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Atylus swammerdami (female + male)
Amphipods are distinguished from shrimps (Decapods) and shrimp like animals (Mysids) by their body plan. Eyes are located latteraly on the head and consist out of ocelli, while mysids and shrimps have stalked eyes located in the fromt of the rostrum (most of the time). Amphipods have a pereosome (first 7 body segments) + pleosome (subsequent 3 body segments) + urosome (last 3 body segments) to which 3 uropods are attached.
This species belongs to the family of the Atylidae and is recognised by the spine on the urosome. Eyes are big and kidney-shaped. Little hairy tufts (setules) on the antenna 2 peduncles of males.
Diastylis sp.
Gastrosaccus spinifer (male)
Mysids are recognised specifically by their statocysts located in the bottom part of the endo uropods of the tailfin at the end of the abdomen. They have lots of exopods on the pereopods, which are slender. Pereopods don't cary any chela or claw like structures. More information on this species is recorded in a tutorial. I wanted to try if the record function could be used in practice:
Pseudocuma similis
Cumaceans are recognised by their curved body plan to make them look like a (,). They have a strong sexual dimorphism and need to be handled with care to distinguish males from females of the same species. Females lack pleopods, while they are present or absent in males. Females also have brood pouches, are larger and also more numerous. Most of the individuals in my samples were females with eggs and young individuals.
On the left: an individual of Diastylis sp. can be recognised by the large telson. Most of the cumaceans don't have a large telson except for 2 families such as the Diastylidae. Individuals of this family are also larger most of the time. A characteristic feature of this individual is the last pereonite (pereonite 5). This is curved backwards to form two spines.
On the right: an individual of the genus Pseudocuma is displayed. The family of the Pseudocumatidae is recognised by their very small telson compared to the other two families. The species Pseudocuma similis is recognised by the truncated telson in females.
Spiophanes bombyx
A small tube living polychaete belonging to the family of the Spionidae. The tube is fragile and consists of loose grains of sediment coupled to an adhesive structure secreted by the worm.
This species is common and recognised by the two "horns" at the prostomium (head) which are actually the prostomial palps. Prostomium can carry two pairs of eyes. Parapodia are not well developped compared to free living polychaetes.
Mesopodopsis slabberi
The same principle is used to recognise mysids as with Gastrosaccus spinifer. This species is easily recognised by its telson which has a peculiar form. The eye stalks are also much longer compared to the cornea.
Spirobranchus sp. (Pomatoceros sp.)
These polychaetes belong to the family of the Serpulidae and lives in calcereous tubes attached to shells or other hard substrates. The individuals from my samples were attached to shells of Mytilus edulis. It is recognised by the tentacle crown at the prostomium. On top of the prostomium, there is a calcereous operculum that can be used when retracting into the tube to close it afterwards.
All pictures of macro- and hyperbenthic fauna on the website are own images taken through the macroscope with my phone. The picture of Jassa falcata in the quiz is from: https://nl.wikipedia.org/wiki/Jassa_falcata
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