Vallorchestia dispar ( Dana, 1852 )

Lowry, J. K., 2012, Talitrid amphipods from ocean beaches along the New South Wales coast of Australia (Amphipoda, Talitridae), Zootaxa 3575, pp. 1-26 : 20-25

Vallorchestia dispar ( Dana, 1852)

( Figs 11–14)

Orchestia dispar Dana, 1852: 204 .— Dana, 1853: 878, pl. 59, fig. 6a–m.— Lowry & Stoddart, 2003: 272.— Lowry & Springthorpe, 2009: 902.

Orchestia gammarellus .— Stebbing, 1906: 532 (in part).

Types. Neotype, male, 14 mm, AM P.85737, north of lagoon, Valla Beach , New South Wales, Australia (30°35'S 153°00'E), under leaves and debris, J. Peart & R. Peart, 10 January 2002. Original types lost according to Springthorpe & Lowry 1994.

Additional material examined. 1 female, AM P.87938, same data as neotype ; 10 specimens, AM P.85736, Valla Park Beach , north of Nambucca Heads, New South Wales (30°35'S 153°00'E), under Zostera , supralittoral, western shore of the lagoon, near mouth, S. Keable & D. Townsend ; 1 specimen, AM P.85730, north of lagoon, Valla Beach , New South Wales, Australia (30°35’S 153°00’E), damp sand, J. Peart & R. Peart, 10 January 2002 ; 1 specimen, AM P.85731, north of lagoon, Valla Beach , New South Wales, Australia (30°35’S 153°00’E), damp sand, J. Peart & R. Peart, 10 January 2002 ; 15 specimens, AM P.85732, north of lagoon, Valla Beach , New South Wales, Australia (30°35’S 153°00’E), damp sand, J. Peart & R. Peart, 10 January 2002 ; 1 specimen, AM P.85734, north of lagoon, Valla Beach , New South Wales, Australia (30°35’S 153°00’E), under leaves and detritus, J. Peart & R. Peart, 10 January 2002 ; 22 specimens, AM P.85735, north of lagoon, Valla Beach , New South Wales, Australia (30°35’S 153°00’E), under leaves and detritus, J. Peart & R. Peart, 10 January 2002 ; 15 specimens, AM P.85741, western shore of lagoon, Valla Beach , New South Wales, Australia (30°35’S 153°00’E), under littoral Zostera wrack, S. Keable & D. Townsend ; 9 males, many females (3 are ovigerous) and juveniles, AM P.87936, Macleay River estuary at Stuarts Point Reserve, New South Wales, Australia (30.82209°S 152.99393°E), supralittoral, flat beach, talitrids living in heavy Zostera debris in estuary inland from beach, J.K. Lowry, J. Dermand & K. Engelberg, 11 February 2010 ( MI NSW 3666 ) ; 8 specimens, AM P.85742, UNSW field station, Smiths Lake , New South Wales, Australia (32°35'S 152°29'E), sandy shore, under drift seaweed on sand, A. Poore, 30 September 2003 .

Type locality. Valla Beach , New South Wales, Australia (30°35’S 153°00’E) .

Description. Based on neotype male, 14 mm, AM P.85737.

Head. Eye medium (1/5–1/3 head length). Antenna 1 short, rarely longer than article 4 of antenna 2 peduncle. Antenna 2 up to half body length; peduncular articles slightly expanded. Mandible left lacinia mobilis 4-dentate. Maxilliped palp article 2 distomedial lobe well developed, 4 reduced, button-shaped.

Pereon. Gnathopod 1 subchelate; coxa smaller than coxa 2, subtriangular, about as broad as deep; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus subtriangular with well developed posterodistal lobe; palm transverse; dactylus shorter than palm. Gnathopod 2 subchelate; coxa similar in size to coxa 3, broader than deep; coxal gill simple (or slightly lobate); basis slightly expanded; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; carpus triangular, reduced (enclosed by merus and propodus), posterior lobe absent, not projecting between merus and propodus; palm acute, smooth, posterodistal corner with groove; dactylus longer than palm, attenuated distally; gill simple, gill not incised. Pereopods 2–4 coxae wider than deep. Pereopods 3–5 gills simple; subequal in size to gills 2 and 6. Pereopods 3–7 cuspidactylate. Pereopod 4 subequal or slightly shorter than pereopod 3; carpus significantly shorter than carpus of pereopod 3; dactylus thickened and pinched posteriorly (different to pereopod 3 dactylus). Pereopod 5 propodus distinctly longer than carpus. Pereopods 6–7 medial surface of merus and carpus with velcro setae. Pereopod 6 subequal in length to pereopod 7; posterior lobe inner view posteroventral corner subquadrate, posterior lobe with 5 or more marginal setae; coxal gill simple, coxal not incised; merus and carpus with T-setae. Pereopod 7 sexually dimorphic; posterodistal lobe present, shallow, broadly rounded; distal articles (merus and carpus) expanded; merus posterior margin evenly rounded; carpus subovate.

Pleon. Pleopods all well developed. Pleopod 1 peduncle with marginal robust setae; biramous, outer ramus subequal in length to peduncle; inner ramus with 11 articles; outer ramus with 12 articles. Pleopod 2 biramous, outer ramus subequal in length to peduncle; inner ramus with 11 articles; outer ramus with 14 articles. Pleopod 3 biramous, outer ramus subequal in length to peduncle; inner ramus with 10 articles; outer ramus with 12 articles. Epimeron 2 subequal in length to epimeron 3. Epimeron 3 posterior margin smooth, posteroventral corner with small subacute tooth, ventral margin without robust setae. Uropod 1 not sexually dimorphic, peduncle with more than 6 robust setae, peduncle with 14 robust setae, distolateral robust seta present; inner ramus subequal in length to outer ramus, with 4 marginal robust setae; outer ramus without marginal robust setae. Uropod 2 not sexually dimorphic; peduncle with 5 robust setae; inner ramus subequal in length to outer ramus, with 3 marginal robust setae; outer ramus with 2 marginal robust setae. Uropod 3 peduncle with 3 robust setae; ramus shorter than peduncle, ramus linear (narrowing), ramus with 6 marginal robust setae. Telson longer than broad, apically incised, dorsal midline entire, with marginal and apical robust setae, telson with 8 or 9 robust setae.

Female (sexually dimorphic characters). Based on female, 9 mm in length, AM P.87938. Gnathopod 1 parachelate; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; propodus subrectangular; palm acute; dactylus longer than palm. Gnathopod 2 mitten-shaped; posterior margin of merus, carpus and propodus each with lobe covered in palmate setae; carpus well developed (not enclosed by merus and propodus), posterior lobe present, projecting between merus and propodus; palm obtuse; dactylus shorter than palm. Pereopods 6 medial surface of merus and carpus without T-setae. Pereopod 7 distal articles (merus and carpus) slender. Oostegites long (length greater than 2 × width), weakly setose or setae absent, setae with simple smooth tips. Uropod 3 peduncle with 3 robust setae; ramus with 5 marginal robust setae.

Remarks. A neotype is established for this material to stabilise this long lost species of Dana 1852.

Distribution. New South Wales: shores of Illawarra ( Dana 1852); Valla Beach (current study); Macleay River (current study); Smiths Lake (current study).