Joeropsis goobita, 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 : 13-18

Taxon classification Animalia Isopoda Joeropsididae

Joeropsis goobita sp. n. Figs 5, 6, 7

Material.

Holotype. ♂ (1.6 mm), Seabird Islet, Lizard Island, 14.69497°S, 145.4657°E, 23 February 2009, outer reef front, dead coral heads, 6-8 m, stn LIZ09-19B, coll. MB-P & NLB (MTQ W31841).

Paratypes. 4 ♂ (1.6, 1.6, 1.5 [dissected, 3 slides], 1.5, 1.3 mm), 8 ♀ (ovig. 1.6 [dissected, 2 slides], non-ovig. 1.7, 1.4, 1.5, 1.5, 1.3, 1.0. 0.9 mm), same data as holotype (MTQ W31251). ♂ (1.6 mm), ♀ (non-ovig. 1.3 mm), North Point, Lizard Island, 14.64553°S, 145.45335°E, 12 April 2008, compacted dead Acropora , 0.5 m, stn CGLI-20C, coll. NLB (MTQ W13977). ♂ (1.6 mm), Seabird Islet, in from lagoon entrance, 14.68900°S, 145.46710°E, patch reef, 11 April 2008, dead coral heads 1.0-2.0 m, stn CGLI-18A, coll. NLB & MB-P. (MTQ W31842). ♂ (1.7 [whole mount], 1.6, 1.5, 1.5 mm), ♀ (non-ovig. 1.6, 1.6, 1.5 mm), juv. (1.0 mm), Yonge Reef, 14.62317°S, 145.6201°E, 13 February 2009, reef pass, dead coral heads, 5 m, stn LIZ09-11A, coll. NLB & MB-P (MTQ W31843). ♂ (1.4, 1.3 mm), ♀ (ovig. 1.6, 1.4, 1.3, non-ovig. 1.6, 1.5 mm), Day Reef, 14.48356°S, 145.5459°E, 13 February 2009, outer reef, coral heads in gully, 10 m, LIZ09-04B, coll. MB-P. (MTQ W31844).

Additional material. 5, not measured, Day Reef, 14.47119 °S, 145.5297°E, 13 February 2009, outer reef, dead coral on vertical wall, 10-12 m, stn LIZ09-03A, coll. MB-P (MTQ W31845). ♂ (in 2 pieces), Day Reef, 14.48283°S, 145.5564°E, 19 February 2009, outer reef front, dead Acropora slab, 10 m, stn LIZ09-13C, coll. NLB & MB-P (MTQ W31846). 1, Yonge Reef, 14.57735°S, 145.61050°E, 10 September 2010, lee side (western) of reef, coral rubble, 10 m, stn LI10-127A, coll. CB (MTQ W33716)

Description.

Body 2.6 as long as greatest width, appearing dorso-ventrally flat, dorsal surfaces matte, dull, moderately setose. Cephalon length 0.5 width, lateral margins converging anteriorly or weakly concave, finely serrate (posterior half). Pseudorostrum 0.5 as long as proximal width, anterior margin rounded. Eyes lateral, with 12 ommatidia, colour orange (when live). Pereonites not compact, widely spaced, without dorsal carinae; tergite lateral margin subtruncate, lateral margins smooth; median keels weak, not carinate. Pleotelson width 1.4 length; dorsal surface with single median and paired submedian low ridges, caudomedial lobe sub-acute; lateral margins convex, each with 5-6 spines.

Antenna 1 with 5 articles; article 1 1.3 as long as wide, distolateral angle not lobed, not serrated, distomesial margin not serrate; article 2 0.5 as long as article 1, 1.2 as long as wide; lateral margins of articles 1 and 2 without cuticular scales; article 3 0.4 as long as article 2; article 4 1.1 as long as article 3; article 5 2.4 as long as article 3, 3 as long as proximal width, distally with 2 aesthetascs. Antenna 2 article 5 3.8 as long as article 3, 1.6 as long as wide, lateral margin strongly convex, with prominent cuticular scales, mesial margin straight; article 6 1.5 as long as width, distally expanded, distal width 2.2 proximal width, 0.6 as long as article 5, lateral margin with cuticular scales on distal one-third, mesial margin with 3 simple setae, distodorsal surface without setae; antenna 2 flagellum with 6 articles, article 1 1.1 as long as peduncle article 6, 2.2 as long as combined lengths of remaining articles.

Mandible palp article 2 with 2 long biserrate setae, article 3 with 3 long pectinate setae. Right incisor with symmetrical cusps, margins convex, distally acute; left mandible incisor similar to right incisor. Molar process distal half finely serrate. Right mandible spine row composed of 7 spines; left spine row without lacinoid spine. Maxilla 1 (not figured) lateral lobe with 9 strongly serrate RS, and 3 simple RS; mesial lobe with 5 long, simple RS. Maxilla 2 (not figured) lateral lobe with 4 long, curved, finely serrate setae (2 short, 2 long); middle lobe with 4 long serrate setae (2 short, 2 long), mesial lobe with 4 long simple setae and many long setules. Maxilliped endite 2 as long as greatest width, extending beyond palp, distal margin evenly rounded, smooth, with shallow distomesial concavity, with 4 mesial tubercular RS, distomesial margin with 3 coupling setae. Maxilliped palp article 2 1.6 as long as article 1, mesial lobe absent, distomesial margin with 1 simple setae; article 3 0.6 as long as article 2, distomesial margin with 4 simple setae; article 4 3.1 as long as wide, mesial margin weakly concave, distally with 4 setae; article 5 0.2 as long as 4, with 4 terminal setae. Epipod 2.3 as long as basal width, distally narrowly rounded; 0.8 as long as palp, 0.4 as long as endite.

Pereopod 1 basis 2.3 as long as wide, inferior margin with 1 simple seta; ischium 0.8 as long as basis, 2.6 as long as wide; merus 0.7 length of ischium, 1.5 as long as wide; carpus 1.0 as long as ischium (1.04), 2.1 as long as wide; propodus 3.1 as long as wide, superior margin with 2 simple setae (and prominent penicillate seta at distal angle); inferior margin with 2 acute RS, dactylus 0.5 as long as propodus, with 2 claws. Pereopods 2-7 sub-similar, more slender than pereopod 1, each with 3 claws. Pereopod 7 basis 2.9 as long as wide; superior margin with 2 short simple setae; ischium 0.8 as long as basis, 2.7 as long as wide, superior margin weakly convex at midpoint, superior margin with 2 simple setae, inferior distal angle with 0 setae; merus 0.7 as long as ischium, 1.8 as long as wide, superodistal angle with 2 simple setae; carpus 0.9 as long as ischium, 3.2 as long as wide, inferior margin with 2 setae (distal one-third with cuticular scale-setae), superior distal angle with 1 prominent pappose seta; propodus 1.2 as long as ischium, 4.5 as long as wide, inferior margin with 2 acute RS, superior margin with 2 simple setae (and distal penicillate seta); dactylus 0.3 as long as propodus.

Pleopod 1 2.2 as long as greatest width, lateral margin strongly concave, apical lobe broadly rounded, with long marginal setae, lateral margin with slender setae, distolateral lobe narrowly rounded, not extending to distal margin. Pleopod 2 protopod 2 as long as midwidth, lateral margin mid-half weakly convex, without setae, distal margin weakly concave, with long marginal cuticular scales, apex acute; stylet in retracted position not reaching apex. Pleopod 3 endopod 1.2 midwidth (medially fused to protopod); exopod article 1 3.0 as long as wide, not extending to endopod apex, lateral margin weakly fringed with cuticular scale-setae; article 2 0.4 as long as article 1, lateral margin with short cuticular scale-setae.

Uropod peduncle extending well beyond margin of pleotelson, mediodistal corner weakly produced and acute, distolateral margin 1 simple submarginal setae, mesial margin smooth. Exopod 0.5 as wide as endopod, 1.5 as long as wide, with 5 simple setae. Endopod 1.3 as long as wide, 1.0 as long as peduncle proximolateral margin, apex with 5 long simple setae.

Female.Pleopod 2 1.3 as long as proximal width, lateral margins weakly convex, posterior margins weakly sinuate, with long cuticular scale-setae, apex with 2 sub-apical simple setae.

Colour pattern.

Head and pereonites 1-4, 6, 7 and pleotelson with loosely spread chromatophores, pereonite 5 clear; pereonites 4 and 6 slightly darker than other pereonites in some specimens. If chromatophores are contracted specimens appear more pale than figured specimen.

Size.

Males 1.3-1.7 mm (mean= 1.5 mm, n=14); ovigerous females 1.3-1.6 mm (mean= 1.5 mm, n=4), non-ovigerous females 0.9-1.6 mm (mean= 1.4 mm, n=12).

Remarks.

Joeropsis goobita sp. n. may be recognized by the setose body surfaces, the relatively short (0.5 long as wide) and anteriorly narrowed head, loosely scattered chromatophores over the dorsum giving a finely spotted and translucent appearance, except for pereonite 5, which is clear; there is no distinct head band and the pseudorostrum is short and anteriorly rounded. The body is noticeably flat in appearance.

Distribution.

North Point, Lizard Island and off Seabird Islet; Day and Yonge Reefs (Fig. 1); depths probably intertidal to 12 m.

Etymology.

The epithet is an Aboriginal word meaning small; noun in apposition.