Diacyclops thomasi

(Forbes, 1882)

Diacyclops thomasi is a cyclopoid copepod in the Cyclopidae, first described by Forbes in 1882. The species exhibits a distinctive involving summer with whole-body encystment at the copepodid IV stage. During encystment, the organism undergoes profound metabolic depression and ultrastructural reorganization of its digestive tract, including of epithelial and accumulation of lipid-rich lacunae.

Cyclops thomasi (8741967598) by NOAA Great Lakes Environmental Research Laboratory. Used under a CC BY-SA 2.0 license.

Pronunciation

How to pronounce Diacyclops thomasi: /ˌdaɪəˈsaɪklɒps ˈtɒməsaɪ/

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Images

Seasonality

Summer observed; encystment occurs during this period, suggesting reduced or suspended activity during warmer months

Life Cycle

includes summer with encystment at the copepodid IV (CIV) stage. Encystment is progressive, with the cyst structure indicating the extent of diapause entry. During encystment, the epithelium undergoes striking : active individuals possess two distinct epithelial (vacuolar B-cells and F/R cells with dense microvilli), while encysted specimens show inactive with concentrated euchromatin, reduced , and large lipid-rich lacunae in the urosome and . An intermediate state occurs at the beginning of encystment.

Behavior

Exhibits encystment during summer —a state characterized by metabolic depression, structural reorganization of digestive tissues, and progressive cyst formation that serves as a protective mechanism against unfavorable conditions