Enigmatic tissue in the orobranchial chamber of cardinalfishes of the genus Siphamia (Perciformes, Apogonidae)

An unusual tissue covering the tongue and occasionally part of the gill chamber of many species of the Indo-Pacific cardinalfish genus Siphamia is described and compared with an earlier description of a similar tissue found in the cichlid species Alcolapia grahami inhabiting lakes of the African Rift Valley. Species of both genera are mouth brooders. The Siphamia tissue is globular and its cells are oblong, whereas the A. grahami tissue is single-layered, with larger, columnar cells. The tissues of both have the characteristics of a mucosa and show evidence of active synthesis. While ion regulation has been proposed for the A. grahami tissue, the function of the Siphamia tissue is unknown, but a role in feeding, or antibiotic or appetite-suppressing functions have been suggested.Keywords: Alcolapia grahami, Cichlidae, histology, SEM, TE

Evolutionary retention of defensive lateral pedal glands in the smallest siphonariid limpet (Gastropoda: Pulmonata)

Despite its cryptic habitat and habits, light and transmission electron microscopy has revealed that like many other siphonariids Siphonaria compressa, the smallest species of this genus, possesses lateral pedal glands. The pear-shaped glands (about 120 μm long × 70 μm maximum diameter) open via a pore, and are multicellular with three types of secretory cell that surround a central lumen. The glands of this minute pulmonate limpet are similar in structure to its larger relatives, suggesting that they are defensive in function.Keywords: defensive secretions, Mollusca, multicellular glands, Siphonariida

Polypropionates from the South African Marine Mollusk <i>Siphonaria oculus</i>

Three new polypropionate metabolites, 6<i>Z</i>,8<i>E</i>-Δ⁸-siphonarienfuranone (<b>1</b>), 6<i>E</i>,8<i>E</i>-Δ⁸-siphonarienfuranone (<b>2</b>), and 6<i>E</i>,8<i>E</i>-3-hydroxy-4,6,8,10,12-pentamethylpentadeca-6,8-dien-5-one (<b>3</b>), and the known polypropionate siphonarienfuranone (<b>4</b>) were isolated from the intertidal South African marine mollusk <i>Siphonaria oculus</i>. Evidence is presented to suggest that <b>1</b>, <b>2</b>, and <b>4</b> may cyclize from an acylic precursor on chromatographic workup of the acetone extract of this mollusk