Ampithoe boiana, 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 : 7-11

Ampithoe boiana sp. nov.

( Figs 1–4 )

Type material. Holotype: AM P61828, male, 5 mm, Bay of Islands , VIC, 38°35’S 142°49.5’E, 28 Apr 1988, 1.5 m, on rock, R. T. Springthorpe & P. B. Berents.

Paratypes: AM P61829, female, 6 mm, type locality .

Other material examined. AM P61830 , many specimens, Henty Reef , Mounts Bay, VIC, 38°47’S 143°40.5’E, 25 Apr 1988, 4– 5 m, on brown algae , R. T. Springthorpe & P. B. Berents . AM P61831 , many specimens, off jetty at Green Island , Rottnest Island, WA, 32°01’S 115°30’E, 21 Dec 1983, 1 m, mixed algal turf , R. T. Springthorpe .

Diagnosis. Antenna 2 robust, better developed than antenna 1, with short, dense setae on ventral margin. Lower lip with lateral lobe longer than medial lobe. Maxilla 1 inner plate with 2 slender setae. Gnathopod 1 carpal lobe rounded; carpus shorter than 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 more than 3 slender setae; carpus much shorter than propodus; palm acute, entire, with a rounded midmedial tooth, with a small subacute 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 1 peduncle without distoventral spur. Uropod 3 peduncle with 8 distal robust setae, outer ramus subequal in length to 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, 5 mm, AM P61828. Head as long as deep. Antenna 2 peduncular article 4 longer than article 5; flagellum 22 articulate. Mandible molar with 6 robust setae in the accessory setal row; palp stout, long, setose along posterior margin, article 1 shorter than article 2 (0.51 x), article 2 longer than article 3 (1.25 x), article 3 longer than article 1 (1.57 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; basis shorter than coxa, with sparse (sometimes plumose) slender setae, posterodistal lobe small and rounded, setae absent; merus produced to form a small, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae only; propodus narrow (length 1.73 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 fringe of long, slender, plumose 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 1.17 x width), ovoid, not produced into an anterodistally setose lobe; dactylus tapering evenly, acute, inner margin denticulate. Pereopod 5 basis without marginal robust setae, with medial slender setae; distal articles slender; propodus not expanded distally, subrectangular, with 2 distal simple striated robust setae; dactylus strongly curved.

Pleon. Epimeron 3 posteroventral corner narrowly rounded. Uropod 1 peduncle with more than 5 robust setae, with a short setal fringe; inner ramus slightly longer than outer 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, setael fringe absent; inner ramus slightly longer than outer ramus, with more than 5 marginal robust setae, slender setae absent; outer ramus with more than 5 marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (1.33 x width), short with respect to the rami length (1.83 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, 6 mm, AM P61829. Antenna 1 longer than antenna 2; peduncle article 1 longer than article 2 (1.19 x), article 2 longer than article 3 (3.08 x), article 3 shorter than article 1 (0.27 x); primary flagellum with 19–25 articles; accessory flagellum absent. Antenna 2 robust and better developed than antenna 1; flagellum with 16–20 articles .

Gnathopod 1 subequal in size to gnathopod 2; coxa smaller than gnathopod 2 coxa; basis with fringe of long, slender, plumose setae, posterodistal lobe with 2 or 3 slender setae; merus produced to form a short, rounded distoventral lobe; propodus ovoid. Gnathopod 2 basis shorter than coxa, posterodistal lobe small and round; carpus longer than merus, shorter than propodus (0.78 x); propodus subrectangular; palm without a midmedial tooth, defined by 1 robust seta; dactylus subequal in length to palm.

Etymology. This species name is an arbitrary combination of letters forming a word. Remarks. Ampithoe boiana sp. nov. most closely resembles A. merimbula sp. nov., but is also similar to A. geographe sp. nov. and A. rosema sp. nov. Each of these species shares an ovoid or subtriangular propodus of gnathopod 2 and a midmedial tooth on the palm. Few features distinguish A. boiana and A. merimbula including: gnathopod 1 coxa size in relation to gnathopod 2 coxa; the basis of gnathopod 1 has only sparse setae ( A. merimbula has a long fringe of plumose setae); and the gnathopod 1 dactylus is subequal to rather than overreaching the palm. The gnathopod 2 propodus and palm shape also varies between the two species.

Habitat. Brown algae.

Distribution. Victoria and Western Australia.

Figures

FIGURE 1. Ampithoe boiana sp. nov., holotype, male, AM P61828, 5 mm. Paratype, female, AM P61829, 6 mm. Bay of Islands, Victoria, Australia.

FIGURE 2. Ampithoe boiana sp. nov., holotype, male, AM P61828, 5 mm. Paratype, female, AM P61829, 6 mm. Bay of Islands, Victoria, Australia. Scales represent 0.5 mm for antennae 1–2 and 0.2 mm for mouthparts. Male antenna 1 missing, left mandible twisted.

FIGURE 3. Ampithoe boiana sp. nov., holotype, male, AM P61828, 5 mm. Paratype, female, AM P61829, 6 mm. Bay of Islands, Victoria, Australia. Scales represent 0.5 mm.

FIGURE 4. Ampithoe boiana sp. nov., holotype, male, AM P61828, 5 mm. Bay of Islands, Victoria, Australia. Scales represent 0.5 mm for pereopods 3–5 and 0.2 mm for uropods 1–3 and telson. Pereopod 5 distal articles twisted, pereopods 6–7 missing.