The Coastal Talitridae (Amphipoda: Talitroidea) of Southern and Western Australia, with Comments on Platorchestia platensis (Krøyer, 1845) Author Serejo, C. S. Author Lowry, J. K. text Records of the Australian Museum 2008 2008-10-01 60 2 161 206 http://dx.doi.org/10.3853/j.0067-1975.60.2008.1491 journal article 10.3853/j.0067-1975.60.2008.1491 2201-4349 5238681 B8C054B3-B585-47BA-BF79-7AFBC6DD7695 Notorchestia naturaliste n.sp. Figs 17–20 Type material . HOLOTYPE : male, 14.8 mm , AM P69121 (1 slide, stubs J046–J049–J052) . PARATYPES : 1 male , 16.2 mm , AM P69122 (stub J061, habitus) ; 1 juvenile male, 15.5 mm , AM P69123 ; 1 female 14.6 mm , AM P69124; (stub J048, SEM micrographs) ; 10 males and 90 females , AM P69125 ; all from Bunker Bay , Cape Naturaliste , Western Australia ( 33°32.39'S 115°1.8'E ), protected small rocky beach, C. Serejo & J.K. Lowry , 24 Oct. 2003 , WA 760 . Type locality . Bunker Bay , Cape Naturaliste , Western Australia ( 33°32.39'S 115°1.8'E ) . Additional material examined . Western Australia : 8 males and 30 females (multicoloured), AM P69126, Blackwood River mouth, Augusta ( 34°19.54'S 115°10.07'E ), flat beach near boat ramp, substrate coarse dark sand with some tan to orange and almost black pebbles, substrate covered with large patches of a green alga, probably Enteromorpha , C. Serejo & J.K. Lowry , 23 Oct. 2003 , WA 758 ; 6 males and 52 females , AM P69127, Slippery Rock , Cape Leuwin ( 34°21.44'S 115°7.64'E ), mixed and dead seaweed lodged between large boulders at the end of a steeply sloping white sand beach, C. Serejo & J.K. Lowry , 23 Oct. 2003 , WA 759 ; 1 male , 1 female and 2 juvenile males, AM P69128, beach, Freshwater Point ( 29°36.34'S 114°58.42'E ), small sandy beach with a lot of dead seagrass and seaweed adjacent to a rocky point, C. Serejo & J.K. Lowry , 28 Oct. 2003 , WA 766 ; 6 males , AM P69129, Denham Beach , Denham , Shark Bay ( 25°56'S 113°32.53'E ), white sandy beach with a strand of dead seagrasses at the high tide mark, C. Serejo & J.K. Lowry , 5 Nov. 2003 , WA 776 . Etymology . This species is named for Cape Naturaliste, the type locality. Diagnosis . Dactylus of gnathopod 1 with row of ventral short setae. Female and male juvenile gnathopod 2 merus with distally pointed posterodistal medial lobe. Gnathopod 2 male , propodus subtriangular; palm acute and sinuous. Coxa 6 posterior lobe posteroventral margins with 6–7 robust setae. Basis of pereopod 7 with lateral sulcus. Telson cleft to half length. Fig. 18. Notorchestia naturaliste n.sp. , holotype male, 14.8 mm, AM P69121, Bunker Bay, Cape Naturaliste, Western Australia. Scales for G1 and P4: 0.2 mm; remainder: 0.5 mm. Description Holotype male , 14.8 mm . Eye medium, 1⁄5–1/3 head length. Antenna 1 short, rarely longer than peduncle article 4 of antenna 2. Antenna 2 shorter than head and first 3 pereonites; peduncular articles narrow; with many robust setae; article 5 longer than article 4. Epistome of upper lip without robust setae. Lower lip distolateral setal tuft absent. Mandible left lacinia mobilis 4-dentate. Maxilliped palp article 2 with distomedial lobe, article 4 present, reduced. Fig. 19. Notorchestia naturaliste n.sp. , holotype male, 14.8 mm, U1–3, EP1–3, T, AM P69121, paratype female, 14.6 mm, G1–2, AM P69124, Bunker Bay, Cape Naturaliste, Western Australia. Scales for U1–3: 0.2 mm; G1–2: 0.3 mm; EP1–3: 0.5 mm; T: 0.1 mm. Gnathopod 1 sexually dimorphic; subchelate; posterior margin of carpus and propodus with rugose lobe; propodus sub-triangular; palm transverse; dactylus shorter than palm, with row of ventral short setae. Gnathopod 2 sexually dimorphic; subchelate; merus without posterodistal medial lobe; carpus triangular, reduced, enclosed by merus and propodus; propodus sub-triangular; palm acute, sinuous, with small midpalmar concavity, posterodistal corner without protuberance; dactylus longer than palm, not attenuated distally. Coxae 2–4 as wide as deep. Pereopods 3–7 cuspidactylate; dactylus with row or patch of dorsal short setae. Pereopod 4 significantly shorter than pereopod 3. Pereopod 4 dactylus thickened and pinched posteriorly, different to pereopod 3 dactylus. Pereopod 5 propodus distinctly longer than carpus. Pereopod 6 not sexually dimorphic; shorter than pereopod 7; coxa posterior lobe anterodistal corner rounded, posteroventral margins with 6–7 robust setae, outer surface with ridge. Pereopod 7 sexually dimorphic; basis with lateral sulcus well developed, posterodistal lobe absent; distal articles slender. Coxal gills simple or slightly lobate. Pereopods 3–5 gills smaller than gills 2 and 6. Pleopods 1–3 well developed, biramous. Pleopod 1 peduncle without setae; pleopods 2–3 peduncles with 5–6 short marginal robust setae. Epimeron 2 subequal in length to epimeron 3. Epimeron 3 posterior margin with setae, posteroventral corner with small subacute spine. Uropod 1 peduncle with 12 robust setae in two rows; distolateral robust seta absent; inner ramus subequal in length to outer ramus; inner ramus with 4 marginal robust setae; outer ramus with 4 marginal robust setae. Uropod 2 peduncle with 11 robust setae in two rows; inner ramus subequal in length to outer ramus, with 5 marginal robust setae; outer ramus with 2 marginal robust setae. Uropod 3 peduncle with 4 robust setae; ramus shorter than peduncle; oval to spatula-shape, broad distally; ramus with 5–6 marginal setae and 4–5 apical setae. Telson longer than broad; incised to half length; with marginal and apical robust setae, about 3 to 5 robust setae per lobe. Fig. 20. Notorchestia naturaliste n.sp. paratype female 14.6 mm, O2–5, BR2–6, AM P69124, holotype male, 14.8 mm, PL1–3, AM P69121, Bunker Bay, Cape Naturaliste, Western Australia. Scales represent 0.2 mm. Female (sexually dimorphic characters), 14.6 mm . Gnathopod 1 parachelate; posterior margin of merus, carpus and propodus without rugose lobe; propodus ovoid; palm very short, acute; dactylus longer than palm, with row of ventral short setae. Gnathopod 2 basis slightly expanded, about 2× longer than wide; merus with distally pointed posterodistal medial lobe; palm obtuse, smooth; dactylus shorter than palm. Pereopod 7 basis with lateral sulcus slightly pronounced. Oostegites longer than wide; setae with simple and/or multi-furcate tips. Oostegites 2–4 moderately setose (around 24 setae). Variation . In juvenile males the process on the merus of gnathopod 2 may be present; the palm of gnathopod 2 is nearly straight and the sulcus on basis of pereopod 7 is slightly pronounced. Remarks . Notorchestia naturaliste n.sp. resembles N. lobata n.sp. in the short antenna 1; heavily setose antenna 2; male gnathopod 1 subchelate, with rugose lobe on carpus and propodus; basis of pereopod 7 with lateral sulcus; and cleft telson. However, N. naturaliste can be distinguished from N. lobata by the sub-triangular shape of propodus of gnathopod 2 (not subquadrate), palm of gnathopod 2 with shallow concavity (not strong concavity in adult males); coxa 6 posterior lobe posteroventral margins with 6–7 robust setae, (not 14–15 setae); basis of pereopod 7 without posteroventral lobe on posterior margin, but with a frontal facial lobe formed from the sulcus ( Fig. 18 ). Notorchestia naturaliste n.sp. occurred only in Western Australia and was found living sympatrically with N. lobata at Slippery Rock, Cape Leuwin. Distribution . Western Australia : Blackwood River mouth; Slippery Rock, Cape Leuwin; Bunker Bay, Cape Naturaliste; Freshwater Point; Denham Beach, Denham, Shark Bay.