Rhizoprionodon acutus (Rüppell, 1837)

Milk Shark

Carcharias acutus Rüppell, 1837: 65, pl. 18 (fig. 4). Lectotype: SMF 2783 (stuffed). Type locality: Jeddah, Saudi Arabia, Red Sea.

Local synonymy: Rhizoprionodon acutus— Filewood, 1973: 4 (PNG); Kailola, 1987: 18 (Darapap; Gogol River mouth; Ramu River mouth; Rabual; Orangerie Bay; Port Moresby; Yule Island); Fricke et al., 2014: 12 (Madang); White et al., 2018: 174, figs (PNG).

PNG voucher material: (24 spec.) AMS I 16667-003, female 605 mm TL, AMS I 16667-006, female 757 mm TL, Bostrem Bay, Madang Harbour, 5°4’58” S, 145°48’4” E, 27 Jul. 1969 ; CSIRO H 7800-01, juvenile male 340 mm TL, Freshwater Bay, Gulf of Papua, 8°6’57.6” S, 145°52’1.2” E, 14–17 m depth, 8 Jun. 2014 ; CSIRO H 7804-01, female 350 mm TL, Freshwater Bay, Gulf of Papua, 8°6’45.6” S, 145°50’49.8” E, 21–22 m depth, 13 Jun. 2014 ; CSIRO H 7812-01, female 360 mm TL, Freshwater Bay, Gulf of Papua, 8°5’24.6” S, 145°51’7.2” E, 13 m depth, 22 Jun. 2014 ; CSIRO H 7824-01, adult male 770 mm TL, east of Fly River mouth, Gulf of Papua, 8°39’ S, 144°6’ E, 11–15 m depth, 12 Dec. 2014 ; CSIRO H 7829-01, juvenile male 360 mm TL, south of Deception Bay, Gulf of Papua, 8°1’53” S, 144°38’48” E, 20–22 m depth, 7 Dec. 2014 ; CSIRO H 7835-02, juvenile male 430 mm TL, south of Deception Bay, Gulf of Papua, 8°2’16” S, 144°38’26” E, 22–23 m depth, 15 Dec. 2014 ; CSIRO H 8007-01, female 420 mm TL, west of Avirara, Gulf of Papua, 8°17’34.08” S, 146°10’34.92” E, 10–12 m depth, 25 Aug. 2015 ; CSIRO H 8163-02 (chondrocranium and dried jaws), adult male 790 mm TL, south of Kerema, Gulf of Papua, 8°3’45” S, 145°46’49” E, 13–18 m depth, 9 Sep. 2015 ; CSIRO H 8162-02 (dried jaws), adult male 790 mm TL, south of Kerema, Gulf of Papua, 8°4’26” S, 145°40’55” E, 17–20 m depth, 7 Sep. 2015 ; CSIRO H 8169-01 (dried jaws), adult male 770 mm TL, Freshwater Bay, Gulf of Papua, 8°8’35” S, 145°56’26” E, 18–26 m depth, 9 Apr. 2015 ; CSIRO H 8164-01 (dried jaws), adult male 790 mm TL, south of Deception Bay, Gulf of Papua, 8°3’53” S, 144°41’8” E, 21–31 m depth, 7 Dec. 2014 ; KFRS E.016A (dried jaws), adult female, KFRS E.016B (dried jaws), adult female, Hall Sound, Central Province, 11/ 12 Nov. 1964 ; KFRS E.279B, juvenile male 305 mm TL, north of Yule Island, Central Province, Apr. 1966 ; KFRS E.668, juvenile male 340 mm TL, Freshwater Bay, Gulf of Papua, 8°8’ S, 146°1’ E, 14–15 m depth, 29 Nov. 2014 ; KFRS E.670, adult male 760 mm TL, east of Fly River mouth, Gulf of Papua, 8°40’ S, 144°7’ E, 13–20 m depth, 2 Dec. 2014 ; KFRS E.700, juvenile male 360 mm TL, Freshwater Bay, Gulf of Papua, 8°5’45” S, 145°52’36” E, 14–16 m depth, 8 Jun. 2014 ; KFRS E.714, juvenile male 320 mm TL, Freshwater Bay, Gulf of Papua, 8°5’38.4 S, 145°50’44.4” E, 14–15 m depth, 16 Jun. 2014 ; KFRS E.723, juvenile male 320 mm TL, Freshwater Bay, Gulf of Papua, 8°6’57.6” S, 145°52’1.2” E, 14–17 m depth, 8 Jun. 2014 ; KFRS E.730, juvenile male 370 mm TL, KFRS E.731, juvenile male 390 mm TL, Freshwater Bay, Gulf of Papua, 8°6’45.6” S, 145°50’49.8” E, 21–22 m depth, 13 Jun. 2014 ; KFRS E.766, female 430 mm TL, south of Deception Bay, Gulf of Papua, 8°1’53” S, 144°38’48” E, 20–22 m depth, 7 Dec. 2014 .

Remarks: First recorded from PNG by Filewood (1973). Sometimes confused with Carcharhinus macloti . Common in the bycatch of the Gulf of Papua prawn trawl fishery and in coastal fisheries in PNG.