Joeropsis makrogenys, 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 : 21-26

Taxon classification Animalia Isopoda Joeropsididae

Joeropsis makrogenys sp. n. Figs 11, 12, 13

Joeropsis sandybrucei . - Bruce 2009b: 805 (part, Lizard Island specimens).

Material.

Holotype. ♂ (3.0 mm), ♀ (ovig. 2.5 mm), Lizard Island, 14.6867°S, 145.4551°E, 30 August 2010, 3 m, shallow lagoon, LI10-037, coll. I. Marin (MTQ W32671).

Paratypes. 3 ♂ (2.3 mm [dissected]; imm. 1.2 1.1 mm), 4 ♀ (non-ovig. 2.5 [dissected], 2.2, 2.0, 1.9 mm), 5 mancas (1.2, 1.2 1.1, 1.1, 1.0 mm), 'High Rock’, east of South Direction Island, 14.82428°S, 145.55270°E, 11 September 2010, reef slope, clean coral rubble, 6 m, LI10-134C, coll. CB (MTQ W34010). ♂ (2.2 mm), ♀ (ovig. 3.1, non-ovig. 2.5 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 W31289). ♂ (1.3 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 W34011). ♀ (non-ovig. 1.3 mm), Day Reef, 14.48283°S, 145.5564°E, 19 February 2009, outer reef front, small rubble in gully, 7.5 m, stn LIZ09-13A, coll. MB-P & NLB (MTQ W34012). ♀ (non-ovig. 2.3 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 W31286). ♂ (2.1, imm 1.1 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 & MBP (MTQ W34013). ♀ (ovig. 2.3 mm), MacGillivray Reef, 14.64792°S, 145.48660°E, 1 September 2010, 14 m, reef slope, coral rubble, LI10-041, coll. M. Capa (MTQ W32691). ♂ (1.6 mm), Day Reef, 14.47045°S, 145.52840°E, 5 September 2010, 17 m, outer reef, dead coral heads, LI10-077B, coll. CB (MTQ W34014). ♀ (non-ovig. 2.6 mm), Lizard Island, 14.6867°S, 145.4551°E, 30 August 2010, 3 m, shallow lagoon, LI10-037, coll. I. Marin (MTQ W34015). ♀ (ovig. 2.8 mm), north side of Lizard Island, 'Washing Machine’, 14.65383°S, 145.46340°E, 27 August 2010, coral rubble, 5 m, LI10-017C, coll. CB (MTQ W34016). ♀ (non-ovig 3.0 mm), imm/manca (0.9 mm), Lizard Island, 'Bommie Bay’, 14.66157°S, 145.46160°E, 8 August 2010, 12 m, coral rubble, LI10-100A, coll. CB (MTQ W34017). ♂ (2.2 mm), imm. (1.3 mm), Lizard Island, 'Bommie Bay’, 14.66157°S, 145.47160°E, 8 September 2010, 8 m, dead coral heads, LI10-101B, coll. CB (MTQ W34018). ♀ (non-ovig. 2.1 mm), Lizard Island, 'Bommie Bay’, 14.6615°S, 145.4717°E, 9 September 2010, 10 m, silty coral in cave, LI10-111, coll. M. Wakeford (MTQ W32952).

Additional material. Lizard Island, non-type specimens from Bruce (2009): 2 ♂ (2.3, 2.1 mm), 8 ♀ (ovig. 3.9, 3.6, 3.5, 3.2, 3.2, 2.8; non-ovig. 3.2, 3.1 mm), imm. (1.2 mm), 14.6890°S, 145.4671°E, patch reef, lagoon entrance in from Seabird Islet, 11 April 2008, dead coral heads, 1.0-2.0 m, stn CGLI-018A, coll. NLB & MB-P (MTQ W13805). ♀ (imm. 1.6 mm), patch reef, in lagoon entrance from Seabird Islet, 14.6890°S, 145.4671°E, 19 April 2008, medium small rubble, 1.0-3.0 m, CGLI-041B, coll. NLB (MTQ W13806). ♂ (1.6 mm), ♀ (ovig. 2.6 mm), North Point, 14.64553°S, 145.45335°E, 12 April 2008, dead coral heads, 1.0-1.5 m, CGLI-20A, coll. NLB (MTQW13807). ♂ (2.0 mm), ♀ (ovig. 2.9 mm), patch reef off LIRS, Casuarina Beach, 14.68039°S, 145.44530°E, 15 April 2008, dead corals, 1.0 m, CGLI-031B, coll. NLB (MTQ W13808). Papua New Guinea, Madang: 19 ♂, ♀ and imm., 5°08.4'S, 145°50.9'E, 28 April 1989, south of Wongat Island, barrier reef back reef, coarse Halimeda covered rubble, 7 m, stn. 14B, coll. NLB & Rosella Ueba (MTQ W19759). 1 specimen, Wongat Island, 5°08.1'S, 145°50.6'E, 1 May 1989, semi-exposed, rubble among alcyonarians, NW corner, 1-2 m, Stn 16, coll. NLB (MTQ W19769). 1 specimen, Masamoz Reef, 5°08.1'S, 145°50.3'E, 24 April 1989, dead plates and Acropora rubble, 12 m, stn 10A, coll. NLB & M. Jebb (MTQ W19772).

Also examined. Joeropsis indica Müller, 1991b, holotype (specimen lacking head and pleotelson + microslide) (SMF 18191) and female paratype (microslide only) (SMF 18192), Beruwala [approx. 37 km south of Colombo], Sri Lanka, 8-16 May 1989, coll. H.-G. Müller.

Description.

Body 3.4 as long as greatest width, dorsal surfaces finely granular, with few setae. Cephalon length 0.7 width, lateral margins weakly sinuate, smooth. Pseudorostrum 0.4 as long as proximal width, anterior margin concave. Eyes lateral, with 12-16 ommatidia, colour black. Pereonites not compact, widely spaced, without dorsal carinae; tergite lateral margin subtruncate, lateral margins smooth; median keels weak, not carinate. Pleotelson width 1.2 length, dorsal surface with single median and paired submedian low ridges, caudomedial lobe narrowly rounded; lateral margins convex, each with 6 spines.

Antenna 1 with 6 articles; article 1 1.4 as long as wide, distolateral angle strongly lobed, strongly serrated, distomesial margin not serrate; article 2 0.5 as long as article 1, 1.3 as long as wide; lateral margins of articles 1 and 2 without cuticular scales; article 3 0.7 as long as article 2; article 4 0.6 as long as article 3; article 5 0.4 as long as article 3, 1.0 as long as proximal width, distally with 2 aesthetascs. Antenna 2 peduncle article 5 1.9 as long as articles 1-4 combined, 5.3 as long as article 3, 2.1 as long as wide, lateral margin distal three-quarters straight, with prominent cuticular scales, mesial margin angled; article 6 1.3 as long as width, distally expanded, distal width 2.1 proximal width, 0.5 as long as article 5, lateral margin without cuticular scales, mesial margin with 3 simple setae, distodorsal surface with few simple setae; flagellum with 6 articles, article 1 1.1 as long as peduncle article 6, 4 as long as combined lengths of remaining articles.

Mandible palp article 2 with 3 long biserrate setae, article 3 with 5 long pectinate setae. Left mandible incisor with lateral cusp thick, produced, distally truncate and mesial cusps rounded, ‘fish-tail’ shape; right incisor with symmetrical cusps, margins convex, distally acute and mesial-most cusp wide, distally subtruncate. Molar process distal half finely serrate. Right mandible spine row composed of 6 spines; left mandible spine row composed of 9 spines, not divided by truncate lobe; with lacinoid spine. Maxilla 1 lateral lobe with 10 strongly serrate RS, and 3 simple RS; mesial lobe with 3 long, simple RS. Maxilla 2 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 2.1 as long as greatest width, extending to distal margin of palp article 3, distal margin entirely oblique, smooth, without distomesial concavity, with 4 mesial tubercular RS, distomesial margin with 3 coupling setae. Maxilliped palp article 2 2.6 as long as article 1, mesial lobe short, distomesial margin with 2 simple setae; article 3 0.7 as long as article 2, distomesial margin with 3 simple setae; article 4 2.7 as long as wide, mesial margin weakly concave, distally with 5 setae; article 5 0.2 as long as 4, with 8 terminal setae.

Pereopod 1 basis 2.3 as long as wide, inferior margin with 4 simple setae (short) inferior margin with 1 simple seta; ischium 0.7 as long as basis, 2.2 as long as wide; merus 0.7 length of ischium, 1.4 as long as wide; carpus 1.1 as long as ischium, 2.7 as long as wide; propodus 4.4 as long as wide, superior margin 4 simple setae; inferior margin with 3 acute RS, dactylus 0.5 as long as propodus, with 2 claws (and acute robust seta). Pereopods 2-7 sub-similar, more slender than pereopod 1, each with 3 claws. Pereopod 7 basis 3.2 as long as wide; superior margin with 7 short simple setae, inferior margin with 2 simple setae; ischium 0.6 as long as basis, 2.5 as long as wide, superior margin convex, with 1 simple seta, inferior distal angle with 1 seta; merus 0.6 as long as ischium, 1.6 as long as wide, superodistal angle with 1 simple seta (superior margin with weak cuticular scales); carpus 1.1 as long as ischium, 3.3 as long as wide, inferior margin with 4 setae, superior distal angle with 2 prominent setae; propodus 1.1 as long as ischium, 3.7 as long as wide, inferior margin with 3 acute RS, superior margin with 4 simple setae (3 short, 1 long); dactylus 0.4 as long as propodus.

Pleopod 1 2.3 as long as greatest width, lateral margin strongly convex, apical lobe broadly rounded, with short and long marginal setae, lateral margin with slender setae, distolateral lobe acute, not extending to distal margin. Pleopod 2 protopod 2.3 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 2.5 midwidth; exopod article 1 2.6 as long as wide, not extending to endopod apex, lateral margin fringed with cuticular scale-spines; article 2 0.6 as long as article 1, lateral and mesial margins with spine-like cuticular scale-setae (mesial margin with setae).

Uropod peduncle extending slightly beyond margin of pleotelson, mediodistal corner strongly produced and acute, distolateral margin 3 simple submarginal setae, mesial margin finely serrate. Exopod 0.7 as wide as endopod, 1.3 as long as wide, with 7 simple setae. Endopod 1.2 as long as wide, 3.3 as long as peduncle proximolateral margin, apex with 0 long simple setae (with 7 pedunculate penicillate setae).

Female.Pleopod 2 1.2 as long as proximal width, lateral margins weakly convex, apex with 4 sub-apical simple setae.

Size.

Males 1.3-2.3 mm, mean 2.0 mm (n=6); ovigerous females 2.3-3.1 mm, mean 2.7 mm (n=3), non-ovigerous females 1.3-3.07 mm, mean 2.2 mm (n=11); all from type series.

Colour pattern.

Head with long dark-brown band extending to lateral margins, and occupying 76% of head length; anterior margin of colour band weakly indented; all other somites white or clear.

Variation.

Pleotelson with six acute teeth (serrations) on lateral margin; anterior most tooth sometimes small and inconspicuous.

Remarks.

Joeropsis makrogenys sp. n. is characterised by a brown head band occupying more than 70% of the head length; short, sub-quadrate, anteriorly concave pseudorostrum; antennula article 1 distolateral angle strongly serrate, large and asymmetrical mandible incisors, and the maxilliped endite with a smooth and obliquely angled distomesial margin, lacking a distinct mesial notch. The mandible and spine row morphology is unique within the genus, and the broadly rounded posterior incisory cusp of the right mandible can usually be seen under stereomicroscopy, in both adults and juveniles.

The colour pattern and mandibular morphology is unique, but is similar to that of Joeropsis indica Müller, 1991b. Comparing the type specimens of Joeropsis indica to Joeropsis makrogenys sp. n. shows that the left mandible incisor of Joeropsis indica is similar to that of Joeropsis makrogenys , but the right mandible of Joeropsis indica lacks the broad cusp; the maxilliped endite of Joeropsis indica (Fig. 12B) distal margin is serrated but not oblique and, contrary to Müller’s (1991b) description, does have distolateral tubercular spines; antenna 1 article 2 is clearly not serrated and the uropods have a weak terminal spike.

The similar Joeropsis sandybrucei Bruce, 2009 differs from Joeropsis makrogenys sp. n. in having the distolateral margin of antennula article 1 smooth (vs serrate), shorter pseudorostrum with mesially angled lateral margins, the maxilliped endite distal margin not oblique, and both mandible incisors have symmetrical acute cusps. The misidentified non-type material of Joeropsis sandybrucei is here re-identified; Joeropsis sandybrucei has not been collected at Lizard Island.

Distribution.

Lizard Island and nearby islands and reefs, South Direction Island, Hicks, Day and Yonge Reefs (Fig. 1); intertidal to 14 metres, with one sample from 30 metres; also Madang, Papua New Guinea.

Etymology.

The epithet combines the Greek words makros (long) and genys (jaw) alluding to the long cusp on the mandible incisor.