ANNELIDA | MOLLUSCA | NEMERTEA | GNATHOSTOMULIDA | PLATYHELMINTHES | XENACOELOMORPHA | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
LOBATOCERBRIDAE | SIPUNCULA | ORBINIIDAE | SOLENOGASTRES | CAUDOFOVEATA | GASTROPODA | PALAEONEMERTEA | ANOPLA | BURSOVAGINOIDEA | FILOSPERMOIDEA | CATENULIDA | NEMERTODERMATIDA | ||||
Lobatocerebrum riegeri n. sp. | Phascoliun strombus | Scoloplos armiger | Dorymenia sarsii | Chaeoderma japonicum | Helminthope psammibionta | Cephalothrix linearis | Procephalo-thrix linearis | Lineus viridens | Gnathostomula peregrina | Rastrognathia macrostoma | Pterognathia meixneri | Stenostomum leucops | Nemertoderma westbaldi | ||
Location of the ventral nerve cords | Intraepithelial | Intraepithelial/subepidermal | Intraepithelial | Subepidermal | Subepidermal | Subepidermal | Subepidermal | Subepidermal | Subepidermal | Intraepithelial | Intraepithelial | Intraepithelial | ? (mainly subepidermal) | Intraepithelia to subepidermal | |
BRAIN | Lobular structure | + | ? | + | - | + | + | + | + | + | - | ? (−) | - | - | - |
Central neuropile | + | + | + | + | + | + | + | + | + | + | ? (+) | + | + | - (only commissures formed) | |
Number of brain commissures | 4 | 2 | 4 | 1 | 1 | 1 | >2 | >2 | >2 | 1 | ? (1) | 1 | 1 | 2 rings (dorsally connected) | |
NERVE CORDS OF THE CENTRAL NERVOUS SYSTEM | Number of posterior longitudinal nerve cords | 1 pair + 1 median cord | 1 pair | 1 pair | 2 pairs (+1 median cord) | 2 pairs | 2 pairs | 1 pair | 1 pair + 1 dorsal median + 1 ventral median cord | 1 pair | 1 pair | 1 pair | 1 pair | 1 pair | - (thin fibres, but no cords) |
Median posterior nerve cord | + | - | - | + | - | - | - | + | - | + (just a short piece) | ? (−) | - | - | - | |
Number of rostral longitudinal nerve cords | 2–9 | 0 | 0 | - | - | 2 pairs | ? | 4 | Approx. 8 pairs | - | ? | >3 paired and 2 unpaired | - | - | |
GANGLIA AND COMMISSURES ALONG THE VENTRAL NERVE CORD | Total number of ganglia | 2 pairs | >2 | >2 | >2 | >2 | >2 | ? | ? | 1 pair | 1 pair | ? (1 pair) | 1 pair | ? | ? |
Nonganglionated posterior commissures | >2 | ? | >2 | >2 | >2 | >2 | ? | 1 | ? | 1 | ? (1) | 1 (2) | ? | - | |
Presence of a subpharyngeal ganglion | + | + | + | + | + | + | + | + | + | + | ? (+) | + | + | - | |
PERIPHERAL NERVOUS SYSTEM | Grid of distinct longitudinal and circular nerves | Nerve plexus | Grid of pairwise arranged longitudinal and several circular nerves per segment | ? | ? | ? | ? | Intraepidermal plexus around the rhynchocoel | Subepidermal plexus, commissural plexus, stomatogastric plexus, proboscidial plexus | 5 longitudinal nerves | 6 longitudinal nerves | 3 dorsal longitudinal nerves | ? | ? | |
References | This study | [40] | [43] | [42] | [77] | [78] | [17] |