Bamarooka bathycephala (Stebbing)

Lowry, J. K. & Stoddart, H. E., 2002, The Amaryllididae of Australia (Crustacea: Amphipoda: Lysianassoidea), Records of the Australian Museum 54, pp. 129-214 : 179-182

Bamarooka bathycephala (Stebbing)

Figs. 45–47

Amaryllis bathycephalus Stebbing, 1888: 699 , pl. 27. Amaryllis bathycephala .– Stebbing, 1906: 24.– Stebbing, 1910a:

633 (list).– Sheard, 1937: 18 (list).–Thurston & Allen, 1969:

354. Amaryllis macrophthalmus .– Della Valle, 1893: 781 (in part).

Material examined. NEW SOUTH WALES: 1 specimen, AM P58124, between Lion Island and Barrenjoey Head, Broken Bay , [approx. 33°33'S 151°22'E] , 25 m, SPCC /UTS, 8 October 1991 . 1 specimen, AM P24058, E of Burwood Beach , 32°58'S 151°45'E , 28 m, mud and gravel, shipek grab, 18 December 1975, HDWBS stn 06010304 . 1 specimen, AM P58754 , Cape Banks , 34°00'S 151°16'E , 45–50 m, The Ecology Lab, January 1991. 1 specimen, P58755, SE of Bate Bay , 34°5.9'S 151°12'E , 35–40 m, The Ecology Lab, January 1991, stn S2 T4 . 1 specimen, AM P58756, same locality , 35–40 m, The Ecology Lab, July 1990, stn S3 T2 . 3 specimens, AM P58757, same locality , 35–40 m, The Ecology Lab, January 1991, stn S3 T4 . 1 specimen, AM P46444, Bass Point , 34°36'S 150°54'E , 35–40 m, The Ecology Lab, 1 February 1990, stn S1 R3 . 1 specimen, AM P58758 , same locality, The Ecology Lab, November 1990, stn S1 T3 . 1 specimen, AM P52920, Wattamolla , 34°08'S 151°08.5'E ,

45–50 m, The Ecology Lab, June 1990, stn S2 R4 . B ASS STRAIT: 9 specimens, NMV J2310 , 42 km SW of Babel Island, Tasmania, eastern Bass Strait , 40°13.8'S 148°39.6'E , 60 m, muddy sand, epibenthic sled, R. Wilson, 14 November 1981, RV Tangaroa , stn BSS-165. 1 specimen, NMV J13928 , 32 km SSW of Cape Otway, western Bass Strait , 39°09'S 143°26'E , 85 m, coarse carbonate sand, G.C.B. Poore, 8 October 1980, HMAS Kimbla, cruise 80-K-1, stn BSS-55. 2 specimens, NMV J7450 , 31 km SSW of Cape Otway, western Bass Strait , 39°08'S 143°24'E , 77 m, medium sand, grab, G.C.B. Poore, 8 October 1980, HMAS Kimbla, stn BSS-56G. 1 specimen, NMV J7452 , 35 km SSW of Cape Otway, Victoria, western Bass Strait , 39°06'S 143°21'E , 59 m, coarse sand, dredge, G.C.B. Poore, 8 October 1980, HMAS Kimbla, stn BSS-57D. 1 specimen, NMV J13929 , 42 km NW of Cape Farewell, King Island, western Bass Strait , 39°19'S 143°38'E , 95 m, coarse sand, carbonate, G.C.B. Poore, 10 October 1980, HMAS Kimbla, cruise 80-K-1, stn BSS 76. 10 specimens, NMV J13930 , 6 km NE of Stanley, Tasmania, central Bass Strait , 40°48.8'S 145°22'E , 22 m, fine sand, M. Gomon & G.C.B. Poore, 4 November 1980, FRV Sarda , stn BSS 114. 9 specimens, NMV J2309 , 25 km S of Cape Otway, Victoria, western Bass Strait , 39°06'S 143°35.8'E , 95 m, fine sand, dredge, M. Gomon et al., 31 January 1981, FRV Hai Kung, stn BSS-118D. 53 specimens, NMV J13931 ; 30 specimens, AM P36889; 26 km SW of Cape Otway, Victoria, western Bass Strait , 39°01'S 143°22'E , 84 m, medium sand, epibenthic sled, M. Gomon et al., 31 January 1981, FRV Hai Kung, stn BSS-120. 5 specimens, NMV J13932 , 31 km S of Cape Otway, Victoria, western Bass Strait , 39°01.0'S 143°15.2'E , 84 m, medium sand, epibenthic sled, M. Gomon et al., 31 January 1981, FRV Hai Kung, stn BSS-121. 2 specimens, NMV J48798 , 94 km N of North Point, Flinders Island, eastern Bass Strait , 38°53.7'S 147°55.2'E , 71 m, medium sand, epibenthic sled, R. Wilson, 17 November 1981, RV Tangaroa , stn BSS 171S. 8 specimens, NMV J3769 , 25 km S of Aireys Inlet, Victoria, central Bass Strait , 38°44.6'S 144°09.0'E , 77 m, fine sand, epibenthic sled, R. Wilson, 19 November 1981, RV Tangaroa , stn BSS-182. 1 specimen, NMV J3772 , 15 km SW of Point Reginald, Victoria, western Bass Strait , 38°50.0'S 143°07.5'E , 69 m, fine sand, grab, R. Wilson, 20 November 1981, RV Tangaroa , stn BSS-186. 2 specimens, NMV J13933 , 70 km SW of Cape Otway, Victoria, western Bass Strait , 39°26.3'S 143°06.8'E , 115 m, sand, epibenthic sled, R. Wilson, 21 November 1981, RV Tangaroa , stn BSS-194. 6 specimens, NMV J13934 , 65 km S of Cape Schanck, Victoria, central Bass Strait , 39°08.3'S 144°43.9'E , 66 m, coarse sand, R. Wilson, 23 November 1981, RV Tangaroa , stn BSS-201 .

Type locality. Off mouth of Port Phillip Bay, Bass Strait, Australia, 38°22.5'S 144°36.5'E, 60 m depth .

Description. Based on female, 11 mm, AM P36889. Head much deeper than long, anterior margin with notch extended into a slit; rostrum present, anteriorly rounded; eye present, ventrally tapered. Antenna 1 peduncular article 1 not ballshaped proximally, distal margin with small medial spine; peduncular article 2 medium length; flagellum without callynophore, calceoli absent. Antenna 2 flagellum about as long as that of antenna 1, without calceoli. Mouthpart bundle subconical. Epistome/upper lip with broad midanterior bulge (lateral view). Mandible lacinia mobilis a stemmed, distally-cusped blade; accessory setal row with intermediate setae; palp article 2 with 4 posterodistal setae, article 3 without A3-seta. Maxilliped outer plate with distal margin smooth, medial margin without notch.

Gnathopod 1 carpus shorter than propodus (0.8×); propodus, posterior margin without robust setae. Gnathopod 2 palm acute, with 3 lateral robust setae, 6 medial robust setae. Pereopods 3 and 4 merus and carpus without setal fringe. Pereopod 4 coxa with anterior margin slightly obtuse, posterior margin rounded, anteroventral corner rounded. Pereopods 5–7 with distal articles elongate, dactyli long and slender. Pereopod 5 basis expanded posterodistally (pear-shaped). Pereopod 7 basis subrectangular, posteroventral corner rounded, posteroventral margin straight.

Epimeron 3 posterior margin smooth, with notch well above rounded posteroventral corner. Uropod 1 peduncle dorsolateral margin with 11 robust setae; outer ramus without large spines between robust setae. Uropod 2 inner ramus slightly constricted. Uropod 3 rami lanceolate; without plumose setae; outer ramus 1-articulate. Telson slightly cleft (about 20%).

Male (sexually dimorphic characters). Based on male, 7.2 mm, AM P36889. Antenna 1 flagellum with callynophore. Antenna 2 flagellum with calceoli. Gnathopod 2 palm without lateral robust setae, with 2 medial robust setae.

Variation. This species shows considerable variation in the robust-setae formula of gnathopod 2 palm. This variation is correlated with the size and/or sex of specimens. For males the range is from 0/1 through 0/2 to 1/2; for females the known range is from 1/4 through 2/4, 4/4 to 4/5. Stebbing (1888: 701) recorded “a row of three short stout spines [= robust setae]… on one side and one or two more on the other”.

An 8.3 mm ovigerous female from east of Burwood Beach, NSW, differs slightly from the Bass Strait population in that the rostrum is slightly less produced, the eye is not quite so tapered and the basis of pereopod 5 is slightly broader distally.

Remarks. Most species of Bamarooka ( B. bathycephala , B. dinjerra , B. endota and B. kimbla ) have ventrally tapered eyes. Bamarooka bathycephala differs from all of these species in the basis of pereopod 5, which is pear-shaped.

Habitat. Bamarooka bathycephala has been collected frequently on sandy sediments and occasionally on mud.

Distribution. Southeastern Australia, from Sydney to Bass Strait; 22–115 m depth.