Joeropsis panstikta, 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 : 29-34

Taxon classification Animalia Isopoda Joeropsididae

Joeropsis panstikta sp. n. Figs 17, 18, 19

Material.

Holotype. ♂ (3.4 mm), Yonge Reef, 14.60681°S, 145.6311°E, 20 February 2009, outer reef front, dead coral, 30 m, stn LIZ09-15B, coll. S. Smith & JC (MTQ W31276).

Paratypes. 7 ♂ (3.3, 3.3, 3.2 [dissected], 3.1 [dissected], 2.8 2.3, 2.1 mm), ♀ 4 (ovig. 3.2 [dissected], non-ovig. 2.9, 2.8, 2.1 mm) same data as holotype (MTQ W31277). 4 ♀ (ovig. 3.0), Yonge Reef, 14.57972°S, 145.61010°E, 20 April 2008, passage, dead Acropora head, 17 m, stn CGLI-046A, coll. MB-P (MTQ W13980). ♂ (2.4 mm), 2 ♀ (non-ovig. 3.4, 3.0 mm), Yonge Reef, 14.61383 °S, 145.6182°E, 18 February 2009, back reef, small coral rubble on sand, 15 m, stn LIZ09-10F, coll. MB-P & NLB(MTQ W31278). ♀ (non-ovig. 3.4 mm), Hicks Reef, 14.44803°S, 145.4992°E, 21 February 2009, outer reef front, dead coral heads on reef edge, 5-7 m, LIZ09-16E, coll. NLB & MB-P (MTQ W31279). 3 ♂ (3.3, 2.5, 2.3 mm), Hicks Reef, 14.44803°S, 145.4992°E, 21 February 2009, outer reef front, small rubble on sand, base of reef edge, 8 m, stn LIZ09-16F, coll. NLB & MB-P (MTQ W31280). ♂ (3.3 mm), Day Reef, 14.47503°S, 145.5366°E, 22 February 2009, outer reef edge, coral rubble, 30 m, stn CWLI-050, coll. S. Smith (MTQ W31281). 16, not measured (♂ 3.2 mm [dissected]), 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 W31195).

Additional material. ♂ (2.7 mm), ♀ (ovig. 3.2, non-ovig. 3.3 mm), Day Reef, 14.50239°S, 145.5089°E, 21 February 2009, outer reef slope, large coral rubble, 30 m, stn CWLI048, coll. JC & K. Mills (MTQ W34165). 9, not measured, 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 W31218). 1, 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 W30465). 7, not measured, Day Reef, 14.47119 °S, 145.5297 °E, 13 February 2009, outer reef, coral rubble in cave on vertical wall, 10-12 m, stn LIZ09-03B, coll. MB-P (MTQ W30466). 7, not measured, Day Reef, 14.50525°S, 145.5612°E, 22 February 2009, outer reef front. coral rubble, 27-29 m, stn LIZ09-17A, coll. Shawn Smith & JC (MTQ W31103). 1, not measured, Hicks Reef, 14.44803°S, 145.4992°E, 21 February 2009, outer reef front, dead coral heads on spur, 16 m, stn LIZ09-16D, coll. MB-P & NLB (MTQ W31287). ♂ (3.0 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 W31081). ♂, ♀ and half specimen (unmeasured) Hicks Reef, 14.48051°S, 145.4873°E, 14 February 2009, outer reef, coral rubble, 2-18 m, stn CWLI-020, coll. C. Watson & Kade Mills (MTQ W31382). ♂ (1.7 mm), Day Reef, 14.48356°S, 145.5459°E, 13 February 2009, outer reef, fine rubble, 10 m, stn LIZ09-04C, coll. MB-P (MTQ W31700). Juvenile, off Coconut Beach, Lizard Island, 14.68441°S, 145.47197°E, 17 February 2009, reef front., small rubble on sand between bommies, 4.5 m, stn LIZ09-09C, coll. NLB & MB-P (MTQ W31285).

Description.

Body 3.5 as long as greatest width, dorsal surfaces smooth, with few setae. Cephalon length 0.7 width, lateral margins weakly concave, smooth. Pseudorostrum 0.6 as long as proximal width, anterior margin rounded. Eyes sublateral, with 16 ommatidia, colour dark brown. Pereonites not compact, widely spaced, without dorsal carinae; tergite lateral margin subtruncate, lateral margins smooth; median keels on sternites 4-7, keels well developed. Pleotelson width 1.2 length; dorsal surface with weak and indistinct sub-lateral ridges, caudomedial lobe narrowly rounded; lateral margins weakly convex, each with 1-2 spines.

Antenna 1 with 7 articles; article 1 1.4 as long as wide, distolateral angle weakly lobed, not serrated, distomesial margin weakly serrate; article 2 0.6 as long as article 1, 1.4 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 0.9 as long as article 3; article 5 0.8 as long as article 3, 2.6 as long as proximal width, distally with 1 aesthetasc (further 2 short articles present). Antenna 2 peduncle article 5 1.6 as long as articles 1-4 combined, 3.8 as long as article 3, 1.6 as long as wide, lateral margin convex, with prominent cuticular scales, mesial margin straight; article 6 2.1 as long as width, distally weakly expanded, distal width 1.9 proximal width, 0.7 as long as article 5, lateral margin with cuticular scales on distal one-third, mesial margin with 8 simple setae, distodorsal surface with few simple setae; flagellum with 8 articles, article 1 1.1 as long as peduncle article 6, 1.9 as long as combined lengths of remaining articles.

Mandible palp article 2 with 3 long biserrate setae (terminally spatulate), article 3 with 9 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 8 spines; divided by truncate lobe; left spine row without lacinoid spine. Maxilla 1 lateral lobe with 11 strongly serrate RS, and 2 simple RS; mesial lobe with 3 long, simple RS. Maxilla 2 lateral lobe with 4 long, curved, finely serrate setae; middle lobe with 4 long serrate setae, mesial lobe with 4 long simple setae and many long setules. Maxilliped endite 1.9 as long as greatest width, extending to distal margin of palp article 4, distal margin evenly rounded, mesially with 2 large serrations, with shallow distomesial concavity, with 4 mesial tubercular RS, distomesial margin with 3 coupling setae. Maxilliped palp article 2 3.7 as long as article 1, mesial lobe extending to distal margin of article 3, distomesial margin with 2 simple setae; article 3 0.5 as long as article 2, distomesial margin with 2 simple setae; article 4 4.0 as long as wide, mesial margin weakly concave, distally with 7 setae; article 5 0.2 as long as 4, with 4 terminal setae.

Pereopod 1 basis 3.0 as long as wide, superior margin with 1 simple seta; ischium 0.7 as long as basis, 3.4 as long as wide; merus 0.6 length of ischium, 2.1 as long as wide; carpus about 1.0 (0.95)as long as ischium, 4.2 as long as wide; propodus 4.2 as long as wide, superior margin 4 simple setae (and 1 distal penicillate seta); inferior margin with 4 acute RS, dactylus 0.3 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 3 short simple setae; ischium 0.7 as long as basis, 2.8 as long as wide, superior margin with 2 simple setae, inferior distal angle without setae; merus 0.6 as long as ischium, 1.5 as long as wide, superodistal angle with 1 simple seta; carpus 0.9 as long as ischium, 3.9 as long as wide, inferior margin with 1 seta (distal three-quarters with cuticular scale-setae), superior distal angle with 1 prominent pappose seta; propodus 1.0 as long as ischium, 5.0 as long as wide, inferior margin with 5 acute RS, superior margin with 2 simple setae (and distal penicillate seta); dactylus 0.4 as long as propodus.

Pleopod 1 2.4 as long as greatest width, lateral margin distally concave, apical lobe triangular, with long marginal setae, lateral margin stiff and slender setae, distolateral lobe acute, extending beyond distal margin. Pleopod 2 protopod 2.4 as long as midwidth, lateral margin mid-half weakly convex, without setae, distal margin weakly concave, with long marginal cuticular scales, apex narrowly rounded; stylet in retracted position reaching apex. Pleopod 3 endopod 1.3 midwidth (fused to protopod); exopod article 1 2.5 as long as wide, not extending to endopod apex, lateral margin weakly fringed with cuticular scale-setae; article 2 0.8 as long as article 1, lateral and mesial margins with long cuticular scale-setae (mesial only, lateral very weakly scaled).

Uropod peduncle extending slightly beyond margin of pleotelson, mediodistal corner strongly produced and acute, distolateral margin 3 simple submarginal setae, mesial margin serrate. Exopod 0.6 as wide as endopod, 1.4 as long as wide, with 9 simple setae (3 long). Endopod 1.3 as long as wide, 0.4 as long as peduncle proximolateral margin, apex with 9 long simple setae.

Female.Pleopod 2 1.3 as long as proximal width, lateral margins weakly convex, posterior margins sinuate (with cuticular scale-setae), apex with 2 sub-apical simple setae. Pleotelson lateral margins each with 7 teeth.

Colour pattern.

All pereonites with reddish-brown chromatophores; head with long and darker band of chromatophores occupying 77% of head length, anterior margin of head band weakly and evenly convex, posterior margin forming blunt triangle; pereonite 1 lateral margins clear, narrow marginal clear area on tergite lateral margin 2-4.

Size.

Males 2.1-3.4 mm (mean 2.9 mm, n=14); ovigerous females 3.0-3.2 mm (n=2), non-ovigerous females 2.1-3.4 mm (mean 2.9 mm, n=6).

Variation.

Male pleotelson margin with 1 or 2 teeth only; females and small males usually with 7 teeth on each margin, with the anterior 2 or 3 teeth smaller than the posterior 3 or 4 teeth.

Remarks.

Joeropsis panstikta sp. n. is common on the outer reefs of the northern Great Barrier Reef and is also one of the largest species present, reaching a size of 3.4 mm. The entire dorsum is covered by clustered reddish-brown chromatophores, with a darker brown head, and the colour pattern together with anteriorly rounded pseudorostrum and large size allows for identification of this species.

Distribution.

Frequent at Hicks, Day and Yonge Reefs; once only at Coconut Beach, Lizard Island (Fig. 1); depths 5 to 30 metres.

Etymology.

The epithet is a contraction of the Greek ‘pantostikta’ (παντός+στικτο), meaning 'spotted all over’.