Scavenging amphipods from the Wallaby-Zenith Fracture Zone : Extending the hadal paradigm beyond subduction trenches

Acknowledgements We would like to thank Nick Cuomo for assis- tance with lander deployments, Prof Darren Evans and Dr James Kitson (Newcastle University, UK) for bench space in the Molecular Diagno- sis Facility, Ed Hendrycks (Canadian Museum of Nature, Canada) for guidance on the Cleonardo sp. identification, and Dr Shannon Flynn (Newcastle University, UK) for constructive comments on manuscript drafts. We extend thanks to the Captain and crew on the 2017 R/V SONNE Expedition SO258 Leg 1, especially joint Chief Scientists Dr Reinhard Werner (GEOMAR, Germany) and Prof Hans-Joachim Wagner (University of Tübingen, Germany) and Oleg Lechenko and Julia Marinova (P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences, Russia) for the acquisition and processing of the bathymetric data. We are appreciative of the reviewers for their constructive comments and suggestions that improved the manuscript. Funding Participation on the R/V SONNE Expedition SO258 was sup- ported by Newcastle University’s Research Infrastructure Fund (RiF), Exploration of Extreme Ocean Environments, awarded to AJJ. The genetic analysis was funded by Newcastle University through internal funds to JNJW and the University of Aberdeen by the Natural Environment Research Council (NERC), UK Grant NE/N01149X/1, awarded to SBP.Peer reviewedPublisher PD

Bait-attending amphipods of the Tonga Trench and depth-stratified population structure in the scavenging amphipod Hirondellea dubia Dahl, 1959

Background The hadal zone encompasses the deepest parts of the world’s ocean trenches from depths of ∼6,000–11,000 m. The communities observed at these depths are dominated by scavenging amphipods that rapidly intercept and consume carrion as it falls to the deepest parts of the trenches. New samples collected in the Tonga Trench provide an opportunity to compare the amphipod assemblages and the population structure of a dominant species, Hirondellea dubia Dahl, 1959, between trenches and with earlier data presented for the Tonga Trench, and other trenches in the South Pacific. Methods Over 3,600 individual scavenging amphipods across 10 species were collected in seven baited traps at two sites; in the Horizon Deep site, the deepest part of the Tonga Trench (10,800 m) and a site directly up-slope at the trench edge (6,250 m). The composition of the bait-attending amphipods is described and a morphometric analysis of H. dubia examines the bathymetric distribution of the different life stages encountered. Results The amphipod assemblage was more diverse than previously reported, seven species were recorded for the first time from the Tonga Trench. The species diversity was highest at the shallower depth, with H. dubia the only species captured at the deepest site. At the same time, the abundance of amphipods collected at 10,800 m was around sevenfold higher than at the shallower site. H. dubia showed clear ontogenetic vertical structuring, with juveniles dominant at the shallow site and adults dominant at the deep site. The amphipods of the deeper site were always larger at comparable life stage. Discussion The numbers of species encountered in the Tonga Trench is less than reported from the New Hebrides and Kermadec trenches, and six species encountered are shared across trenches. These findings support the previous suggestion that the fauna of the New Hebrides, Tonga and Kermadec Trenches may represent a single biogeographic province. The ontogenetic shift in H. dubia between the two Tonga Trench sites supports the hypothesis of interspecific competition at the shallower bathymetric range of the species, and the presence of competitive physiological advantages that allow the adults at the trench axis to exploit the more labile organic material that reaches the bottom of the trench

Figure 9 from: Peart RA, Lörz A-N (2018) Ampithoidae (Crustacea, Amphipoda) from New Zealand. ZooKeys 733: 25-48. https://doi.org/10.3897/zookeys.733.14052

Ampithoidae is a family of marine Amphipoda with approximately 230 species, belonging to 16 genera. The family has a worldwide distribution as algal dwellers. So far only five species are known from New Zealand. Recent collections and examination of historic collection material added two new species, which are described herein. An overview of and a key to the New Zealand Ampithoidae is provided

Ampithoe Leach 1814

Key to males of Australian Ampithoe 1 Uropod 1 distoventral spur present, rounded and reduced in male and absent in female; pereopods 5–7 prehensile; telsonic cusps large (Fig. 49).................................................................................................. 17 - Uropod 1 distoventral spur absent on both male and female; pereopods 5–7 simple; telsonic cusps small or absent (Fig. 65)............................................................................................................................................ 2 2 Gnathopod 1 palm excavate (Fig. 52).......................................................................................................... 3 - Gnathopod 1 palm straight or convex (Fig. 60)........................................................................................... 7 3 Gnathopod 2 palm without midmedial tooth (Fig. 52)................................................................................ 4 - Gnathopod 2 palm with midmedial tooth (Fig. 20)..................................................................................... 6 4 Gnathopod 1 palm with midmedial tooth (Fig. 52)..................................................................................... 5 - Gnathopod 1 palm without midmedial tooth (Fig. 41)................................ A. ngana Poore & Lowry, 1997 5 Uropod 3 peduncle without marginal robust setae (Fig. 53) ........................................ A. peronana sp. nov. - Uropod 3 peduncle with marginal robust setae (Fig. 13) ............................................... A. eremitis sp. nov. 6 Gnathopod 2 palm excavate (Fig. 20) ................................................................................. A. hiana sp. nov. - Gnathopod 2 palm entire (Fig. 56) ......................................................................... A. pseudongana sp. nov. 7 Gnathopod 2 propodus subrectangular (Fig. 6)........................................................................................... 8 - Gnathopod 2 propodus ovoid, subtriangular or rounded (Fig. 64)............................................................ 10 8 Gnathopod 2 palm midmedial tooth absent (Fig. 6) ..................................... A. caddi Poore & Lowry, 1997 - Gnathopod 2 palm midmedial tooth present (Fig. 60)................................................................................. 9 9 Gnathopod 2 propodus produced anterodistally to form a setose lobe (Fig. 60) ....... Ampithoe roly sp. nov. - Gnathopod 2 propodus not produced to form a lobe (Fig. 24) .......................................... A. hyalos sp. nov. 10 Gnathopod 2 palm with midmedial tooth (Fig. 64)................................................................................... 11 - Gnathopod 2 palm without midmedial tooth (Fig. 28).............................................................................. 14 11 Gnathopod 1 carpal lobe subacute (Fig. 64).............................................................................................. 12 - Gnathopod 1 carpal lobe rounded (Fig. 38)............................................................................................... 13 12 Gnathopod 2 dactylus shorter than palm (Fig. 64) .......................................................... A. rosema sp. nov. - Gnathopod 2 dactylus overeaching the palm (Fig. 16) ............................................... A. geographe sp. nov. 13 Pereopod 6 basis with marginal robust setae (Fig. 39) ............................................... A. merimbula sp. nov. - Pereopod 6 basis without marginal robust setae (Fig. 4) .................................................. A. boiana sp. nov. 14 Gnathopod 2 without densely setose margins (Fig. 28)............................................................................. 15 - Gnathopod 2 with long non-plumose setae on margins (Fig. 72).............................................................. 16 15 Gnathopod 2 basis posterodistal lobe with robust setae on the margin (Fig. 28) .... Ampithoe katae sp. nov. - Gnathopod 2 basis posterodistal lobe with slender setae on the margin (Fig. 9) Ampithoe cookana sp. nov. 16 Gnathopod 1 palm with midmedial tooth (Fig. 72) ....................................................... A. ulladulla sp. nov. - Gnathopod 1 palm without midmedial tooth (Fig. 44) .................................................. A. ningaloo sp. nov. 17 Gnathopod 2 propodal palm incised (Fig. 31)........................................................................................... 18 - Gnathopod 2 propodal palm entire (Fig. 68)............................................................................................. 19 18 Antenna 2 poorly setose (Fig. 31) ................................................................................. A. kava Myers, 1985 - Antenna 2 with short dense setae on the margins (Fig. 47) .......................................... A. parakava sp. nov. 19 Gnathopod 2 basis lobe with 3 marginal slender setae (Fig. 68) ..................................... A. rotunda sp. nov. - Gnathopod 2 basis lobe with 3 marginal robust setae (Fig. 34) .................................... A. meganae sp. nov.Published as part of Peart, Rachael A., 2007, A review of the Australian species of Ampithoe Leach, 1814 (Crustacea: Amphipoda: Ampithoidae) with descriptions of seventeen new species, pp. 1-95 in Zootaxa 1566 (1) on pages 6-7, DOI: 10.11646/zootaxa.1566.1.1, http://zenodo.org/record/509606

Ampithoe pseudongana Peart 2007, sp. nov.

Ampithoe pseudongana sp. nov. (Figs 54–57) Type material. Holotype: WAM C38540, male, 9 mm, Shelley Beach, Bunker Bay, near Cape Naturaliste, S of Bussleton, WA, 33°32.56’S 115°01.79’E, 4 Dec 2000, 0.5 m, from mixed brown algae (mainly Sargassum sp.), R. A. Peart. Paratypes: WAM C38541, female, 10 mm, type locality; AM P61877, 15 specimens, type locality; AM P61875 – P61876, 4 specimens, Shelley Beach, Bunker Bay, near Cape Naturaliste, S of Bussleton, WA, 33°32.56’S 115°01.79’E, 4 Dec 2000, 0.5 m, R. Peart; AM P61878 – P61880, 8 specimens, from seagrass, Eagle Beach, near Cape Naturaliste, SW of Bussleton, WA, 33°33.69’S 115°03.90’E, 5 Dec 2000, 0.5 m, R. Peart; AM P61881 – P61884, 25 specimens, Canal Rocks, south of Yallingup, WA, 33°40.28’S 114°59.67’E, 6 Dec 2000, 0.5 m, from Sargassum sp., R. Peart. Diagnosis. Antenna 2 robust, better developed than antenna 1, with short, dense setae on ventral margin. Lower lip with lateral lobe longer than medial lobe. Maxilla 1 inner plate with three slender setae. Gnathopod 1 carpal lobe subacute; carpus shorter than propodus; palm excavate, without midmedial tooth, with a posterodistal tooth defining palm; dactylus subequal in length to palm. Gnathopod 2 without densely setose margins; basis posterodistal lobe large and rounded, with more than 3 slender setae; carpus shorter than propodus; palm acute, entire, with a rounded midmedial tooth, with a small subacute posterodistal tooth defining palm, with 1 defining robust seta; dactylus subequal in length to palm. Pereopod 3 basis narrow; merus expanded. Pereopods 5–7 weakly prehensile. Pereopod 5 merus subrectangular. Uropod 3 peduncle with 10 distal robust setae, outer ramus shorter than inner ramus, with patch of small conical lateral denticles, without lateral setal fringe; inner ramus with 7 distal robust setae. Telson distally rounded, apical cusps small. Description. Based on holotype, male, 9 mm, WAM C38540. Head as long as deep. Antenna 2 peduncular article 4 longer than article 5; flagellum 14-articulate. Mandible molar with 4 or 5 robust setae in accessory setal row; palp stout, long, apically setose, article 1 shorter than article 2 (0.32 x), article 2 longer than article 3 (1.3 x), article 3 longer than article 1 (2.38 x). Lower lip mandibular lobe with curved margins, rounded apically. Maxilla 1 palp with apical robust setae. Maxilla 2 inner plate narrow, outer plate broader. Maxilliped outer plate with developed setation (robust setae large). Pereon. Gnathopod 1 coxa subequal to gnathopod 2 coxa, produced distoventrally, distoventral margin rounded, anterior margin concave, ventral margin with a row of small setules; basis subequal to coxa, with sparse (sometimes plumose) slender setae, posterodistal lobe reduced, 2 or 3 slender setae; merus produced to form a small, acute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with 1 robust seta and slender setae; propodus narrow (length 1.66 x width), subrectangular; palm with 1 defining robust seta; dactylus inner margin denticulate. Gnathopod 2 coxa ventral margin with a row of small setules; basis shorter than coxa, with fringe of long, slender, plumose setae; merus produced to form a short, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae only; propodus broad (length 0.97 x width), subtriangular, not produced into an anterodistally setose lobe; dactylus tapering evenly, acute, inner margin denticulate. Pereopod 5 basis with marginal robust setae, with medial slender setae; distal articles slender; propodus slightly expanded distally, subrectangular, with 3 distal simple striated robust setae; dactylus strongly curved. Pereopod 6 basis posterior margin rounded proximally, straight distally, with marginal robust setae, without medial slender setae; merus subrectangular; propodus slightly expanded distally, with 3 distal simple striated robust setae; dactylus strongly curved. Pereopod 7 basis with marginal robust setae, with medial slender setae; propodus defined distally by 3–5 simple robust setae. Pleon. Epimeron 3 posteroventral corner broadly rounded. Uropod 1 peduncle with more than 5 robust setae, with a long setal fringe; inner ramus slightly shorter than outer ramus, with more than 5 marginal robust setae, slender setae absent; outer ramus with 3–5 marginal robust setae, slender setae absent. Uropod 2 peduncle with more than 5 robust setae, setal fringe absent; inner ramus slightly shorter than outer ramus, with more than 5 marginal robust setae, slender setae absent; outer ramus with 3–5 marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (1.37 x width), short with respect to the rami length (1.94 x), with marginal robust setae absent, marginal slender setae absent, with more than 5 distal slender setae; inner ramus with more than 5 distal slender setae. Telson with apical and lateral slender setae. Female. (sexually dimorphic characters). Based on paratype, 10 mm, WAM C38541. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2 (1.31 x), article 2 longer than article 3 (3.3 x), article 3 shorter than article 1 (0.23 x); primary flagellum with 14 articles; accessory flagellum absent. Antenna 2 with sparse setae on ventral margin; flagellum with 22 articles. Gnathopod 1 subequal in size to gnathopod 2, not densely setose on margins; basis shorter than coxa, with fringe of long, slender, plumose setae, posterodistal lobe small and round; merus produced to form a short, rounded distoventral lobe; carpus anterior margin with slender setae only; propodus ovoid; palm convex, without posterodistal tooth defining the palm. Gnathopod 2 basis with sparse (sometimes plumose) slender setae, posterodistal lobe small and round; propodus ovoid; palm without a midmedial tooth. Etymology. This species is very similar to A. ngana Poore & Lowry, 1997, from the east coast of Australia, the species name alludes to this similarity. Remarks. Ampithoe pseudongana sp. nov. is similar to A. ngana, A. eremitis sp. nov., A. hiana sp. nov. and A. peronana sp. nov., but is closest in morphology to A. hiana. Characters distinguishing A. pseudongana from A. hiana are outlined under the account of the latter. Habitat. Brown algae: Cystophora sp., Sargassum sp. Distribution. Cape Naturaliste, Western Australia, Australia.Published as part of Peart, Rachael A., 2007, A review of the Australian species of Ampithoe Leach, 1814 (Crustacea: Amphipoda: Ampithoidae) with descriptions of seventeen new species, pp. 1-95 in Zootaxa 1566 (1) on pages 69-74, DOI: 10.11646/zootaxa.1566.1.1, http://zenodo.org/record/509606

Cymadusa tattersalli Peart 2004

Cymadusa tattersalli Peart, 2004 (Figs. 27–28) Cymadusa tattersalli Peart, 2004. Cymadusa setosa.— Tattersall, 1922: 1 –19. Cymadusa filosa.— Ledoyer, 1982: 130–135, figs 44–46 (form A) Type material. Holotype: male, 17 mm, TMAG G 3932, Woodman Point, Cockburn Sound, Western Australia, Australia, 32 °08’S, 115 ° 45 ’E, 14 July 1973, T.M. Walker & D.D. Bray. Paratypes: TMAG G 3931 (female), AM P 51282 (female and male); TMAG G 3933 (male); TMAG G 3934 –G 3938 (females and males – 5 specimens), type locality. Material examined. AM P61927, 6 specimens, northern reef flat, Heron Island, Great Barrier Reef, Queensland, Australia, 23 ° 27 ’S 151 ° 55 ’E, 14 February 1999, 0.5 m, Padina australis, R. Peart & S. Richards. AM P61928, 1 specimen; AM P61929, 1 specimen, Dictyotales sp.; AM P61930, 1 specimen; AM P62510, 1 specimen; AM P62511, 2 specimens; AM P62512, 4 specimens, Padina sp. and Lobophora sp., west side of Malus Island, Dampier Archipelago, Western Australia, Australia, 26 ° 30.612 ’S 116 ° 38.918 ’E, 27 August 1999, 2.8 m, R. Peart. AM P62513, 2 specimens, Dictyota sp.; AM P62514, 8 specimens, Padina sp., Tish Point, Rosemary Island, Dampier Archipelago, Western Australia, Australia, 20 ° 29.671 ’S 116 ° 35.894 ’E, 30 August 1999, 0.5 m, R. Peart. AM P62515, 4 specimens, Dictyota sp.; AM P62515, 3 specimens, Padina sp., 4.2 m, south side of Kendrew Island, Dampier Archipelago, Western Australia, Australia, 20 ° 28.987 ’S 116 ° 32.549 ’E, 30 August 1999, 4 m, R. Peart. AM P62516, 1 specimen, Bare Rock, Dampier Archipelago, Western Australia, Australia, 20 ° 32.849 ’S 116 ° 26.705 ’E, 31 August 1999, 15 m, under rocks, M. Hewitt. AM P62517, 2 specimens, Eaglehawk Island, Dampier Archipelago, Western Australia, Australia, 20 ° 38.939 ’S 116 ° 26.218 ’E, 3 September 1999, 10 m, red algae, R. Peart. Diagnosis. Antenna 1 accessory flagellum with 2 articles. Maxilla 1 inner plate with 5 slender setae. Gnathopod 1 with long, dense, plumose setae on margins; merus produced to form a small, subacute distoventral lobe; carpus longer than propodus; palm acute, convex, without midmedial tooth, without posterodistal tooth defining palm, with 1 defining robust seta. Gnathopod 2 with long plumose setae on margins; merus produced to form a short, subacute distoventral lobe; carpus shorter than propodus; palm acute, entire, with subquadrate midmedial tooth, with small subacute posterodistal tooth defining palm, without defining robust seta; dactylus shorter than palm, tapering evenly, acute. Epimeron 3 posteroventral corner with small acute tooth. Uropod 3 peduncle with 7 distal robust setae; outer ramus with patch of small conical lateral denticles, with lateral setal fringe. Telson distally rounded, apical cusps small, with apical and lateral slender setae. Habitat. This species occurs on a variety of brown algae living at 0.5–10 m depth. Remarks. Cymadusa tattersalli is closely related to C. setosa (Haswell, 1879) and C. filosa Savigny, 1816 (see Peart 2004). This is the first time Cymadusa tattersalli has been recorded from the east coast of Australia. Distribution. Cockburn Sound, Abrolhos Islands, Dampier Archipelago, Western Australia; Heron Island, Queensland, Australia.Published as part of Peart, Rachael A., 2007, A review of Australian Cymadusa (Crustacea: Amphipoda: Ampithoidae) with descriptions of eight new species, pp. 1-53 in Zootaxa 1540 on pages 33-35, DOI: 10.5281/zenodo.17779

Cymadusa heronensis Peart, 2007, sp. nov.

Cymadusa heronensis sp. nov. (Figs. 8–11) Type material. Holotype: male, 4 mm, AM P 61906, northern reef flat, Heron Reef, Heron Island, Great Barrier Reef, Queensland, Australia, 23 ° 27 ’S 151 ° 55 ’E, 14 February 1999, 0.5 m, from Sargassum sp., R. Peart & S. Richards. Paratypes: AM P 61907 (female, 4 mm), AM P 61908 (females and males, 10 specimens), type locality. Other material examined. AM P 61909 (females and males, 24 specimens), southern reef flat, Heron Reef, Heron Island, Great Barrier Reef, 23 ° 27 ’S 151 ° 55 ’E, from Dictyota sp., 11 February 1999, 0.5 m, R. Peart & S. Richards. AM P 61910 (2 specimens), AM P 61911 (5 specimens), AM P 61912 (28 specimens), AM P 61913 (6 specimens), AM P 61914 (3 specimens), southern reef flat, Heron Reef, Heron Island, Great Barrier Reef, 23 ° 27 ’S 151 ° 55 ’E, from Padina australis, 11 February 1999, 0.5 m, R. Peart & S. Richards. AM P 61915 (9 specimens), northern reef flat, Heron Reef, Heron Island, Great Barrier Reef, 23 ° 27 ’S 151 ° 55 ’E, 14 February 1999, 0.5 m, from Caulerpa sp., S. Smith. Diagnosis. Antenna 1 accessory flagellum with one article. Maxilla 1 inner plate with one slender seta. Gnathopod 1 with sparsely setose margins; merus produced to form a small, subacute distoventral lobe; carpus shorter than propodus; palm acute, entire, with midmedial tooth, with posterodistal tooth defining palm, with a defining robust seta. Gnathopod 2 with long slender setae on margins, not plumose; merus produced to form a short, subacute distoventral lobe; carpus shorter than propodus; palm acute, excavate, without midmedial tooth, with small subacute posterodistal tooth defining palm, without defining robust seta; dactylus shorter than palm, tapering evenly, acute point. Epimeron 3 posteroventral corner narrowly rounded. Uropod 3 peduncle with 3 distal robust setae; outer ramus with patch of small conical lateral denticles, without lateral setal fringe. Telson distally truncate, apical cusps small, with oblique lateral and medial rows of slender setae. Description. Male (based on holotype male 4 mm, AM P 61906). Head as long as deep. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2 (1.09 x), article 2 longer than article 3 (3.06 x), article 3 shorter than article 1 (0.3 x); primary flagellum with 21–30 articles. Antenna 2 slender, similar to antenna 1, sparsely setose on ventral margin; peduncular article 4 longer than article 5; flagellum 9 -articulate. Mandible triturating; with 5 robust setae in the accessory setal row; palp slender, long, apically setose, article 1 shorter than article 2 (0.56 x), article 2 longer than article 3 (1.11 x), article 3 longer than article 1 (1.61 x). Lower lip with lateral lobe longer than medial lobe; mandibular lobe with curved margins, rounded apically. Maxilla 1 palp well developed, with apical robust setae. Maxilla 2 inner plate narrow, outer plate broader. Maxilliped outer plate with developed setation (robust setae large). Pereon. Gnathopod 1 coxa smaller than gnathopod 2 coxa, produced distoventrally, distoventral margin rounded, anterior margin straight, ventral margin with a row of slender setae of different lengths, not plumose; basis shorter than coxa, with sparse (sometimes plumose) slender setae, posterodistal lobe small and rounded, one slender seta; merus anterior margin with setae absent; carpus longer than merus, subtriangular, carpal lobe subacute, anterior margin with slender setae only; propodus broad (length 1.43 x width), ovoid; dactylus subequal in length to palm, inner margin denticulate. Gnathopod 2 coxa ventral margin with a row of slender setae of varying lengths, not plumose; basis subequal to coxa, with sparse slender setae, posterodistal lobe small and rounded, with one slender setae; merus anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae only; propodus broad (length 1.09 x width), ovoid, not produced into an anterodistally setose lobe; dactylus inner margin denticulate. Pereopod 5 basis with marginal robust setae, without medial slender setae; merus subrectangular; distal articles broad; propodus slightly expanded distally, subrectangular, distally with 3 simple striated robust setae; dactylus strongly curved. Pereopod 6 basis posterior margin rounded, with marginal robust setae, without medial slender setae; merus subrectangular; propodus slightly expanded distally, with 3 distal simple striated robust setae; dactylus strongly curved. Pereopod 7 basis with marginal robust setae, without medial slender setae; propodus defined distally by 3–5 simple robust setae. Pleon. Uropod 1 peduncle with more than 5 robust setae, with long setal fringe; inner ramus slightly longer than outer ramus, with 1 or 2 marginal robust setae, slender setae absent; outer ramus with 3–5 marginal robust setae, slender setae absent. Uropod 2 peduncle with 1 or 2 robust setae, setal fringe absent; inner ramus slightly longer than outer ramus, with 3–5 marginal robust setae, slender setae absent; outer ramus with 1 or 2 marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (length 1.28 x width), short with respect to rami length (1.97 x), marginal robust setae absent, marginal slender setae absent, with 3– 5 distal slender setae; outer ramus subequal to inner ramus, with 1 recurved and 1 straight robust seta; inner ramus with 3 distal robust setae, with 3–5 distal slender setae. Female (sexually dimorphic characters; based on paratype, 4 mm, AM P 61907). Antenna 1 peduncular article 1 longer than article 2 (1.18 x), article 2 longer than article 3 (2.48 x), article 3 shorter than article 1 (0.34 x); primary flagellum with 20 articles. Antenna 2 flagellum with seven articles. Gnathopod 1 subequal in size to gnathopod 2; coxa subequal in size to gnathopod 2 coxa; basis subequal in length to coxa, posterodistal lobe reduced, without setae; merus produced to form a short, rounded distoventral lobe; carpal lobe rounded; propodus narrow (length 1.53 x width); palm convex, without midmedial tooth, without posterodistal tooth defining the palm. Gnathopod 2 without densely setose margins; basis posterodistal lobe with 2 or 3 slender setae; palm entire, with a rounded midmedial tooth, defined by 1 robust setae; dactylus subequal in length to palm. Etymology. This species is named after the type locality, Heron Island. Remarks. Cymadusa heronensis is similar to C. thagaay sp. nov. Both species have a 1 -articulate accessory flagellum on antenna 1, the gnathopod 1 palm is entire and has a distal defining tooth, epimeron 3 does not have a defining tooth, and the uropod 3 peduncle does not have marginal robust setae. However, the two species differ because C. heronensis does not have a robust seta defining the palm of gnathopod 2 (present in C. thagaay), the gnathopod 2 propodus is not produced to form a setose lobe (lacking in C. thagaay), and the uropod 3 outer ramus has a patch of lateral denticles (absent in C. thagaay). Habitat. Cymadusa heronensis sp. nov. has been collected from the algae Dictyota sp., Padina sp., Sargassum sp. and Caulerpa sp. from 0.5 m depth on the reef flat. Distribution. Heron Island, Queensland, Australia.Published as part of Peart, Rachael A., 2007, A review of Australian Cymadusa (Crustacea: Amphipoda: Ampithoidae) with descriptions of eight new species, pp. 1-53 in Zootaxa 1540 on pages 13-18, DOI: 10.5281/zenodo.17779

Cymadusa munnu Poore & Lowry 1997

Cymadusa munnu Poore & Lowry, 1997 (Figs. 19–20) Cymadusa munnu Poore & Lowry, 1997: 918 –922, figs 14–17. Type material. Holotype: female, 16.5 mm, AM P 45081, Shark Bay, Port Jackson, New South Wales, Australia, 33 ° 51.2 ’S 151 ° 15.9 ’E, 2 February 1995, 1– 2 m, on Dictyopteris acrostichoides, A.G.B. Poore. Paratypes: male, 23.9 mm, AM P 45082, Shelly Beach, Cronulla, New South Wales, Australia, 34 °04’S 151 °09’E, 3 August 1994, 1– 2 m, on Homoeostrichus sinclairi, A.G.B. Poore; females, AM P45083, 3 specimens, Shelly Beach, Cronulla, New South Wales, Australia, 34 °04’S 151 °09’E, 3 August 1994, 1– 2 m, on Zonaria diesingiana, A.G.B. Poore; female, AM P45084, 1 specimen, Shark Bay, Port Jackson, New South Wales, Australia, 33 ° 51.2 ’S 151 ° 15.9 ’E, 2 February 1995, 1– 2 m, on Dictyopteris acrostichoides, A.G.B. Poore; male, AM P45085, 1 specimen, Shark Bay, Port Jackson, New South Wales, Australia, 33 ° 51.2 ’S 151 ° 15.9 ’E, 11 March 1995, 0–0.5 m, on Champia sp., E. Taylor-Wood. Other material examined. AM P59661, 1 specimen; AM P59662, 3 specimens; AM P59663, 1 specimen; AM P59667, 1 specimen, on Sargassum sp.; AM P59664, 2 specimens; AM P59665, 1 specimen; AM P59666, 3 specimens, on Dictyota sp.; AM P59659, 2 specimens; AM P59660, 1 specimen, on Padina sp., off Harbord Baths, Sydney, 33 ° 46.99 ’S 151 ° 17.61 ’E, New South Wales, Australia, 8 December 1999, 5 m, R. Peart & K. Dempsey. Diagnosis. Antenna 1 accessory flagellum with 1 article. Maxilla 1 inner plate with 3 slender setae. Gnathopod 1 without densely setose margins; merus produced to form a small, acute distoventral lobe; carpus subequal to propodus; palm acute, entire, without midmedial tooth, without posterodistal tooth defining palm, with 1 defining robust seta. Gnathopod 2 with long setae on margins, not plumose; merus produced to form a short, subacute distoventral lobe; carpus much shorter than propodus; palm acute, entire, with a subacute midmedial tooth, without posterodistal tooth defining palm, with 1 defining robust seta; dactylus subequal in length to palm, tapering evenly, acute. Epimeron 3 posteroventral corner broadly rounded. Uropod 3 peduncle with seven distal robust setae; outer ramus with patch of small conical lateral denticles, with lateral setal fringe. Telson distally truncate, apical cusps small, with lateral and oblique medial rows of slender setae. Habitat. Cymadusa munnu occurs on the brown algae Dictyopteris acrostichoides, Homoeostrichus sinclarii, Zonaria diesingiana, Delisea pulchra and Champia sp., 0–m depth (Poore & Lowry 1997). Distribution. Sydney, New South Wales, Australia.Published as part of Peart, Rachael A., 2007, A review of Australian Cymadusa (Crustacea: Amphipoda: Ampithoidae) with descriptions of eight new species, pp. 1-53 in Zootaxa 1540 on pages 26-27, DOI: 10.5281/zenodo.17779

Cymadusa setosa Haswell 1879

Cymadusa setosa (Haswell, 1879) (Figs. 24–26) Ampithoe setosa Haswell, 1879: 338 [type locality: Kurnell, Botany Bay, New South Wales, Australia, by neotype designation (Peart 2004)] Ampithoe flindersi Stebbing, 1888: 1120, pl. 18 [type locality: Flinders Passage, Gulf of Carpentaria, Queensland, 10 ° 30 ’S, 142 ° 18 ’E] [new synonymy]. Grubia setosa.— Stebbing, 1906: 644. Cymadusa compta.— Bousfield, 1973: 182 –183, pl. LV. 2.— Nelson, 1980 (ecology). Grubia filosa.— Schellenberg, 1928: 666, fig. 206.— K.H. Barnard, 1937: 171 –172. Shoemaker, 1935: 245 –249, figs 4– 5. Cymadusa filosa.— J.L. Barnard, 1955: 29 –30, fig. 15 (with references).— J.L. Barnard, 1965: 3 (key).— Rabindranth, 1972: 173 –175, figs 8–9.— Griffiths, 1973: 277 –278; 1974 a: 225; 1974 b: 274; 1975: 106; 1976: 25 (key).— Ledoyer, 1984: 15 –18, figs 5–6 (Group II setose). Cymadusa setosa.— Peart, 2004 (full synonymy, key and references). Type material. Neotype, male, 10.5 mm, AM P 10853, on rocky shores between tide marks, Kurnell, Botany Bay, New South Wales, Australia, 34 ° 0.1 ’S 151 °13.0’E, 27 October 1927, F. A. McNeill & T. Iredale. Other material examined. Holotype of Ampithoe flindersi Stebbing, 1888, female, NHM 89.5. 15.136, Flinders Passage, Gulf of Carpentaria, Queensland, 10 ° 30 ’S, 142 ° 18 ’E, “Challenger” stn 186. Diagnosis. Antenna 1 accessory flagellum with 2 articles. Maxilla 1 inner plate with 11 slender seta. Gnathopod 1 with long dense plumose setae on margins; merus produced to form a long, acute distoventral lobe; carpus much longer than propodus; palm acute, entire, without midmedial tooth, without posterodistal tooth defining palm, with 1 defining robust seta. Gnathopod 2 with long plumose setae on margins; merus produced to form a short, subacute distoventral lobe; carpus shorter than propodus; palm acute, entire, with subquadrate midmedial tooth, with small subacute posterodistal tooth defining palm, without defining robust seta; dactylus shorter than palm, tapering evenly, acute. Epimeron 3 posteroventral corner with subacute tooth. Uropod 3 peduncle with 7 distal robust setae; outer ramus without patch of small conical lateral denticles, with lateral setal fringe. Telson distally truncate, apical cusps small, with lateral and apical slender setae. Habitat. Rock pools. Remarks. Peart (2004) redescribed Cymadusa setosa and discussed its status and disjunct distribution in relation to similar species, especially C. filosa Savigny, 1816. Stebbing (1888) described Ampithoe flindersi from Flinders Passage, Gulf of Carpentaria. Restudy of the type material and the detailed type description of A. flindersi shows that it was based on female Cymadusa setosa, not C. filosa as proposed by Barnard & Karaman (1991). Therefore, the two species are herein synonymised. Distribution. New South Wales and Queensland, Australia; United States of America; Puerto Rico, Caribbean Sea; Hawaiian Islands and New Caledonia, Pacific Ocean; southern tip of India, Indian Ocean.Published as part of Peart, Rachael A., 2007, A review of Australian Cymadusa (Crustacea: Amphipoda: Ampithoidae) with descriptions of eight new species, pp. 1-53 in Zootaxa 1540 on pages 31-33, DOI: 10.5281/zenodo.17779