PIKTSCH: OSTEOLOGY AND RELATIONSHIPS OF TETRABRACHIUM 



KFRS 871, 46 mm SL, northwest of Yule Island, 

 Gulf of Papua, New Guinea, March 1963. KFRS 

 1483, 52 mm SL, Kerema Bay, Gulf of Papua, 5 

 May 1969. KFRS 2953, 62 mm SL, 6.5-8 km off 

 Kerema Point, Gulf of Papua, prawn trawl, 14.6 m, 

 9 May 1973. KFRS 3017, 58 mm SL, Kerema Bay, 

 Gulf of Papua, 9-13 m, September-October 1970. 

 KFRS 3023, 61 mm SL, Kerema Bay, Gulf of 

 Papua, 9-13 m, September-October 1970. KFRS 

 3082, 50 mm SL, FRV Rossel, Yule Island. Gulf of 

 Papua, trawl, 18-24 m, January-February 1971. 



USNM 177873, 52 mm SL. between Hayman 

 and Magnetic Islands, Queensland, trawl, 18-46 

 m. May-June 1957. 



WAM P21473-001. 67 mm SL, Vansittart Bay, 

 West Australia, 14°04' S, 126°17' E, 26 May 1968. 

 WAM P26130-001, 2(58 and 67 mm SL), Broome 

 Bay, Napier, West Australia, 14°00' S, 126°36' E, 

 26 November 1968. WAM P26832-001, 34 mm SL, 

 Wokam and Uru Islands, Indonesia, 5°30' S, 

 134° 12' E, 15 June 1970. WAM P26833-001, 47 

 mm SL, Aru Island, Indonesia, 5°30' S, 134°12' E. 

 16 June 1971. WAM P26540-001, 53 mm SL, 

 Mermaid Passage, Dampier Arch, West Australia, 

 16°25' S, i23°20' E, prawn trawl, 8 September 

 1977. WAM P26834-001, 35 mm SL, west of 

 Dongara, West Australia, 29°15' S, 114°01' E, 20 

 March 1972. 



Diagnosis. — Mouth small, opening dorsally, 

 bones of jaws nearly vertical, nearly completely 

 hidden by folds of skin; lower lip lined with small, 

 cutaneous papillae; eyes small, close-set, pro- 

 truding from dorsal surface of head; anterior half 

 of frontals separate, posterior half meeting on 

 midline; pterosphenoid present; parietals sepa- 

 rated by supraoccipital; mesopterygoid absent; 

 ectopterygoid triradiate, T-shaped; dorsal head 

 of quadrate narrow, less than width of metaptery- 

 goid; interhyal with a medial, posterolaterally 

 directed process; interopercle flat, broad; pha- 

 ryngobranchial I present; epibranchial teeth ab- 

 sent; ceratobranchials toothless; toothed portion 

 of ceratobranchial V expanded; hypohyals II and 

 III bifurcated; ossified basibranchials absent; 

 small basihyal present; neural spines of preural 

 centra 14-22 short, spatulate, not interdigitating 

 with proximal radials of soft dorsal fin; epurals 

 absent; three dorsal fin spines without intercon- 

 necting membrane; illicial cavity absent (Brad- 

 bury 1967); illicium reduced, without esca, 

 emerging anterior to eyes; second dorsal fin spine 

 covered with cutaneous filaments, emerging from 



between eyes; third dorsal fin spine nearly com- 

 pletely covered with skin of head, distal tip 

 emerging on posterior margin of cranium; illicial 

 pterygiophore and pterygiophore of third dorsal 

 fin spine with highly compressed, bladelike dorsal 

 expansions, each expansion with a foramen within 

 which lie medially directed prongs of proximal end 

 of respective dorsal fin spine; soft dorsal fin rays 

 16-17; anal fin rays 11-12; pectoral fin rays 

 9, divided into dorsal portion of 4 rays intercon- 

 nected by membrane, ventral portion of 5 inter- 

 connected rays, dorsalmost ray attached to lateral 

 surface of body by membrane; pectoral lobe at- 

 tached to posteriormost ray of pelvic fin by mem- 

 brane; three pectoral radials; skin naked except 

 for very few microscopic spinules associated with 

 pores of acoustico-lateralis system. 



Description (Figure 1). — Body strongly com- 

 pressed, elongate (greatest depth <50% SL); head 

 compressed, short (<32% SL); cranium strongly 

 oblique in position, posterior end of cranium and 

 anterior vertebrae raised forming a prominent 

 convex hump; mouth small, width <16% SL; 



Figure l. — Tetrabrachium ocellatum: A. Holotype, BMNH 

 1879.5.14.618, 51 mm SL, after Giinther 1880: B. Diagram 

 showing webbing between lower portion of pectoral fin and body, 

 and between pectoral and pelvic fins. 



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