Joeropsis wattora, 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 : 45-49

Taxon classification Animalia Isopoda Joeropsididae

Joeropsis wattora sp. n. Figs 28, 29, 30

Material.

Holotype. ♂ (2.2 mm), Lizard Island, 14.6867°S, 145.4551°E, 30 August 2010, 3 m, shallow lagoon, LI10-037, coll. I. Marin (MTQ W34019).

Paratypes. ♂ (1.2 mm), off Palfrey Is, 14.68687°S, 145.43764°E, 16 April 2008, 7 m, hard, current swept bottom, CGLI-035, coll. MB-P (MTQ W13978). ♂ (1.6, imm 1.5 mm), ♀ (non-ovig. 2.2 [part dissected], 1.7 [dissected], 1.7, 1.6, 1.5 mm), same data as holotype (MTQ W32678).

Description.

Body 4.6 as long as greatest width, dorsal surfaces finely granular, without setae. Cephalon length 0.8 width, lateral margins straight, smooth. Pseudorostrum 0.7 as long as proximal width, anterior margin narrowly truncate. Eyes sublateral, with 8-12 ommatidia, colour black. Pereonites not compact, widely spaced, without dorsal carinae; tergite lateral margin subtruncate, lateral margins smooth; median keels on sternites 5-7, keels well developed. Pleotelson width 1.1 length, dorsal surface with single median and paired submedian low ridges, caudomedial lobe broadly rounded; lateral margins weakly convex, each with 5 spines.

Antenna 1 with 6 articles; article 1 1.5 as long as wide, distolateral angle strongly lobed, strongly serrated, distomesial margin with single serration; 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 0.5 as long as article 2; article 4 0.9 as long as article 3; article 5 1.5 as long as article 3, 3.09 as long as proximal width, distally with 2 aesthetascs. Antenna 2 peduncle article 5 1.8 as long as articles 1-4 combined, 3.7 as long as article 3, 2.6 as long as wide, lateral margin weakly convex, with small cuticular scales, mesial margin straight; article 6 1.4 as long as width, distally weakly expanded, distal width 1.9 proximal width, 0.6 as long as article 5, lateral margin without cuticular scales, mesial margin with 6 simple setae, distodorsal surface with scattered simple setae; flagellum with 6 articles, article 1 0.8 as long as peduncle article 6, 2 as long as combined lengths of remaining articles.

Mandible palp both damaged in dissections; right incisor with symmetrical cusps, margins convex, distally acute; left mandible incisor similar to right incisor. Molar process distal third finely serrate. Right mandible spine row composed of 8 spines; left mandible spine row composed of 9 spines, left mandible spine row divided by truncate lobe; without lacinoid spine. Maxilla 1 lateral lobe with 10 strongly serrate RS, and 3 simple RS; mesial lobe with 4 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 2.2 as long as greatest width, extending to middle of palp article 4, distal margin subtruncate, finely serrate, with shallow distomesial concavity, with 4 mesial tubercular RS, distomesial margin with 3 coupling setae. Maxilliped palp article 2 1.4 as long as article 1, mesial lobe extending to mid-margin of article 3, distomesial margin with 2 simple setae; article 3 0.7 as long as article 2, distomesial margin with 1 simple seta; article 4 5.4 as long as wide, mesial margin weakly concave, distally with 4 setae; article 5 0.2 as long as 4, with 8 terminal setae. Epipod 3.6 as long as basal width, distally acute; 1.1 as long as palp, 1.9 as long as endite.

Pereopod 1 basis 3.4 as long as wide, superior margin with 3 simple setae, inferior margin with 3 simple setae; ischium 0.7 as long as basis, 3.3 as long as wide superior margin with 1 simple seta, inferior margin with 2 simple setae; merus 0.6 length of ischium, 1.9 as long as wide superior margin with 1 simple seta, inferior margin with 1 simple seta and 1 submarginal simple seta; carpus 1.1 as long as ischium, 3.95 as long as wide, superior margin with 1 short simple seta, inferior margin with 4 simple seta; propodus 5.3 as long as wide, superior margin 2 simple setae (1 brush-tipped; distal angle only); 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 3 claws. Pereopod 7 basis 3.4 as long as wide; superior margin with 5 short simple setae; ischium 0.8 as long as basis, 3.4 as long as wide, superior margin weakly convex at midpoint, superior margin with 2 simple setae, inferior distal angle with 0 setae (inferior margin with 2 setae); merus 0.6 as long as ischium, 1.9 as long as wide, superodistal angle with 1 simple seta (weak cuticular scales), inferior margin with 3 simple seta; carpus 0.9 as long as ischium, 4.8 as long as wide, inferior margin with 4 setae, superior distal angle with 3 simpee setae; propodus 1.1 as long as ischium, 6.3 as long as wide, inferior margin with 2 acute RS, superior margin with 3 simple setae and prominent pappose seta; dactylus 0.4 as long as propodus.

Pleopod 1 2.4 as long as greatest width, lateral margin strongly concave, apical lobe narrowly rounded, mesial margin weakly oblique, with long marginal setae, lateral margin with slender setae, distolateral lobe acute, 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 concave, with long marginal cuticular scales, apex narrowly rounded; stylet in retracted position extending beyond apex.

Uropod peduncle extending slightly beyond margin of pleotelson, mediodistal corner weakly produced and acute, distolateral margin 2 simple submarginal setae, mesial margin smooth. Exopod 0.8 as wide as endopod, 1.4 as long as wide, with 8 simple setae. Endopod 1.3 as long as wide, 0.4 as long as peduncle proximolateral margin, apex with 6 long simple setae.

Female. Female dissection of pleopods failed.

Size.

Males 1.3-2.2 mm, mean 1.4 mm (n=3); non-ovigerous females 1.5-2.1 mm, mean 2.7 mm (n=5); all from the type series.

Remarks.

The colour pattern of Joeropsis wattora sp. n. is closely similar to species such as Joeropsis makrogenys sp. n. and Joeropsis sandybrucei , both with a wide, dark brown head band. Joeropsis wattora can be identified by the elongate body (4.7 as long as wide) with widely spaced pereonites, anteriorly narrowed pseudorostrum (the pseudorostrum is anteriorly concave in both Joeropsis makrogenys sp. n. and Joeropsis sandybrucei ) and the small size (mean adult length 1.6 mm).

Variation.

Pleotelson spines range from 3 to 5 per margin, with large specimens having 3 or 4 spines.

Distribution.

Lizard Island lagoon and off Palfrey Island, Lizard Island Group (Fig. 1); 3-7 metres.

Etymology.

The epithet wattora is an Aboriginal word meaning long, in the sense of elongate; noun in apposition.