Grammonus thielei Nielsen & Cohen 2004

Diagnosis: Fin rays in dorsal 66; anal 41; pectoral 21. Vertebrae 11 + 27 (ural elements counted as 1). Head length 33% SL. One large lateral line pore (equal to posterior supraorbital pore) near angle of opercle. The caudal fin is free of the dorsal and anal fins (Ref. 56143).

Dorsal soft rays (total): 66; Analsoft rays: 41

Observed in limestone caves and sinkholes which are probably connected at depths between 2 and 30 meters; often in lightless chambers without current, few are found at the entrance of caves where they hide beneath rock ledges. No reaction to torchlight was shown and escape distance was only about 2 centimeters; mostly were seen motionless, with only a slight movement of the fins maintaining the fishes' position (Ref. 56143).