Ampithoe meganae, Peart, 2007

Peart, Rachael A., 2007, A review of the Australian species of Ampithoe Leach, 1814 (Crustacea: Amphipoda: Ampithoidae) with descriptions of seventeen new species, Zootaxa 1566 (1), pp. 1-95 : 44-48

Ampithoe meganae sp. nov.

( Figs 32–35 )

Type material. Holotype: AM P61854, male, 2 mm, Mangrove Beach , Lizard Island, Great Barrier Reef, QLD, 14°40.99’S 145°27.63’E, 19 Nov 1999, 3 m, on Turbinaria sp. on reef, M. Huggett . Paratypes: AM P61855, female, 3 mm, Mangrove Beach , Lizard Island, Great Barrier Reef, QLD, 14°40.99’S 145°27.63’E, 19 Nov 1999, 3 m, on Turbinaria sp. on reef, M. Huggett ; AM P61856, 2 specimens, off Casaurina beach, Lizard Island, Great Barrier Reef, QLD, 14°40.63’S 145°26.71’E, 21 Nov 1999, 1 m, on Padina sp. on reef , R. Peart, K. Dempsey & M. Huggett ; AM P61857, 5 specimens, off Casaurina Beach , Lizard Island, Great Barrier Reef, QLD, 14°40.63’S 145°26.71’E, 21 Nov 1999, 1 m, on green algae on reef , R. Peart, K. Dempsey & M. Huggett .

Diagnosis. Antenna 2 slender, similar to antenna 1, with short, dense setae on ventral margin. Lower lip with lateral lobe longer than medial lobe. Maxilla 1 inner plate with 1 slender seta. Gnathopod 1 carpal lobe rounded; carpus subequal to propodus; palm convex, without midmedial tooth, without posterodistal tooth defining palm; dactylus subequal in length to palm. Gnathopod 2 without densely setose margins; basis posterodistal lobe large and rounded, with 2 or 3 robust setae; carpus much shorter than propodus; palm acute, entire, without a midmedial tooth, with a small subacute posterodistal tooth defining palm, without a defining robust seta; dactylus subequal in length to palm. Pereopod 3 basis narrow; merus narrow. Pereopods 5–7 simple. Pereopod 5 merus subrectangular. Uropod 3 peduncle with 3 distal robust setae, outer ramus shorter than inner ramus, without patch of small conical lateral denticles, without lateral setal fringe; inner ramus with 3 distal robust setae. Telson distally rounded, apical cusps small.

Description. Based on holotype, male, 2 mm, AM P61854. Head as long as deep. Mandible molar with 3 or 4 robust setae in the accessory setal row; palp slender, long, apically setose, article 1 shorter than article 2 (0.45 x), article 2 subequal to article 3 (1.06 x), article 3 longer than article 1 (2.08 x). Lower lip mandibular lobe with curved margins, subacute apically. Maxilla 1 palp with apical robust setae. Maxilla 2 inner plate narrow, outer plate broader. Maxilliped outer plate with reduced setation (robust setae small).

Pereon. Gnathopod 1 without densely setose margins; coxa smaller than gnathopod 2 coxa, produced dis- toventrally, distoventral margin rounded, anterior margin concave, ventral margin with a row of small setules; basis longer than coxa, with sparse (sometimes plumose) slender setae, posterodistal lobe small and rounded, 1 slender seta; merus produced to form a small, rounded distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae only; propodus narrow (length 1.63 x width), ovoid; palm with 1 defining robust seta; dactylus inner margin denticulate. Gnathopod 2 coxa ventral margin with a row of small setules; basis subequal to coxa, with sparse slender setae; merus produced to form a short, subacute distoventral lobe, anterior margin with setae absent; carpus subequal to merus, subtriangular, anterior margin with slender setae only; propodus broad (length 1.13 x width), ovoid, not produced into an anterodistally setose lobe; dactylus tapering evenly, acute, inner margin denticulate. Pereopod 5 basis with marginal robust setae, without medial slender setae; distal articles slender; propodus not expanded distally, subrectangular, with 2 distal simple striated robust setae; dactylus strongly curved.

Pleon. Uropod 2 peduncle with 1 or 2 robust setae, setal fringe absent; rami subequal in length; inner ramus with 1 or 2 marginal robust setae, slender setae absent; outer ramus with 3–5 marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (1.5 x width), long with respect to the rami length

(2.17 x), marginal robust setae absent, marginal slender setae absent, with 3–5 distal slender setae; inner ramus with 1 or 2distal slender setae. Telson with apical and lateral slender setae.

Female. (sexually dimorphic characters). Based on paratype, female, 3 mm, AM P61855. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2 (1.19 x), article 2 longer than article 3 (2.33 x), article 3 shorter than article 1 (0.36 x); primary flagellum with 10–20 articles; accessory flagellum absent. Antenna 2 slender, similar to antenna 1, with sparse setae on ventral margin; peduncular article 4 subequal in length to article 5; flagellum 9-articulate. Gnathopod 1 subequal in size to gnathopod 2; coxa subequal in size to gnathopod 2 coxa; basis shorter than coxa; merus produced to form a short, subacute distoventral lobe; carpus shorter than propodus (0.89 x); propodus subrectangular; palm with midmedial tooth. Gnathopod 2 basis posterodistal lobe small and round, with 1 slender seta; carpus longer than merus, shorter than propodus (0.86 x); propodus narrow (length 1.74 x width); palm without tooth defining palm, defined by 1 robust seta.

Etymology. Named after Megan Huggett who assisted in the collection of this species.

Remarks. Ampithoe meganae sp. nov. is similar to Ampithoe rotunda sp. nov. Differences between A. meganae and A rotunda include: the gnathopod 1 coxa distoventral corner is rounded versus acute; the gna- thopod 2 basis posterodistal lobe has three marginal robust setae rather than three marginal slender setae; the uropod 3 peduncle does not have marginal slender setae (present in A. rotunda ) and the uropod 3 outer ramus does not have a patch of lateral denticles (present in A. rotunda ).

Habitat. Brown and green reef algae; 1–3 m.

Distribution. Lizard Island, Queensland, Australia.

Figures

FIGURE 32. Ampithoe meganae sp. nov., holotype, male, AM P61854, 2 mm. Paratype, female, AM P61855, 3 mm. Lizard Island, Queensland, Australia.

FIGURE 33. Ampithoe meganae sp. nov., holotype, male, AM P61854, 2 mm. Paratype, female, AM P61855, 3 mm.Lizard Island, Queensland, Australia. Scales represent 0.2 mm. Male antennae are missing.

FIGURE 34. Ampithoe meganae sp. nov., holotype, male, AM P61854, 2 mm. Paratype, female, AM P61855, 3 mm. Lizard Island, Queensland, Australia. Scales represent 0.2 mm.

FIGURE 35. Ampithoe meganae sp. nov., holotype, male, AM P61854, 2 mm. Lizard Island, Queensland, Australia. Scales represent 0.2 mm for pereopods 3–5 and uropod 2 and 0.1 mm for uropod 3 and telson. Pereopods 6–7 are missing.