Ampithoe meganae Peart, 2007

Hughes, L. E. & Lowry, J. K., 2009, Ampithoidae *, Zootaxa 2260 (1), pp. 153-219 : 164-167

Ampithoe meganae Peart, 2007

( Figs 7 , 8 )

Ampithoe meganae Peart, 2007b: 44 , figs. 32–35 (key).

Ampithoe rotunda Peart, 2007b: 83 , figs. 66–69 (key).

Material examined. Holotype, male, AM P61854 ( QLD 1370 ) . Paratypes. 1 female, AM P61855 ( QLD 1370 ); 5 unsexed, AM P61857 ( QLD 1397 ); 3 unsexed, AM P76972 ( QLD 1637 ); 2 unsexed, AM P75874 ( QLD 1851 ); 3 unsexed, AM P75876 ( QLD 1860 ); many unsexed, AM P75875 ( QLD 1894 ); 8 unsexed, AM P75661 ( QLD 1938 ); 14 unsexed, AM P75663 ( QLD 1941 ); 9 unsexed, AM P75666 ( QLD 1944 ); 2 unsexed, AM P76971 ( QLD 1952 ); many unsexed, AM P75669 ( QLD 1966 ); many unsexed, AM P76798 ( QLD 1966 ); 6 unsexed, AM P75664 ( QLD 1969 ); 1 unsexed, AM P76970 ( QLD 1969 ); 3 unsexed, AM P75667 ( QLD 1980 ); 4 unsexed, AM 76799 ( QLD 1980 ); 3 unsexed, AM P76968 (1983); 3 unsexed, AM P75665 ( QLD 1983 ); 3 unsexed, AM P75668 ( QLD 2003 ); 4 unsexed, AM P76969 ( QLD 2006 ); 15 unsexed, AM P75662 ( QLD 2006 ); many unsexed, AM P76973 ( SEL /LZI-5-2) .

Type locality. Mangrove Beach , Lizard Island, Queensland, Australia (14°40.99’S 145°27.63’E), living on Turbinaria sp. , 3 m.

Description. Based on holotype, male, 2 mm, AM P61854.

Head. Head as long as deep. Antenna 1 missing. Antenna 2 missing. Upper lip directed nearly straight down, lateral margins each with midlateral notch. Mandible molar well developed, triturating, accessory setal row with 4 serrate setae; palp 3–articulate, apically setose; article 1 shorter than article 2; article 2 subequal in length to article 3, slender setae present. Lower lip outer plates notched, forming a deep distal cleft, lateral lobe distinctly longer than medial lobe; mandibular lobe with curved margins, subacute apically. Maxilla 1 inner plate with 1 setae; palp article 2 slender. Maxilla 2 inner plate narrower than outer plate. Maxilliped outer plate with row of small robust setae along medial margin.

Pereon. Coxae 1–4 deeper than broad. Gnathopod 1 smaller than gnathopod 2; coxa distinctly smaller than coxa 2, anteroventrally produced, anterior margin slightly concave, anteroventral corner rounded; basis shorter than coxa, anterodistal lobe rounded, with 1 slender seta; merus posterodistal lobe subacute; carpus about 1.5 x as long as broad, shorter than propodus, anterior margin with slender setae, posterior margin convex; propodus narrow, subovoid; palm acute, convex, without posterodistal corner with 1 robust seta defining palm; dactylus subequal in length to palm, inner margin crenate. Gnathopod 2 coxa without long, plumose setal fringe on ventral margin; basis with sparse slender setae, with large, rounded anterodistal lobe with 3 robust setae along anterodistal margin; merus margin without anterodistal lobe; carpus much shorter than propodus, cup-shaped; propodus broad, less than 1.5 x as long as broad, subovoid, not produced into an anterodistally setose lobe; palm acute, entire, with posterodistal corner, subquadrate, without palm defining robust setae; dactylus overreaching palm, tapering evenly, apically acute, inner margin crenate. Pereopods 3– 4 basis slightly expanded; merus longer than carpus. Pereopods 5–7 simple. Pereopod 5 without medial slender setae; distal articles slender; propodus not expanded distally, with 1 anterodistal striated robust seta; dactylus strongly curved. Pereopod 6 basis posterior margin straight. Pereopod 7 similar to pereopod 6.

Pleon. Epimera 2–3 posteroventral corner broadly rounded. Uropod 1 peduncle with small rounded distoventral spine. Uropod 2 peduncle with 2 robust setae; outer ramus with 3 lateral robust seta; inner ramus with 2 lateral robust setae. Uropod 3 peduncle longer than broad, about 2 x length of rami, without marginal slender setae, with 3 distal peduncular robust setae, with 5 distal slender setae; outer ramus with 2 large recurved distal robust setae, without lateral robust or slender setae; inner ramus with 2 distal slender setae, without lateral robust setae. Telson subtrapezoidal, apically truncated, with small apical cusp on each distolateral corner, with 2 pair of lateral and 1 pair of apical slender setae, and 1 pair of apical plumose setae.

Female (sexually dimorphic characters). Based on paratype, female, 3 mm, AM P61855. Gnathopod 1 subequal in size to gnathopod 2; coxa subequal to coxa 2; basis shorter than coxa; merus anterodistal lobe subacute. Gnathopod 2 basis with small anterodistal lobe, anterodistal margin with 1 slender seta; carpus shorter than propodus, subtriangular; propodus narrow, greater than 1.5 x as long as broad; palm slightly sinusoidal, posterodistal corner rounded, with 1 robust seta defining palm; dactylus subequal in length to palm.

Habitat. Red, brown and green algae, including Halimeda sp. and also on dead coral covered with epiphytes.

Remarks. Ampithoe rotunda Peart, 2007b is placed in synonymy with A. meganae . The only difference between these taxa appears to be the size of the uropod 3 peduncle. Peart (2007b) lists several other differences including, the number of robust setae on the anterodistal lobe of the basis of male gnathopod 2 and the presence of slender setae on uropod 3. However, in the material examined here these differences are variable among individuals.

Ampithoe meganae is very similar to A. kulafi Barnard, 1970 and A. lafkui Appadoo & Myers, 2004 , all of which have the distinctive subovoid-shaped propodus of male gnathopod 2. These three species vary mostly in the form of the gnathopod 1 coxa, which is produced and rounded in A. meganae , produced and acute in A. kulafi and not produced in A. lafkui . In A. meganae and A. kulafi the uropod 1 peduncle has a rounded, distoventral spine which is absent in A. lafkui .

Ampithoe meganae is most similar to Ampithoe kulafi , a variable species which has been recorded from localities across the Indo-Pacific. The description of A. lafkui by Appadoo & Myers (2004) has accounted for some of this variation, but there exists a range of material showing several shapes of the coxa of gnathopod 1 (anteroventrally produced or not produced, with a rounded or acute anteroventral corner) and uropod 3 with the rounded distoventral spine present or absent. There currently appears to be no species name for specimens with coxa 1 sub-acutely produced and the uropod 3 peduncle with a rounded distoventral spine ( Sivaprakasam 1971). Furthermore, A. kulafi of Ledoyer (1979a) is figured without the uropod 1 rounded peduncular distoventral spine. These species remain with A. kulafi but need closer examination.

Ampithoe meganae can be distinguished from other GBR Ampithoidae by its small body size, by its proportionally large, subovoid propodus on male gnathopod 2 and by its dactylus which over-reaches the palm and often rests in a cross position along the medial surface.

Distribution. Australia. Queensland: Torres Strait (current study); Lizard Island ( Peart 2007b; current study); Heron Island ( Peart 2007b); One Tree Island (current study).

Figures

FIGURE 7. Ampithoe meganae Peart, 2007b, holotype, male, 2 mm, AM P61854, Lizard Island, Great Barrier Reef (based on Peart 2007b).

FIGURE 8. Ampithoe meganae Peart, 2007b, holotype, male, 2 mm, AM P61854, paratype, female, 3 mm, AM P61855, Lizard Island, Great Barrier Reef (based on Peart 2007b).