Haptolana yarraloola, Bruce, Niel L., 2008

Bruce, Niel L., 2008, New species and a new genus of Cirolanidae (Isopoda: Cymothoida: Crustacea) from groundwater in calcretes in the Pilbarra, northern Western Australia, Zootaxa 1823, pp. 51-64 : 59-62

Haptolana yarraloola sp. nov.

Material examined. All material from Western Australia.

Holotype: ɗ (5.3 mm), Yarraloola Station, 21°37’58.8”S, 115°57’40.8” E, 17 June 2003, altitude of 70 m, site code PSS 089, field bore code, PANASLK4, coll. Jane Mcrae ( WAM C39321).

Paratypes: Ψ (non-ovig. 5.6 mm, pleon in two pieces), same data as holotype ( WAM C39322). Ψ (nonovig. 5.0 mm), 21°37’58.8”S, 115°57’8.0”E, 17 June 2003, site code PSS 089, field bore code PANNASLK4, coll. Jim S. Cocking ( WAM C39323). ɗ (4.6 mm, dissected), Robe 6A, 21°317’53.4”S, 115°51’21.0” E, 4 April 2003, altitude of 60 m, site code PSS 075, field bore code G7073010P, coll. Mike Scanlon ( WAM C39324). Ψ (non-ovig. 5.5 mm), Robe River, 21°37’58.8”S, 115°57’8.0”E, 5 April 2003, site code PSS 089, field bore code PANASLK4 (MTQ W13693).

Description. Body 3.6 times as long as greatest width, dorsal surfaces smooth, widest at pereonite 4, lateral margins subparallel. Rostral point present, minute. Eyes absent Pereonite 1 and coxae 2–3 each with posteroventral angle rounded; coxae 5–7 with incomplete oblique carina; posterior margins of pereonites 5–7 smooth. Pleon with pleonite 1 largely concealed by pereonite 7; 3–5 posterior margin smooth; posterolateral angles of pleonite 2 forming acute point, not posteriorly produced; pleonite 3 with posterolateral margins extending to but not beyond posterior margin of pleonite 5, expanded, posteriorly produced; clearly extending beyond posterior margin of pleonite 5, posterolateral margin of pleonite 4 acute. Pleotelson 1.1 times as long as anterior width; lateral margins convex, margins smooth, posterior margin converging to caudomedial point, with small distinct median point, with 4 robust setae.

Antennule peduncle articles 1 and 2 entirely fused; articles 4 and 5 1.3 times as long as combined lengths of articles 1 and 2, article 3 5.3 times as long as wide; flagellum with 8 articles, extending to posterior of pereonite 1. Antenna peduncle article 4 2.2 times as long as wide, 2.2 times as long as article 3, inferior margin with 1 plumose seta, and 1 short simple seta; article 5 1.5 times as long as article 4, 3.8 times as long as wide, inferior margin with 2 pappose setae, superior distal angle with cluster of 4 short simple setae (and 1 plumose); flagellum with 18 articles, extending to pereonite 6.

Mandible molar process anterior margin with 14 flat teeth; without proximal cluster of long simple setae; right mandible spine row composed of 5 spines, left with 7 spines; palp article 2 with 6 distolateral setae, palp article 3 with 10 robust biserrate setae. Maxillule mesial lobe with 3 large CPS RS; lateral lobe with 13 RS. Maxilla lateral lobe with 3 long simple setae; middle lobe with 5 long simple setae (2 finely serrate); mesial lobe with 5 distal simple setae, with 3 proximal CPS. Maxilliped palp article 2 mesial margin with 2 slender setae, lateral margin distally with 1 slender setae; article 3 mesial margin with 4 slender setae, lateral margin with 3 slender setae; article 4 mesial margin with 6 slender setae, lateral margin with 1 slender seta; article 5 distal margin 6 setae, lateral margin with 2 setae; endite with 4 long CPS, and 1 coupling seta.

Pereopod 1 basis 2.0 times as long as greatest width, superior distal angle with 1 acute seta; ischium 0.7 times as long as basis, inferior margin with 1 seta, superior distal margin with 1 RS; merus inferior margin with 2 molariform RS, set as two groups, superior distal angle with 3 setae; carpus inferior margin with 1 RS (and 2 slender setae); propodus 2.2 times as long as wide, inferior margin with 2 RS (and 4 distal setae); dactylus 0.6 as long as propodus. Pereopod 2 ischium inferior margin with 1 stout, bluntly rounded RS, superior distal margin with 1 RS; merus inferior margin with 3 stout RS (acute), set as two groups, superior distal margin with 2 acute RS; carpus inferodistal angle with 2 RS (acute); propodus 1.8 as long as wide, with 5 clusters of acute RS (as 3, 3, 4, 3 and 1, arranged in a V-orientation); dactylus 0.9 as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 similar to pereopod 7. Pereopod 7 basis 2.1 times as long as greatest width, superior margin convex, inferior margin with 2 palmate setae; ischium 0.8 as long as basis, inferior margin with 3 RS (set as 1 and 2), superior distal angle with 2 RS, inferior distal angle with 3 RS; merus 0.3 as long as ischium, 0.9 times as long as wide, inferior margin without RS, superior distal angle with 3 RS, inferior distal angle with 3 RS; carpus 0.6 as long as ischium, inferior margin with 1 RS, superior distal angle with 2 RS, inferior distal angle with 6 RS; propodus 1.1 as long as ischium, 2.6 times as long as wide, inferior margin with 4 clusters of RS (as 4, 4, 2 and 2), superior distal angle with 3 slender setae (1 palmate), inferior distal angle with 3 RS; dactylus 0.8 as long as propodus.

Penes low tubercles.

Pleopod 1 exopod 1.5 times as long as wide, lateral margin strongly convex, distally broadly rounded, mesial margin strongly convex, with PMS from distal one-third, with 29 PMS; endopod 1.5 times as long as wide, distally subtruncate, lateral margin straight, with PMS on distal margin only, endopod with 12 PMS; peduncle 1.7 times as wide as long; mesial margin with 4 coupling setae. Pleopod 2 exopod with 34 PMS, endopod with 16 PMS; appendix masculina with parallel margins, 1.3 times as long as endopod, distally bluntly rounded. Pleopod 3 exopod with 36 PMS. Pleopod 4 exopod with 36 PMS. Pleopod 5 exopod with 25 PMS. Pleopods 2–5 peduncle distolateral margin with prominent acute RS, 3–5 endopods without distomesial serrate scales.

Uropod peduncle ventrolateral margin with 2 RS, lateral margin with medial short acute RS, posterior lobe about three-quarters as long as endopod; rami extending to pleotelson apex, marginal setae in single tier, apices acute. Endopod apically shallowly bifid; lateral margin weakly convex, proximal lateral margin with 1 RS; distal lateral margin with 1 RS, mesial margin weakly convex, with 5 RS. Exopod not extending to end of endopod, 3.2 times as long as greatest width, apically not bifid; lateral margin convex, with 5 RS; mesial margin convex, with 3 RS.

Variation. Pleotelson RS (4 specimens) from 4 (3 times); one apparently aberrant female with 12 RS (as 3+9). Uropod endopod (n = 8) mesial margin with 4–7 RS, with 4 (50%), lateral margin all with 1+1; exopod mesial margin (n = 10) with 2–4 RS, with 7 (70%) most frequent, lateral margin (n = 9) with 4 (33.3%) or 5 (66.7%) RS.

Remarks. Haptolana yarraloola sp. nov., together with Haptolana pholeta Bruce and Humphreys, 1993 , can be immediately separated from all other congeners, none of which occur on the Australian continent, by the broadly rounded frontal lamina that is visible in dorsal view and the straight appendix masculina. Haptolana yarraloola is identified by the posterior margins of the pleotelson being distinctly angled (vs smoothly curved in H. pholeta ) and the posterior margin having four robust setae (vs eight). Other differences are that H. yarraloola has a longer antennal flagellum (extending to pereonite 6 vs pereonite 5), smaller endopods on pleopods 3–5 and more robust setae on pereopod 2, 6 and 7 than does H. pholeta .