Leucothoe sparsa, White & Thomas, 2009

White, Kristine N. & Thomas, James Darwin, 2009, Leucothoidae *, Zootaxa 2260 (1), pp. 494-555 : 535-538

Leucothoe sparsa sp. nov.

( Figs 25 , 26 )

Type material. Holotype, male, 2.9 mm, AM P 71036, Picnic Beach , Palfrey Island , Lizard Island (14°41.69'S 145°26.89'E), algal mat and fine sediment from rubble bottom, reef flat, 3 m, S. LeCroy, 27 February 2005 ( QLD 1708 ).

Type locality. Palfrey Island , Lizard Island, Queensland, Australia (14°41.69'S 145°26.89'E) .

Etymology. After the Latin ‘ sparse ’, meaning ‘sprinkle’ and referring to the sparse mediofacial setal row on the gnathopod 2 propodus.

Description. Based on holotype, male, 2.9 mm, AM P71036.

Head. Head length less than pereonite 1+2, anterior margin rounded, without serrations or teeth, anterodistal margin rounded without cusp, ventral cephalic keel rounded, rostrum small to medium; eyes with 10 or more ocelli, oval. Antenna 1 0.3 x body length; flagellum 6-articulate, peduncle width less than 2 x article 2. Antenna 2 0.3 x body length, longer than antenna 1; flagellum 4-articulate. Mandibles lacking molars, palp 3-articulate, ratio of articles 1 – 3, 1.0:2.8:2.0, article 2 with 2 distal and 3 proximal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible lacinia mobilis large, strongly toothed, with 8 accessory setae; right mandible lacinia mobilis small, with 8 accessory setae. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins weakly setose. Maxilla 1 palp 1-articulate with 3 distal setae; outer plate with 6 distal spines and 3 thin distal setae. Maxilla 2 inner plate with 3 robust and 5 thin distal setae; outer plate with 18 distal setae. Maxilliped inner plates fused, distal margin with v-shaped indentation, with short spines and long setae; outer plate smooth, reduced, reaching less than half of palp article 1, with 2 distal setae and 1 distal spine; palp 4- articulate, article 4 slender, slightly recurved.

Pereon. Coxae 1–4 relative widths 1.0:1.1:0.9:1.5. Gnathopod 1 coxa smooth, setose, anterodistal corner produced, truncated, distal margin straight, posterodistal margin rounded, facial setae absent; basis constricted proximally, anterior margin with 4 setae; posterior margin bare; ischium bare; carpus and propodus distally tapered; carpus length 7.2 x width, proximal margin serrate, distal margin setose; propodus straight, palm serrate with 4 distal setae; dactylus smooth, reaching 0.4 x propodus length. Gnathopod 2 coxa length subequal to width, slightly wider than coxa 3, smooth, bare, anterodistally rounded, distal margin evenly rounded, posterior margin straight, facial setae absent; basis linear, without tubercles or serrations, anterior margin with 3 setae, posterior margin bare; ischium with 2 posterodistal setae; carpus 0.7 x propodus length, recurved, distally tapered, anterior margin weakly serrate; propodus posterior margin without teeth/serrations, with 1 sparse mediofacial setal row above midline, reaching 0.5 x propodus length, 1 row of 8 submarginal setae, palm convex with 3 minor projections; dactylus curved, proximal margin smooth, anterior margin distally subacute, reaching 0.7 x propodus length. Pereopod 3 coxa length 1.6 x width, anterodistal corner over-riding distal face of coxa 2 and extending below it, smooth, setose, anterior margin evenly rounded, distal margin oblique, posterior margin slightly concave, facial setae absent. Pereopod 4 coxa smooth, setose, anterior margin evenly rounded, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5–7 coxa facial setae absent; basis length width ratio 1:0.9, posterior margins smooth. Pereopod 5 basis posterior margin setose. Pereopods 6–7 posterior margins bare.

Pleon. Epimeron 1 with tuft of 4 anteroventral setae. Epimeron 2 with 4 ventral setae. Epimeron 3 bare, posteroventral corner subquadrate. Uropods 1–3 relative lengths 1.0:0.7:1.1; peduncle and outer ramus subequal to inner ramus length; inner and outer ramus lined with short setae. Uropod 1 inner ramus with robust setae, outer ramus without robust setae. Uropod 2 peduncle and outer ramus 0.8 x inner ramus length. inner ramus with 1 robust seta; outer ramus without spines. Uropod 3 inner and outer ramus with robust setae. Telson 1.9 x longer than wide, apex bidentate.

Female (sexually dimorphic characters). Unknown.

Habitat. In an algal mat and fine sediment from rubble bottom.

Remarks. Leucothoe sparsa sp. nov. has a distinctly sparse mediofacial setal row on gnathopod 2 propodus. The anterodistal tuft of epimeron 1 setae is shared with L. alcyone , L. ashleyae , L. assimilis , L. bidens , L. furina , L. germanalcyone , L. saron and L. thula sp. nov. The bidentate telson is also found in L. basilobata , L. cheiriserra , L. commensalis , L. ctenochasma , L. diemensis , L. laticoxa and Leucothoe eumilli sp. nov.

Distribution. Australia. Queensland: Lizard Island (current study).

Figures

FIGURE 25. Leucothoe sparsa sp. nov., holotype, male, 2.9 mm, AM P71036 (QLD 1708), Picnic Beach, Palfrey Island, Great Barrier Reef.

FIGURE 26. Leucothoe sparsa sp. nov., holotype, male, 2.9 mm, AM P71036 (QLD 1708), Picnic Beach, Palfrey Island, Great Barrier Reef.