Description of Granuloreticulosa
Amoeboid organisms, mostly marine; pseudopodia extend from the cell body as a series of strands which divide and anastomose; structure of the net is always changing, and granular cytoplasm moves actively in both directions along the strands, which internally have microtubules. The appearance and behaviour of the pseudopodial network is held by many to be synapomorphic. The group is dominated by the foraminifera, the trophic cells of which occupy multichambered or agglutinated tests. Some organisms that live in a single chambered test (the Monothalamida) and some without tests (Athalamids) may be included. Because branching dynamic pseudopodial networks may be found in some taxa that may not be granuloreticulosea (such as Microcometes, a flagellate, Biomyxa, gymnophreids, Gymnophrydium, vampyrellids, leptomyxids, various slime moulds, etc.), the monophyly of the group is still uncertain. Some taxa assigned by others to this group, such as the Komokiacca and Biomyxa, are excluded here - even though there are undoubtedly some monothalamid and athalamid relatives of the foraminifera. Some taxa with complex life cycles (phases involving production of gametes separated by phases involving asexual reproduction); with or without flagellated swarmers; with or without nuclear dimorphism. Many with endosymbiotic algae. Ultrastructural identity: Mitochondria with tubular cristae. Nuclear envelope may be supported by fibrous sheath. Pseudopodia containing microtubules but not in geometric arrays, also with dark osmiophilic bodies. Flagellated stage generally unstudied, but it is now generally agreed that the flagella are without tripartite hairs. Wall of testate forms variable in composition and make-up. Synapomorphy: Usually said to be branching or anastomosing dynamic filamentous pseudopodial system, but this needs to be confirmed. About 40,000 species; most are foraminifera.