Tooth Mg/Ca ratios and Aristotle's lantern morphometrics reflect trophic types in echinoids.

Several studies have inferred the ecological significance regarding the morphometrics of Aristotle's lantern and the mechanical properties of magnesium in echinoid teeth. This study attempts to combine these aspects, connecting them to the trophic habits of three native and an invasive echinoid in the Eastern Mediterranean Sea. Spatiotemporal data from the central and southern Aegean Sea were obtained, regarding the relative size of lanterns and demi-pyramids of , , and the invasive echinoid and the Mg/Ca ratios of four zones on the tooth cross-section.

Mechanical defensive adaptations of three Mediterranean sea urchin species.

In the Mediterranean, and are important drivers of benthic ecosystems, often coexisting in sublittoral communities. However, the introduction of the invasive diadematoid , which utilizes venomous spines, may affect these communities. To describe the mechanical properties of the test and spines of these three species, specimens were collected in winter of 2019 from the sublittoral zone of the Dodecanese island complex, southeastern Aegean Sea.

Abundance and population characteristics of the invasive sea urchin Diadema setosum (Leske, 1778) in the south Aegean Sea (eastern Mediterranean).

Background: The Indo-Pacific sea urchin Diadema setosum has invaded the Mediterranean Sea and has spread along many locations in the southeastern part of the basin, where established populations exist on the shallow subtidal rocky shore. Diadema setosum is a ubiquitous species, of particular ecological importance due to the high levels of grazing pressure it imposes on benthic communities. Its biology, however, is not adequately studied, especially along its introduced range of distribution.

Chemical Composition and Microstructural Morphology of Spines and Tests of Three Common Sea Urchins Species of the Sublittoral Zone of the Mediterranean Sea.

In the Mediterranean Sea, the species , and often coexist, occupying different subareas of the same habitat. The mechanical and chemical properties of their calcitic skeletons are affected both by their microstructural morphology and chemical composition. The present study describes the main morphologic features and the possible temporal differences in elemental composition of the test and spines of the three species, while also determining the molar ratio of each element of their crystalline phase.