought that both species belonged to the T. phoenicopterus- complex ( Raikov, 1962; Foissner & Dragesco, 1996b). In the present study, we supply new information for T. prenanti , based on a Chinese population. Analysis of all data available indicates that T. prenanti should be considered as a distinct species.

Improved diagnosis: Body length in vivo 400–2000 Μm; head dark in colour and clearly distinguishable from trunk; 14–26 somatic kineties on right side; glabrous stripe occupying entire left side; single nuclear group composed of four to ten macronuclei and two or three micronuclei; cortical granules tiny, colourless, densely distributed.

Description of the new population: Fully extended cells about 800 × 20 Μm in vivo, flexible, dorsoventrally flattened, ribbon-like and distinctly tripartite with head, neck and trunk regions; head claviform and tail pointed ( Figs 5A–C, 6A–C). Body often dark greyish or grey-brownish at low magnification due to multiple inclusions, e.g. the dumbbell-like inclusions ( Fig. 6G). Single nuclear group located in mid-body with a few crystals in the nuclear group ( Fig. 6H); composed of four to ten macronuclei, each 10–15 Μm in diameter, and two micronuclei, each 2–3 Μm in diameter and closely associated with macronuclei; nuclear group conspicuously lighter in appearance than surrounding area ( Figs 5 A, 6A –C). Cortical granules colourless c. 0.5 Μm in diameter, scattered between ciliary rows on right side and in glabrous stripe. Width of the glabrous stripe about same as cell width ( Figs 5E, F, 6D, E). Locomotion by gliding between sand grains and organic debris.

Right side of cell densely ciliated, left side unciliated, dominated by glabrous stripe ( Figs 5H, 6M). Somatic kineties consisting of dikinetids with cilia about 10 Μm long. 15–23 kineties on trunk. Anterior and posterior secant system on left side of glabrous stripe surrounded by bristle kinety ( Figs 5H, 6M, N). Oral ciliature consisting of singlerowed circumoral kinety, open on left side and interrupted by two inserted brosse kineties ( Figs 5I, J, 6J, K).

TRACHELORAPHIS OLIGOSTRIATA ( RAIKOV, 1962) FOISSNER & DRAGESCO, 1996

( FIGS 7, 8; TABLE 3)

This species was originally reported by Raikov (1962) andredescribedindetailbyFoissner&Dragesco(1996b). Our population matches both descriptions well, therefore only a brief redescription is given here.

Improved diagnosis: Body length in vivo 200–800 Μm, with small and indistinct head; cortical granules tiny and colourless, sparsely distributed; usually six to eight somatic kineties on right side; number of macronuclei extremely variable, (mostly five to 25) forming a strand; about three to 15 micronuclei; glabrous stripe about same width as body.

Description of the Chinese population: Fully extended cells about 500–800 Μm long in vivo; body flexible and contractile, head and neck rather transparent and indistinctly separated from trunk ( Figs 7A–C, 8A–C). Cortical granules tiny, about 0.5 Μm long, sparsely distributed on glabrous stripe ( Figs 7E, 8F). Endoplasm light-todark grey due to numerous refractile inclusions ( Fig 8D, E). Macronuclei extremely variable in number, i.e. five to 43, but usually fewer than 25; three to 15 micronuclei; nuclei usually in groups of two or three macronuclei and one or two micronuclei, arranged in a strand ( Figs 7D, F, J, 8H, L). Locomotion by gliding between sand grains and organic debris.

Infraciliature as shown in Figures 7 and 8. Six complete somatic kineties consisting entirely of dikinetids; no anterior or posterior secant system formed at cell margin. Glabrous stripe about same width as body. Oral ciliature composed of single-rowed circumoral kinety, interrupted by one inserted brosse kinety ( Figs 7H, I, 8I, J).