Leucothoe odontiskos, White & Thomas, 2009

White, Kristine N. & Thomas, James Darwin, 2009, Leucothoidae *, Zootaxa 2260 (1), pp. 494-555 : 521-525

Leucothoe odontiskos sp. nov.

( Figs 17 , 18 )

Type material. Holotype, male, 2.8 mm, AM P 79812, North Point , Lizard Island (~ 14°38’S 145°27’E), rubble sample from vertical cliffs and unconsolidated bottom rubble, 12.2 m, J. D. Thomas, 28 January 1989 ( JDT / LIZ 13 ) . Paratype, female, 2.5 mm, AM P 79813, same station data .

Additional material examined. 1 female, 1 male ( JDT / LIZ 13 ) .

Type locality. North Point , Lizard Island, Queensland, Australia (~ 14°38’S 145°27’E) .

Etymology. After the Greek ‘ odontiskos ’, meaning ‘little tooth’ and referring to the tooth-like dentition along the gnathopod 1 propodus palm.

Description. Based on holotype, male, 2.8 mm, AM P79812.

Head. Head length less than pereonite 1+2, anterior margin rounded, without serrations or teeth, anterodistal margin subquadrate without cusp, ventral cephalic keel rounded, rostrum small to medium; eyes with 10 or more ocelli, round. Antenna 1 0.3 x body length; flagellum 5-articulate, peduncle width less than 2 x article 2. Antenna 2 0.3 x body length, shorter than antenna 1; flagellum 4-articulate. Mandibles lacking molars, palp 3-articulate, ratio of articles 1 – 3, 1.0:3.8:1.4, article 2 with 2 distal 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 weakly setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins weakly setose. Maxilla 1 palp 1-articulate with 4 distal setae; outer plate with 7 distal spines. Maxilla 2 inner plate with 8 distal setae; outer plate with 5 distal setae. Maxilliped inner plates fused, distal margin with v-shaped indentation, with short spines and long setae; outer plate serrate, reduced, reaching less than half of palp article 1, with 5 distal setae and 1 distal spine; palp 4-articulate, article 4 slender, slightly recurved.

Pereon. Coxae 1–4 relative widths 1.0:1.0:0.9:1.4. Gnathopod 1 coxa smooth, bare, anterodistal corner produced, broadly rounded, distal margin straight, posterodistal margin subquadrate, facial setae absent; basis constricted proximally, anterior margin with 2 short setae, posterior margin bare; ischium bare; carpus and propodus distally tapered; carpus length 19.3 x width, distal ornamentation absent, proximal margin smooth, distal margin setose; propodus straight, palm dentate with nine distal setae; dactylus smooth, reaching 0.2 x propodus length. Gnathopod 2 coxa length subequal to width, slightly wider than coxa 3, smooth, setose, anterodistally rounded, distal margin evenly rounded, posterior margin straight, facial setae absent; basis linear, without tubercles or serrations, anterior margin with 4–8 setae, posterior margin with 1–5 setae; ischium with 1 posterior seta; carpus 0.4 x propodus length, straight, distally truncate, anterior margin serrate; propodus posterior margin without teeth/serrations, with 2 mediofacial setal rows, primary mediofacial setal row above midline, reaching 0.9 x propodus length, secondary mediofacial setal row with 3 setae, 1 row of 6 submarginal setae; palm convex with 3 minor projections; dactylus slightly recurved, proximal margin smooth, anterior margin distally subacute, reaching 0.9 x propodus length. Pereopod 3 coxa length 1.2 x width, anterodistal corner over-riding distal face of coxa 2 and extending below it, smooth, setose, anterior margin evenly rounded, distal margin straight, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, setose, anterior margin rounded, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5–7 coxa facial setae absent; basis width length ratios 1:1.6, 1:1.5, 1:1.5, posterior margins smooth, setose.

Pleon. Epimera 1–3 bare. Epimeron 2 with 3 ventral setae. Epimeron 3 posteroventral margin subquadrate. Uropod 1 missing. Uropods 2–3 relative lengths 1.0:1.4; inner and outer ramus lined with short marginal setae, with robust setae. Uropod 2 peduncle 0.7x inner ramus length; outer ramus broken, length unknown. Uropod 3 peduncle subequal in length with inner ramus; outer ramus subequal in length with inner ramus. Telson 2.2 x longer than wide, apex tridentate.

Female (sexually dimorphic characters). Based on paratype, female, 2.5 mm, AM P 79813. Gnathopod 1 carpus without distal setae. Gnathopod 2 carpus anterior margin smooth; dactylus with proximal spine, strongly recurved .

Habitat. In coral rubble from vertical cliffs and unconsolidated bottom rubble.

Remarks. Leucothoe odontiskos sp. nov. shares its uni-articulate maxilla 1 palp with L. hipposideros sp. nov., L. laevipalma sp. nov., L. pollexa sp. nov., L. sparsa sp. nov., L. thula sp. nov. and L. undulata sp. nov. This character has not been found in any described Leucothoe to date, although an “indistinct suture” in the maxilla 1 palp has been reported in L. assimilis , L. basilobata , L. cheiriserra and L. urospinosa . Leucothoe odontiskos sp. nov. shares its serrate maxilliped outer plate with L. basilobata , L. cheiriserra ., L. ctenochasma , L. laurensi , L. orkneyi , L. squalidens , L. hipposideros , L. laevipalma sp. nov., L. serrata sp. nov. and L. undulata . The dentate propodus palm of gnathopod 1 is similar to L. ashleyae ; L. basilobata ; L. hipposideros and L. undulata , but lacks the triangular teeth found in L. hipposideros . This species is similar to L. ashleyae , females of L. assimilis , L. barana , females of L. gracilis , L. kensleyi , L. ubouhu , L. bova sp. nov., L. laevipalma , L. makrommatos sp. nov. and L. undulata in its gnathopod 2 propodus secondary mediofacial setal row.

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

Figures

FIGURE 17. Leucothoe odontiskos sp. nov., holotype, male, 2.8 mm, AM P79812; paratype, female, 2.5 mm, AM P79813 (JDT/LIZ 13), North Point, Lizard Island, Great Barrier Reef.

FIGURE 18. Leucothoe odontiskos sp. nov., holotype, male, 2.8 mm, AM P79812 (JDT/LIZ 13), North Point, Lizard Island, Great Barrier Reef.