Septibranchia

Septibranchia
Systematics
Trunk :	Molluscs (mollusca)
Sub-stem :	Shell molluscs (Conchifera)
Class :	Mussels (Bivalvia)
Subclass :	Autolamellibranchiata
Superordinate :	Anomalodesmata
Order :	Septibranchia
Scientific name
	Septibranchia
	Pelseneer , 1888

The Septibranchia are an order of the mussels (Bivalvia), which are placed in the subclass Autolamellibranchiata for the superordinate order Anomalodesmata . The oldest representatives of this group are known from the Upper Cretaceous.

Characteristics

The order is characterized by cases with mostly unequal keys, the rear end of which is often elongated. The shell is aragonitic with pearlescent prismatic microstructures. The castle is largely reduced. The ligament is internal and has supports. The characteristic feature of this group are the so-called "septibranch" gills. According to recent studies, this type of gill could also have arisen convergently within the anomalodesmata.

Way of life

The representatives of the order Septibranchia have developed a very unusual way of life for mussels: They predatorily live on small crabs . The basis for catching prey is the gill, designed as a muscular septum, through which the mantle cavity is divided into two chambers and which enables an abrupt, powerful influx of water. The animals live mostly buried in the soft sediment and only stretch the large siphons over the sediment surface. If a small crab swims near these siphons, a stimulus is triggered by tactile organs on the surface of the siphons or on sensory tentacles. While the Verticordiidae catch their prey with sticky tentacles, in the Poromyidae and Cuspidariidae it gets into the mantle cavity with the help of the inflow siphos , as the mussel suddenly sucks in a larger amount of water with the crab by contraction of the septum. The flap at the base of the Sipho prevents it from escaping. Poromya granulata can put its inflow siphon like a hood over the prey and then move in. In this way transported into the mantle cavity, the victim is brought into the mouth with the labial palps and devoured with the help of the muscular esophagus. The proteins are digested with the help of a strong protease in the mussel's stomach.

Systematics

The order contains the following superfamilies:

Verticordioidea Stoliczka, 1870
Poromyoidea Dall, 1886
Cuspidarioidea Dall, 1886

literature

Michael Amler, Rudolf Fischer & Nicole Rogalla: mussels (Haeckel library, vol. 5). Enke Verlag, Stuttgart 2000 ISBN 3-13-118391-8 .
Rüdiger Bieler & Paula M. Mikkelsen: Bivalvia. A look at the branches . In: Zoological Journal of the Linnean Society of London , Vol. 148 (2006), pp. 223-235, ISSN 0024-4082 .

Web links

Mikko's Phylogeny Archive - Anomalodesmata

Individual evidence

↑ JA Allen, Rhona E. Morgan: The functional morphology of Atlantic deep water species of the families Cuspidariidae and Poromyidae (Bivalvia): an analysis of the evolution of the septibranch condition. Philosophical transactions of the Royal Society of London: B, Royal Society London, Volume 294, Issue 1073, London 1981.
^ Robert GB Reid, Alison M. Reid (1974): The carnivorous habit of members of the septibranch genus Cuspidaria (Mollusca: Bivalvia). Sarsia, 56 (1), pp. 47-56, DOI: 10.1080 / 00364827.1974.10411261
^ Brian Morton: Prey capture in the carnivorous septibranch Poromya granulata (Bivalvia: Anomalodesmata: Poromyacea). Sarsia, 66, pp. 241-256, 1981 ( picture ).

[allen-morgan-1] JA Allen, Rhona E. Morgan: The functional morphology of Atlantic deep water species of the families Cuspidariidae and Poromyidae (Bivalvia): an analysis of the evolution of the septibranch condition. Philosophical transactions of the Royal Society of London: B, Royal Society London, Volume 294, Issue 1073, London 1981.

[reid-2] Robert GB Reid, Alison M. Reid (1974): The carnivorous habit of members of the septibranch genus Cuspidaria (Mollusca: Bivalvia). Sarsia, 56 (1), pp. 47-56, DOI: 10.1080 / 00364827.1974.10411261

[3] Brian Morton: Prey capture in the carnivorous septibranch Poromya granulata (Bivalvia: Anomalodesmata: Poromyacea). Sarsia, 66, pp. 241-256, 1981 ( picture ).