Cerapus bundegi, Lowry & Berents, 2005

Lowry, K. & Berents, P. B., 2005, Algal-tube Dwelling Amphipods in the Genus Cerapus from Australia and Papua New Guinea (Crustacea: Amphipoda: Ischyroceridae), Records of the Australian Museum 57 (2), pp. 153-164 : 154-157

Cerapus bundegi n.sp.

Figs. 1–2

Type material. HOLOTYPE, 3, 4.77 mm, AM P62291 ; PARATYPE, ♀, 3.85 mm, AM P62385 ; 41 PARATYPES, AM P62381 ; PARATYPE, 3, 3.54 mm, AM P62383 ; PARATYPE, 3, 2.74 mm, AM P62384; north of jetty, Cottesloe Beach , Perth, Western Australia, Australia, 31°59'S 115°45'E, just outside limestone reef, sand with scattered seagrass, 4 m, J. Just, 3 April 1984, AU 28. 21 PARATYPES, AM P62382, off end of South Mole , Arthur Head, Fremantle, Western Australia, Australia, 32°3'S 115°44'E, brown & red algae, 6 m , R. T. Springthorpe , 25 December 1983, WA 274 .

Additional material. 2 specimens, AM P62292, Sargassum sp. and sand, 2.3 m; 6 specimens, AM P62332, broad-leaf Sargassum sp. , sand & algal bottom, 2.8 m; 3 juveniles, AM P62334, fine Dictyota sp. and sand, 2.6 m; 2 specimens, AM P62338, broad-leaf Sargassum sp. and sand, 2.9 m; 13, AM P62339, fine Sargassum sp. and sand, 2.9 m; 13, AM P62340, Padina sp. , Lobophora sp. and sand, 2.7 m; 1♀, AM P62341, fine Dictyota sp. and sand, 2.3 m; 3 juveniles, AM P62387, Padina sp. and sand, 2.3 m; 13, AM P62392, Dictyotales and sand, 2.8 m; 4 specimens, AM P62395, Sargassum sp. and sand, 2.7 m; 3 specimens, AM P62397, Dictyotales and sand, 2.8 m; 2 specimens, AM P62404, Sargassum sp. and sand, 2.9 m, west side of Malus Island, Dampier Archipelago, Western Australia, Australia, 26°30.61'S 116°38.92'E, R.A. Peart, 27 September 1999, WA 661. 13, AM P62388, south side of Kendrew Island, Dampier Archipelago, Western Australia, Australia, 20°20.63'S 116°31.99'E, Sargassum sp. and sand, 3.8 m, R.A. Peart, 30 August 1999, WA 694. 4 specimens, AM P62389, mixed brown algae, 17 m, M. Hewitt; 3 juveniles, AM P62391, Dictyopteris sp. , 17 m, P. Morrison, Nelson Rocks, Dampier Archipelago, Western Australia, Australia, 20°26.51'S 116°40.23'E, 7 September 1999, WA 715. 433, AM P62386, Dictyopteris sp. , intertidal zone, 0.5 m; 1♀, AM P62394, Padina sp. , intertidal, 0.5 m, Tish Point, Rosemary Island, Dampier Archipelago, Western Australia, Australia, 20°29.67'S 116°35.89'E, R.A. Peart, 30 August 1999, WA 685. 11 specimens, AM P62335, beach at north end of Bundegi Reef, Exmouth Gulf, Western Australia, Australia, 21°49'S 114°11'E, rocky rubble, coralline algae with green epiphyte, 2 m, H.E. Stoddart, 4 January 1984. Many specimens, AM P62336, seagrass with bases and sand, 2 m; 12 specimens, AM P62398, mixed algae, 2 m, J.K. Lowry; many specimens, AM P62393, south Ned’s Camp, Cape Range National Park, Western Australia, Australia, 22°00'S 113°55'E, seagrass, 2 m, R. T. Springthorpe, 31 December 1983. many specimens, AM P62337, Ned’s Camp, Cape Range National Park, Western Australia, Australia, 21°59'S 113°55'E, green algae, 1.5 m, R. T. Springthorpe, 2 January 1984, WA 380. 6 specimens, AM P62290, 4 m, R. T. Springthorpe; 3 specimens, AM P62333, mixed coralline algae, 4 m, J.K. Lowry, Red Bluff, Kalbarri, Western Australia, Australia, 27°42'S 114°9'E, 10 January 1984. 4 specimens, AM P62286, 16 specimens, AM P62285, reef close to shore, Champion Bay, Geraldton, Western Australia, Australia, 28°45.88'S 114°36.83'E, Ecklonia radiata on shallow rocky reef at low tide, 0.5 m, R.A. Peart, 28 November 2000. 4 specimens, AM P62396, Seven Mile Beach, Western Australia, Australia, 29°11'S 114°53'E, Amphibolis sp. (seagrass), 1 m, G.J. Edgar, 6 June 1987. 2 specimens, AM P62402, 10 specimens, AM P62406, 5 specimens, AM P62403, 2♀♀, AM P62405, Cottesloe Beach,Perth, Western Australia, Australia, 31°59'S 115°45'E, sand patch on limestone reef with algae & seagrass ( Amphibolis sp. ), 2 m, J. Just, 2–3 March 1984. 13, AM P62390, reef west of groyne, 2 km south of Cape Peron, Western Australia, Australia, 32°16'S 115°41'E, Caulerpa sp. in deep channels in limestone reef, 6 m, J.K. Lowry, 26 December 1983, WA 302. 1♀, AM P62399, sponges, 6 m, R. T.Springthorpe; 5 specimens, AM P62400, Caulerpa sp. , 6 m, J.K.Lowry; 2 juveniles, AM P62401, orange gorgonacean, 6 m, R. T. Springthorpe, end of South Mole,Arthur Head, Fremantle, Western Australia, Australia, 32°3'S 115°44'E, 25 December 1983, WA 286.

Diagnosis. Head, rostrum long, apically acute; anteroventral corner subquadrate. Antenna 1 peduncular article 1 longer than article 3, swollen along posterior margin. Pereonite 2 with sternal keel. Pereopod 5 merus posterior lobe with 4 plumose setae.

Description. Based on holotype male, 4.77 mm. Head, rostrum long, apically acute, length 0.4× head; lateral cephalic lobe with ventral corner rounded, subocular margin weakly recessed, anteroventral corner subquadrate, ventral margin horizontal, posterior margin vertical. Antenna 1 long, length 0.5× body length; peduncular article 1 longer than (1.2×) peduncular article 3, not produced anterodistally and anteromedially, swollen along posterior margin, posterodistal corner not produced; flagellum 6-articulate; article 1 short. Antenna 2 length 0.9× antenna 1; flagellum 5- articulate; article 1 short. Epistome and upper lip fused, straight. Mandible with palp article 2 long and slender, length 3.1× breadth, 1.2× article 3; palp article 3 slender, blade-like, long, 3.3× breadth.

Pereon. Pereonite 1 without lateral keel; without sternal keel. Pereonite 2 with sternal keel. Pereonite 3 without sternal keel. Pereonite 5 length 2.1× depth.

Gnathopod 1 coxa not fused to pereonite 1, length 1.4× depth, without anteroventral lobe; basis length 1.6× depth; carpus, length 1.2× depth with setose posterior lobe, broad; palm extremely acute, with barbed robust setae. Gnathopod 2 carpochelate; coxa not fused to pereonite 2, length 1.7× depth, without anteroventral lobe or cusp; basis short, broad, length 1.3× breadth; carpus long, broad, length 1.2× breadth; palm shallowly excavate, anterodistal tooth small, located near articulation with propodus, posterodistal tooth well defined, medium, length 1.2× width; propodus broad, slightly curved, length 3.2× width, without proximal tooth on posterior margin, posterodistal corner smooth, without tooth; dactylus, length 0.7× propodus. Male gnathopod 2 changes significantly through growth stages. Figure 1 illustrates these changes for specimens ranging in size from 2.74 to 4.77 mm.

Pereopod 3 coxa not fused to pereonite 3, length 2.2× depth, without anteroventral lobe; basis, length 1.7× breadth, evenly rounded, with simple setae along anterior margin, without denticles along anterior margin; ischium long, length 1.6× breadth; merus short, length 0.8× breadth, without ridges. Pereopod 4 coxa not fused to pereonite 4, length 2× depth, without anteroventral lobe; basis length 1.3× breadth, with simple setal group midway along anterior margin; ischium long, length 2× breadth; merus short, length 1× breadth. Pereopod 5 coxa length 1.3× depth, without patches of small setae, without setae along ventral margin; merus with anterior lobe not extending beyond anterior margin of carpus, posterior lobe with 4 plumose setae; propodus with 1 seta along posterior margin; dactylus short, uncinate with one accessory hook. Pereopod 6 coxa without setal fringe ventrally, without patch of small setae near anterior margin; basis without patch of small setae near anterior margin; merus, length 1.2× breadth; dactylus short, uncinate, with two accessory hooks. Pereopod 7 coxa without posterodorsal lobe, without patch of small setae; merus, length 1.7× breadth; dactylus, short, uncinate, with two accessory hooks.

Pleon. Pleopods 1 to 3 decreasing in size. Pleopod 1 inner ramus 8-articulate; outer ramus 8-articulate, article 1 evenly swollen. Pleopod 2 biramous; inner ramus reduced, 1- articulate; outer ramus, broad, 1-articulate. Pleopod 3 present; inner ramus present, reduced; 1-articulate. Uropod 1 biramous, peduncle with distoventral corona of cuticular teeth, length 1.4× outer ramus; rami with distoventral corona of cuticular teeth; outer ramus with lateral row of denticles, without medial setae, with 9 lateral setae, with large apical robust seta without smaller slender setae; inner ramus, length 0.5× outer ramus, without medial or lateral setae, with large apical robust seta without smaller slender setae. Uropod 2 uniramous, length of peduncle 2.4× breadth, 3.8× ramus; ramus small, with 4 denticles and 1 apical seta. Uropod 3 uniramous, peduncle length 1.5× breadth; ramus with 3 curved hooks. Telson length 0.5× breadth, moderately cleft, 0.6× length, each lobe with 17–18 anteriorly directed hooks, in 2 rows.

Female (sexually dimorphic characters). Based on paratype female, 3.85 mm (P62385). Antenna 1 flagellum 4- articulate. Pereonite 2 without sternal keel. Pereonite 5 length 1.5× depth. Gnathopod 1 coxa length 1.7× depth; basis length 2.3× depth; carpus, length 1.1× depth with setose posterior lobe. Gnathopod 2 subchelate; coxa length 1.9× depth; basis slender, length 1.8× breadth; carpus short, compressed, length 1.3× breadth. Pereopod 5 coxa length 1.5× depth, with setae along ventral margin. Oostegites from gnathopod 2 to pereopod 5.

Etymology. The species is named after Bundegi Reef, in the northern part of its range.

Tube. Wrapped, parchment-like; seagrass and algae “wrapped” to form a tube.

Habitat. Littoral, 0.5 to 6 m depth.

Life-style. Epifaunal sediment, algal or seagrass dwellers.

Remarks. Cerapus bundegi is a common, widespread species along the western Australian coast. The tubes of C. bundegi and C. volucola are almost identical, but morphologically the species differ in many ways. The most obvious differences are the shape of male gnathopod 2, and the number of dorsal recurved hooks on the telson (17–18 in C. bundegi and 14–15 in C. volucola ).

Distribution. Western Australia: Malus Island, Kendrew Island, Nelson Rocks, Tish Point, Rosemary Island, all in the Dampier Archipelago; Bundegi Reef, Exmouth Gulf, Ned’s Camp, Cape Range National Park; Red Bluff, Kalbarri; Champion Bay, Geraldton; Seven Mile Beach; Cottesloe Beach, Perth; Cape Peron; South Mole, Arthur Head, Fremantle (20°S to 32°S).