Sapphirina

Thompson J.V., 1829

Sea Sapphires

Sapphirina is a of marine planktonic copepods in the Sapphirinidae, commonly known as sea sapphires. Males exhibit striking iridescent structural coloration ranging from gold to deep blue, produced by multilayered guanine crystal plates beneath the . Females are translucent and lack this coloration. The genus comprises specialized of pelagic tunicates (salps), with some exhibiting a complex involving both parasitic and predatory phases.

Pronunciation

How to pronounce Sapphirina: /sæfɪˈraɪnə/

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Identification

Males distinguished by brilliant iridescence with -specific spectral patterns; structural coloration caused by interference from multilayered guanine crystal plates beneath the body surface. Females translucent and non-iridescent. Specific identification requires examination of morphological features and spectral characteristics: S. angusta and S. opalina show dual spectral peaks (~420 nm and >750 nm); S. auronitens and S. gastrica peak at >500 nm; S. ovatolanceolata peaks between 430–600 nm; S. metallina shows variable peaks across wide wavelength range.

Habitat

Epipelagic zone of the open ocean; associated with dense swarms of pelagic tunicates (salps), particularly Thalia democratica and Pegea .

Diet

Specialized of pelagic tunicates (salps); S. angusta has been documented in a specialized predator-prey relationship with Thalia democratica.

Life Cycle

Includes both parasitic and predatory phases; ovigerous females observed lodged inside salp zooids near entry orifices, with high relative to other planktonic copepods. Males have been found attached inside salp bodies, though this differs from earlier behavioral observations.

Behavior

Spiral-swimming when stimulated by light; males exhibit significantly higher swimming speed and turning frequency than females. Positive at light intensities >0.05×10¹⁴ quanta cm⁻² s⁻¹ for wavelengths of 430 nm and 580 nm. No significant diel variation in swimming activity under continuous darkness. -specific photoresponses: S. gastrica shows increased locomotion across broad wavelength range (430–580 nm), while S. opalina shows peak activity at 430 nm. Iridescence can be modulated by physical manipulation of the multilayer crystal structure.

Ecological Role

Specialized of salps in open-ocean epipelagic ; proposed role in mate recognition system involving male iridescence, fast spiral-swimming, and -specific photoresponses.