Crangon allmanni
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| Kinahan , 1860 |
Crangon allmanni , also called furrow shrimp , is a species of shrimp from the genus Crangon within the family of Crangonidae . It isnative tothe Northeast Atlantic and is not fished commercially.
features
Crangon allmanni can reach a body length of up to 75 mm, but is usually shorter. It has a brownish-gray to reddish-gray color. The short rostrum is about half the length of the eyes and is narrow with a rounded tip. The carapace is smooth except for a dorsal spine and a pair of side spines (Branchiostegal spines). Crangon allmanni differs from the North Sea shrimp ( Crangon crangon ) by a deep, longitudinal , dorsal furrow on the sixth and thus rearmost pleon segment . An elevation (Carinae) runs parallel to the furrow on each side. There are two pairs of small side spikes on the telson .
Male and female specimens can be identified by microscopic examination of the swimming legs . On the endopodit of the second swimming leg of the male there is a clamp-like appendix ( appendix masculina ).
distribution and habitat
The occurrences of Crangon allmanni are restricted to the eastern boreal zone of the Atlantic Ocean. The species is distributed from the White Sea to the Bay of Biscay as well as in the entire North Sea , near Iceland and in the Kattegat . They are found at depths of 20 to 250 m, occasionally up to 360 m. It occurs on sandy or muddy seabeds.
Way of life
Crangon allmanni feeds mainly on crustaceans (Crustacea) and ring worms (Annelida). Besides be mollusks (Mollusca), Foraminiferen (Foraminifera) and brittle stars (Ophiuroidea) eaten. Whiting scales have been found in the stomachs of some specimens .
Crangon allmanni is single sex . The first egg-bearing females appear in small numbers at the end of the first week of December. In April and May, the number of egg-bearing females reached a maximum of 26%, a further maximum was seen in offshore populations in July. Newly laid eggs are translucent gold, round and 0.39 mm in diameter. In the course of development, the eggs become elongated and reach a length of about 0.69 mm by the time they hatch. The females carry up to 2500 eggs on average, larger specimens can carry up to 7000 eggs. The development time to the larva is about seven weeks. Most animals live to be three years old, some live to be a year older. Males may die sooner, shortly after copulation .
etymology
With the epithet allmanni who honored Erstbeschreiber John R. Kinahan the Irish naturalist George J. Allman . According to Allen, the spelling allmanni is a lapsus calami (spelling mistake) and the correct spelling should be allmani .
Individual evidence
- Jump up ↑ Joana Campos, Cláudia Moreira, Fabiana Freitas & Henk W. van der Veer: Short review of the eco-geography of Crangon . In: Journal of Crustacean Biology . 32, No. 2, 2012, pp. 159-169. doi : 10.1163 / 193724011X615569 .
- ↑ Fish stocks online ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ PJ Hayward, JS Ryland: Handbook of the Marine Fauna of North-West Europe. Oxford University Press, 1990, ISBN 978-0198540557 , p. 425.
- ↑ a b First description in Proceedings of the Natural History Society of Dublin 2. ( Online )
- ↑ Andrew Hosie: Crangon allmanni. A shrimp. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programs, 2009. ( Online )
- ↑ a b Crangon allmani the Marine Species Identification Portal.
- ↑ a b c d e J. A. Allen: On the biology of Crangon allmani Kinahan in Northumberland Waters. In: Journal of the Marine Biological Association of the UK. 1960, 39, pp. 481-508. ( Online ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice .; PDF; 7.8 MB)
