Cerapus volucola, 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 : 160-163

Cerapus volucola n.sp.

Figs. 7–9

Type material. HOLOTYPE, 3, 3.20 mm, AM P62408; 12 PARATYPES, AM P62407 ; PARATYPE, 3, 2.84 mm, AM P62409 ; PARATYPE, ♀, 3.92 mm, AM P62410; False Orford Ness , northeast of Cape York, Queensland, Australia, 11°23'S 142°52'E, rock, brown algae and sand, 4 m, D. Blake, 18 February 1979 .

Additional material. 13, AM P62419; 2 specimens , AM P62413, Padoz Natun reef, Madang Lagoon, Papua New Guinea, 5°09.60'S 145°48.77'E, Halimeda & epiphytic algae on rubble consolidated by sponges, 8 m, D. Gochfeld, 15 December 1993; 1♀ , AM P62414, Padoz Natun reef, Madang Lagoon, Papua New Guinea, 5°09.60'S 145°48.77'E, Halimeda & epiphytic algae on rubble consolidated by sponges, 8 m, D. Gochfeld, 2 January 1994. 3 specimens , AM P62411, half way between Lizard Island and Carter Reef, Queensland, Australia, 14°37'S 145°33'E, 38 m, J.Leis, 26 November 1981. 5 specimens , AM P62417, Magnetic Island , Queensland, Australia, 19°8'S 146°50'E, among Sargassum , 3 m, G. Edgar 13 August 1981. 1 ovigerous female , AM P62415, north Wistari Reef , Capricorn Group, Great Barrier Reef, Queensland, Australia, 23°29'S 151°53'E, coral sand, 24 m, D. Fisk, 11 November 1978; 1♀ , AM P62416, northwest Wistari Reef , Great Barrier Reef, Queensland, Australia, 23°29'S 151°53'E, sand, 24 m, D. Fisk, 16 December 1978. 1♀ , AM P62418, Middle Reef , North Stradbroke Island, Queensland, Australia, 27°24.4'S 153°32'E, Zonaria , 20 m, K.B. Attwood and E.L.A. Ho, 4 June 1993 .

Diagnosis. Head, rostrum long, apically acute; anteroventral corner rounded. Antenna 1 peduncular article 1 longer than article 3, swollen along posterior margin. Pereonite 2 without sternal keel. Pereopod 5 merus posterior lobe with 2 plumose setae.

Description. Based on holotype male, 3.20 mm (P62408) and paratype female, 3.92 mm (P62410). With chocolatecoloured stripe around margin of head and dorsal surface of peduncle of antenna 1. Head, rostrum long, apically acute, length 0.3× head; lateral cephalic lobe with ventral corner rounded, subocular margin weakly recessed, anteroventral corner rounded, ventral margin horizontal, posterior margin vertical. Antenna 1 long, length 0.5× body 162 Records of the Australian Museum (2005) Vol. 57 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 1× antenna 1; flagellum 6-articulate; article 1 short. Epistome and upper lip fused, straight. Mandible with palp article 2 long and slender, length 2.7× breadth, 1.1× article 3; palp article 3 slender, blade-like, long, 3.5× breadth.

Pereon. Pereonites 1 to 3 without lateral or sternal keels. Pereonite 5 length 1.6× depth.

Gnathopod 1 coxa fused to pereonite 1, without anteroventral lobe; basis length 1.75× depth; carpus, length 1.25× depth with setose posterior lobe, broad; palm extremely acute, with barbed robust setae. Gnathopod 2 carpochelate; coxa fused to pereonite 2, without anteroventral lobe or cusp; basis short, broad, length 1.35× breadth; carpus long, broad, length 1.1× breadth; palm deeply excavate, anterodistal tooth large, located distal to articulation with propodus, posterodistal tooth well defined, medium, length 1.3× width; propodus very broad, slightly curved, length 2.5× width, without tooth on posterior margin, posterodistal corner smooth, without tooth; dactylus, length 0.7× propodus.

Pereopod 3 coxa fused to pereonite 3, with narrow anteroventral lobe; basis, length 1.5× breadth, evenly rounded, with plumose setal group and simple setae along anterior margin, without denticles along anterior margin; ischium long, length 1.6× breadth; merus short, length 1× breadth, without ridges. Pereopod 4 coxa fused to pereonite, with anterior lobe; basis length 1.3× breadth, with plumose setal group midway along anterior margin; ischium long, length 1.8× 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 extending beyond anterior margin of carpus, posterior lobe with 2 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 1.6× breadth; dactylus short, uncinate, with two accessory hooks. Pereopod 7 coxa without posterodorsal lobe, without patch of small setae; merus, length 2.2× breadth; dactylus, short, uncinate, with two accessory hooks.

Pleon. Pleopods 1 to 3 decreasing in size. Pleopod 1 inner ramus 7-articulate; outer ramus 5-articulate, article 1 evenly swollen. Pleopod 2 biramous; inner ramus reduced, 1- articulate; outer ramus, broad, 2-articulate. Pleopod 3 present; inner ramus present, reduced; 1-articulate. Uropod 1 biramous, peduncle with distoventral corona of cuticular teeth, length 1.3× outer ramus; rami with distoventral corona of cuticular teeth; outer ramus with lateral row of denticles, without medial setae, with 5 lateral setae, with large apical robust seta without smaller slender setae; inner ramus, length 0.6× outer ramus, without medial or lateral setae, with large apical robust seta without smaller slender setae. Uropod 2 uniramous, length of peduncle 2.5× breadth, 4.6× 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 0.4× breadth, moderately cleft, 0.6× length, each lobe with 14–15 anteriorly directed hooks in 2 rows.

Female (sexually dimorphic characters). Based on paratype female, 3.92 mm (P62410). Gnathopod 1 coxa not fused to pereonite 1, length 1.5× depth; basis length 2.3× depth; carpus, length 1.1× depth with setose posterior lobe, narrow. Gnathopod 2 subchelate; basis length 1.6× breadth; carpus length 1.3× breadth; propodus palm extremely acute; dactylus length 0.8× propodus. Oostegites from gnathopod 2 to pereopod 5.

Etymology. The species name is derived from the Latin words volumen for scroll and cola for inhabit.

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

Habitat. Littoral, 3 to 38 m depth.

Life-style. Algal or seagrass dwellers.

Remarks. Cerapus volucola is a widespread species known from Madang Lagoon in northern Papua New Guinea, all along the Great Barrier Reef in northeastern Australia, to North Stradbroke Island in southern Queensland. 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. Papua New Guinea: Padoz Natun reef, Madang Lagoon. Australia, Queensland: False Orford Ness, northeast of Cape York; Lizard Island and Carter Reef; Magnetic Island; Wistari Reef, Capricorn Group; Middle Reef, North Stradbroke Island (5°S to 27 °S).

ACKNOWLEDGMENTS. We thank the late Sharne Wiedland for her beautiful illustrations of the whole animals and tubes; Roger Springthorpe for assistance with illustrations. This research was supported by a grant from the Australian Biological Resources Study.