Anatomy and systematics of Anodontites Elongatus (Swainson) from Amazon and Parana Basins, Brazil (Mollusca, Bivalvia, Unionoida, Mycetopodidae)

The anatomy of Anodontiies elongatus (Swainson, 1823), a rare species restricted to the Amazon and Parana Basins, is described by first time, showing a group of conchological and anatomical characters exclusive of this species that may be analyzed to identify it. Diagnosis of A. elongatus: shell long antero-posteriorly, umbones prominent, periostracum opaque and smooth, two posterior radial striae; middle fold of mantle edge veiy tall; gill long antero-posteriorly and short dorso-ventrally, extending about a half of it total length beyond visceral mass; palps proportionally small, several furrows in its outer surface; stomach without esophageal transversal ridjp, dorsal hood and gastric shield poorly developed, major typhlosole entering in ddd , posterior pouch of sa³ very-long; style sac reduced, without crystalline style; distal region of intestine and rectum with a well developed typhlosole, "T" in section, other intestinal regions without folds; gonad gonochoristic

Isognomon bicolor (C.B. Adams) (Bivalvia, Isognomonidae): primeiro registro para o Brasil, redescrição da espécie e considerações sobre a ocorrência e distribuição de Isognomon na costa brasileira Isognomon bicolor (C.B. Adams) (Bivalvia, Isognomonidae): first record to the Brazilian littoral, redescription of the species and comments on the occurrence and distribution of Isognomon in the Brazilian coast

<abstract language="eng">The bivalve family Isognomonidae is represented in the Western Atlantic by the living genera Crenatula Lamarck, 1804 and Isognomon Solander, 1786. I. alatus (Gmelin, 1791) and I. radiatus (Anton, 1839) are the only Isognomonidae referred to the Brazilian malacofauna. The present work refers to the first record and geographic distribution of I. bicolor along the Brazilian littoral, and presents a re-description of the species based on shell characters, which include those of the prodissoconch. The occurrence of I. alatus and I. radiatus along the Brazilian littoral could not be confirmed, despite the intensive search for these Isognomonidae from Rio Grande do Norte through Rio Grande do Sul

The family Donacidae (Bivalvia: Tellinoidea) in Thai waters

The species belonging to the family Donacidae living in Thailand waters are herein revised. After an exhaustive bibliographical search, 29 nominal species were found from this area. Materials from several institutions and specimens collected during fieldwork in Phuket and the Gulf of Thailand were studied. All the type materials were illustrated and redescribed. Details of the type localities, repositories, habitats and biogeographical distribution are discussed. In addition, some collected specimens and the type materials of the valid species and synonyms are illustrated. Currently, eight valid species are confirmed as living in Thailand waters: Donax (Deltachion) spinosus Gmelin, 1791, Donax (Deltachion) semigranosus (Dunker, 1877), Donax (Dentilatona) incarnatus Gmelin, 1791, Donax (Hecuba) scortum (Linnaeus, 1758), Donax (Latona) cuneatus Linnaeus, 1758, Donax (Latona) faba Gmelin, 1791, Donax (Latona) solidus Spengler, 1798 and Donax (Paraserrula) introradiatus Reeve, 1855. The presence of Donax (Deltachion) semisulcatus Hanley, 1843, Donax brazieri Smith, 1892, Donax (Tentidonax) veruinus Hedely, 1913 and Donax victoris Fischer-Piette, 1942 in Thailand waters remains uncertain. These species have been reported in the study area in the literature, but they were not sampled during this study.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Printrakoon, Cheewarat. Kasetsart University; Tailandi