Epistylis semiciculus, Zhou & Wang & Yang & Gu, 2019
|
publication ID |
https://doi.org/ 10.1016/j.ijppaw.2019.09.006 |
|
persistent identifier |
https://treatment.plazi.org/id/E24DB579-FF99-F014-BA12-3259FB36CD85 |
|
treatment provided by |
Felipe |
|
scientific name |
Epistylis semiciculus |
| status |
|
Genus Epistylis Ehrenberg, 1830 View in CoL View at ENA .
Epistylis semiciculus n. sp.
Host and site: pereopods and gills of Procambarus clarkia . Prevalence and sampling sites: shown in Table 1.
Diagnosis. Extended zooids vase-shaped. Macronucleus C-shaped
I, morphotype I collected on April 28th, 2016 and 9th January, 2019; II, morphotype II collected on May 8th, 2016; n, number of specimens measured; Min, Minimum; Max, Maximum; Mean, arithmetic mean; SD, standard deviation; CV, coefficient of variation in %; P, P value.
with variable orientation. One contractile vacuole ventrally located below peristomial lip. Number of silverlines 152–238 from peristome to scopula. Three rows of P1 equaled in length. Three rows of P2 terminate at same level. The inner row of P3 shorter than other the two rows.
3.1. Type locality
Morphotype I was found in freshwater crayfish pond in Qianjiang City (30̊15′ N; 112̊47′ E) and Xiaogan City (31̊01′ N; 113̊50’ E), Hubei Province, China.
Morphotype II was found in freshwater crayfish pond in Qianjiang City (30̊15′ N; 112̊47’ E), Hubei Province, China.
Type material: The protargol-stained slide containing the holotype specimen and the silver nitrate strained slide containing the paratype have been deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences , Beijing, China, with registration number HB2016001 and HB2016002. Three protargol-stained slides have been deposited in the Department of Aquatic Animal Medicine , College of Fisheries , Huazhong Agricultural University , Wuhan , China, with registration number zt201604281, zt201604282 and zt201604283 .
Etymology: The species-group name Epistylis semiciculus refers to the semicircular peristomial disk.
3.2. Description
Morphotypes I detected adhering onto the pereopods and the gills of Procambarus clarkia ( Fig. 1A View Fig ). Colonies consisted of 4–6 zooids ( Figs. 1C View Fig and 4A View Fig ) with extremely short secondary stalks (mean length 43 μm) ( Fig. 1C View Fig ). Zooids measured 80–105 × 30–55 (average 87.6 × 42.6) μm with length-to-width radio of 2:1 ( Fig. 1C View Fig ). Secondary stalk average 42.5 μm in length ( Fig. 1C View Fig ). Peristomial lip average 9.6 (8.2–11.6) μm in thickness and 41.1 (30.8–35.5) μm in diameter. Peristomial disk 19.7 (17.8–21.7) μm in diameter, and evidently elevated above peristome at a height of 7.2 (5.0–9.2) μm ( Table 2). Numerous granules were distributed uniformly in the zooids ( Fig. 1C View Fig ).
Morphotype II adhered onto the pereopods of Procambarus clarkia ( Fig. 1B View Fig ). Colonies approximately consisted of 90 zooids ( Figs. 1D View Fig and 4B View Fig ). The expanded zooids measured 135–170 × 60–90 (153.8 × 73.6) μm ( Figs. 1E View Fig and 4C View Fig ) with average length-to-width radio of 2:1. Secondary stalk averaged 2278.5 μm in length ( Fig. 1D View Fig ). Peristomial lip, measured 57.1 (54.3–62.5) μm in diameter and 13.1 (10.3–15.5) μm in thickness ( Fig. 1E View Fig ). Peristomial disk measured 33.3 (30.2–37.9) μm in diameter with an average height of 11.1 (9.6–13.9) μm ( Table 2). The cytoplasm near the scopula was darker than that of the other regions because of different density of gray granules ( Fig. 1E View Fig ).
Despite the morphometry and granules, the two morphotypes presented congruent morphological characteristics. Zooids presented a vase-shaped body ( Fig. 1C, E View Fig ). Peristomial disk revealed semicircle-shaped and evidently elevated above peristomial lip ( Fig. 1G and H View Fig ). Shallow longitudinal and obvious transverse striations visible on stalk surface ( Fig. 1F View Fig ). Single contractile vacuole dorsally located blow peristomial lip ( Fig. 1E View Fig ). C-shaped macronucleus located at anterior body with longitudinal (48% zooids, Fig. 1G View Fig ) or transverse (52% zooids, Fig. 1H View Fig ) orientation. Transverse striations were clearly visible on pellicle at ×1000 magnification ( Fig. 1I View Fig ).
Zooids detected leaving stalk and transforming free-swimming form (telotrochs). Body shape of telotrochs slightly similar to that of mobilids in morphology ( Fig. 2A View Fig ). C-shaped macronucleus oriented at center zooids ( Fig. 2E and F View Fig ). Oral infraciliature ( Fig. 2B and C View Fig ) and transverse striations detected on oral region at ×1000 magnification ( Fig. 2D View Fig ). Individual telotroch can swim by using cilia ( Fig. 2A View Fig ).
Macronucleus presented C-shaped with transverse or longitudinal orientation after protargol strained ( Fig. 3B and C View Fig ) and silver impregnated ( Fig. 3I View Fig ). Aboral trochal band revealed at anterior 65% of zooid length ( Fig. 3C View Fig ). Oral infraciliature of the two morphotypes was identical after protargol straining ( Figs. 3A View Fig and 4D View Fig ). Polykinety (P) turned 1.5 times around peristomial disk with the hapokinety (H). Germinal kinety emerged at distal end of polykinety and hapokinety ( Figs. 3A View Fig and 4D View Fig ). Polykinety transformed into infundibular polykinetids 1–3 (P1–3) within infundibulum ( Fig. 3A View Fig ). Three rows of P1 equaled in length ( Fig. 3A, D View Fig ). Three rows of P2 terminated at same level ( Fig. 3E and F View Fig ). Inner row of P3 shorter other equal two rows ( Fig. 3E and F View Fig ). After dry silver impregnated, transverse silverlines ( Fig. 3G and H View Fig , 4E View Fig ) and pores ( Figs. 3G View Fig and 4E View Fig ) detected on pellicle. The average numbers of silverlines from peristome to scopula 172 (morphotype I) and 196 (morphotype II).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.