Amber annelid worm
| Amber annelid worm | ||||||||||||
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Amber Annelworm ( Alitta succinea ), Epitoke |
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| Scientific name | ||||||||||||
| Alitta succinea | ||||||||||||
| ( Frey & Leuckart , 1847) |
The Amber annelid ( Alitta succinea , frequent synonyms : Nereis succinea , Neanthes succinea ) is a cosmopolitan marine annelid of the genus Alitta within the polychaete - Family of Nereididae .
features
The amber annelid grows up to 19 cm long and then has around 160 segments . On the prostomium are a pair of short antennae without antenna supports, a pair of two-part palps and two pairs of eyes arranged in a trapezoid. The dorsal Tentakular - Cirrus clouds are longer than the ventral; the second dorsal cirrus extends to the third to eighth, rarely to the fifteenth segment. The pharynx has a pair of toothed jaws. The mouth and maxillary rings have conical paragnaths.
The parapodia of the first two bristle-bearing segments are single-branched with three lobes. All other parapodies have two branches with four lobes. In the parapodia of the anterior segments of the Notopodium the lobe of the acicula is bilobed and the dorsal cirrus is as long or shorter than the lobe of the parapodium. In the posterior segments, the dorsal lobes of the notopodium are enlarged, with the dorsal cirrus beginning almost at the end. The ventral cirrus is shorter than the lobes. The thorn and sickle-bearing bristles have a small ring distally.
The animal has a dark head and a brownish front body. The rear section is greenish, yellowish or reddish with white spots or very dark.
The epitoke of the male animal has seven bristle-bearing segments with dorsal cirrus, which initially widen distally and taper at the tip. The ventral cirrus of the first five segments is similar. The dorsal cirrus shows ventral warts in the changed area. In the epitoke of the female, the dorsal and ventral cirrus of the first five segments are somewhat widened and smooth in the changed area. The changed parapodia in females begin on the 14th to 15th segment and are normal again from the 25th to 56th segment.
Distribution, habitat and way of life
Alitta succinea is cosmopolitan on sandy substrate in the brackish water of the great estuaries, including the North Sea , the English Channel , Skagerrak and Kattegat .
The amber annelworm feeds on detritus, diatoms , dinoflagellates , protozoa and microscopic multicellular animals by ingesting substrate particles and digesting the adhering food particles.
Life cycle
The amber annelid worm has separate sexes, with females and males of roughly equal size and external fertilization. Both females and males metamorphose at sexual maturity to a floating form with enlarged, more lobed parapodia, known as epitoke or heteronereis. The epitokes come together in great numbers and die after the eggs and sperm are released for external fertilization. 36 hours after fertilization, the eggs develop into hairy, two-segmented larvae that swim freely as zooplankton . The larvae sink to the seabed when they have 9 to 12 segments and metamorphose into creeping worms.
literature
- Stanley J. Edmonds: Fauna of Australia, Volume 4A. Polychaetes & Allies. The Southern Synthesis 4. Commonwealth of Australia, 2000. Class Polychaeta. Pp. 158-162, Family Aphroditidae.
Web links
- J. Masterson: Neanthes succinea Frey and Leuckart, 1847. Smithsonian Marine Station, Indian River Lagoon Species Inventory
- MJ de Kluijver et al .: Nereis succinea Frey & Leuckart, 1847. Macrobenthos of the North Sea - Polychaeta, Marine Species Identification Portal
Individual evidence
- ↑ a b Erica V. Pardo, Daniel M. Dauer (2003): Particle size selection in individuals from epifaunal versus infaunal populations of the nereidid polychaete Neanthes succinea (Polychaeta: Nereididae). Hydrobiologia 496 (1-3), pp. 355-360.