Ingesta analyses
Analyses of the intestine revealed, that Gastropteron rubrumtakes in sand particles, Foraminifera and diatoms (Figure 3D-G). However, spicules of the tylostyle type were also found, which indicate Heteroscleromorpha sponges, like Axinellida, Biemnida, Merliida, Polymastiida, Clionaida, Tethyida and Suberitida, as additional food (see Morrow & Cárdenas, 2015) (Figure 3A–C). The prey structures extracted from the distal region of the intestine (see Figure 3G) were more brittle and fractured than those from the proximal region of the intestine (compare with Figure 3D).