Ampithoe ningaloo, 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 : 55-59

Ampithoe ningaloo sp. nov.

( Figs 42–45 )

Type material. Holotype: WAM C38534, male, 4 mm, from channel in Ningaloo Reef, off Ned’s Camp, Cape Range National Park , Western Australia, 21°59’S 113°54.5’E, 31 Dec 1983, 6 m, on Pocillopora sp. , J. K. Lowry . Paratype: WAM C38535, female, 6 mm, type locality .

Diagnosis. Lower lip with lateral lobe longer than medial lobe. Maxilla 1 inner plate with three slender setae. Gnathopod 1 carpal lobe subacute; carpus shorter than propodus; palm convex, without midmedial tooth, without posterodistal tooth defining palm; dactylus subequal in length to palm. Gnathopod 2 with long setae on margins, not plumose; basis posterodistal lobe large and rounded, with 2 or 3 robust setae; carpus shorter than propodus; palm acute, excavate, without midmedial tooth, with small subacute posterodistal tooth defining palm, without defining robust setae; dactylus subequal in length to palm. Pereopod 3 basis narrow; merus narrow. Pereopods 5–7 simple. Pereopod 5 merus subrectangular. Uropod 3 peduncle with 6 distal robust setae, outer ramus subequal to inner ramus, without patch of small conical lateral denticles, without lateral setal fringe; inner ramus with 3 distal robust setae. Telson distally truncate, apical cusps small.

Description. Based on holotype, male, 4 mm, WAM C38534. Head longer than deep. Mandible molar with 5 robust setae in accessory setal row; palp stout, long, setose along posterior margin; article 1 shorter than article 2 (0.48 x), article 2 longer than article 3 (1.14 x), article 3 longer than article 1 (1.8 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 larger than 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 sparse (sometimes plumose) slender setae, posterodistal lobe small and rounded, 1 slender seta; merus produced to form a small, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with 2 robust setae and slender setae; propodus narrow (length 1.94 x width), subrectangular; palm with 1 defining robust seta; dactylus inner margin denticulate. Gnathopod 2 coxa ventral margin with a row of small setules; basis longer than coxa, with sparse slender setae; merus produced to form a short, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with 3 or 4 robust setae and slen- der setae; propodus broad (length 1.29 x width), ovoid, 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 not expanded distally, subrectangular, with 3 distal simple striated robust setae; dactylus strongly curved.

Pleon. Epimeron 3 posteroventral corner broadly rounded. Uropod 1 peduncle with more than 5 robust setae, with long setal fringe; rami subequal in length; inner ramus with more than 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; rami subequal in length. Uropod 3 peduncle longer than broad (1.5 x width), short with respect to rami length (1.75 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, 6 mm, WAM C38535. Antenna 1 longer than antenna 2, peduncular article 1 subequal in length to article 2 (1.02 x), article 2 longer than article 3 (3 x), article 3 shorter than article 1 (0.33 x); primary flagellum 27-articulate; accessory flagellum absent. Antenna 2 robust and better developed than antenna 1, with sparse setae on ventral margin, peduncular article 4 subequal in length to article 5; flagellum 16-articulate. Gnathopod 1 subequal in size to gnathopod 2; coxa subequal in size to gnathopod 2 coxa; basis shorter than coxa, posterodistal lobe with 2 or 3 slender setae; merus produced to form a short, rounded distoventral lobe, anterior margin with setae absent; carpus anterior margin with 1 robust seta and slender setae; palm with midmedial tooth. Gnathopod 2 without densely setose margins; basis shorter than coxa, posterodistal lobe small and round, with 1 robust seta; merus produced to form a small, rounded distoventral lobe; carpus anterior margin with 1 robust seta and slender setae; propodus not produced anterodistally; palm entire, without tooth defining palm, defined by 1 robust seta.

Etymology. This species name is derived from the type locality of Ningaloo Reef; used as a noun in apposition.

Remarks. Ampithoe ningaloo sp. nov. is similar to Ampithoe ulladulla sp. nov., sharing an entire gnathopod 1 palm; an ovoid or subtriangular gnathopod 2 propodus; absence of a midmedial tooth on the gnathopod 2 palm and long simple setae on the margins of the gnathopods. The two species differ most obviously in the shapes of the palms of gnathopods 1 and 2. Ampithoe ningaloo has a convex gnathopod 1 palm and an excavate gnathopod 2 palm, whereas A. ulladulla has an entire gnathopod 1 palm with a rounded midmedial tooth and a small subacute defining tooth, and an entire, broad gnathopod 2 palm defined by a small subacute tooth.

Habitat. Ampithoe ningaloo occurs in coral at a depth of 6 m.

Distribution. Ningaloo Reef, Western Australia, Australia.

Figures

FIGURE 42. Ampithoe ningaloo sp. nov., holotype, male, WAM C38534, 4 mm. Paratype, female, WAM C 38535, 6 mm. Ningaloo Reef, off Neds Camp, Cape Range National Park, Western Australia, Australia.

FIGURE 43. Ampithoe ningaloo sp. nov., holotype, male, WAM C38534, 4 mm. Paratype, female, WAM C 38535, 6 mm. Ningaloo Reef, off Neds Camp, Cape Range National Park, Western Australia, Australia. Scales represent 0.5 mm for antennae 1–2 and 0.2 mm for mouthparts. Male antennae are missing.

FIGURE 44. Ampithoe ningaloo sp. nov., holotype, male, WAM C38534, 4 mm. Paratype, female, WAM C 38535, 6 mm. Ningaloo Reef, off Neds Camp, Cape Range National Park, Western Australia, Australia. Scales represent 0.5 mm.

FIGURE 45. Ampithoe ningaloo sp. nov., holotype, male, WAM C38534, 4 mm. Ningaloo Reef, off Neds Camp, Cape Range National Park, Western Australia, Australia. Scales represent 0.5 mm for pereopods 3–5 and 0.2 mm for uropods 1, 3 and telson. Pereopods 6–7 and uropod 2 are missing.