Ampithoe merimbula, 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 : 48-53

Ampithoe merimbula sp. nov.

( Figs 36–39 )

Type material. Holotype: AM P61858, male, 7 mm, Merimbula Wharf, Merimbula, NSW, 36°53.92’S 149°55.64’E, 18 May 1995, 8 m, on red algae, K. Attwood.

Paratypes: AM P61859, female, 7 mm, SSE of wharf, Merimbula Point, Merimbula, NSW, 36°54.06’S 149°55.79’E, 15 May, 1995, 12.9 m, on brown algae, P. B. Berents ; AM P61860, females and males, 12 specimens, Merimbula Wharf, Merimbula, NSW, 36°53.92’S 149°55.64’E, 18 May 1995, 8 m, on red algae, K. Attwood .

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 three slender setae. Gnathopod 1 carpal lobe rounded; carpus shorter than propodus; palm convex, without midmedial tooth, without posterodistal tooth defining palm; dactylus overreaching palm. Gnathopod 2 without densely setose margins; basis posterodistal lobe large and rounded, with 1 robust seta and 2 or 3 slender setae; carpus much shorter than propodus; palm acute, entire, with a rounded midmedial tooth, without a posterodistal tooth defining palm, without a defining robust seta; dactylus overreaching palm. Pereopod 3 basis expanded; merus narrow. Pereopods 5–7 simple. Pereopod 5 merus subrectangular. Uropod 3 peduncle with 6 distal robust setae, outer ramus shorter than inner ramus, without patch of small conical lateral denticles, without lateral setal fringe; inner ramus with 4 distal robust setae. Telson distally rounded, apical cusps small.

Description. Based on holotype, male, 7 mm, AM P61858. Head as long as deep. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2 (1.27 x), article 2 longer than article 3 (2.7 x), article 3 shorter than article 1 (0.29 x); primary flagellum with 31 articles. Antenna 2 peduncular article 4 longer than article 5; flagellum 21 articulate. Mandible molar with 5 or 6 robust setae in accessory setal row; palp stout, long, setose along posterior margin, article 1 shorter than article 2 (0.45 x), article 2 longer than article 3 (1.32 x), article 3 longer than article 1 (1.6 x). Lower lip mandibular lobe with curved margins, rounded apically. Maxilla 1 palp with apical robust setae. Maxilla 2 inner plate narrow, outer plate broader. Maxilliped outer plate with developed setation (robust setae large).

Pereon. Gnathopod 1 without densely setose margins; coxa subequal to gnathopod 2 coxa, produced distoventrally, distoventral margin rounded, anterior margin concave, ventral margin with a row of small setules along ventral margin; basis subequal to coxa, with fringe of long, slender, plumose setae, posterodistal lobe large and round, setae absent; 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 2.07 x width), ovoid; palm with 1 defining robust seta; dactylus inner margin denticulate. Gnathopod 2 coxa ventral margin with a row of small setules along ventral margin; basis subequal to coxa, with fringe of long, slender, plumose setae; merus produced to form a short, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae only; propodus broad (length 1.25 x width), ovoid, not produced into an anterodistally setose lobe; dactylus tapering evenly, acute, inner margin denticulate. Pereopod 5 basis with marginal robust setae, with medial slender setae; distal articles slender; propodus slightly expanded distally, subrectangular, with 3 distal simple striated robust setae; dactylus slightly curved. Pereopod 6 basis posterior margin rounded, without marginal robust setae, without medial slender setae; merus subrectangular; propodus slightly expanded distally, with 3 distal simple striated robust setae; dactylus strongly curved. Pereopod 7 basis without marginal robust setae, with medial slender setae; propodus defined distally by 3–5 simple robust setae.

Pleon. Epimeron 3 posteroventral corner broadly rounded. Uropod 1 peduncle with more than 5 robust setae, with a long setal fringe; rami subequal in length; inner ramus with 3–5 marginal robust setae, slender setae absent; outer ramus with more than 5 marginal robust setae, slender setae absent. Uropod 2 peduncle with 3–5 robust setae, setal fringe absent; inner ramus slightly shorter than outer ramus, with more than 5 mar- ginal robust setae, slender setae absent; outer ramus with more than 5 marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (1.55 x width), short with repect to rami length (1.66 x), marginal robust setae absent, marginal slender setae absent, with 3–5 distal slender setae; inner ramus with 3–5 distal slender setae. Telson with apical and lateral slender setae.

Female. (sexually dimorphic characters). Based on paratype, female, 7 mm, AM P61859. Antenna 1 primary flagellum with 35 articles. Antenna 2 flagellum with 26 articles. Gnathopod 1 subequal in size to gnathopod 2; basis posterodistal lobe small and round, with 2 or 3 slender setae; carpal lobe subacute. Gnathopod 2 basis shorter than coxa, posterodistal lobe small and round, with 2 or 3 slender setae; carpus shorter than propodus (0.66 x); palm without a midmedial tooth, with small subacute posterodistal tooth defining palm, defined by 1 robust seta; dactylus subequal in length to palm .

Etymology. This species is named for the type locality, Merimbula; used as a noun in apposition.

Remarks. Ampithoe merimbula sp. nov. most closely resembles A. boiana sp. nov.; differences are outlined under the account of the latter.

Habitat. Red and brown algae.

Distribution. Merimbula, New South Wales, Australia.

Figures

FIGURE 36. Ampithoe merimbula sp. nov., holotype, male, AM P61858, 7 mm. Paratype, female, AM P61859, 7 mm. Merimbula Wharf, Merimbula, New South Wales, Australia.

FIGURE 37. Ampithoe merimbula sp. nov., holotype, male, AM P61858, 7 mm. Paratype, female, AM P61859, 7 mm. Merimbula Wharf, Merimbula, New South Wales, Australia. Scales represent 0.5 mm for antennae 1–2 and 0.2 mm for mouthparts.

FIGURE 38. Ampithoe merimbula sp. nov., holotype, male, AM P61858, 7 mm. Paratype, female, AM P61859, 7 mm. Merimbula Wharf, Merimbula, New South Wales, Australia. Scales represent 0.5 mm.

FIGURE 39. Ampithoe merimbula sp. nov., holotype, male, AM P61858, 7 mm. Merimbula Wharf, Merimbula, New South Wales, Australia. Scales represent 0.5 mm for pereopods 3–7 and 0.2 mm for uropods 1–3 and telson.