Nemertea

A possible mechanism for the evolution of aposematic colouration in solitary nemerteans (phylum Nemertea).

Observed and expected frequencies of samples by counts of individuals of A) Isopoda, B) Pisionidens indica, C) Scolelepis squamata D) Nemertea, E) Total fauna and F) counts of taxa number in Mondonguillo beach to low tide level.

Considering the inventory done by Biota Project FAPESP (Steiner and Amaral, 1999), it is possible to infer that Japi Mountain is an important area to conserve unique species described for the state of Sao Paulo, like Nemertea Prostoma eilhardi (Montgomeri, 1894) (Forneris, 1999b) and Nematomorpha Paragordiusflavescens Linstow, 1906 (Forneris, 1999c), even with the low identification resolution of some less abundant taxa.

Malacobdella arrokeana (Nemertea: Bdellonemertea), a new species of nemertean from southwest Atlantic Ocean entocommensal in Panopea abbreviata (Bivalvia: Heterodonta: Hiatellidae) in Argentina.

Phylum Taxa Brava Navegantes Total Beach Beach Annelida Capitellidae 8 114 122 Paraonidae 42 11 53 Lumbrineridae 35 0 35 Spionidae 25 5 30 Onuphidae 25 1 26 Mageloniidae 17 2 19 Orbiniidae 7 0 7 Pilargidae 4 2 6 Oweniidae 4 1 5 Goniadidae 3 0 3 Nereidae 3 0 3 Ampharetidae 1 0 1 Flabelligeridae 1 0 1 Glyceridae 1 0 1 Magelona 1 0 1 variolamellata Poecilochaetidae 1 0 1 Sigalionidae 1 0 1 Sigambra 1 0 1 Arthropoda Amphipoda 137 3 140 Cumacea 13 11 24 Brachyura 7 0 7 Decapoda 3 0 3 Tanaidacea 2 0 2 Echinodermata Ophiuroidea 1 0 1 Enteropneusto Enteropneusto 1 0 1 Mollusca Bivalvia 15 44 59 Gastropoda 3 1 4 Heleobia 1 0 1 Nemertea Nemertea 7 2 9 Total 362 195 557 Table 2.

Se identificaron 229 especies correspondientes a 11 Filos: Annelida (Polychaeta), Arthropoda (Pycnogonida, Malacostraca, Ostracoda), Bryozoa, Chordata (Ascidiacea), Cnidaria (Anthozoa, Hydrozoa), Echinodermata (Echinoidea, Ophiuroidea, Holothuroidea, Asteroidea), Mollusca (Gastropoda, Bivalvia, Polyplacophora, Cephalopoda, Scaphopoda), Nemertea (Anopla, Enopla), Platyhelminthes, Porifera y Sipuncula, todos son grupos representativos de comunidades bentonicas costeras (Tabla 1, Apendice I).

Nemertea (ribbon worms) is one such phylum that has yet to be assessed for the extent of self-fertility among its hermaphroditic species.

rosea copepodits 29.993 26 Appendicularia 4.291 13 Fishes eggs 0.082 5 Meroneuston (larvae) Nemertea (Muller) 0.002 1 Polychaeta (11 types) 16.446 24 Sipunculida (pelagosphaera) 0.002 1 Barnacles (nauplius + cypris) 0.606 11 Decapod crustaceans 0.258 11 Bryozoa(cyphonaute) 2.410 19 Gastropoda (bilobed larvae) 0.007 2 Bivalvia (right charnel 21.118 18 + umbonated) Echinodermata (pluteus) 0.419 11 Total 92.243 %

Unique to the phylum Nemertea, the pilidium is an unmistakable planktonic larva found in one group of nemerteans, the Pilidiophora.

El total de taxa identificados en el Centro 1 fue de 105; 44 de estos taxa correspondieron al Phylum Annelida/ Clase Polychaeta, 28 al Phylum Arthropoda, 9 al Phylum Echinodermata, 20 al Phylum Mollusca, 1 al Phylum Nematoda, 1 al Phylum Nemertea, 1 al Phylum Platyelminthes y 1 al Phylum Priapula.

Comparative morphology and evolution of the nephridia in Nemertea. J.

In marine worms belonging to the phylum Nemertea, oocyte maturation and fertilization are regulated by the same general kinds of signals that control such processes in mammals.

Fundamental properties of the spiralian developmental program are displayed by the basal nemertean Carinoma tremaphoros (Paleonemertea, Nemertea).

Although adult morphology varies vastly across the group, many core Lophotrochozoa (including the Mollusca, Annelida [including Vestimentifera, Pogonophora, and Echiura, and possibly Myzostoma, and Sipunculida], Gnathostomulida, Nemertea, dicyemid Mesozoa, Entoprocta, and some Platyhelminthes [including polyclad Turbellaria, Catenulida, and Macrostomida]) exhibit spiral cleavage, a highly conserved pattern of early development.

The Palaeone-mertea appears to be a basal paraphyletic assemblage within the Nemertea. The other two major groups of nemerteans are the stylet-bearing Hoplonemertea and the recently defined clade Pilidiophora, which is characterized by the pilidium larva and includes the Heteronemertea as well as the genus Hubrechtella.