Leucothoe serrata, White, Kristine N. & Thomas, James Darwin, 2009

White, Kristine N. & Thomas, James Darwin, 2009, Leucothoidae *, Zootaxa 2260 (1), pp. 494-555 : 531-532

Leucothoe serrata sp. nov.

( Figs 23 , 24 )

Type material. Holotype, male, 2.4 mm, AM P 79781, Half Mile Opening, Yonge Reef (14°34.333’S 145°36.866’E), Spirastrella vagabunda (sponge), channel between outer barrier reefs, amphipod sucking unit, 13 m, K. Klebba, 5 March 2005 ( QLD 1822 ) . Paratype, female, 3.1 mm, AM P 79782; same station data .

Additional material examined. 1 male, AM P 79291 ( QLD 1643 ) ; 2 females, AM P 71212 ( QLD 1755 ) ; 1 female, AM P 71253 ( QLD 1775 ) ; 1 female, 1 male, AM P 71443 ( QLD 1820 ) ; 4 females, AM P 71373 ( QLD 1822 ) .

Type locality. Yonge Reef , Lizard Island, Queensland, Australia (14°34.333’S 145°36.866’E) .

Etymology. After the Latin ‘ serra ’, meaning ‘saw’ and referring to the many serrate characters found in this species.

Description. Based on holotype, male, 2.4 mm, AM P79781.

Head. Head length less than pereonite 1+2, anterior margin truncate, without serrations or teeth, anterodistal margin quadrate with cusp, ventral cephalic keel quadrate, rostrum small to medium; eyes with 10 or more ocelli, round. Antenna 1 0.3 x body length; flagellum 6-articulate, peduncle width less than 2 x article 2. Antenna 2 0.2 x body length, shorter than antenna 1; flagellum 3-articulate. Mandibles lacking molars, palp 3-articulate, ratio of articles 1 – 3, 1.0:4.8:4.1, article 2 with 3 – 4 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 setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins weakly setose. Maxilla 1 palp 2-articulate with 3 distal setae; outer plate with nine distal spines. Maxilla 2 inner plate with 4 distal setae; outer plate with nine distal setae. Maxilliped inner plates fused, distal margin with v-shaped indentation, with short spines and long setae; outer plate serrate, reduced, reaching half of palp article 1, with 4 distal setae; palp 4-articulate, article 4 slender, slightly recurved.

Pereon. Coxae 1–4 relative widths 1.0:2.0:1.4:2.0. Gnathopod 1 coxa serrate, setose, anterodistal corner produced, subtriangular, distal margin straight, posterodistal margin subquadrate, facial setae absent; basis widened proximally, anterior margin with 4 setae, posterior margin with 4 setae; ischium bare; carpus and propodus distally tapered; carpus length 15.5 x width, proximal margin dentate, distal margin setose; propodus straight, palm smooth with proximal and distal dentition and nine distal setae; dactylus smooth, reaching 0.2 x propodus length. Gnathopod 2 coxa length 1.2 x width, much wider than coxa 3, smooth, bare, anterodistally subquadrate, distal margin evenly rounded, posterior margin rounded, facial setae absent; basis constricted proximally, without tubercles or serrations, anterior margin with 8 setae, posterior margin with 5 setae; ischium with 5 posterior and 2 posterodistal setae; carpus 0.7 x propodus length, curved, distally tapered, anterior margin weakly serrate; propodus posterior margin without serrations/teeth, with 1 mediofacial setal row above midline, reaching 0.6 x propodus length, 1 row of 6 submarginal setae, palm convex with 7 major projections; dactylus curved, proximal margin smooth, anterior margin distally subacute, reaching 0.6 x propodus length. Pereopod 3 coxa length 1.3 x width, anterodistal corner over-riding distal face of coxa 2 and extending below it, serrate, bare, anterior margin evenly rounded, distal margin slightly convex, posterior margin straight, facial setae absent. Pereopod 4 coxa serrate, bare, anterior margin tapered, distal margin evenly rounded, posterior margin mildly excavate, facial setae absent. Pereopods 5–7 coxa facial setae absent; basis l width length ratios 1:1.4, 1:1.3, 1:1.5, posterior margins serrate, bare.

Pleon. Epimera 1–3 bare. Epimeron 2 with 4 ventral setae. Epimeron 3 posteroventral margin subquadrate. Uropods 1–2 peduncle subequal to inner ramus length. Uropods 1–3 relative lengths 1.0:0.8:0.8; inner and outer ramus with robust setae. Uropod 1 peduncle with 2 rows of spines; outer and inner ramus subequal in length. Uropod 2 outer ramus 0.8 x inner ramus length. Uropod 3 peduncle 1.3 x inner ramus length; outer ramus subequal to inner ramus length. Telson 2.4 x longer than wide, with 2 proximal setae, apex tridentate.

Female (sexually dimorphic characters). No sexual dimorphism.

Habitat. In the sponge, Spirastrella vagabunda ( Ridley, 1884) from a channel between outer barrier reefs.

Remarks. Leucothoe serrata sp. nov. shares its narrow gnathopod 1 propodus with L. cheiriserra and L. gavialis and the serrate maxilliped outer plate with L. basilobata , L. cheiriserra , L. ctenochasma , L. laurensi , L. orkneyi , L. squalidens , L. hipposideros sp. nov., L. laevipalma sp. nov., L. odontiskos sp. nov. and L. undulata sp. nov. The smooth gnathopod 1 propodus palm of L. serrata is similar to L. flammosa , L. laevipalma and L. rudicula sp. nov., with the exception of the proximal and distal dentition in L. serrata . The serrate coxae of L. serrata are fairly unusual and shared only with L. banwarthii , L. gracilis and L. makrommatos sp. nov. The strong gnathopod 2 propodus palm dentition is shared with L. ashleyae , L. hornelli , L. stegoceras , L. adelphe sp. nov. and L. rudicula .

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

Figures

FIGURE 23. Leucothoe serrata sp. nov., holotype, male, 2.4 mm, AM P79781; paratype, female, 3.14 mm, AM P79782 (QLD 1822), Half Mile Opening, Yonge Reef, Great Barrier Reef.

FIGURE 24. Leucothoe serrata sp. nov., holotype, male, 2.4 mm, AM P79781; paratype, female, 3.14 mm, AM P79782 (QLD 1822), Half Mile Opening, Yonge Reef, Great Barrier Reef.