Acineta nitocrae
Common Name:
A suctorian ciliate
Synonyms and Other Names:
Identification:
This unicellular protest possesses a short, narrow stalk with a suction-like cup at its base. The narrow stalk then widens into the main body of the organism – a single cell protected by a rigid lorica (covering) that contains a dark macronucleus. The lorica gives rise to retractable actinophores covered in long tentacles with enlarged ends. In contrast to other species in the genus, A. nitocrae is more elongated and flattened (length to width ratio = approximately 3:1) and has a shorter and more curved stalk, a longer macronucleus, and more triangularly-shaped actinophores (Dovgal 1984; Grigorovich et al. 2001).
Size:
From the stalk to the tip of the actinophore, 79-105 µm in length (Dovgal 1984; Grigorovich et al. 2001).
Native Range:
A Ponto-Caspian species, A. nitocrae is known from the northern Black Sea coast and various regions in the Dnieper River drainage in the Ukraine (Dovgal 1984; Grigorovich et al. 2001).
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This map only depicts Great Lakes introductions.
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Great Lakes Nonindigenous Occurrences:
A. nitocrae was recorded in Lake Erie in 1997 and the Detroit River in 1999 (Grigorovich et al. 2001). Given that its known hosts, Nitokra spp., are distributed in all the Great Lakes except Lake Superior (Hudson et al. 1998; Lesko et al. 2003), A. nitocrae may be present in these water bodies as well.
Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Acineta nitocrae are found here.
Table last updated 5/2/2024
† Populations may not be currently present.
Ecology:
A. nitocrae lives as an epizooic on or near the caudal rami of harpacticoid copepod hosts. In North America, recorded host species include Nitokra hibernica and N. incerta. In the Ukraine, host species include these two copepods as well as N. lacustris and Canthocamptus staphylinus. The preferred host is N. hibernica (Grigorovich et al. 2001).
Adult Acineta spp. give rise to larval tomites (swarmers), which emerge from a parent cell. Tomites do not require nutrition, but swim via cilia to find a host. They settle, attaching with a newly grown suction-cup end, then metamorphose into fixed organisms that can feed using tentacles. The ideal water temperature for this species is 4-11°C, and densities greatly decline at 19-23°C. A. nitocrae can tolerate salinities of 0.1-5 ppt or possibly higher (Dovgal 1984; Grigorovich et al. 2001).
Means of Introduction:
Likely introduced to the Great Lakes in ballast water, either as free-swimming larvae or as sessile adults attached to a copepod host (Grigorovich et al. 2001).
Status:
Established in the Lake Erie drainage, and possibly in other areas of the Great Lakes where the copepods N. hibernica and/or N. incerta are present.
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
There is little or no evidence to support that Acineta nitocrae has significant environmental impacts in the Great Lakes.
Potential:
Acineta nitocrae is commensal with the Great Lakes nonindigenous copepods Nitokra hibernica and N. incerta (Grigorovich et al. 2001). However, high densities could potentially affect hosts’ exoskeletons, movement, respiration, nutrient uptake, and reproduction (Grigorovich et al. 2001). With the exception of Lake Superior, Nitokra species are abundant throughout the Great Lakes. It is possible that these copepods will transport A. nitocrae to Lake Superior if they continue to spread (Grigorovich et al. 2001, Hudson et al. 1998, Lesko et al. 2003).
There is little or no evidence to support that Acineta nitocrae has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Acineta nitocrae has significant beneficial effects in the Great Lakes.
Management:
Regulations (pertaining to the Great Lakes)
There are no known regulations for this species.
Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
There are no known biological control methods for this species.
Physical
There are no known physical control methods for this species.
Chemical
There are no known chemical control methods for this species.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
References
(click for full reference list)
Author:
Kipp, R.M., A.K.Bogdanoff, and A. Fusaro.
Contributing Agencies:
Revision Date:
9/13/2019
Citation for this information:
Kipp, R.M., A.K.Bogdanoff, and A. Fusaro., 2024, Acineta nitocrae: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatLakes/FactSheet.aspx?Species_ID=2367&Potential=N&Type=0&HUCNumber=DGreatLakes, Revision Date: 9/13/2019, Access Date: 5/2/2024
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.