Arcitalitrus orara, R Peart, 2006

R Peart, 2006, The Amphipod Genus Arcitalitrus (Crustacea: Amphipoda: Talitridae) of New South Wales Forests, With Descriptions of Six New Species, Records of the Australian Museum 58, pp. 97-118 : 103-105

Arcitalitrus orara n.sp.

Figs. 5, 21–23

Type material. HOLOTYPE, ♀, 11.0 mm, AM P60954, December 1999, M. Gray, G. Milledge and H. Smith . PARATYPES, ♀ AM P60953 ; 3 specimens, AM P60952 . Paratypes are all from the type locality.

Type locality. Junction of Urumbilum Creek road and Loudens road, Orara State Forest (30°19'35"S 152°55'00"E), New South Wales .

Australia: approximately 1.2 km south of Killiekrankie Mountain , Horseshoe road, Oakes State Forest (30°30'10"S 152°32'15"E), 7 specimens, 11–24 November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; America Bay Track, Kuring-gai Chase National Park (33°36'10"S 151°16'16"E), 10 specimens, 2–16 December 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; nearly 2 km east of Mount Kariong , Brisbane Water National Park (33°27'50"S 151°17'04"E), 42 specimens, 1–15 December 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; end of Little North Arm road, west bank of Rosewood River , Dorrigo National Park (30°24'06"S 152°46'18"E), 35 specimens, 10–24 November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; Rickersby road, Gladstone State Forest (30°32'46"S 152°45'07"E), 10 specimens, 12–25 November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; 0.5 km north northeast of junction with Zeehan road, Cooks Creek Trail (30°31'30"S 152°44'40"E), 27 specimens, 12– 25 November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; junction of Moonpar and Mills road, Moonpar State Forest (30°14'36"S 152°37'33"E), 19 specimens, 9–23 December 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; 2 km south southwest of Bostobrick , Cristophersons Mountain , 30°17'45"S 152°37'04"E, 30 specimens, 9–23 November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; Pacific Highway, 0.7 km southeast of Bird Gully Swamp , Muogamarra Nature Reserve (33°33'42"S 151°11'15"E), 45 specimens, 2–16 December 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; Sirius road, approximately 2 km from junction with Horseshoe road, Oakes State Forest (30°29'19"S 152°35'27"E), 15 specimens, 11–24 November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; Horseshoe road, approximately 0.5 km north of Scotchman Peak , Diehappy State Forest (30°28'30"S 152°39'43"E), 3 specimens, November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith; Horseshoe road, 3.5 km southeast of Thora, Scotchman State Forest (30°26'25"S 152°47'30"E), 9 specimens, 10–24 November 1999, collected using pitfall traps, M. Gray, G. Milledge and H. Smith .

Description. Based on holotype female. Body shape normally laterally compressed; cuticle calcification absent. Eye large (greater than 1 ⁄ 3 head length). Antenna 2 longer than head and first 3 pereonites; peduncular articles narrow. carpus not expanded; propodus subrectangular; palm absent; dactylus longer than palm. Gnathopod 2 not sexually dimorphic; chelate; narrow; merus and carpus expanded posteriorly; propodus “mitten-like”; palm obtuse; smooth; dactylus shorter than palm. Pereopods 3–7 long (½ length of body); simplidactylate. Pereopod 4 carpus similar in length to pereopod 3 carpus, dactylus similar to pereopod 3 dactylus. Pereopod 7 posterodistal lobe present. Gill 2 lobate, not incised. Gills 3–5 lobate, smaller than gills 2 and 6. Gill 6 lobate, anterior margin convoluted, subapically incised along posterior margin. Oostegites long (length greater than 2× width), weakly setose, setae with simple smooth tips. Epimera 1 to 3 not convergent. Epimeron 2 subequal in length to epimeron 3. Epimeron 3 posteroventral margin smooth, posteroventral corner with small subacute tooth. Pleopod 1 well developed, biramous, rami subequal in length to peduncle; inner ramus with 11 articles; outer ramus with 8 articles, outer ramus with 6–10 articles. Pleopod 2 well developed, biramous, rami shorter than peduncle; inner ramus with 7 articles; outer ramus with 5 articles. Pleopod 3 reduced, rami absent. Uropod 1 not sexually dimorphic; peduncle with 6 robust setae on peduncle; inner ramus shorter than outer ramus, with 3 robust setae on the margins, with 3 apical robust setae; outer ramus without marginal robust setae, with 3 apical robust setae. Uropod 2 not sexually dimorphic; peduncle with 3 robust setae; inner ramus subequal in length to outer ramus, with 2 marginal robust setae, 4 apical robust setae; outer ramus without marginal robust setae, with 3 apical robust setae. Uropod 3 peduncle with 1 robust setae; ramus shorter than peduncle, ramus bud-like (broad), with 2 robust setae. Telson as broad as long, entire, with marginal and apical robust setae, with 3–5 robust setae per lobe.

Etymology. Named for Orara State Forest, the type locality and treated as a noun in apposition.

Habitat. Forest floor leaf-litter.

Remarks. Arcitalitrus orara is a member of the “sylvaticus” species group. It differs from other species in the group in having bud-like rami on uropod 3, an entire telson and, except for Ar. nana , in having a large eye. Arcitalitrus orara and Ar. sylvaticus both have reduced numbers of articles on the outer ramus of pleopod 2. Arcitalitrus orara , Ar. belbucca and Ar. nana all have the inner ramus of uropod 1 shorter than the outer.

Distribution. New South Wales: Orara State Forest; Oakes State Forest; Kuring-gai Chase National Park; Brisbane Water National Park; Dorrigo National Park; Gladstone State Forest; Cooks Creek Trail; Moonpar State Forest; Cristophersons Mountain; Muogamarra Nature Reserve; north of Scotchman Peak, Diehappy State Forest; Scotchman State Forest.