Parametacystis pulchra, Jiang & Wang & Liao & Al-Farraj & Warren & Hu, 2024

Jiang, Limin, Wang, Congcong, Liao, Lijian, Al-Farraj, Saleh A., Warren, Alan & Hu, Xiaozhong, 2024, Re-evaluation of the systematic position of the order Prostomatida (Protista: Ciliophora), with the establishment of two new genera and two new species, Zoological Journal of the Linnean Society 200 (4), pp. 849-864 : 854-855

publication ID

https://doi.org/ 10.1093/zoolinnean/zlad116

publication LSID

lsid:zoobank.org:pub:8E04CA83-16B0-4A9F-80B0-267704C75165C

DOI

https://doi.org/10.5281/zenodo.11248013

persistent identifier

https://treatment.plazi.org/id/03DD8799-886F-A169-ACD3-F924FBB2FA7C

treatment provided by

Plazi

scientific name

Parametacystis pulchra
status

gen. nov., sp. nov.

Parametacystis pulchra gen. nov., sp. nov.

( Fig. 4 View Figure 4 ; Table 1 View Table 1 )

Zoobank registration: urn:lsid:zoobank.org:act:1F7796F3-5ABA-4955-AD9A-B3A9BF7D4030

Diagnosis: Cell cylindrical, 40–75 μm × 15–25 μm in vivo; without lorica or caudal cilium; ‘head’ region present; single globular to ellipsoidal macronucleus and single ellipsoidal micronucleus; cortical granules spherical and colourless; circumoral kinety composed of 7–10 dikinetids, forming a semi-circle; perioral kineties forming six transverse monokinetidal rings; 24–32 monokinetidal longitudinal somatic kineties, kinetids of which form 20–36 transverse rings.

Type locality: Intertidal zone of Yellow Sea coast near Zhanqiao Pier, Qingdao (36°04ʹ03″N, 120°19ʹ35″E), Shandong Province, China. The salinity was 31‰ and the water temperature 10°C GoogleMaps .

Type specimens: A protargol slide containing the holotype specimen (registration number: JLM2021112901-1; Fig. 4B, C View Figure 4 ) was deposited in the Laboratory of Protozoology , Ocean University of China. A second protargol slide (registration number: JLM2021112901-2) containing paratype specimens was deposited in the Marine Biological Museum , Chinese Academy of Sciences, Qingdao .

Etymology: The species-group name pulchra (Latin feminine of pulcher = beautiful) refers to its beautiful shape.

Description: Cell size in vivo ~40–75 μm × ~15–25 μm, on average 60 μm × 20 μm, with a length-to-width ratio of 2–4:1 ( Fig. 4A, F, G View Figure 4 ). Body flexible and slightly contractile, almost cylindrical but progressively narrowed from middle to both ends ( Fig. 4A, F, G View Figure 4 ). Oral bulge rather conspicuous and distinctly projecting from body; without oral basket or nematodesmata; cytostome central and apical, inconspicuous ( Fig. 4A, F, G View Figure 4 ). Posterior end of body truncated owing to presence of a large, non-contractile caudal vacuole, ~5–9 μm in diameter ( Fig. 4A, F, G View Figure 4 ). Ectoplasm with distinct transverse furrows ( Fig. 4A, F, G View Figure 4 ). Network of furrows extends over entire body surface, consisting of regular rectangles (one between adjacent kineties), which is likely to be the silverline system ( Fig. 4D, H View Figure 4 ). Cortical granules spherical, colourless, ~0.5–0.6 μm in diameter, arranged regularly along somatic kineties ( Fig. 4D, H View Figure 4 ). Cytoplasm colourless, usually containing several ellipsoidal or globular granules ( Fig. 4A, F–H View Figure 4 ). One macronucleus, globular or slightly ellipsoidal in shape, ~6–8 μm × 5–8 μm after protargol staining, located slightly above mid-region of cell; one micronucleus, ellipsoidal, ~3 × 2 μm after protargol staining, located in a small groove adjacent to macronucleus ( Fig. 4A, J View Figure 4 ). No contractile vacuole observed. Locomotion by swimming moderately fast in upper layer of water, with anterior end swinging from side to side.

Most somatic cilia ~6–7 μm long; perioral cilia well developed and ~9–10 μm long ( Fig. 4A, F, G View Figure 4 ). Somatic ciliature composed of 24–32 longitudinal monokinetidal kineties regularly disposed around the body; kinetids form 26–42 uniformly spaced transverse rings ( Fig. 4B, C, I View Figure 4 ). Perioral kineties more closely spaced than other somatic kineties, located between circumoral kinety and other somatic kineties, consisting of six transverse monokinetidal rings ( Fig. 4B, C, E, K, L View Figure 4 ). Other somatic kinetids form 20–36 transverse rings. Circumoral kinety incomplete, composed of 7–10 dikinetids that form a semi-circle ( Fig. 4B, C, E, K, L View Figure 4 ).

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