Joeropsis jiigurru, Bruce, Niel L., 2015

Bruce, Niel L., 2015, Joeropsididae Nordenstam, 1933 (Crustacea, Isopoda, Asellota) from the Lizard Island region of the Great Barrier Reef, Queensland, Australia, ZooKeys 491, pp. 1-62 : 18-20

Taxon classification Animalia Isopoda Joeropsididae

Joeropsis jiigurru sp. n. Figs 8, 9, 10

Material.

All material from the Lizard Island region, northern Great Barrier Reef, Queensland.

Holotype. ♂ (1.9 mm), Hicks Reef, 14.44803°S, 145.4992°E, 21 February 2009, outer reef front, coral rubble under bommie overhang, 15 m, stn LIZ09-16B, coll. NLB & MB-P (MTQ W33666).

Paratypes. ♀ (ovig. 1.3 mm), Day Reef, 14.48539°S, 145.5464°E, 19 February 2009, outer reef front, coral rubble in gully, 17 m, stn LIZ09-12F, coll. NLB & MB-P (MTQ W33667). ♂ (1.9 mm), Yonge Reef, 14.57735°S, 145.61050°E, 10 September 2010, inner reef front, silty coral rubble under bommie overhang, 5 m, stn LI10-127B, coll. CB (MTQ W33668).

Description.

Body 2.9 as long as greatest width, dorsal surfaces polished in appearance, without setae. Cephalon length 0.7 width, lateral margins straight, finely serrate (proximal half). Pseudorostrum 1.2 as long as proximal width, anterior margin acute (lateral margin anteriorly concave). Eyes sublateral, with 4 ommatidia, colour dark brown. Pereonites compact, close to each other (posteriorly compact, anteriorly spaced), without dorsal carinae; tergite lateral margin subtruncate (tergite lateral margin 1-5 serrate), lateral margins 1-4 finely serrate; median keels on sternites 1-6, keels well developed (on sternites 1-3; serrate). Pleotelson width 0.9 length; dorsal surface with single median and paired submedian low ridges, caudomedial lobe broadly rounded; lateral margins weakly convex, each with 8 spines.

Antenna 1 with 5 articles; article 1 1.2 as long as wide, distolateral angle strongly lobed, strongly serrated, distomesial margin not serrate; article 2 0.8 as long as article 1, 0.8 as long as wide; lateral margins of articles 1 and 2 with cuticular scales on distal margins; article 3 0.4 as long as article 2; article 4 0.4 as long as article 3; article 5 1.3 as long as article 3, 1.6 as long as proximal width, distally with 3 aesthetascs. Antenna 2 peduncle article 5 1.7 as long as articles 1-4 combined, 2.9 as long as article 3, 1.7 as long as wide, lateral margin convex, with prominent cuticular scales, mesial margin weakly convex; article 6 1.7 as long as width, distally expanded, distal width 2.2 proximal width, 0.7 as long as article 5, lateral margin without cuticular scales, mesial margin with 10 simple setae, distodorsal surface without setae; flagellum with 6 articles, article 1 0.7 as long as peduncle article 6, 1.6 as long as combined lengths of remaining articles.

Mandible palp article 2 with 3 long biserrate setae, article 3 with 5 long pectinate setae. Right incisor with 5 cusps (4 large, 1 small), margins convex, distally acute; left mandible incisor similar to right incisor. Molar process distal quarter finely serrate. Right mandible spine row composed of 8 spines; left spine row not divided by truncate lobe, without lacinoid spine. Maxilliped endite 2.3 as long as greatest width, extending to distal margin of palp article 4, distal margin evenly rounded, smooth, with shallow distomesial concavity, with 3 mesial tubercular RS (and 1 triangular RS), distomesial margin with 3 coupling setae. Maxilliped palp article 2 4.8 as long as article 1, mesial lobe extending to distal margin of article 3, distomesial margin with 1 simple seta; article 3 0.4 as long as article 2, distomesial margin with 2 simple setae; article 4 2.9 as long as wide, mesial margin weakly concave, distally with 2 setae; article 5 0.1 as long as 4, with 7 terminal setae. Epipod 4.3 as long as basal width, distally narrowly rounded; 1.0 as long as palp, 0.4 as long as endite.

Pereopod 1 basis 4.4 as long as wide, inferior margin with 2 simple setae; ischium 0.6 as long as basis, 2.3 as long as wide; merus 0.6 length of ischium, 0.5 as long as wide; carpus 1.0 as long as ischium, 5.1 as long as wide; propodus 5.6 as long as wide, superior margin 2 simple setae; inferior margin with 2 acute RS, dactylus 0.4 as long as propodus, with 2 claws. Pereopods 2-7 sub-similar, more slender than pereopod 1, each with 2 claws. Pereopod 7 basis 3.2 as long as wide; superior margin with 1 short simple seta; ischium 0.8 as long as basis, 3.1 as long as wide, superior margin weakly convex at midpoint, superior margin with 2 simple setae (and cuticular scales), inferior distal angle with 0 setae; merus 0.6 as long as ischium, 2.3 as long as wide, superodistal angle with 2 simple setae; carpus 1.0 as long as ischium, 5.5 as long as wide, inferior margin with 2 setae, superior distal angle with 1 prominent pappose seta; propodus 1.0 as long as ischium, 6.3 as long as wide, inferior margin with 2 acute RS, superior margin with 1 simple setae (and distal penicillate seta); dactylus 0.4 as long as propodus.

Pleopod 1 2.4 as long as greatest width, lateral margin weakly concave, apical lobe broadly rounded, with short marginal setae, lateral margin with slender setae, distolateral lobe narrowly rounded, not extending to distal margin. Pleopod 2 protopod 2.6 as long as midwidth, lateral margin mid-half weakly convex, without setae, distal margin weakly convex, without marginal cuticular scales, apex broadly rounded; stylet in retracted position extending beyond apex. Pleopod 3 endopod 2.4 midwidth; exopod article 1 3.6 as long as wide, extending to endopod apex, lateral margin densely fringed with cuticular scale-setae; article 2 0.5 as long as article 1, lateral and mesial margins with short cuticular scale-setae and with spine-like cuticular scale-setae (spine-like distally only).

Uropod peduncle extending slightly beyond margin of pleotelson, mediodistal corner weakly produced and acute, distolateral margin with 4 simple submarginal setae, mesial margin finely serrate. Exopod 0.7 as wide as endopod, 1.1 as long as wide, with 5 simple setae. Endopod 0.8 as long as wide, 0.3 as long as peduncle proximolateral margin, apex with 9 long simple setae.

Female.Pleopod 2 1.3 as long as proximal width with weak median longitudinal carina, lateral margins straight, posterior margins straight, with cuticular scales.

Colour pattern.

White with narrow transverse red–brown band on head and posterior of pereonites 1, 2 and 4; interocular head band occupies 10% of head length.

Size.

Males 1.9 mm, ovigerous female 1.3 mm.

Remarks.

Joeropsis jiigurru sp. n. is most readily recognized by the distinctive colour pattern of four narrow transverse bands, running between the eyes and across pereonites 1, 2 and 4. The eyes are noticeably small, the lateral margins of the head and tergite lateral margin 2-4 are serrate, the pleotelson is relatively broad, with eight well-developed teeth on each lateral margin, the pseudorostrum is anteriorly acute, and the pereopods are relatively slender, with all pereopods with two dactylar claws. The male holotype has well-developed serrated mid-sternal keels-an apparently unique character for the genus.

Distribution.

Lizard Island region: Hicks, Day and Yonge Reefs (Fig. 1); at depths 5 to 17 metres.

Etymology.

The epithet is the Aboriginal name for Lizard Island in the language of the Dingaal people (DERM Lizard Island http://www.derm.qld.gov.au/parks/lizard-island/culture.html); noun in apposition.