A shot in the dark: Comparative morphology of the bioluminescent tube organs in tubeshoulders (Platytroctidae)
Fig 5
Longitudinal histological sections and external anatomy of the caudal tube organ in P. apus (SIO 77-54).
(A) Two dorsal caudal tube organs in lateral view and (B) potential developing luminescent-fluid cells (*) in the lumen of a caudal tube organ in P. apus. Variation in the number of dorsal caudal tube organs in Platytroctes apus, showing (C) two (USNM 206894), (D) three (USNM 206894), (E) four (USNM 206893), and (F) five (USNM 201649) caudal tube organs. Arrows point towards terminal caudal tube opening. Note: Ventral tube organs on the caudal peduncle in P. apus also vary in number. Anterior is to the left in all figure panels, such that the posteriorly-directed terminal openings of the caudal tube organs are located to the right. Abbreviations: dermis (d), tube organ (t), pigment layer (pl), modified scale (ms), luminescent fluid (lf), muscle (m).