Amphicutis stygobita (Echinodermata, Ophiuroidea, Amphilepidida, Amphilepididae), a brooding brittle star from anchialine caves in The Bahamas: feeding, reproduction, morphology, paedomorphisms and troglomorphisms

SEMs of vertebrae ends, Amphicutis stygobita A–D, Amphilepis patens E–F. A dorsal/side view, proximal end up showing muscle flanges, articulating facets (top) and proximal extension of center of dorsal muscle flanges (upper left) to form dorsal process that supports dorsal articulating facets (on opposite side, out of view) B tilted proximal end showing dorsal muscle flanges in front, 2 ventral articulating facets behind, insertion point for intervertebral ligaments, dorsal view C proximal face showing: 1Y (yellow) left dorsal muscle flange, 1G (green) right dorsal muscle flange, 2 (black) dorsal process, 3Y (yellow) left dorsal articulating facet, 3G (green) right dorsal articulating facet, 4Y (yellow) left ventral articulating facet, 4G (green) right ventral articulating facet, 5Y (yellow) left side of ventral process, 5G (green) right side of ventral process, 6Y (yellow) left ventral muscle flange, 6G (green) right ventral muscle flange, 7 (red) median socket, 8 (white) insertion points for intervertebral ligaments D distal face showing: 1G (green) right dorsal muscle flange, 1Y (yellow) left dorsal muscle flange, 2 median depression, 3G (green) right dorsal articulating facet, 3Y (yellow) left dorsal articulating facet, 4G (green) right ventral articulating facet, 4Y (yellow) left ventral articulating facet, 5G (green) right side of ventral depression, 5Y (yellow) left side of ventral depression, 6G (green) right ventral muscle flange, 6Y (yellow) left ventral muscle flange, 7 (red) median process. (If image D is turned over face down to left to meet image C, green structures connect with corresponding green structures, yellow with yellow, red with red, and black with black), E proximal face of Amphilepis patens vertebra, large dorsal muscle flanges with growth rings, thick dorsal and ventral processes with articulating facets, F distal face of A. patens vertebra, large dorsal and ventral muscle flanges with growth rings, thick rounded tongue-shaped median process. Abbreviations as in Fig. 7 plus: IIL – insertion for intervertebral ligaments, MP – median process, VP – ventral process.